Gas Foil Bearing Technology Advancements for Closed Brayton Cycle Turbines

NASA Technical Reports Server (NTRS)

Howard, Samuel A.; Bruckner, Robert J.; DellaCorte, Christopher; Radil, Kevin C.

2007-01-01

Closed Brayton Cycle (CBC) turbine systems are under consideration for future space electric power generation. CBC turbines convert thermal energy from a nuclear reactor, or other heat source, to electrical power using a closed-loop cycle. The operating fluid in the closed-loop is commonly a high pressure inert gas mixture that cannot tolerate contamination. One source of potential contamination in a system such as this is the lubricant used in the turbomachine bearings. Gas Foil Bearings (GFB) represent a bearing technology that eliminates the possibility of contamination by using the working fluid as the lubricant. Thus, foil bearings are well suited to application in space power CBC turbine systems. NASA Glenn Research Center is actively researching GFB technology for use in these CBC power turbines. A power loss model has been developed, and the effects of a very high ambient pressure, start-up torque, and misalignment, have been observed and are reported here.

Acoustic Modeling for Aqua Ventus I off Monhegan Island, ME

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whiting, Jonathan M.; Hanna, Luke A.; DeChello, Nicole L.

2013-10-31

The DeepCwind consortium, led by the University of Maine, was awarded funding under the US Department of Energy’s Offshore Wind Advanced Technology Demonstration Program to develop two floating offshore wind turbines in the Gulf of Maine equipped with Goldwind 6 MW direct drive turbines, as the Aqua Ventus I project. The Goldwind turbines have a hub height of 100 m. The turbines will be deployed in Maine State waters, approximately 2.9 miles off Monhegan Island; Monhegan Island is located roughly 10 miles off the coast of Maine. In order to site and permit the offshore turbines, the acoustic output mustmore » be evaluated to ensure that the sound will not disturb residents on Monhegan Island, nor input sufficient sound levels into the nearby ocean to disturb marine mammals. This initial assessment of the acoustic output focuses on the sound of the turbines in air by modeling the assumed sound source level, applying a sound propagation model, and taking into account the distance from shore.« less

Three-dimensional Numerical Analysis on Blade Response of Vertical Axis Tidal Current Turbine Under Operational Condition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Ye; Karri, Naveen K.; Wang, Qi

Tidal power as a large-scale renewable source of energy has been receiving significant attention recently because of its advantages over the wind and other renewal energy sources. The technology used to harvest energy from tidal current is called a tidal current turbine. Though some of the principles of wind turbine design are applicable to tidal current turbines, the design of latter ones need additional considerations like cavitation damage, corrosion etc. for the long-term reliability of such turbines. Depending up on the orientation of axis, tidal current turbines can be classified as vertical axis turbines or horizontal axis turbines. Existing studiesmore » on the vertical axis tidal current turbine focus more on the hydrodynamic aspects of the turbine rather than the structural aspects. This paper summarizes our recent efforts to study the integrated hydrodynamic and structural aspects of the vertical axis tidal current turbines. After reviewing existing methods in modeling tidal current turbines, we developed a hybrid approach that combines discrete vortex method -finite element method that can simulate the integrated hydrodynamic and structural response of a vertical axis turbine. This hybrid method was initially employed to analyze a typical three-blade vertical axis turbine. The power coefficient was used to evaluate the hydrodynamic performance, and critical deflection was considered to evaluate the structural reliability. A sensitivity analysis was also conducted with various turbine height-to-radius ratios. The results indicate that both the power output and failure probability increase with the turbine height, suggesting a necessity for optimal design. An attempt to optimize a 3-blade vertical axis turbine design with hybrid method yielded a ratio of turbine height to radius (H/R) about 3.0 for reliable maximum power output.« less

Characterizing large river sounds: Providing context for understanding the environmental effects of noise produced by hydrokinetic turbines

DOE PAGES

Bevelhimer, Mark S.; Deng, Z. Daniel; Scherelis, Constantin C.

2016-01-06

Underwaternoise associated with the installation and operation of hydrokinetic turbines in rivers and tidal zones presents a potential environmental concern for fish and marine mammals. Comparing the spectral quality of sounds emitted by hydrokinetic turbines to natural and other anthropogenic sound sources is an initial step at understanding potential environmental impacts. Underwater recordings were obtained from passing vessels and natural underwater sound sources in static and flowing waters. Static water measurements were taken in a lake with minimal background noise. Flowing water measurements were taken at a previously proposed deployment site for hydrokinetic turbines on the Mississippi River, where soundsmore » created by flowing water are part of all measurements, both natural ambient and anthropogenic sources. Vessel sizes ranged from a small fishing boat with 60 hp outboard motor to an 18-unit barge train being pushed upstream by tugboat. As expected, large vessels with large engines created the highest sound levels, which were, on average, 40 dB greater than the sound created by an operating hydrokinetic turbine. As a result, a comparison of sound levels from the same sources at different distances using both spherical and cylindrical sound attenuation functions suggests that spherical model results more closely approximate observed sound attenuation.« less

Characterizing large river sounds: Providing context for understanding the environmental effects of noise produced by hydrokinetic turbines.

PubMed

Bevelhimer, Mark S; Deng, Z Daniel; Scherelis, Constantin

2016-01-01

Underwater noise associated with the installation and operation of hydrokinetic turbines in rivers and tidal zones presents a potential environmental concern for fish and marine mammals. Comparing the spectral quality of sounds emitted by hydrokinetic turbines to natural and other anthropogenic sound sources is an initial step at understanding potential environmental impacts. Underwater recordings were obtained from passing vessels and natural underwater sound sources in static and flowing waters. Static water measurements were taken in a lake with minimal background noise. Flowing water measurements were taken at a previously proposed deployment site for hydrokinetic turbines on the Mississippi River, where sounds created by flowing water are part of all measurements, both natural ambient and anthropogenic sources. Vessel sizes ranged from a small fishing boat with 60 hp outboard motor to an 18-unit barge train being pushed upstream by tugboat. As expected, large vessels with large engines created the highest sound levels, which were, on average, 40 dB greater than the sound created by an operating hydrokinetic turbine. A comparison of sound levels from the same sources at different distances using both spherical and cylindrical sound attenuation functions suggests that spherical model results more closely approximate observed sound attenuation.

Modeling of Aerosols in Post-Combustor Flow Path and Sampling System

NASA Technical Reports Server (NTRS)

Wey, Thomas; Liu, Nan-Suey

2006-01-01

The development and application of a multi-dimensional capability for modeling and simulation of aviation-sourced particle emissions and their precursors are elucidated. Current focus is on the role of the flow and thermal environments. The cases investigated include a film cooled turbine blade, the first-stage of a high-pressure turbine, the sampling probes, the sampling lines, and a pressure reduction chamber.

46 CFR 112.20-10 - Diesel or gas turbine driven emergency power source.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Power Source § 112.20-10 Diesel or gas turbine driven emergency power source. Simultaneously with the operation of the transfer means under § 112.20-5, the diesel engine or gas turbine driving the final... 46 Shipping 4 2011-10-01 2011-10-01 false Diesel or gas turbine driven emergency power source. 112...

46 CFR 112.20-10 - Diesel or gas turbine driven emergency power source.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Power Source § 112.20-10 Diesel or gas turbine driven emergency power source. Simultaneously with the operation of the transfer means under § 112.20-5, the diesel engine or gas turbine driving the final... 46 Shipping 4 2010-10-01 2010-10-01 false Diesel or gas turbine driven emergency power source. 112...

Numerical modeling of the effects of a free surface on the operating characteristics of Marine Hydrokinetic Turbines

NASA Astrophysics Data System (ADS)

Adamski, Samantha; Aliseda, Alberto

2012-11-01

Marine Hydrokinetic (MHK) turbines are a growing area of research in the renewable energy field because tidal currents are a highly predictable clean energy source. The presence of a free surface may influence the flow around the turbine and in the wake, critically affecting turbine performance and environmental effects through modification of wake physical variables. The characteristic Froude number that control these processes is still a matter of controversy, with the channel depth and turbine's depth, blade tip depth and diameter as potential candidates for a length scale used in literature. We use the Volume of Fluid model to track the free surface dynamics in a RANS simulation with a BEMT model of the turbine to understand the physics of the wake-free surface interactions. Pressure and flow rate boundary conditions for channel's inlet, outlet and air side have been tested in an effort to determine the optimum set of simulation conditions for MHK turbines in rivers or estuaries. Stability and accuracy in terms of power extraction and kinetic and potential energy budgets are considered. The goal of this research is to determine, quantitatively in non dimensional parameter space, the limit between negligible and significant free surface effects on MHK turbine analysis. Supported by DOE through the National Northwest Marine Renewable Energy Center.

An analytic approach to optimize tidal turbine fields

NASA Astrophysics Data System (ADS)

Pelz, P.; Metzler, M.

2013-12-01

Motivated by global warming due to CO2-emission various technologies for harvesting of energy from renewable sources are developed. Hydrokinetic turbines get applied to surface watercourse or tidal flow to gain electrical energy. Since the available power for hydrokinetic turbines is proportional to the projected cross section area, fields of turbines are installed to scale shaft power. Each hydrokinetic turbine of a field can be considered as a disk actuator. In [1], the first author derives the optimal operation point for hydropower in an open-channel. The present paper concerns about a 0-dimensional model of a disk-actuator in an open-channel flow with bypass, as a special case of [1]. Based on the energy equation, the continuity equation and the momentum balance an analytical approach is made to calculate the coefficient of performance for hydrokinetic turbines with bypass flow as function of the turbine head and the ratio of turbine width to channel width.

Numerical simulation of a cross flow Marine Hydrokinetic turbine.

NASA Astrophysics Data System (ADS)

Hall, Taylor; Aliseda, Alberto

2011-11-01

In the search for alternative sources of energy, the kinetic energy of water currents in oceans, rivers and estuaries is being explored as predictable and environmentally benign. We are investigating the flow past a cross flow turbine in which a helical blade under hydrodynamic forces turns around a shaft perpendicular to the free stream. This type of turbine, while very different from the classical horizontal axis turbine commonly used in the wind energy field, presents advantages for stacking in very narrow constricted channels where the water currents are consistently high and therefore turbine installation may be economically feasible. We use a model of a helical four-bladed turbine in cross flow to investigate the efficiency of the energy capture and the dynamics of the turbulent wake. Scale model experiments in a flume are used to validate the numerical results on a stationary configuration as an initial step towards creating an accurate numerical model of the turbine. The simulation of the rotating turbine provides a full perspective on the effect of angular position on flow detachment and vortex shedding from the blade, as well as on the fluctuations of the shaft torque produced (a problematic feature of this type of turbine). The results are analyzed in terms of hydrodynamic optimization of the blade and its structural loading. Supported by DOE through the Northwest National Marine Renewable Energy Center.

Modeling energy production of solar thermal systems and wind turbines for installation at corn ethanol plants

NASA Astrophysics Data System (ADS)

Ehrke, Elizabeth

Nearly every aspect of human existence relies on energy in some way. Most of this energy is currently derived from fossil fuel resources. Increasing energy demands coupled with environmental and national security concerns have facilitated the move towards renewable energy sources. Biofuels like corn ethanol are one of the ways the U.S. has significantly reduced petroleum consumption. However, the large energy requirement of corn ethanol limits the net benefit of the fuel. Using renewable energy sources to produce ethanol can greatly improve its economic and environmental benefits. The main purpose of this study was to model the useful energy received from a solar thermal array and a wind turbine at various locations to determine the feasibility of applying these technologies at ethanol plants around the country. The model calculates thermal energy received from a solar collector array and electricity generated by a wind turbine utilizing various input data to characterize the equipment. Project cost and energy rate inputs are used to evaluate the profitability of the solar array or wind turbine. The current state of the wind and solar markets were examined to give an accurate representation of the economics of each industry. Eighteen ethanol plant locations were evaluated for the viability of a solar thermal array and/or wind turbine. All ethanol plant locations have long payback periods for solar thermal arrays, but high natural gas prices significantly reduce this timeframe. Government incentives will be necessary for the economic feasibility of solar thermal arrays. Wind turbines can be very profitable for ethanol plants in the Midwest due to large wind resources. The profitability of wind power is sensitive to regional energy prices. However, government incentives for wind power do not significantly change the economic feasibility of a wind turbine. This model can be used by current or future ethanol facilities to investigate or begin the planning process for a solar thermal array or wind turbine. The model is meant to aide in the planning stages of a renewable energy project, and advanced investigation will be needed to move forward with that project.

Modeling Innovations Advance Wind Energy Industry

NASA Technical Reports Server (NTRS)

2009-01-01

In 1981, Glenn Research Center scientist Dr. Larry Viterna developed a model that predicted certain elements of wind turbine performance with far greater accuracy than previous methods. The model was met with derision from others in the wind energy industry, but years later, Viterna discovered it had become the most widely used method of its kind, enabling significant wind energy technologies-like the fixed pitch turbines produced by manufacturers like Aerostar Inc. of Westport, Massachusetts-that are providing sustainable, climate friendly energy sources today.

Onshore industrial wind turbine locations for the United States up to March 2014

USGS Publications Warehouse

Diffendorfer, James E.; Kramer, Louisa; Ancona, Zachary H.; Garrity, Christopher P.

2015-01-01

Wind energy is a rapidly growing form of renewable energy in the United States. While summary information on the total amounts of installed capacity are available by state, a free, centralized, national, turbine-level, geospatial dataset useful for scientific research, land and resource management, and other uses did not exist. Available in multiple formats and in a web application, these public domain data provide industrial-scale onshore wind turbine locations in the United States up to March 2014, corresponding facility information, and turbine technical specifications. Wind turbine records have been collected and compiled from various public sources, digitized or position verified from aerial imagery, and quality assured and quality controlled. Technical specifications for turbines were assigned based on the wind turbine make and model as described in public literature. In some cases, turbines were not seen in imagery or turbine information did not exist or was difficult to obtain. Uncertainty associated with these is recorded in a confidence rating.

Onshore industrial wind turbine locations for the United States up to March 2014.

PubMed

Diffendorfer, Jay E; Kramer, Louisa A; Ancona, Zach H; Garrity, Christopher P

2015-11-24

Wind energy is a rapidly growing form of renewable energy in the United States. While summary information on the total amounts of installed capacity are available by state, a free, centralized, national, turbine-level, geospatial dataset useful for scientific research, land and resource management, and other uses did not exist. Available in multiple formats and in a web application, these public domain data provide industrial-scale onshore wind turbine locations in the United States up to March 2014, corresponding facility information, and turbine technical specifications. Wind turbine records have been collected and compiled from various public sources, digitized or position verified from aerial imagery, and quality assured and quality controlled. Technical specifications for turbines were assigned based on the wind turbine make and model as described in public literature. In some cases, turbines were not seen in imagery or turbine information did not exist or was difficult to obtain. Uncertainty associated with these is recorded in a confidence rating.

Onshore industrial wind turbine locations for the United States up to March 2014

PubMed Central

Diffendorfer, Jay E.; Kramer, Louisa A.; Ancona, Zach H.; Garrity, Christopher P.

2015-01-01

Wind energy is a rapidly growing form of renewable energy in the United States. While summary information on the total amounts of installed capacity are available by state, a free, centralized, national, turbine-level, geospatial dataset useful for scientific research, land and resource management, and other uses did not exist. Available in multiple formats and in a web application, these public domain data provide industrial-scale onshore wind turbine locations in the United States up to March 2014, corresponding facility information, and turbine technical specifications. Wind turbine records have been collected and compiled from various public sources, digitized or position verified from aerial imagery, and quality assured and quality controlled. Technical specifications for turbines were assigned based on the wind turbine make and model as described in public literature. In some cases, turbines were not seen in imagery or turbine information did not exist or was difficult to obtain. Uncertainty associated with these is recorded in a confidence rating. PMID:26601687

An implementation of an aeroacoustic prediction model for broadband noise from a vertical axis wind turbine using a CFD informed methodology

NASA Astrophysics Data System (ADS)

Botha, J. D. M.; Shahroki, A.; Rice, H.

2017-12-01

This paper presents an enhanced method for predicting aerodynamically generated broadband noise produced by a Vertical Axis Wind Turbine (VAWT). The method improves on existing work for VAWT noise prediction and incorporates recently developed airfoil noise prediction models. Inflow-turbulence and airfoil self-noise mechanisms are both considered. Airfoil noise predictions are dependent on aerodynamic input data and time dependent Computational Fluid Dynamics (CFD) calculations are carried out to solve for the aerodynamic solution. Analytical flow methods are also benchmarked against the CFD informed noise prediction results to quantify errors in the former approach. Comparisons to experimental noise measurements for an existing turbine are encouraging. A parameter study is performed and shows the sensitivity of overall noise levels to changes in inflow velocity and inflow turbulence. Noise sources are characterised and the location and mechanism of the primary sources is determined, inflow-turbulence noise is seen to be the dominant source. The use of CFD calculations is seen to improve the accuracy of noise predictions when compared to the analytic flow solution as well as showing that, for inflow-turbulence noise sources, blade generated turbulence dominates the atmospheric inflow turbulence.

Prediction of Francis Turbine Prototype Part Load Pressure and Output Power Fluctuations with Hydroelectric Model

NASA Astrophysics Data System (ADS)

Alligné, S.; Nicolet, C.; Béguin, A.; Landry, C.; Gomes, J.; Avellan, F.

2017-04-01

The prediction of pressure and output power fluctuations amplitudes on Francis turbine prototype is a challenge for hydro-equipment industry since it is subjected to guarantees to ensure smooth and reliable operation of the hydro units. The European FP7 research project Hyperbole aims to setup a methodology to transpose the pressure fluctuations induced by the cavitation vortex rope from the reduced scale model to the prototype generating units. A Francis turbine unit of 444MW with a specific speed value of ν = 0.29, is considered as case study. A SIMSEN model of the power station including electrical system, controllers, rotating train and hydraulic system with transposed draft tube excitation sources is setup. Based on this model, a frequency analysis of the hydroelectric system is performed for all technologies to analyse potential interactions between hydraulic excitation sources and electrical components. Three technologies have been compared: the classical fixed speed configuration with Synchronous Machine (SM) and the two variable speed technologies which are Doubly Fed Induction Machine (DFIM) and Full Size Frequency Converter (FSFC).

The Open Source DataTurbine Initiative: Streaming Data Middleware for Environmental Observing Systems

NASA Technical Reports Server (NTRS)

Fountain T.; Tilak, S.; Shin, P.; Hubbard, P.; Freudinger, L.

2009-01-01

The Open Source DataTurbine Initiative is an international community of scientists and engineers sharing a common interest in real-time streaming data middleware and applications. The technology base of the OSDT Initiative is the DataTurbine open source middleware. Key applications of DataTurbine include coral reef monitoring, lake monitoring and limnology, biodiversity and animal tracking, structural health monitoring and earthquake engineering, airborne environmental monitoring, and environmental sustainability. DataTurbine software emerged as a commercial product in the 1990 s from collaborations between NASA and private industry. In October 2007, a grant from the USA National Science Foundation (NSF) Office of Cyberinfrastructure allowed us to transition DataTurbine from a proprietary software product into an open source software initiative. This paper describes the DataTurbine software and highlights key applications in environmental monitoring.

Investigation of wind turbine effects on Evapotranspiration using surface energy balance model based on satellite-derived data

NASA Astrophysics Data System (ADS)

hassanpour Adeh, E.; Higgins, C. W.

2014-12-01

Wind turbines have been introduced as an energy source that does not require a large expenditure of water. However, recent simulation results indicate that wind turbines increase evaporation rates from the nearby land. In this research the effect of wind energy on irrigated agriculture is determined using a Surface Energy Balance Algorithm (SEBAL) on Landsat data spanning a 30 year interval. The analysis allows the characterization of evapotranspiration (ET) before and after wind turbine installations. The time history of ET from Landsat data will be presented for several major wind farms across the US. These data will be used to determine the impact on water demand due to presence of wind turbines.

Wind turbine sound pressure level calculations at dwellings.

PubMed

Keith, Stephen E; Feder, Katya; Voicescu, Sonia A; Soukhovtsev, Victor; Denning, Allison; Tsang, Jason; Broner, Norm; Leroux, Tony; Richarz, Werner; van den Berg, Frits

2016-03-01

This paper provides calculations of outdoor sound pressure levels (SPLs) at dwellings for 10 wind turbine models, to support Health Canada's Community Noise and Health Study. Manufacturer supplied and measured wind turbine sound power levels were used to calculate outdoor SPL at 1238 dwellings using ISO [(1996). ISO 9613-2-Acoustics] and a Swedish noise propagation method. Both methods yielded statistically equivalent results. The A- and C-weighted results were highly correlated over the 1238 dwellings (Pearson's linear correlation coefficient r > 0.8). Calculated wind turbine SPLs were compared to ambient SPLs from other sources, estimated using guidance documents from the United States and Alberta, Canada.

Modeling of a Sequential Two-Stage Combustor

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Liu, N.-S.; Gallagher, J. R.; Ryder, R. C.; Brankovic, A.; Hendricks, J. A.

2005-01-01

A sequential two-stage, natural gas fueled power generation combustion system is modeled to examine the fundamental aerodynamic and combustion characteristics of the system. The modeling methodology includes CAD-based geometry definition, and combustion computational fluid dynamics analysis. Graphical analysis is used to examine the complex vortical patterns in each component, identifying sources of pressure loss. The simulations demonstrate the importance of including the rotating high-pressure turbine blades in the computation, as this results in direct computation of combustion within the first turbine stage, and accurate simulation of the flow in the second combustion stage. The direct computation of hot-streaks through the rotating high-pressure turbine stage leads to improved understanding of the aerodynamic relationships between the primary and secondary combustors and the turbomachinery.

Design of airborne wind turbine and computational fluid dynamics analysis

NASA Astrophysics Data System (ADS)

Anbreen, Faiqa

Wind energy is a promising alternative to the depleting non-renewable sources. The height of the wind turbines becomes a constraint to their efficiency. Airborne wind turbine can reach much higher altitudes and produce higher power due to high wind velocity and energy density. The focus of this thesis is to design a shrouded airborne wind turbine, capable to generate 70 kW to propel a leisure boat with a capacity of 8-10 passengers. The idea of designing an airborne turbine is to take the advantage of higher velocities in the atmosphere. The Solidworks model has been analyzed numerically using Computational Fluid Dynamics (CFD) software StarCCM+. The Unsteady Reynolds Averaged Navier Stokes Simulation (URANS) with K-epsilon turbulence model has been selected, to study the physical properties of the flow, with emphasis on the performance of the turbine and the increase in air velocity at the throat. The analysis has been done using two ambient velocities of 12 m/s and 6 m/s. At 12 m/s inlet velocity, the velocity of air at the turbine has been recorded as 16 m/s. The power generated by the turbine is 61 kW. At inlet velocity of 6 m/s, the velocity of air at turbine increased to 10 m/s. The power generated by turbine is 25 kW.

Characterizing large river sounds: Providing context for understanding the environmental effects of noise produced by hydrokinetic turbines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bevelhimer, Mark S.; Deng, Z. Daniel; Scherelis, Constantin

2016-01-01

Underwater noise associated with the installation and operation of hydrokinetic turbines in rivers and tidal zones presents a potential environmental concern for fish and marine mammals. Comparing the spectral quality of sounds emitted by hydrokinetic turbines to natural and other anthropogenic sound sources is an initial step at understanding potential environmental impacts. Underwater recordings were obtained from passing vessels of different sizes and other underwater sound sources in both static and flowing waters. Static water measurements were taken in a lake with minimal background noise. Flowing water measurements were taken at a previously proposed deployment site for hydrokinetic turbines onmore » the Mississippi River, where the sound of flowing water is included in background measurements. The size of vessels measured ranged from a small fishing boat with a 60 HP outboard motor to an 18-unit barge train being pushed upstream by tugboat. As expected, large vessels with large engines created the highest sound levels, and when compared to the sound created by an operating HK turbine were many times greater. A comparison of sound levels from the same sources at different distances using both spherical and cylindrical sound attenuation functions suggests that spherical model results more closely approximate observed values.« less

CFD simulations of power coefficients for an innovative Darrieus style vertical axis wind turbine with auxiliary straight blades

NASA Astrophysics Data System (ADS)

Arpino, F.; Cortellessa, G.; Dell'Isola, M.; Scungio, M.; Focanti, V.; Profili, M.; Rotondi, M.

2017-11-01

The increasing price of fossil derivatives, global warming and energy market instabilities, have led to an increasing interest in renewable energy sources such as wind energy. Amongst the different typologies of wind generators, small scale Vertical Axis Wind Turbines (VAWT) present the greatest potential for off grid power generation at low wind speeds. In the present work, Computational Fluid Dynamic (CFD) simulations were performed in order to investigate the performance of an innovative configuration of straight-blades Darrieus-style vertical axis micro wind turbine, specifically developed for small scale energy conversion at low wind speeds. The micro turbine under investigation is composed of three pairs of airfoils, consisting of a main and auxiliary blades with different chord lengths. The simulations were made using the open source finite volume based CFD toolbox OpenFOAM, considering different turbulence models and adopting a moving mesh approach for the turbine rotor. The simulated data were reported in terms of dimensionless power coefficients for dynamic performance analysis. The results from the simulations were compared to the data obtained from experiments on a scaled model of the same VAWT configuration, conducted in a closed circuit open chamber wind tunnel facility available at the Laboratory of Industrial Measurements (LaMI) of the University of Cassino and Lazio Meridionale (UNICLAM). From the proposed analysis, it was observed that the most suitable model for the simulation of the performances of the micro turbine under investigation is the one-equation Spalart-Allmaras, even if under the conditions analysed in the present work and for TSR values higher than 1.1, some discrepancies between numerical and experimental data can be observed.

Effect of Wind Turbine Wakes on the Performance of a Real Case WRF-LES Simulation

NASA Astrophysics Data System (ADS)

Doubrawa, P.; Montornès, A.; Barthelmie, R. J.; Pryor, S. C.; Giroux, G.; Casso, P.

2017-05-01

The main objective of this work is to estimate how much of the discrepancy between measured and modeled flow parameters can be attributed to wake effects. The real case simulations were performed for a period of 15 days with the Weather Research and Forecasting (WRF) model and nested down to a Large-Eddy Simulation (LES) scale of ∼ 100 m. Beyond the coastal escarpment, the site is flat and homogeneous and the study focuses on a meteorological mast and a northern turbine subjected to the wake of a southern turbine. The observational data set collected during the Prince Edward Island Wind Energy Experiment (PEIWEE) includes a sonic anemometer at 60 m mounted onto the mast, and measurements from the two turbines. Wake versus free stream conditions are distinguished based on measured wind direction while assuming constant expansion for the wake of the southern turbine. During the period considered the mast and northern turbine were under the southern turbine wake ∼ 16% and ∼ 11% of the time, respectively. Under these conditions, the model overestimates the wind speed and underestimates the turbulence intensity at the mast but not at the northern turbine, where the effect of wakes on the model error is unclear and other model limitations are likely more important. The wind direction difference between the southern and northern turbines is slightly underestimated by the model regardless of whether free stream or wake conditions are observed, indicating that it may be due to factors unrelated to the wake development such as surface forcings. Finally, coupling an inexpensive wake model to the high-fidelity simulation as a post-processing tool drives the simulated wind speeds at the mast significantly closer to the observed values, but the opposite is true at the coastal turbine which is in the far wake. This indicates that the application of a post-processing wake correction should be performed with caution and may increase the wind speed errors when other important sources of uncertainty in the model and data are not considered.

SLB-STO-D ANALYSIS REPORT: MODELING AND SIMULATION ANALYSIS OF FUEL, WATER, AND WASTE REDUCTIONS IN BASE CAMPS: 50, 300, AND 1000 PERSONS

DTIC Science & Technology

2017-08-21

panels only produce power when the sun is out, turbines only produce power when there xiii is wind , etc. For these sources to be fully utilized...hybrid energy system mounted on a towable trailer consisting of an onboard diesel generator, solar panels, wind turbines , and an energy storage...limited to certain times of day—solar panels only produce power when the sun is out, turbines only produce power when there is wind , etc. For these

Recommendations on Model Fidelity for Wind Turbine Gearbox Simulations; NREL (National Renewable Energy Laboratory)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keller, J.; Lacava, W.; Austin, J.

2015-02-01

This work investigates the minimum level of fidelity required to accurately simulate wind turbine gearboxes using state-of-the-art design tools. Excessive model fidelity including drivetrain complexity, gearbox complexity, excitation sources, and imperfections, significantly increases computational time, but may not provide a commensurate increase in the value of the results. Essential designparameters are evaluated, including the planetary load-sharing factor, gear tooth load distribution, and sun orbit motion. Based on the sensitivity study results, recommendations for the minimum model fidelities are provided.

Potassium-Rankine Power Conversion Subsystem Modeling for Nuclear Electric Propulsion

NASA Technical Reports Server (NTRS)

Johnson, Gregory A.

1993-01-01

A potassium-Rankine power conversion system model was developed under Contract No. NAS3-25808 for the NASA-LeRC. This model predicts potassium-Rankine performance for turbine inlet temperatures (TIT) from 1200 - 1600 K, TIT to condenser temperature ratios from 1.25-1.6, power levels from 100 to 10,000 kWe, and lifetimes from 2-10 years. The model is for a Rankine cycle with reheat for turbine stage moisture control. The model assumes heat is supplied from a lithium heat transport loop. The model does not include a heat source or a condenser/heat rejection system model. These must be supplied by the user.

Hardware-in-the-Loop emulator for a hydrokinetic turbine

NASA Astrophysics Data System (ADS)

Rat, C. L.; Prostean, O.; Filip, I.

2018-01-01

Hydroelectric power has proven to be an efficient and reliable form of renewable energy, but its impact on the environment has long been a source of concern. Hydrokinetic turbines are an emerging class of renewable energy technology designed for deployment in small rivers and streams with minimal environmental impact on the local ecosystem. Hydrokinetic technology represents a truly clean source of energy, having the potential to become a highly efficient method of harvesting renewable energy. However, in order to achieve this goal, extensive research is necessary. This paper presents a Hardware-in-the-Loop emulator for a run-of-the-river type hydrokinetic turbine. The HIL system uses an ABB ACS800 drive to control an induction machine as a significant means of replicating the behavior of the real turbine. The induction machine is coupled to a permanent magnet synchronous generator and the corresponding load. The ACS800 drive is controlled through the software system, which comprises of the hydrokinetic turbine real-time simulation through mathematical modeling in the LabVIEW programming environment running on a NI CompactRIO (cRIO) platform. The advantages of this method are that it can provide a means for testing many control configurations without requiring the presence of the real turbine. This paper contains the basic principles of a hydrokinetic turbine, particularly the run-of-the-river configurations along with the experimental results obtained from the HIL system.

Short-term Wind Forecasting at Wind Farms using WRF-LES and Actuator Disk Model

NASA Astrophysics Data System (ADS)

Kirkil, Gokhan

2017-04-01

Short-term wind forecasts are obtained for a wind farm on a mountainous terrain using WRF-LES. Multi-scale simulations are also performed using different PBL parameterizations. Turbines are parameterized using Actuator Disc Model. LES models improved the forecasts. Statistical error analysis is performed and ramp events are analyzed. Complex topography of the study area affects model performance, especially the accuracy of wind forecasts were poor for cross valley-mountain flows. By means of LES, we gain new knowledge about the sources of spatial and temporal variability of wind fluctuations such as the configuration of wind turbines.

Simulation of Turbine Tone Noise Generation Using a Turbomachinery Aerodynamics Solver

NASA Technical Reports Server (NTRS)

VanZante, Dale; Envia, Edmane

2010-01-01

As turbofan engine bypass ratios continue to increase, the contribution of the turbine to the engine noise signature is receiving more attention. Understanding the relative importance of the various turbine noise generation mechanisms and the characteristics of the turbine acoustic transmission loss are essential ingredients in developing robust reduced-order models for predicting the turbine noise signature. A computationally based investigation has been undertaken to help guide the development of a turbine noise prediction capability that does not rely on empiricism. As proof-of-concept for this approach, two highly detailed numerical simulations of the unsteady flow field inside the first stage of a modern high-pressure turbine were carried out. The simulations were computed using TURBO, which is an unsteady Reynolds-Averaged Navier-Stokes code capable of multi-stage simulations. Spectral and modal analysis of the unsteady pressure data from the numerical simulation of the turbine stage show a circumferential modal distribution that is consistent with the Tyler-Sofrin rule. Within the high-pressure turbine, the interaction of velocity, pressure and temperature fluctuations with the downstream blade rows are all possible tone noise source mechanisms. We have taken the initial step in determining the source strength hierarchy by artificially reducing the level of temperature fluctuations in the turbine flowfield. This was accomplished by changing the vane cooling flow temperature in order to mitigate the vane thermal wake in the second of the two simulations. The results indicated that, despite a dramatic change in the vane cooling flow, the computed modal levels changed very little indicating that the contribution of temperature fluctuations to the overall pressure field is rather small compared with the viscous and potential field interaction mechanisms.

Nesting large-eddy simulations within mesoscale simulations for wind energy applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lundquist, J K; Mirocha, J D; Chow, F K

2008-09-08

With increasing demand for more accurate atmospheric simulations for wind turbine micrositing, for operational wind power forecasting, and for more reliable turbine design, simulations of atmospheric flow with resolution of tens of meters or higher are required. These time-dependent large-eddy simulations (LES), which resolve individual atmospheric eddies on length scales smaller than turbine blades and account for complex terrain, are possible with a range of commercial and open-source software, including the Weather Research and Forecasting (WRF) model. In addition to 'local' sources of turbulence within an LES domain, changing weather conditions outside the domain can also affect flow, suggesting thatmore » a mesoscale model provide boundary conditions to the large-eddy simulations. Nesting a large-eddy simulation within a mesoscale model requires nuanced representations of turbulence. Our group has improved the Weather and Research Forecasting model's (WRF) LES capability by implementing the Nonlinear Backscatter and Anisotropy (NBA) subfilter stress model following Kosovic (1997) and an explicit filtering and reconstruction technique to compute the Resolvable Subfilter-Scale (RSFS) stresses (following Chow et al, 2005). We have also implemented an immersed boundary method (IBM) in WRF to accommodate complex terrain. These new models improve WRF's LES capabilities over complex terrain and in stable atmospheric conditions. We demonstrate approaches to nesting LES within a mesoscale simulation for farms of wind turbines in hilly regions. Results are sensitive to the nesting method, indicating that care must be taken to provide appropriate boundary conditions, and to allow adequate spin-up of turbulence in the LES domain.« less

High-resolution LES of the rotating stall in a reduced scale model pump-turbine

NASA Astrophysics Data System (ADS)

Pacot, Olivier; Kato, Chisachi; Avellan, François

2014-03-01

Extending the operating range of modern pump-turbines becomes increasingly important in the course of the integration of renewable energy sources in the existing power grid. However, at partial load condition in pumping mode, the occurrence of rotating stall is critical to the operational safety of the machine and on the grid stability. The understanding of the mechanisms behind this flow phenomenon yet remains vague and incomplete. Past numerical simulations using a RANS approach often led to inconclusive results concerning the physical background. For the first time, the rotating stall is investigated by performing a large scale LES calculation on the HYDRODYNA pump-turbine scale model featuring approximately 100 million elements. The computations were performed on the PRIMEHPC FX10 of the University of Tokyo using the overset Finite Element open source code FrontFlow/blue with the dynamic Smagorinsky turbulence model and the no-slip wall condition. The internal flow computed is the one when operating the pump-turbine at 76% of the best efficiency point in pumping mode, as previous experimental research showed the presence of four rotating cells. The rotating stall phenomenon is accurately reproduced for a reduced Reynolds number using the LES approach with acceptable computing resources. The results show an excellent agreement with available experimental data from the reduced scale model testing at the EPFL Laboratory for Hydraulic Machines. The number of stall cells as well as the propagation speed corroborates the experiment.

Simulation for Grid Connected Wind Turbines with Fluctuating

NASA Astrophysics Data System (ADS)

Ye, Ying; Fu, Yang; Wei, Shurong

This paper establishes the whole dynamic model of wind turbine generator system which contains the wind speed model and DFIG wind turbines model .A simulation sample based on the mathematical models is built by using MATLAB in this paper. Research are did on the performance characteristics of doubly-fed wind generators (DFIG) which connected to power grid with three-phase ground fault and the disturbance by gust and mixed wind. The capacity of the wind farm is 9MW which consists of doubly-fed wind generators (DFIG). Simulation results demonstrate that the three-phase ground fault occurs on grid side runs less affected on the stability of doubly-fed wind generators. However, as a power source, fluctuations of the wind speed will run a large impact on stability of double-fed wind generators. The results also show that if the two disturbances occur in the meantime, the situation will be very serious.

Global Value Chain and Manufacturing Analysis on Geothermal Power Plant Turbines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akar, Sertac; Augustine, Chad; Kurup, Parthiv

In this study, we have undertaken a robust analysis of the global supply chain and manufacturing costs for components of Organic Rankine Cycle (ORC) Turboexpander and steam turbines used in geothermal power plants. We collected a range of market data influencing manufacturing from various data sources and determined the main international manufacturers in the industry. The data includes the manufacturing cost model to identify requirements for equipment, facilities, raw materials, and labor. We analyzed three different cases; 1) 1 MW geothermal ORC Turboexpander 2) 5 MW ORC Turboexpander 3) 20 MW geothermal Steam Turbine

Accounting for unsearched areas in estimating wind turbine-caused fatality

USGS Publications Warehouse

Huso, Manuela M.P.; Dalthorp, Dan

2014-01-01

With wind energy production expanding rapidly, concerns about turbine-induced bird and bat fatality have grown and the demand for accurate estimation of fatality is increasing. Estimation typically involves counting carcasses observed below turbines and adjusting counts by estimated detection probabilities. Three primary sources of imperfect detection are 1) carcasses fall into unsearched areas, 2) carcasses are removed or destroyed before sampling, and 3) carcasses present in the searched area are missed by observers. Search plots large enough to comprise 100% of turbine-induced fatality are expensive to search and may nonetheless contain areas unsearchable because of dangerous terrain or impenetrable brush. We evaluated models relating carcass density to distance from the turbine to estimate the proportion of carcasses expected to fall in searched areas and evaluated the statistical cost of restricting searches to areas near turbines where carcass density is highest and search conditions optimal. We compared 5 estimators differing in assumptions about the relationship of carcass density to distance from the turbine. We tested them on 6 different carcass dispersion scenarios at each of 3 sites under 2 different search regimes. We found that even simple distance-based carcass-density models were more effective at reducing bias than was a 5-fold expansion of the search area. Estimators incorporating fitted rather than assumed models were least biased, even under restricted searches. Accurate estimates of fatality at wind-power facilities will allow critical comparisons of rates among turbines, sites, and regions and contribute to our understanding of the potential environmental impact of this technology.

Hydroelectric System Response to Part Load Vortex Rope Excitation

NASA Astrophysics Data System (ADS)

Alligné, S.; Nicolet, C.; Bégum, A.; Landry, C.; Gomes, J.; Avellan, F.

2016-11-01

The prediction of pressure and output power fluctuations amplitudes on Francis turbine prototype is a challenge for hydro-equipment industry since it is subjected to guarantees to ensure smooth and reliable operation of the hydro units. The European FP7 research project Hyperbole aims to setup a methodology to transpose the pressure fluctuations induced by the cavitation vortex rope on the reduced scale model to the prototype generating units. A Francis turbine unit of 444MW with a specific speed value of v = 0.29, is considered as case study. A SIMSEN model of the power station including electrical system, controllers, rotating train and hydraulic system with transposed draft tube excitation sources is setup. Based on this model, a frequency analysis of the hydroelectric system is performed to analyse potential interactions between hydraulic excitation sources and electrical components.

Potential of neuro-fuzzy methodology to estimate noise level of wind turbines

NASA Astrophysics Data System (ADS)

Nikolić, Vlastimir; Petković, Dalibor; Por, Lip Yee; Shamshirband, Shahaboddin; Zamani, Mazdak; Ćojbašić, Žarko; Motamedi, Shervin

2016-01-01

Wind turbines noise effect became large problem because of increasing of wind farms numbers since renewable energy becomes the most influential energy sources. However, wind turbine noise generation and propagation is not understandable in all aspects. Mechanical noise of wind turbines can be ignored since aerodynamic noise of wind turbine blades is the main source of the noise generation. Numerical simulations of the noise effects of the wind turbine can be very challenging task. Therefore in this article soft computing method is used to evaluate noise level of wind turbines. The main goal of the study is to estimate wind turbine noise in regard of wind speed at different heights and for different sound frequency. Adaptive neuro-fuzzy inference system (ANFIS) is used to estimate the wind turbine noise levels.

Computational Acoustic Beamforming for Noise Source Identification for Small Wind Turbines.

PubMed

Ma, Ping; Lien, Fue-Sang; Yee, Eugene

2017-01-01

This paper develops a computational acoustic beamforming (CAB) methodology for identification of sources of small wind turbine noise. This methodology is validated using the case of the NACA 0012 airfoil trailing edge noise. For this validation case, the predicted acoustic maps were in excellent conformance with the results of the measurements obtained from the acoustic beamforming experiment. Following this validation study, the CAB methodology was applied to the identification of noise sources generated by a commercial small wind turbine. The simulated acoustic maps revealed that the blade tower interaction and the wind turbine nacelle were the two primary mechanisms for sound generation for this small wind turbine at frequencies between 100 and 630 Hz.

Contribution of large scale coherence to wind turbine power: A large eddy simulation study in periodic wind farms

NASA Astrophysics Data System (ADS)

Chatterjee, Tanmoy; Peet, Yulia T.

2018-03-01

Length scales of eddies involved in the power generation of infinite wind farms are studied by analyzing the spectra of the turbulent flux of mean kinetic energy (MKE) from large eddy simulations (LES). Large-scale structures with an order of magnitude bigger than the turbine rotor diameter (D ) are shown to have substantial contribution to wind power. Varying dynamics in the intermediate scales (D -10 D ) are also observed from a parametric study involving interturbine distances and hub height of the turbines. Further insight about the eddies responsible for the power generation have been provided from the scaling analysis of two-dimensional premultiplied spectra of MKE flux. The LES code is developed in a high Reynolds number near-wall modeling framework, using an open-source spectral element code Nek5000, and the wind turbines have been modelled using a state-of-the-art actuator line model. The LES of infinite wind farms have been validated against the statistical results from the previous literature. The study is expected to improve our understanding of the complex multiscale dynamics in the domain of large wind farms and identify the length scales that contribute to the power. This information can be useful for design of wind farm layout and turbine placement that take advantage of the large-scale structures contributing to wind turbine power.

A fish-eye view of riverine hydropower systems. Understanding the biological response to turbine passage

DOE PAGES

Pracheil, Brenda M.; DeRolph, Christopher R.; Schramm, Michael P.; ...

2016-01-01

One-way connectivity maintained by fish passing through hydropower turbines in fragmented rivers can be important to population dynamics, but can introduce a new and significant source of mortality due to turbine-associated mortality. Sources of mortality during downstream turbine passage can come from several sources including blade strike, shear forces, cavitation, or pressure decreases, and parsing the contributions of these individual forces is important for advancing and deploying turbines that minimize these impacts to fishes. We used a national hydropower database and conducted a systematic review of the literature to accomplish three goals: (1) report on the spatial distribution of turbinemore » types and generation capacities in the USA, (2) determine fish mortality rates among turbine types and fish species and (3) examine relationships between physical forces similar to those encountered during fish turbine passage and fish injury and mortality. We found that while Francis turbines generate 56% of all US hydropower and have the highest associated fish mortality of any turbine type, these turbines are proportionally understudied compared to less-common and less injury-associated Kaplan turbines, particularly in the Pacific Northwest. While juvenile salmonid species in actual or simulated Kaplan turbine conditions were the most commonly studied, the highest mortality rates were reported in percid fishes passing through Francis turbines. Also, although there are several mechanisms of turbine-associated injury, barotrauma was the most commonly studied with swim bladder rupture, exopthalmia, eye gas bubbles, and prolapsed cloaca being the most serious symptoms associated with rapid pressure decreases. Future studies should focus on understanding which species are most at-risk to turbine passage mortality and, subsequently, increasing the diversity of taxonomy and turbine types in evaluations of turbine mortality.« less

A fish-eye view of riverine hydropower systems. Understanding the biological response to turbine passage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pracheil, Brenda M.; DeRolph, Christopher R.; Schramm, Michael P.

One-way connectivity maintained by fish passing through hydropower turbines in fragmented rivers can be important to population dynamics, but can introduce a new and significant source of mortality due to turbine-associated mortality. Sources of mortality during downstream turbine passage can come from several sources including blade strike, shear forces, cavitation, or pressure decreases, and parsing the contributions of these individual forces is important for advancing and deploying turbines that minimize these impacts to fishes. We used a national hydropower database and conducted a systematic review of the literature to accomplish three goals: (1) report on the spatial distribution of turbinemore » types and generation capacities in the USA, (2) determine fish mortality rates among turbine types and fish species and (3) examine relationships between physical forces similar to those encountered during fish turbine passage and fish injury and mortality. We found that while Francis turbines generate 56% of all US hydropower and have the highest associated fish mortality of any turbine type, these turbines are proportionally understudied compared to less-common and less injury-associated Kaplan turbines, particularly in the Pacific Northwest. While juvenile salmonid species in actual or simulated Kaplan turbine conditions were the most commonly studied, the highest mortality rates were reported in percid fishes passing through Francis turbines. Also, although there are several mechanisms of turbine-associated injury, barotrauma was the most commonly studied with swim bladder rupture, exopthalmia, eye gas bubbles, and prolapsed cloaca being the most serious symptoms associated with rapid pressure decreases. Future studies should focus on understanding which species are most at-risk to turbine passage mortality and, subsequently, increasing the diversity of taxonomy and turbine types in evaluations of turbine mortality.« less

Dynamic stresses in a Francis model turbine at deep part load

NASA Astrophysics Data System (ADS)

Weber, Wilhelm; von Locquenghien, Florian; Conrad, Philipp; Koutnik, Jiri

2017-04-01

A comparison between numerically obtained dynamic stresses in a Francis model turbine at deep part load with experimental ones is presented. Due to the change in the electrical power mix to more content of new renewable energy sources, Francis turbines are forced to operate at deep part load in order to compensate stochastic nature of wind and solar power and to ensure grid stability. For the extension of the operating range towards deep part load improved understanding of the harsh flow conditions and their impact on material fatigue of hydraulic components is required in order to ensure long life time of the power unit. In this paper pressure loads on a model turbine runner from unsteady two-phase computational fluid dynamics simulation at deep part load are used for calculation of mechanical stresses by finite element analysis. Therewith, stress distribution over time is determined. Since only few runner rotations are simulated due to enormous numerical cost, more effort has to be spent to evaluation procedure in order to obtain objective results. By comparing the numerical results with measured strains accuracy of the whole simulation procedure is verified.

Computational Acoustic Beamforming for Noise Source Identification for Small Wind Turbines

PubMed Central

Lien, Fue-Sang

2017-01-01

This paper develops a computational acoustic beamforming (CAB) methodology for identification of sources of small wind turbine noise. This methodology is validated using the case of the NACA 0012 airfoil trailing edge noise. For this validation case, the predicted acoustic maps were in excellent conformance with the results of the measurements obtained from the acoustic beamforming experiment. Following this validation study, the CAB methodology was applied to the identification of noise sources generated by a commercial small wind turbine. The simulated acoustic maps revealed that the blade tower interaction and the wind turbine nacelle were the two primary mechanisms for sound generation for this small wind turbine at frequencies between 100 and 630 Hz. PMID:28378012

A weak-scattering model for turbine-tone haystacking

NASA Astrophysics Data System (ADS)

McAlpine, A.; Powles, C. J.; Tester, B. J.

2013-08-01

Noise and emissions are critical technical issues in the development of aircraft engines. This necessitates the development of accurate models to predict the noise radiated from aero-engines. Turbine tones radiated from the exhaust nozzle of a turbofan engine propagate through turbulent jet shear layers which causes scattering of sound. In the far-field, measurements of the tones may exhibit spectral broadening, where owing to scattering, the tones are no longer narrow band peaks in the spectrum. This effect is known colloquially as 'haystacking'. In this article a comprehensive analytical model to predict spectral broadening for a tone radiated through a circular jet, for an observer in the far field, is presented. This model extends previous work by the authors which considered the prediction of spectral broadening at far-field observer locations outside the cone of silence. The modelling uses high-frequency asymptotic methods and a weak-scattering assumption. A realistic shear layer velocity profile and turbulence characteristics are included in the model. The mathematical formulation which details the spectral broadening, or haystacking, of a single-frequency, single azimuthal order turbine tone is outlined. In order to validate the model, predictions are compared with experimental results, albeit only at polar angle equal to 90°. A range of source frequencies from 4 to 20kHz, and jet velocities from 20 to 60ms-1, are examined for validation purposes. The model correctly predicts how the spectral broadening is affected when the source frequency and jet velocity are varied.

Mechanical power efficiency of modified turbine blades

NASA Astrophysics Data System (ADS)

Mahmud, Syahir; Sampebatu, Limbran; Kwang, Suendy Ciayadi

2017-01-01

Abstract-The problem of energy crisis has become one of the unsolved issues until today. Indonesia has a lot of non-conventional energy sources that does not utilized effectively yet. For that the available resources must utilized efficiently due to the energy crisis and the growing energy needs. Among the abundant resources of energy, one potential source of energy is hydroelectric energy. This research compares the mechanical power efficiency generated by the Darrieus turbine, Savonius turbine and the Darrieus-Savonius turbine. The comparation of the mechanical power amongst the three turbine starts from the measurement of the water flow rate, water temperature, turbine rotation and force on the shaft on each type of turbine. The comparison will show the mechanical power efficiency of each turbine to find the most efficient turbine that can work optimally. The results show that with 0.637m/s flow velocity and 44.827 Watt of water flow power, the Darrieus-Savonius turbine can generate power equal to 29.927 Watt and shaft force around by 17 N. The Darrieus-Savonius turbine provides around 66.76% efficiency betwen the three turbines; Darrieus turbine, Savonius turbine and the Darrieus-Savonius turbine. Overall, the Darrieus Savonius turbine has the ability to work optimally at the research location.

1:50 Scale Testing of Three Floating Wind Turbines at MARIN and Numerical Model Validation Against Test Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dagher, Habib; Viselli, Anthony; Goupee, Andrew

The primary goal of the basin model test program discussed herein is to properly scale and accurately capture physical data of the rigid body motions, accelerations and loads for different floating wind turbine platform technologies. The intended use for this data is for performing comparisons with predictions from various aero-hydro-servo-elastic floating wind turbine simulators for calibration and validation. Of particular interest is validating the floating offshore wind turbine simulation capabilities of NREL’s FAST open-source simulation tool. Once the validation process is complete, coupled simulators such as FAST can be used with a much greater degree of confidence in design processesmore » for commercial development of floating offshore wind turbines. The test program subsequently described in this report was performed at MARIN (Maritime Research Institute Netherlands) in Wageningen, the Netherlands. The models considered consisted of the horizontal axis, NREL 5 MW Reference Wind Turbine (Jonkman et al., 2009) with a flexible tower affixed atop three distinct platforms: a tension leg platform (TLP), a spar-buoy modeled after the OC3 Hywind (Jonkman, 2010) and a semi-submersible. The three generic platform designs were intended to cover the spectrum of currently investigated concepts, each based on proven floating offshore structure technology. The models were tested under Froude scale wind and wave loads. The high-quality wind environments, unique to these tests, were realized in the offshore basin via a novel wind machine which exhibits negligible swirl and low turbulence intensity in the flow field. Recorded data from the floating wind turbine models included rotor torque and position, tower top and base forces and moments, mooring line tensions, six-axis platform motions and accelerations at key locations on the nacelle, tower, and platform. A large number of tests were performed ranging from simple free-decay tests to complex operating conditions with irregular sea states and dynamic winds.« less

Small Scale Air Driven Generator

DTIC Science & Technology

2016-12-01

the wire is wound around the stator, the more windings the higher the voltage as seen in equation two from [10], de N dt Φ = , (2) where N is...was a Maxwell BMOD0500 P016 B02 16 volt 500 farad capacitor shown in Figure 8. Typical uses for this particular model are in wind turbines ... turbine , in this case a turbocharger, provided a constant source of shaft power which was used to spin a small permanent magnet motor. With the

Micro turbine engines for drones propulsion

NASA Astrophysics Data System (ADS)

Dutczak, J.

2016-09-01

Development of micro turbine engines began from attempts of application of that propulsion source by group of enthusiasts of aviation model making. Nowadays, the domain of micro turbojet engines is treated on a par with “full size” aviation constructions. The dynamic development of these engines is caused not only by aviation modellers, but also by use of micro turbojet engines by army to propulsion of contemporary drones, i.e. Unmanned Aerial Vehicles (UAV) or Unmanned Aerial Systems (UAS). On the base of selected examples the state of art in the mentioned group of engines has been presented in the article.

Gas turbine engine active clearance control

NASA Technical Reports Server (NTRS)

Deveau, Paul J. (Inventor); Greenberg, Paul B. (Inventor); Paolillo, Roger E. (Inventor)

1985-01-01

Method for controlling the clearance between rotating and stationary components of a gas turbine engine are disclosed. Techniques for achieving close correspondence between the radial position of rotor blade tips and the circumscribing outer air seals are disclosed. In one embodiment turbine case temperature modifying air is provided in flow rate, pressure and temperature varied as a function of engine operating condition. The modifying air is scheduled from a modulating and mixing valve supplied with dual source compressor air. One source supplies relatively low pressure, low temperature air and the other source supplies relatively high pressure, high temperature air. After the air has been used for the active clearance control (cooling the high pressure turbine case) it is then used for cooling the structure that supports the outer air seal and other high pressure turbine component parts.

An Analysis of the Use of Energy Audits, Solar Panels, and Wind Turbines to Reduce Energy Consumption from Non Renewable Energy Sources

DTIC Science & Technology

2015-04-15

the Use of Energy Audits, Solar Panels, and Wind Turbines to Reduce Energy Consumption from Non Renewable Energy Sources Energy is a National...Park, NC 27709-2211 Energy Audits, Energy Conservation, Renewable Energy, Solar Energy, Wind Turbine Use, Energy Consumption REPORT DOCUMENTATION PAGE 11...in non peer-reviewed journals: An Analysis of the Use of Energy Audits, Solar Panels, and Wind Turbines to Reduce Energy Consumption from Non

Experimental characterization of turbulent inflow noise on a full-scale wind turbine

NASA Astrophysics Data System (ADS)

Buck, Steven; Oerlemans, Stefan; Palo, Scott

2016-12-01

An extensive experimental campaign was conducted on a 108-m diameter 2.3-MW wind turbine in order to assess the effect of inflow turbulence conditions on wind turbine acoustics. Over 50 h of continuous acoustic data was acquired at power-generating wind speeds. Twelve precision microphones were used, arranged in a one rotor radius ring about the turbine tower in order to assess the directivity of the noise emission. Turbine operational and atmospheric conditions were gathered simultaneously with acoustics measurements. The testing and analysis constitute perhaps the most thorough experimental characterization of turbulent inflow noise from a wind turbine to date. Turbulence intensities typically varied between 10 percent and 35 percent, and wind speeds covered most of the operational range of the wind turbine, from cut-on to well above its rated power. A method was developed for using blade-mounted accelerometers for determining the turbulence conditions in the immediate vicinity of the blades, which are the primary turbulence noise generating bodies. The method uses the blades' vibrational energy within a specified frequency range to estimate the overall turbulence conditions by assuming a von Kármán turbulence spectrum. Using this method, a clear positive correlation is shown between turbulence intensity and noise levels. The turbulence noise is dominant at low frequencies and is primarily observed in the upwind and downwind directions. Low frequency noise increases by as much as 6 dB for the range of turbulence conditions measured. Comparisons are made between the measured turbine noise directivity and theory using a simple acoustic model of the turbine as three point-sources. Strong agreement is found between the theoretical leading edge noise directivity model and the measured low frequency noise directivity.

Numerical Modeling of Hydrokinetic Turbines and their Environmental Effects

NASA Astrophysics Data System (ADS)

Javaherchi, Teymour; Aliseda, Alberto

2010-11-01

Energy extraction from ocean tides via hydrokinetic turbines has recently attracted scientists and engineers attention as a highly predictable source of renewable energy. However, since the most promising locations in terms of resources and proximity to the end users are in fragile estuarine ecosystems, numerous issues concerning the environmental impact of this technology need to be addressed a priori before large scale deployment. In this work we use numerical simulations to study the possible environmental effects of hydrokinetic turbines through their influence on physical flow variables such as pressure and velocity. The velocity deficit created in the turbulent wake of a turbine affects the settling of suspended sediment in the water column and can lead to deposition into artificial patterns that will alter the benthic ecosystem. On the other side of the spectrum, pressure fluctuation through turbine blades and in blade tip vortices can damage internal organs of marine species as they swim through the device, particularly for small juveniles that behave like Lagrangian trackers. We present sedimentation statistics to understand the sensitivity of this phenomena to turbine operating conditions and sediment properties. We also show pressure history for slightly buoyant Lagrangian particles moving through the turbine and correlations with damage thresholds obtained from laboratory experiments.

Large-Scale Simulations and Detailed Flow Field Measurements for Turbomachinery Aeroacoustics

NASA Technical Reports Server (NTRS)

VanZante, Dale

2008-01-01

The presentation is a review of recent work in highly loaded compressors, turbine aeroacoustics and cooling fan noise. The specific topics are: the importance of correct numerical modeling to capture blade row interactions in the Ultra Efficient Engine Technology Proof-of-Concept Compressor, the attenuation of a detonation pressure wave by an aircraft axial turbine stage, current work on noise sources and acoustic attenuation in turbines, and technology development work on cooling fans for spaceflight applications. The topic areas were related to each other by certain themes such as the advantage of an experimentalist s viewpoint when analyzing numerical simulations and the need to improve analysis methods for very large numerical datasets.

A STRONGLY COUPLED REACTOR CORE ISOLATION COOLING SYSTEM MODEL FOR EXTENDED STATION BLACK-OUT ANALYSES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Haihua; Zhang, Hongbin; Zou, Ling

2015-03-01

The reactor core isolation cooling (RCIC) system in a boiling water reactor (BWR) provides makeup cooling water to the reactor pressure vessel (RPV) when the main steam lines are isolated and the normal supply of water to the reactor vessel is lost. The RCIC system operates independently of AC power, service air, or external cooling water systems. The only required external energy source is from the battery to maintain the logic circuits to control the opening and/or closure of valves in the RCIC systems in order to control the RPV water level by shutting down the RCIC pump to avoidmore » overfilling the RPV and flooding the steam line to the RCIC turbine. It is generally considered in almost all the existing station black-out accidents (SBO) analyses that loss of the DC power would result in overfilling the steam line and allowing liquid water to flow into the RCIC turbine, where it is assumed that the turbine would then be disabled. This behavior, however, was not observed in the Fukushima Daiichi accidents, where the Unit 2 RCIC functioned without DC power for nearly three days. Therefore, more detailed mechanistic models for RCIC system components are needed to understand the extended SBO for BWRs. As part of the effort to develop the next generation reactor system safety analysis code RELAP-7, we have developed a strongly coupled RCIC system model, which consists of a turbine model, a pump model, a check valve model, a wet well model, and their coupling models. Unlike the traditional SBO simulations where mass flow rates are typically given in the input file through time dependent functions, the real mass flow rates through the turbine and the pump loops in our model are dynamically calculated according to conservation laws and turbine/pump operation curves. A simplified SBO demonstration RELAP-7 model with this RCIC model has been successfully developed. The demonstration model includes the major components for the primary system of a BWR, as well as the safety system components such as the safety relief valve (SRV), the RCIC system, the wet well, and the dry well. The results show reasonable system behaviors while exhibiting rich dynamics such as variable flow rates through RCIC turbine and pump during the SBO transient. The model has the potential to resolve the Fukushima RCIC mystery after adding the off-design two-phase turbine operation model and other additional improvements.« less

Impacts of an offshore wind farm on the lower marine atmosphere

NASA Astrophysics Data System (ADS)

Volker, P. J.; Huang, H.; Capps, S. B.; Badger, J.; Hahmann, A. N.; Hall, A. D.

2013-12-01

Due to a continuing increase in energy demand and heightened environmental consciousness, the State of California is seeking out more environmentally-friendly energy resources. Strong and persistent winds along California's coast can be harnessed effectively by current wind turbine technology, providing a promising source of alternative energy. Using an advanced wind farm parameterization implemented in the Weather Research & Forecast model, we investigate the potential impacts of a large offshore wind farm on the lower marine atmosphere. Located offshore of the Sonoma Coast in northern California, this theoretical wind farm includes 200-7 megawatt, 125 m hub height wind turbines which are able to provide a total of 1.4 TW of power for use in neighboring cities. The wind turbine model (i.e., the Explicit Wake Parameterization originally developed at the Danish Technical University) acts as a source of drag where the sub-grid scale velocity deficit expansion is explicitly described. A swath consisting of hub-height velocity deficits and temperature and moisture anomalies extends more than 100 km downstream of the wind farm location. The presence of the large modern wind farm also creates flow distortion upstream in conjunction with an enhanced vertical momentum and scalar transport.

Effect of thermal stability/complex terrain on wind turbine model(s): a wind tunnel study to address complex atmospheric conditions

NASA Astrophysics Data System (ADS)

Guala, M.; Hu, S. J.; Chamorro, L. P.

2011-12-01

Turbulent boundary layer measurements in both wind tunnel and in the near-neutral atmospheric surface layer revealed in the last decade the significant contribution of the large scales of motions to both turbulent kinetic energy and Reynolds stresses, for a wide range of Reynolds number. These scales are known to grow throughout the logarithmic layer and to extend several boundary layer heights in the streamwise direction. Potentially, they are a source of strong unsteadiness in the power output of wind turbines and in the aerodynamic loads of wind turbine blades. However, the large scales in realistic atmospheric conditions deserves further study, with well controlled boundary conditions. In the atmospheric wind tunnel of the St. Anthony Falls Laboratory, with a 16 m long test section and independently controlled incoming flow and floor temperatures, turbulent boundary layers in a range of stability conditions, from the stratified to the convective case, can be reproduced and monitored. Measurements of fluctuating temperature, streamwise and wall normal velocity components are simultaneously obtained by an ad hoc calibrated and customized triple-wire sensor. A wind turbine model with constant loading DC motor, constant tip speed ratio, and a rotor diameter of 0.128m is used to mimic a large full scale turbine in the atmospheric boundary layer. Measurements of the fluctuating voltage generated by the DC motor are compared with measurements of the blade's angular velocity by laser scanning, and eventually related to velocity measurements from the triple-wire sensor. This study preliminary explores the effect of weak stability and complex terrain (through a set of spanwise aligned topographic perturbations) on the large scales of the flow and on the fluctuations in the wind turbine(s) power output.

Detection of gear cracks in a complex gearbox of wind turbines using supervised bounded component analysis of vibration signals collected from multi-channel sensors

NASA Astrophysics Data System (ADS)

Li, Zhixiong; Yan, Xinping; Wang, Xuping; Peng, Zhongxiao

2016-06-01

In the complex gear transmission systems, in wind turbines a crack is one of the most common failure modes and can be fatal to the wind turbine power systems. A single sensor may suffer with issues relating to its installation position and direction, resulting in the collection of weak dynamic responses of the cracked gear. A multi-channel sensor system is hence applied in the signal acquisition and the blind source separation (BSS) technologies are employed to optimally process the information collected from multiple sensors. However, literature review finds that most of the BSS based fault detectors did not address the dependence/correlation between different moving components in the gear systems; particularly, the popular used independent component analysis (ICA) assumes mutual independence of different vibration sources. The fault detection performance may be significantly influenced by the dependence/correlation between vibration sources. In order to address this issue, this paper presents a new method based on the supervised order tracking bounded component analysis (SOTBCA) for gear crack detection in wind turbines. The bounded component analysis (BCA) is a state of art technology for dependent source separation and is applied limitedly to communication signals. To make it applicable for vibration analysis, in this work, the order tracking has been appropriately incorporated into the BCA framework to eliminate the noise and disturbance signal components. Then an autoregressive (AR) model built with prior knowledge about the crack fault is employed to supervise the reconstruction of the crack vibration source signature. The SOTBCA only outputs one source signal that has the closest distance with the AR model. Owing to the dependence tolerance ability of the BCA framework, interfering vibration sources that are dependent/correlated with the crack vibration source could be recognized by the SOTBCA, and hence, only useful fault information could be preserved in the reconstructed signal. The crack failure thus could be precisely identified by the cyclic spectral correlation analysis. A series of numerical simulations and experimental tests have been conducted to illustrate the advantages of the proposed SOTBCA method for fatigue crack detection. Comparisons to three representative techniques, i.e. Erdogan's BCA (E-BCA), joint approximate diagonalization of eigen-matrices (JADE), and FastICA, have demonstrated the effectiveness of the SOTBCA. Hence the proposed approach is suitable for accurate gear crack detection in practical applications.

Feasibility study on a strain based deflection monitoring system for wind turbine blades

NASA Astrophysics Data System (ADS)

Lee, Kyunghyun; Aihara, Aya; Puntsagdash, Ganbayar; Kawaguchi, Takayuki; Sakamoto, Hiraku; Okuma, Masaaki

2017-01-01

The bending stiffness of the wind turbine blades has decreased due to the trend of wind turbine upsizing. Consequently, the risk of blades breakage by hitting the tower has increased. In order to prevent such incidents, this study proposes a deflection monitoring system that can be installed to already operating wind turbine's blades. The monitoring system is composed of an estimation algorithm to detect blade deflection and a wireless sensor network as a hardware equipment. As for the estimation method for blade deflection, a strain-based estimation algorithm and an objective function for optimal sensor arrangement are proposed. Strain-based estimation algorithm is using a linear correlation between strain and deflections, which can be expressed in a form of a transformation matrix. The objective function includes the terms of strain sensitivity and condition number of the transformation matrix between strain and deflection. In order to calculate the objective function, a simplified experimental model of the blade is constructed by interpolating the mode shape of a blade from modal testing. The interpolation method is effective considering a practical use to operating wind turbines' blades since it is not necessary to establish a finite element model of a blade. On the other hand, a sensor network with wireless connection with an open source hardware is developed. It is installed to a 300 W scale wind turbine and vibration of the blade on operation is investigated.

Modernization of vertical Pelton turbines with the help of CFD and model testing

NASA Astrophysics Data System (ADS)

Mack, Reiner; Gola, Bartlomiej; Smertnig, Martin; Wittwer, Bernhard; Meusburger, Peter

2014-03-01

The modernization of water turbines bears a high potential of increasing the already installed hydropower capacity. In many projects the existing waterways allow a substantial increase of the available flow capacity and with it the energy output. But also the upgrading onto a state of the art hydraulic, mechanical and electrical design will increase the available power considerably after the rehabilitation. The two phase nature of the flow in Pelton turbines requires for the hydraulic refurbishment special care in the application of the available design methods. Where the flow in the high pressure section of the turbine is mainly of one phase nature, CFD has been used as a standard tool for many years. Also the jet quality, and with it the exploration of the source of flow disturbances that cause poor free surface quality can be investigated with CFD. The interaction of the jet with the buckets of the runner is also examined by means of CFD. However, its accuracy with respect to hydraulic efficiency is, because of the two phase flow and the transient flow process, in very few cases good enough for a reliable and accurate prediction of absolute numbers. The optimization of hydraulic bucket profiles is therefore always checked with measurements in homologous scaled model turbines. A similar situation exists for the housing flow after the water is discharged from the runner. Here also CFD techniques are available to explore the general mechanisms. However, due to the two phase flow nature, where only a very small space is filled with moving water, the experimental setup in a model turbine is always the final proof for optimizations of housing inserts and modifications. The hydraulic design of a modernization project for a power station equipped with vertical Pelton turbines of two different designs is described in the proposed paper. It will be shown, how CFD is applied to determine the losses in the high pressure section and how these results are combined with the model tests carried out in the hydraulic laboratory. Finally a comparison is made in between the achieved model turbine results with measurements carried out in the prototype.

46 CFR 111.10-5 - Multiple energy sources.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Multiple energy sources. 111.10-5 Section 111.10-5...-GENERAL REQUIREMENTS Power Supply § 111.10-5 Multiple energy sources. Failure of any single generating set energy source such as a boiler, diesel, gas turbine, or steam turbine must not cause all generating sets...

46 CFR 111.10-5 - Multiple energy sources.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Multiple energy sources. 111.10-5 Section 111.10-5...-GENERAL REQUIREMENTS Power Supply § 111.10-5 Multiple energy sources. Failure of any single generating set energy source such as a boiler, diesel, gas turbine, or steam turbine must not cause all generating sets...

46 CFR 111.10-5 - Multiple energy sources.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Multiple energy sources. 111.10-5 Section 111.10-5...-GENERAL REQUIREMENTS Power Supply § 111.10-5 Multiple energy sources. Failure of any single generating set energy source such as a boiler, diesel, gas turbine, or steam turbine must not cause all generating sets...

46 CFR 111.10-5 - Multiple energy sources.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Multiple energy sources. 111.10-5 Section 111.10-5...-GENERAL REQUIREMENTS Power Supply § 111.10-5 Multiple energy sources. Failure of any single generating set energy source such as a boiler, diesel, gas turbine, or steam turbine must not cause all generating sets...

46 CFR 111.10-5 - Multiple energy sources.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Multiple energy sources. 111.10-5 Section 111.10-5...-GENERAL REQUIREMENTS Power Supply § 111.10-5 Multiple energy sources. Failure of any single generating set energy source such as a boiler, diesel, gas turbine, or steam turbine must not cause all generating sets...

Damage severity assessment in wind turbine blade laboratory model through fuzzy finite element model updating

NASA Astrophysics Data System (ADS)

Turnbull, Heather; Omenzetter, Piotr

2017-04-01

The recent shift towards development of clean, sustainable energy sources has provided a new challenge in terms of structural safety and reliability: with aging, manufacturing defects, harsh environmental and operational conditions, and extreme events such as lightning strikes wind turbines can become damaged resulting in production losses and environmental degradation. To monitor the current structural state of the turbine, structural health monitoring (SHM) techniques would be beneficial. Physics based SHM in the form of calibration of a finite element model (FEMs) by inverse techniques is adopted in this research. Fuzzy finite element model updating (FFEMU) techniques for damage severity assessment of a small-scale wind turbine blade are discussed and implemented. The main advantage is the ability of FFEMU to account in a simple way for uncertainty within the problem of model updating. Uncertainty quantification techniques, such as fuzzy sets, enable a convenient mathematical representation of the various uncertainties. Experimental frequencies obtained from modal analysis on a small-scale wind turbine blade were described by fuzzy numbers to model measurement uncertainty. During this investigation, damage severity estimation was investigated through addition of small masses of varying magnitude to the trailing edge of the structure. This structural modification, intended to be in lieu of damage, enabled non-destructive experimental simulation of structural change. A numerical model was constructed with multiple variable additional masses simulated upon the blades trailing edge and used as updating parameters. Objective functions for updating were constructed and minimized using both particle swarm optimization algorithm and firefly algorithm. FFEMU was able to obtain a prediction of baseline material properties of the blade whilst also successfully predicting, with sufficient accuracy, a larger magnitude of structural alteration and its location.

A coupled aero-structural model of a HAWT blade for dynamic load and response prediction in time-domain for health monitoring applications

NASA Astrophysics Data System (ADS)

Sauder, Heather Scot

To reach the high standards set for renewable energy production in the US and around the globe, wind turbines with taller towers and longer blades are being designed for onshore and offshore wind developments to capture more energy from higher winds aloft and a larger rotor diameter. However, amongst all the wind turbine components wind turbine blades are still the most prone to damage. Given that wind turbine blades experience dynamic loads from multiple sources, there is a need to be able to predict the real-time load, stress distribution and response of the blade in a given wind environment for damage, flutter and fatigue life predictions. Current methods of wind-induced response analysis for wind turbine blades use approximations that are not suitable for wind turbine blade airfoils which are thick, and therefore lead to inaccurate life predictions. Additionally, a time-domain formulation can prove to be especially advantageous for predicting aerodynamic loads on wind turbine blades since they operate in a turbulent atmospheric boundary layer. This will help to analyze the blades on wind turbines that operate individually or in a farm setting where they experience high turbulence in the wake of another wind turbine. A time-domain formulation is also useful for examining the effects of gusty winds that are transient in nature like in gust fronts, thunderstorms or extreme events such as hurricanes, microbursts, and tornadoes. Time-domain methods present the opportunity for real-time health monitoring strategies that can easily be used with finite element methods for prediction of fatigue life or onset of flutter instability. The purpose of the proposed work is to develop a robust computational model to predict the loads, stresses and response of a wind turbine blade in operating and extreme wind conditions. The model can be used to inform health monitoring strategies for preventative maintenance and provide a realistic number of stress cycles that the blade will experience for fatigue life prediction procedures. To fill in the gaps in the existing knowledge and meet the overall goal of the proposed research, the following objectives were accomplished: (a) improve the existing aeroelastic (motion- and turbulence-induced) load models to predict the response of wind turbine blade airfoils to understand its behavior in turbulent wind, (b) understand, model and predict the response of wind turbine blades in transient or gusty wind, boundary-layer wind and incoherent wind over the span of the blade, (c) understand the effects of aero-structural coupling between the along-wind, cross-wind and torsional vibrations, and finally (d) develop a computational tool using the improved time-domain load model to predict the real-time load, stress distribution and response of a given wind turbine blade during operating and parked conditions subject to a specific wind environment both in a short and long term for damage, flutter and fatigue life predictions.

40 CFR 60.4390 - What are my reporting requirements if I operate an emergency combustion turbine or a research and...

Code of Federal Regulations, 2011 CFR

2011-07-01

... operate an emergency combustion turbine or a research and development turbine? 60.4390 Section 60.4390... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Stationary Combustion Turbines Reporting § 60.4390 What are my reporting requirements if I operate an emergency combustion turbine or a research...

40 CFR 60.4390 - What are my reporting requirements if I operate an emergency combustion turbine or a research and...

Code of Federal Regulations, 2010 CFR

2010-07-01

... operate an emergency combustion turbine or a research and development turbine? 60.4390 Section 60.4390... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Stationary Combustion Turbines Reporting § 60.4390 What are my reporting requirements if I operate an emergency combustion turbine or a research...

40 CFR 60.4390 - What are my reporting requirements if I operate an emergency combustion turbine or a research and...

Code of Federal Regulations, 2012 CFR

2012-07-01

... operate an emergency combustion turbine or a research and development turbine? 60.4390 Section 60.4390... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Stationary Combustion Turbines Reporting § 60.4390 What are my reporting requirements if I operate an emergency combustion turbine or a research...

40 CFR 60.4390 - What are my reporting requirements if I operate an emergency combustion turbine or a research and...

Code of Federal Regulations, 2014 CFR

2014-07-01

... operate an emergency combustion turbine or a research and development turbine? 60.4390 Section 60.4390... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Stationary Combustion Turbines Reporting § 60.4390 What are my reporting requirements if I operate an emergency combustion turbine or a research...

40 CFR 60.4390 - What are my reporting requirements if I operate an emergency combustion turbine or a research and...

Code of Federal Regulations, 2013 CFR

2013-07-01

... operate an emergency combustion turbine or a research and development turbine? 60.4390 Section 60.4390... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Stationary Combustion Turbines Reporting § 60.4390 What are my reporting requirements if I operate an emergency combustion turbine or a research...

Wind Turbine Gust Prediction Using Remote Sensing Data

NASA Astrophysics Data System (ADS)

Towers, Paul; Jones, Bryn

2013-11-01

Offshore wind energy is a growing energy source as governments around the world look for environmentally friendly solutions to potential future energy shortages. In order to capture more energy from the wind, larger turbines are being designed, leading to the structures becoming increasingly vulnerable to damage caused by violent gusts of wind. Advance knowledge of such gusts will enable turbine control systems to take preventative action, reducing turbine maintenance costs. We present a system which can accurately forecast the velocity profile of an oncoming wind, given only limited spatial measurements from light detection and ranging (LiDAR) units, which are currently operational in industry. Our method combines nonlinear state estimation techniques with low-order models of atmospheric boundary-layer flows to generate flow-field estimates. We discuss the accuracy of our velocity profile predictions by direct comparison to data derived from large eddy simulations of the atmospheric boundary layer.

Impacts of a large array of offshore wind farms on precipitation during hurricane Harvey

NASA Astrophysics Data System (ADS)

Pan, Y.; Archer, C. L.

2017-12-01

Hurricane Harvey brought to the Texas coast possibly the heaviest rain ever recorded in U.S. history, which then caused flooding at unprecedented levels. Previous studies have shown that large arrays of offshore wind farms can extract kinetic energy from a hurricane and thus reduce the wind and storm surge. This study will quantitatively test weather the offshore turbines may also affect precipitation patterns. The Weather Research Forecast model is employed to model Harvey and the offshore wind farms are parameterized as elevated drag and turbulence kinetic energy sources. The turbines (7.8 MW Enercon-126 with rotor diameter D=127 m) are placed along the coast of Texas and Louisiana within 100 km from the shore, where the water depth is below 200 meters. Three spacing between turbines are considered (with the number of turbines in parenthesis): 7D×7D (149,936), 9D×9D (84,339), and 11D×11D (56,226). A fourth case (9D×9D) with a smaller area and thus less turbines (33,363) is added to the simulations to emphasize the impacts of offshore turbines installed specifically to protect the city of Houston, which was flooded heavily during hurricane Harvey. The model is integrated for 24 hours from 00UTC Aug 26th, 2017 to 00UTC Aug 27th, 2017. Model results indicate that the offshore wind farms have a strong impact on the distribution of 24-hour accumulated precipitation, with an obvious decrease onshore, downstream of the wind farms, and an increase in the offshore areas, upstream of or within the wind farms. A sector covering the metro-Houston area is chosen to study the sensitivity of the four different wind farm layouts. The spatial-average 24-hour accumulated precipitation is decreased by 37%, 28%, 20% and 25% respectively for the four cases. Compared with the control case with no wind turbines, increased horizontal wind divergence and lower vertical velocity are found where the precipitation is reduced onshore, whereas increased horizontal wind convergence and higher vertical velocity occur upstream or within the offshore wind farms. These preliminary results suggest that large arrays of offshore wind turbines can effectively protect the coast from heavy rain during hurricanes and that smart layouts with fewer turbines over smaller areas can be almost as effective as those with more turbines over larger areas.

Validation of an Actuator Line Model Coupled to a Dynamic Stall Model for Pitching Motions Characteristic to Vertical Axis Turbines

NASA Astrophysics Data System (ADS)

Mendoza, Victor; Bachant, Peter; Wosnik, Martin; Goude, Anders

2016-09-01

Vertical axis wind turbines (VAWT) can be used to extract renewable energy from wind flows. A simpler design, low cost of maintenance, and the ability to accept flow from all directions perpendicular to the rotor axis are some of the most important advantages over conventional horizontal axis wind turbines (HAWT). However, VAWT encounter complex and unsteady fluid dynamics, which present significant modeling challenges. One of the most relevant phenomena is dynamic stall, which is caused by the unsteady variation of angle of attack throughout the blade rotation, and is the focus of the present study. Dynamic stall is usually used as a passive control for VAWT operating conditions, hence the importance of predicting its effects. In this study, a coupled model is implemented with the open-source CFD toolbox OpenFOAM for solving the Navier-Stokes equations, where an actuator line model and dynamic stall model are used to compute the blade loading and body force. Force coefficients obtained from the model are validated with experimental data of pitching airfoil in similar operating conditions as an H-rotor type VAWT. Numerical results show reasonable agreement with experimental data for pitching motion.

Powering embedded electronics for wind turbine monitoring using multi-source energy harvesting techniques

NASA Astrophysics Data System (ADS)

Anton, S. R.; Taylor, S. G.; Raby, E. Y.; Farinholt, K. M.

2013-03-01

With a global interest in the development of clean, renewable energy, wind energy has seen steady growth over the past several years. Advances in wind turbine technology bring larger, more complex turbines and wind farms. An important issue in the development of these complex systems is the ability to monitor the state of each turbine in an effort to improve the efficiency and power generation. Wireless sensor nodes can be used to interrogate the current state and health of wind turbine structures; however, a drawback of most current wireless sensor technology is their reliance on batteries for power. Energy harvesting solutions present the ability to create autonomous power sources for small, low-power electronics through the scavenging of ambient energy; however, most conventional energy harvesting systems employ a single mode of energy conversion, and thus are highly susceptible to variations in the ambient energy. In this work, a multi-source energy harvesting system is developed to power embedded electronics for wind turbine applications in which energy can be scavenged simultaneously from several ambient energy sources. Field testing is performed on a full-size, residential scale wind turbine where both vibration and solar energy harvesting systems are utilized to power wireless sensing systems. Two wireless sensors are investigated, including the wireless impedance device (WID) sensor node, developed at Los Alamos National Laboratory (LANL), and an ultra-low power RF system-on-chip board that is the basis for an embedded wireless accelerometer node currently under development at LANL. Results indicate the ability of the multi-source harvester to successfully power both sensors.

40 CFR 63.6085 - Am I subject to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) National Emission Standards for Hazardous Air Pollutants for Stationary Combustion Turbines What This... operate a stationary combustion turbine located at a major source of HAP emissions. (a) Stationary combustion turbine means all equipment, including but not limited to the turbine, the fuel, air, lubrication...

40 CFR 63.6085 - Am I subject to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

...) National Emission Standards for Hazardous Air Pollutants for Stationary Combustion Turbines What This... operate a stationary combustion turbine located at a major source of HAP emissions. (a) Stationary combustion turbine means all equipment, including but not limited to the turbine, the fuel, air, lubrication...

40 CFR 63.6085 - Am I subject to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) National Emission Standards for Hazardous Air Pollutants for Stationary Combustion Turbines What This... operate a stationary combustion turbine located at a major source of HAP emissions. (a) Stationary combustion turbine means all equipment, including but not limited to the turbine, the fuel, air, lubrication...

40 CFR 63.6085 - Am I subject to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... Standards for Hazardous Air Pollutants for Stationary Combustion Turbines What This Subpart Covers § 63.6085... combustion turbine located at a major source of HAP emissions. (a) Stationary combustion turbine means all... comprising any simple cycle stationary combustion turbine, any regenerative/recuperative cycle stationary...

The influence of a wall function on turbine blade heat transfer prediction

NASA Technical Reports Server (NTRS)

Whitaker, Kevin W.

1989-01-01

The second phase of a continuing investigation to improve the prediction of turbine blade heat transfer coefficients was completed. The present study specifically investigated how a numeric wall function in the turbulence model of a two-dimensional boundary layer code, STAN5, affected heat transfer prediction capabilities. Several sources of inaccuracy in the wall function were identified and then corrected or improved. Heat transfer coefficient predictions were then obtained using each one of the modifications to determine its effect. Results indicated that the modifications made to the wall function can significantly affect the prediction of heat transfer coefficients on turbine blades. The improvement in accuracy due the modifications is still inconclusive and is still being investigated.

Measurement and prediction of broadband noise from large horizontal axis wind turbine generators

NASA Technical Reports Server (NTRS)

Grosveld, F. W.; Shepherd, K. P.; Hubbard, H. H.

1995-01-01

A method is presented for predicting the broadband noise spectra of large wind turbine generators. It includes contributions from such noise sources as the inflow turbulence to the rotor, the interactions between the turbulent boundary layers on the blade surfaces with their trailing edges and the wake due to a blunt trailing edge. The method is partly empirical and is based on acoustic measurements of large wind turbines and airfoil models. Spectra are predicted for several large machines including the proposed MOD-5B. Measured data are presented for the MOD-2, the WTS-4, the MOD-OA, and the U.S. Windpower Inc. machines. Good agreement is shown between the predicted and measured far field noise spectra.

A comparison between exposure-response relationships for wind turbine annoyance and annoyance due to other noise sources.

PubMed

Janssen, Sabine A; Vos, Henk; Eisses, Arno R; Pedersen, Eja

2011-12-01

Surveys have shown that noise from wind turbines is perceived as annoying by a proportion of residents living in their vicinity, apparently at much lower noise levels than those inducing annoyance due to other environmental sources. The aim of the present study was to derive the exposure-response relationship between wind turbine noise exposure in L(den) and the expected percentage annoyed residents and to compare it to previously established relationships for industrial noise and transportation noise. In addition, the influence of several individual and situational factors was assessed. On the basis of available data from two surveys in Sweden (N=341, N=754) and one survey in the Netherlands (N=725), a relationship was derived for annoyance indoors and for annoyance outdoors at the dwelling. In comparison to other sources of environmental noise, annoyance due to wind turbine noise was found at relatively low noise exposure levels. Furthermore, annoyance was lower among residents who received economical benefit from wind turbines and higher among residents for whom the wind turbine was visible from the dwelling. Age and noise sensitivity had similar effects on annoyance to those found in research on annoyance by other sources. © 2011 Acoustical Society of America

Large-scale wind turbine structures

NASA Technical Reports Server (NTRS)

Spera, David A.

1988-01-01

The purpose of this presentation is to show how structural technology was applied in the design of modern wind turbines, which were recently brought to an advanced stage of development as sources of renewable power. Wind turbine structures present many difficult problems because they are relatively slender and flexible; subject to vibration and aeroelastic instabilities; acted upon by loads which are often nondeterministic; operated continuously with little maintenance in all weather; and dominated by life-cycle cost considerations. Progress in horizontal-axis wind turbines (HAWT) development was paced by progress in the understanding of structural loads, modeling of structural dynamic response, and designing of innovative structural response. During the past 15 years a series of large HAWTs was developed. This has culminated in the recent completion of the world's largest operating wind turbine, the 3.2 MW Mod-5B power plane installed on the island of Oahu, Hawaii. Some of the applications of structures technology to wind turbine will be illustrated by referring to the Mod-5B design. First, a video overview will be presented to provide familiarization with the Mod-5B project and the important components of the wind turbine system. Next, the structural requirements for large-scale wind turbines will be discussed, emphasizing the difficult fatigue-life requirements. Finally, the procedures used to design the structure will be presented, including the use of the fracture mechanics approach for determining allowable fatigue stresses.

Automated wind load characterization of wind turbine structures by embedded model updating

NASA Astrophysics Data System (ADS)

Swartz, R. Andrew; Zimmerman, Andrew T.; Lynch, Jerome P.

2010-04-01

The continued development of renewable energy resources is for the nation to limit its carbon footprint and to enjoy independence in energy production. Key to that effort are reliable generators of renewable energy sources that are economically competitive with legacy sources. In the area of wind energy, a major contributor to the cost of implementation is large uncertainty regarding the condition of wind turbines in the field due to lack of information about loading, dynamic response, and fatigue life of the structure expended. Under favorable circumstances, this uncertainty leads to overly conservative designs and maintenance schedules. Under unfavorable circumstances, it leads to inadequate maintenance schedules, damage to electrical systems, or even structural failure. Low-cost wireless sensors can provide more certainty for stakeholders by measuring the dynamic response of the structure to loading, estimating the fatigue state of the structure, and extracting loading information from the structural response without the need of an upwind instrumentation tower. This study presents a method for using wireless sensor networks to estimate the spectral properties of a wind turbine tower loading based on its measured response and some rudimentary knowledge of its structure. Structural parameters are estimated via model-updating in the frequency domain to produce an identification of the system. The updated structural model and the measured output spectra are then used to estimate the input spectra. Laboratory results are presented indicating accurate load characterization.

User's manual for PRESTO: A computer code for the performance of regenerative steam turbine cycles

NASA Technical Reports Server (NTRS)

Fuller, L. C.; Stovall, T. K.

1979-01-01

Standard turbine cycles for baseload power plants and cycles with such additional features as process steam extraction and induction and feedwater heating by external heat sources may be modeled. Peaking and high back pressure cycles are also included. The code's methodology is to use the expansion line efficiencies, exhaust loss, leakages, mechanical losses, and generator losses to calculate the heat rate and generator output. A general description of the code is given as well as the instructions for input data preparation. Appended are two complete example cases.

Investigation of a Novel Turbulence Model and Using Leading-Edge Slots for Improving the Aerodynamic Performance of Airfoils and Wind Turbines

NASA Astrophysics Data System (ADS)

Beyhaghi, Saman

Because of the problems associated with increase of greenhouse gases, as well as the limited supplies of fossil fuels, the transition to alternate, clean, renewable sources of energy is inevitable. Renewable sources of energy can be used to decrease our need for fossil fuels, thus reducing impact to humans, other species and their habitats. The wind is one of the cleanest forms of energy, and it can be an excellent candidate for producing electrical energy in a more sustainable manner. Vertical- and Horizontal-Axis Wind Turbines (VAWT and HAWT) are two common devices used for harvesting electrical energy from the wind. Due to the development of a thin boundary layer over the ground surface, the modern commercial wind turbines have to be relatively large to be cost-effective. Because of the high manufacturing and transportation costs of the wind turbine components, it is necessary to evaluate the design and predict the performance of the turbine prior to shipping it to the site, where it is to be installed. Computational Fluid Dynamics (CFD) has proven to be a simple, cheap and yet relatively accurate tool for prediction of wind turbine performance, where the suitability of different designs can be evaluated at a low cost. High accuracy simulation methods such as Large Eddy Simulation (LES) and Detached Eddy Simulation (DES) are developed and utilized in the past decades. Despite their superior importance in large fluid domains, they fail to make very accurate predictions near the solid surfaces. Therefore, in the present effort, the possibility of improving near-wall predictions of CFD simulations in the near-wall region by using a modified turbulence model is also thoroughly investigated. Algebraic Stress Model (ASM) is employed in conjunction with Detached Eddy Simulation (DES) to improve Reynolds stresses components, and consequently predictions of the near-wall velocities and surface pressure distributions. The proposed model shows a slightly better performance as compared to the baseline DES. In the second part of this study, the focus is on improving the aerodynamic performance of airfoils and wind turbines in terms of lift and drag coefficients and power generation. One special type of add-on feature for wind turbines and airfoils, i.e., leading-edge slots are investigated through numerical simulation and laboratory experiments. Although similar slots are designed and employed for aircrafts, a special slot with a reversed flow direction is drilled in the leading edge of a sample wind turbine airfoil to study its influence on the aerodynamic performance. The objective is to vary the five main geometrical parameters of slot and characterize the performance improvement of the new design under different operating conditions. A number of Design of Experiment and optimization studies are conducted to determine the most suitable slot configuration to maximize the lift or lift-over-drag ratio. Results indicate that proper sizing and placement of slot can improve the lift coefficient, while it has negligible negative impact on the drag. Some recommendations for future investigation on slot are proposed at the end. The performance of a horizontal axis wind turbine blade equipped with leading-edge slot is also studied, and it is concluded that slotted blades can generate about 10% more power than solid blades, for the two operating conditions investigated. The good agreement between the CFD predictions and experimental data confirms the validity of the model and results.

Numerical Simulation of Complex Turbomachinery Flows

NASA Technical Reports Server (NTRS)

Chernobrovkin, A. A.; Lakshiminarayana, B.

1999-01-01

An unsteady, multiblock, Reynolds Averaged Navier Stokes solver based on Runge-Kutta scheme and Pseudo-time step for turbo-machinery applications was developed. The code was validated and assessed against analytical and experimental data. It was used to study a variety of physical mechanisms of unsteady, three-dimensional, turbulent, transitional, and cooling flows in compressors and turbines. Flow over a cylinder has been used to study effects of numerical aspects on accuracy of prediction of wake decay and transition, and to modify K-epsilon models. The following simulations have been performed: (a) Unsteady flow in a compressor cascade: Three low Reynolds number turbulence models have been assessed and data compared with Euler/boundary layer predictions. Major flow features associated with wake induced transition were predicted and studied; (b) Nozzle wake-rotor interaction in a turbine: Results compared to LDV data in design and off-design conditions, and cause and effect of unsteady flow in turbine rotors were analyzed; (c) Flow in the low-pressure turbine: Assessed capability of the code to predict transitional, attached and separated flows at a wide range of low Reynolds numbers and inlet freestream turbulence intensity. Several turbulence and transition models have been employed and comparisons made to experiments; (d) leading edge film cooling at compound angle: Comparisons were made with experiments, and the flow physics of the associated vortical structures were studied; and (e) Tip leakage flow in a turbine. The physics of the secondary flow in a rotor was studied and sources of loss identified.

Experimental and numerical analysis of natural bio and syngas swirl flames in a model gas turbine combustor

NASA Astrophysics Data System (ADS)

Iqbal, S.; Benim, A. C.; Fischer, S.; Joos, F.; Kluβ, D.; Wiedermann, A.

2016-10-01

Turbulent reacting flows in a generic swirl gas turbine combustor model are investigated both numerically and experimentally. In the investigation, an emphasis is placed upon the external flue gas recirculation, which is a promising technology for increasing the efficiency of the carbon capture and storage process, which, however, can change the combustion behaviour significantly. A further emphasis is placed upon the investigation of alternative fuels such as biogas and syngas in comparison to the conventional natural gas. Flames are also investigated numerically using the open source CFD software OpenFOAM. In the numerical simulations, a laminar flamelet model based on mixture fraction and reaction progress variable is adopted. As turbulence model, the SST model is used within a URANS concept. Computational results are compared with the experimental data, where a fair agreement is observed.

Pressure Mapping and Efficiency Analysis of an EPPLER 857 Hydrokinetic Turbine

NASA Astrophysics Data System (ADS)

Clark, Tristan

A conceptual energy ship is presented to provide renewable energy. The ship, driven by the wind, drags a hydrokinetic turbine through the water. The power generated is used to run electrolysis on board, taking the resultant hydrogen back to shore to be used as an energy source. The basin efficiency (Power/thrust*velocity) of the Hydrokinetic Turbine (HTK) plays a vital role in this process. In order to extract the maximum allowable power from the flow, the blades need to be optimized. The structural analysis of the blade is important, as the blade will undergo high pressure loads from the water. A procedure for analysis of a preliminary Hydrokinetic Turbine blade design is developed. The blade was designed by a non-optimized Blade Element Momentum Theory (BEMT) code. Six simulations were run, with varying mesh resolution, turbulence models, and flow region size. The procedure was developed that provides detailed explanation for the entire process, from geometry and mesh generation to post-processing analysis tools. The efficiency results from the simulations are used to study the mesh resolution, flow region size, and turbulence models. The results are compared to the BEMT model design targets. Static pressure maps are created that can be used for structural analysis of the blades.

Experiments on the magnetic coupling in a small scale counter rotating marine current turbine

NASA Astrophysics Data System (ADS)

Kim, I. C.; Lee, N. J.; Wata, J.; Hyun, B. S.; Lee, Y. H.

2016-05-01

Modern economies are dependent on energy consumption to ensure growth or sustainable development. Renewable energy sources provide a source of energy that can provide energy security and is renewable. Tidal energy is more predictable than other sources or renewable energy like the sun or wind. Horizontal axis marine current turbines are currently the most advanced and commercially feasible option for tidal current convertors. A dual rotor turbine is theoretically able to produce more power than a single rotor turbine at the same fluid velocity. Previous experiments for a counter rotating dual rotor horizontal axis marine current turbine used a mechanical oil seal coupling that caused mechanical losses when water entered through small gaps at the shaft. A new magnetic coupling assembly eliminates the need for a shaft to connect physically with the internal mechanisms and is water tight. This reduces mechanical losses in the system and the effect on the dual rotor performance is presented in this paper.

Mean-line Modeling of an Axial Turbine

NASA Astrophysics Data System (ADS)

Tkachenko, A. Yu; Ostapyuk, Ya A.; Filinov, E. P.

2018-01-01

The article describes the approach for axial turbine modeling along the mean line. It bases on the developed model of an axial turbine blade row. This model is suitable for both nozzle vanes and rotor blades simulations. Consequently, it allows the simulation of the single axial turbine stage as well as a multistage turbine. The turbine stage model can take into account the cooling air flow before and after a throat of each blade row, outlet straightener vanes existence and stagger angle controlling of nozzle vanes. The axial turbine estimation method includes the loss estimation and thermogasdynamic analysis. The single stage axial turbine was calculated with the developed model. The obtained results deviation was within 3% when comparing with the results of CFD modeling.

Integration of permanent magnet synchronous generator wind turbines into power grid

NASA Astrophysics Data System (ADS)

Abedini, Asghar

The world is seeing an ever-increasing demand for electrical energy. The future growth of electrical power generation needs to be a mix of technologies including fossil fuels, hydro, nuclear, wind, and solar. The federal and state energy agencies have taken several proactive steps to increase the share of renewable energy in the total generated electrical power. In 2005, 11.1% of the total 1060 GW electricity generation capacity was from Renewable Energy Sources (RES) in the US. The power capacity portfolio included 9.2% from hydroelectric, 0.87% from wind, and 0.7% from biomass. Other renewable power capacity included 2.8 GW of geothermal, 0.4 GW of solar thermal, and 0.2 GW of solar PV. Although the share of renewable energy sources is small compared with the total power capacity, they are experiencing a high and steady growth. The US is leading the world in wind energy growth with a 27% increase in 2006 and a projected 26% increase in 2007, according to the American Wind Energy Association (AWEA). The US Department of Energy benchmarked a goal to meet 5% of the nation's energy need by launching the Wind Powering America (WPA) program. Although renewable energy sources have many benefits, their utilization in the electrical grid does not come without cost. The higher penetration of RES has introduced many technical and non-technical challenges, including power quality, reliability, safety and protection, load management, grid interconnections and control, new regulations, and grid operation economics. RES such as wind and PV are also intermittent in nature. The energy from these sources is available as long as there is wind or sunlight. However, these are energies that are abundant in the world and the power generated from these sources is pollution free. Due to high price of foundation of wind farms, employing variable speed wind turbines to maximize the extracted energy from blowing wind is more beneficial. On the other hand, since wind power is intermittent, integrating energy storage systems with wind farms has attracted a lot of attention. These two subjects are addressed in this dissertation in detail. Permanent Magnet Synchronous Generators (PMSG) are used in variable speed wind turbines. In this thesis, the dynamic of the PMSG is investigated and a power electronic converter is designed to integrate the wind turbine to the grid. The risks of PMSG wind turbines such as low voltage ride through and short circuits, are assessed and the methods of mitigating the risks are discussed. In the second section of the thesis, various methods of smoothing wind turbine output power are explained and compared. Two novel methods of output power smoothing are analyzed: Rotor inertia and Super capacitors. The advantages and disadvantages of each method are explained and the dynamic model of each method is developed. The performance of the system is evaluated by simulating the wind turbine system in each method. The concepts of the methods of smoothing wind power can be implemented in other types of wind turbines such as Doubly Fed Induction Generator (DFIG) wind turbines.

Wind Turbine Failures - Tackling current Problems in Failure Data Analysis

NASA Astrophysics Data System (ADS)

Reder, M. D.; Gonzalez, E.; Melero, J. J.

2016-09-01

The wind industry has been growing significantly over the past decades, resulting in a remarkable increase in installed wind power capacity. Turbine technologies are rapidly evolving in terms of complexity and size, and there is an urgent need for cost effective operation and maintenance (O&M) strategies. Especially unplanned downtime represents one of the main cost drivers of a modern wind farm. Here, reliability and failure prediction models can enable operators to apply preventive O&M strategies rather than corrective actions. In order to develop these models, the failure rates and downtimes of wind turbine (WT) components have to be understood profoundly. This paper is focused on tackling three of the main issues related to WT failure analyses. These are, the non-uniform data treatment, the scarcity of available failure analyses, and the lack of investigation on alternative data sources. For this, a modernised form of an existing WT taxonomy is introduced. Additionally, an extensive analysis of historical failure and downtime data of more than 4300 turbines is presented. Finally, the possibilities to encounter the lack of available failure data by complementing historical databases with Supervisory Control and Data Acquisition (SCADA) alarms are evaluated.

Low Wind Speed Turbine Project Phase II: The Application of Medium-Voltage Electrical Apparatus to the Class of Variable Speed Multi-Megawatt Low Wind Speed Turbines; 15 June 2004--30 April 2005

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erdman, W.; Behnke, M.

2005-11-01

Kilowatt ratings of modern wind turbines have progressed rapidly from 50 kW to 1,800 kW over the past 25 years, with 3.0- to 7.5-MW turbines expected in the next 5 years. The premise of this study is simple: The rapid growth of wind turbine power ratings and the corresponding growth in turbine electrical generation systems and associated controls are quickly making low-voltage (LV) electrical design approaches cost-ineffective. This report provides design detail and compares the cost of energy (COE) between commercial LV-class wind power machines and emerging medium-voltage (MV)-class multi-megawatt wind technology. The key finding is that a 2.5% reductionmore » in the COE can be achieved by moving from LV to MV systems. This is a conservative estimate, with a 3% to 3.5% reduction believed to be attainable once purchase orders to support a 250-turbine/year production level are placed. This evaluation considers capital costs as well as installation, maintenance, and training requirements for wind turbine maintenance personnel. Subsystems investigated include the generator, pendant cables, variable-speed converter, and padmount transformer with switchgear. Both current-source and voltage-source converter/inverter MV topologies are compared against their low-voltage, voltage-source counterparts at the 3.0-, 5.0-, and 7.5-MW levels.« less

Torsional vibration characteristic study of the grid-connected DFIG wind turbine

NASA Astrophysics Data System (ADS)

Yu, Songtao; Xie, Da; Wu, Wangping; Gu, Chenghong; Li, Furong

2017-01-01

This paper studies the torsional vibration characteristics of the grid-connected doubly-fed induction generator (DFIG) wind turbine by small signal analysis method. Firstly a detailed small-signal stability union model of the grid-connected DFIG wind turbine is developed, including the mechanical system and electrical system. To study the dynamic characteristic of the blade, gearbox, low speed and high speed shafts, a three mass shaft model for the mechanical system is adopted. At the same time, small signal models of DFIG, the voltage source converter (VSC) and the transmission line of the electrical system are developed respectively. Then, through calculating the eigenvalues of the state matrix A and the corresponding participation factors, the modal analysis is conducted in the shaft torsional vibration issues. And the impact of the system parameters including the series compensation capacitor, the flat-wave reactor, the PI parameters, especially the speed controller of generator rotor on shaft torsional vibration are discussed. The results show that the speed controller strengthens association between the mechanical system and the electrical system, and also produces a low-frequency oscillation mode.

A One Dimensional, Time Dependent Inlet/Engine Numerical Simulation for Aircraft Propulsion Systems

NASA Technical Reports Server (NTRS)

Garrard, Doug; Davis, Milt, Jr.; Cole, Gary

1999-01-01

The NASA Lewis Research Center (LeRC) and the Arnold Engineering Development Center (AEDC) have developed a closely coupled computer simulation system that provides a one dimensional, high frequency inlet/engine numerical simulation for aircraft propulsion systems. The simulation system, operating under the LeRC-developed Application Portable Parallel Library (APPL), closely coupled a supersonic inlet with a gas turbine engine. The supersonic inlet was modeled using the Large Perturbation Inlet (LAPIN) computer code, and the gas turbine engine was modeled using the Aerodynamic Turbine Engine Code (ATEC). Both LAPIN and ATEC provide a one dimensional, compressible, time dependent flow solution by solving the one dimensional Euler equations for the conservation of mass, momentum, and energy. Source terms are used to model features such as bleed flows, turbomachinery component characteristics, and inlet subsonic spillage while unstarted. High frequency events, such as compressor surge and inlet unstart, can be simulated with a high degree of fidelity. The simulation system was exercised using a supersonic inlet with sixty percent of the supersonic area contraction occurring internally, and a GE J85-13 turbojet engine.

Equipment for fully homologous bulb turbine model testing in Laval University

NASA Astrophysics Data System (ADS)

R, Fraser; D, Vallée; Y, Jean; C, Deschênes

2014-03-01

Within the context of liberalisation of the energy market, hydroelectricity remains a first class source of clean and renewable energy. Combining the growing demand of energy, its increasing value and the appreciation associated to the sustainable development, low head sites formerly considered as non-profitable are now exploitable. Bulb turbines likely to equip such sites are traditionally developed on model using right angle transmission leading to piers enlargement for power take off shaft passage, thus restricting possibilities to have fully homologous hydraulic passages. Aiming to sustain good quality development on fully homologous scale model of bulb turbines, the Hydraulic Machines Laboratory (LAMH) of Laval University has developed a brake with an enhanced power to weight ratio. This powerful brake is small enough to be located in the bulb shell while dissipating power without mandatory test head reduction. This paper first presents the basic technology of this brake and its application. Then both its main performance capabilities and dimensional characteristics will be detailed. The instrumentation used to perform accurate measurements will be finally presented.

RANS computations for identification of 1-D cavitation model parameters: application to full load cavitation vortex rope

NASA Astrophysics Data System (ADS)

Alligné, S.; Decaix, J.; Müller, A.; Nicolet, C.; Avellan, F.; Münch, C.

2017-04-01

Due to the massive penetration of alternative renewable energies, hydropower is a key energy conversion technology for stabilizing the electrical power network by using hydraulic machines at off design operating conditions. At full load, the axisymmetric cavitation vortex rope developing in Francis turbines acts as an internal source of energy, leading to an instability commonly referred to as self-excited surge. 1-D models are developed to predict this phenomenon and to define the range of safe operating points for a hydropower plant. These models require a calibration of several parameters. The present work aims at identifying these parameters by using CFD results as objective functions for an optimization process. A 2-D Venturi and 3-D Francis turbine are considered.

Compressor and Turbine Multidisciplinary Design for Highly Efficient Micro-gas Turbine

NASA Astrophysics Data System (ADS)

Barsi, Dario; Perrone, Andrea; Qu, Yonglei; Ratto, Luca; Ricci, Gianluca; Sergeev, Vitaliy; Zunino, Pietro

2018-06-01

Multidisciplinary design optimization (MDO) is widely employed to enhance turbomachinery components efficiency. The aim of this work is to describe a complete tool for the aero-mechanical design of a radial inflow turbine and a centrifugal compressor. The high rotational speed of such machines and the high exhaust gas temperature (only for the turbine) expose blades to really high stresses and therefore the aerodynamics design has to be coupled with the mechanical one through an integrated procedure. The described approach employs a fully 3D Reynolds Averaged Navier-Stokes (RANS) solver for the aerodynamics and an open source Finite Element Analysis (FEA) solver for the mechanical integrity assessment. Due to the high computational cost of both these two solvers, a meta model, such as an artificial neural network (ANN), is used to speed up the optimization design process. The interaction between two codes, the mesh generation and the post processing of the results are achieved via in-house developed scripting modules. The obtained results are widely presented and discussed.

Panel method for the wake effects on the aerodynamics of vertical-axis wind turbines

NASA Astrophysics Data System (ADS)

Goyal, Udit; Rempfer, Dietmar

2011-11-01

A formulation based on the panel method is implemented for studying the unsteady aerodynamics of straight-bladed vertical-axis wind turbines. A combination of source and vortex distributions is used to represent an airfoil in Darrieus type motion. Our approach represents a low-cost computational technique that takes into account the dynamic changes in angle of attack of the blade during a cycle. A time-stepping mechanism is introduced for the wake convection, and its effects on the aerodynamic forces on the blade are discussed. The focus of the study is to describe the effect of the trailing wakes on the upstream flow conditions and coefficient of performance of the turbines. Results show a decrease in Cp until the wake structure develops and assumes a quasi-steady behavior. A comparison with other models such as single and multiple streamtubes is discussed, and optimization of the blade pitch angle is performed to increase the instantaneous torque and hence the power output from the turbine.

Numerical investigations on the aerodynamic performance of wind turbine: Downwind versus upwind configuration

NASA Astrophysics Data System (ADS)

Zhou, Hu; Wan, Decheng

2015-03-01

Although the upwind configuration is more popular in the field of wind energy, the downwind one is a promising type for the offshore wind energy due to its special advantages. Different configurations have different aerodynamic performance and it is important to predict the performance of both downwind and upwind configurations accurately for designing and developing more reliable wind turbines. In this paper, a numerical investigation on the aerodynamic performance of National Renewable Energy Laboratory (NREL) phase VI wind turbine in downwind and upwind configurations is presented. The open source toolbox OpenFOAM coupled with arbitrary mesh interface (AMI) method is applied to tackle rotating problems of wind turbines. Two 3D numerical models of NREL phase VI wind turbine with downwind and upwind configurations under four typical working conditions of incoming wind velocities are set up for the study of different unsteady characteristics of the downwind and upwind configurations, respectively. Numerical results of wake vortex structure, time histories of thrust, pressure distribution on the blade and limiting streamlines which can be used to identify points of separation in a 3D flow are presented. It can be concluded that thrust reduction due to blade-tower interaction is small for upwind wind turbines but relatively large for downwind wind turbines and attention should be paid to the vibration at a certain frequency induced by the cyclic reduction for both configurations. The results and conclusions are helpful to analyze the different aerodynamic performance of wind turbines between downwind and upwind configurations, providing useful references for practical design of wind turbine.

Open Source Initiative Powers Real-Time Data Streams

NASA Technical Reports Server (NTRS)

2014-01-01

Under an SBIR contract with Dryden Flight Research Center, Creare Inc. developed a data collection tool called the Ring Buffered Network Bus. The technology has now been released under an open source license and is hosted by the Open Source DataTurbine Initiative. DataTurbine allows anyone to stream live data from sensors, labs, cameras, ocean buoys, cell phones, and more.

Wind turbines and idiopathic symptoms: The confounding effect of concurrent environmental exposures.

PubMed

Blanes-Vidal, Victoria; Schwartz, Joel

2016-01-01

Whether or not wind turbines pose a risk to human health is a matter of heated debate. Personal reactions to other environmental exposures occurring in the same settings as wind turbines may be responsible of the reported symptoms. However, these have not been accounted for in previous studies. We investigated whether there is an association between residential proximity to wind turbines and idiopathic symptoms, after controlling for personal reactions to other environmental co-exposures. We assessed wind turbine exposures in 454 residences as the distance to the closest wind turbine (Dw) and number of wind turbines <1000m (Nw1000). Information on symptoms, demographics and personal reactions to exposures was obtained by a blind questionnaire. We identified confounders using confounders' selection criteria and used adjusted logistic regression models to estimate associations. When controlling only for socio-demographic characteristics, log10Dw was associated with "unnatural fatigue" (ORadj=0.38, 95%CI=0.15-1.00) and "difficulty concentrating" (ORadj=0.26, 95%CI=0.08-0.83) and Nw1000 was associated with "unnatural fatigue" (ORadj=1.35, 95%CI=1.07-1.70) and "headache" (ORadj=1.26, 95%CI=1.00-1.58). After controlling for personal reactions to noise from sources different from wind turbines and agricultural odor exposure, we did not observe a significant relationship between residential proximity to wind turbines and symptoms and the parameter estimates were attenuated toward zero. Wind turbines-health associations can be confounded by personal reactions to other environmental co-exposures. Isolated associations reported in the literature may be due to confounding bias. Copyright © 2016 Elsevier Inc. All rights reserved.

Fatigue impact on Mod-1 wind turbine design

NASA Technical Reports Server (NTRS)

Stahle, C. V., Jr.

1978-01-01

Fatigue is a key consideration in the design of a long-life Wind Turbine Generator (WTG) system. This paper discusses the fatigue aspects of the large Mod-1 horizontal-axis WTG design starting with the characterization of the environment and proceeding through the design. Major sources of fatigue loading are discussed and methods of limiting fatigue loading are described. NASTRAN finite element models are used to determine dynamic loading and internal cyclic stresses. Recent developments in determining the allowable fatigue stress consistent with present construction codes are discussed relative to their application to WTG structural design.

SPATIALLY-EXPLICIT BAT IMPACT SCREENING TOOL FOR WIND TURBINE SITING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Versar, Inc.; Exponent, Inc.

As the U.S. seeks to increase energy production from renewable energy sources, development of wind power resources continues to grow. One of the most important ecological issues restricting wind energy development, especially the siting of wind turbines, is the potential adverse effect on bats. High levels of bat fatality have been recorded at a number of wind energy facilities, especially in the eastern United States. The U.S. Department of Energy contracted with Versar, Inc., and Exponent to develop a spatially-explicit site screening tool to evaluate the mortality of bats resulting from interactions (collisions or barotrauma) with wind turbines. The resultingmore » Bat Vulnerability Assessment Tool (BVAT) presented in this report integrates spatial information about turbine locations, bat habitat features, and bat behavior as it relates to possible interactions with turbines. A model demonstration was conducted that focuses on two bat species, the eastern red bat (Lasiurus borealis) and the Indiana bat (Myotis sodalis). The eastern red bat is a relatively common tree-roosting species that ranges broadly during migration in the Eastern U.S., whereas the Indiana bat is regional species that migrates between a summer range and cave hibernacula. Moreover, Indiana bats are listed as endangered, and so the impacts to this species are of particular interest. The model demonstration used conditions at the Mountaineer Wind Energy Center (MWEC), which consists of 44 wind turbines arranged in a linear array near Thomas, West Virginia (Tucker County), to illustrate model functions and not to represent actual or potential impacts of the facility. The turbines at MWEC are erected on the ridge of Backbone Mountain with a nacelle height of 70 meters and a collision area of 72 meters (blade height) or 4,071 meters square. The habitat surrounding the turbines is an Appalachian mixed mesophytic forest. Model sensitivity runs showed that bat mortality in the model was most sensitive to perceptual range and flying height. The BVAT model demonstration found that after 30 model iterations, Red bats suffered greater rates of mortality (i.e., 2.5 times the number of bats killed per 10-day period) than Indiana bats, primarily resulting from the higher flying height of the red bat. The model described in this report is a first release. There are opportunities to expand and enhance the model in the future. For example, additional focus on the model experience would include adding project level saving/loading, integrating the outputs (trajectory mapping) into the main output window, and providing tools for preparing habitat maps. In addition to the model framework, the actual modeling options could be enhanced by adding associative learning (including additional behavioral states), adding additional movement models, and exploring the information transfer among bats. Ultimately, this standalone model could be integrated into ArcGIS as a plugin.« less

Adaptive neuro-fuzzy methodology for noise assessment of wind turbine.

PubMed

Shamshirband, Shahaboddin; Petković, Dalibor; Hashim, Roslan; Motamedi, Shervin

2014-01-01

Wind turbine noise is one of the major obstacles for the widespread use of wind energy. Noise tone can greatly increase the annoyance factor and the negative impact on human health. Noise annoyance caused by wind turbines has become an emerging problem in recent years, due to the rapid increase in number of wind turbines, triggered by sustainable energy goals set forward at the national and international level. Up to now, not all aspects of the generation, propagation and perception of wind turbine noise are well understood. For a modern large wind turbine, aerodynamic noise from the blades is generally considered to be the dominant noise source, provided that mechanical noise is adequately eliminated. The sources of aerodynamic noise can be divided into tonal noise, inflow turbulence noise, and airfoil self-noise. Many analytical and experimental acoustical studies performed the wind turbines. Since the wind turbine noise level analyzing by numerical methods or computational fluid dynamics (CFD) could be very challenging and time consuming, soft computing techniques are preferred. To estimate noise level of wind turbine, this paper constructed a process which simulates the wind turbine noise levels in regard to wind speed and sound frequency with adaptive neuro-fuzzy inference system (ANFIS). This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method.

Adaptive Neuro-Fuzzy Methodology for Noise Assessment of Wind Turbine

PubMed Central

Shamshirband, Shahaboddin; Petković, Dalibor; Hashim, Roslan; Motamedi, Shervin

2014-01-01

Wind turbine noise is one of the major obstacles for the widespread use of wind energy. Noise tone can greatly increase the annoyance factor and the negative impact on human health. Noise annoyance caused by wind turbines has become an emerging problem in recent years, due to the rapid increase in number of wind turbines, triggered by sustainable energy goals set forward at the national and international level. Up to now, not all aspects of the generation, propagation and perception of wind turbine noise are well understood. For a modern large wind turbine, aerodynamic noise from the blades is generally considered to be the dominant noise source, provided that mechanical noise is adequately eliminated. The sources of aerodynamic noise can be divided into tonal noise, inflow turbulence noise, and airfoil self-noise. Many analytical and experimental acoustical studies performed the wind turbines. Since the wind turbine noise level analyzing by numerical methods or computational fluid dynamics (CFD) could be very challenging and time consuming, soft computing techniques are preferred. To estimate noise level of wind turbine, this paper constructed a process which simulates the wind turbine noise levels in regard to wind speed and sound frequency with adaptive neuro-fuzzy inference system (ANFIS). This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method. PMID:25075621

Valve exploiting the principle of a side channel turbine

NASA Astrophysics Data System (ADS)

Jandourek, Pavel; Pochylý, František; Haban, Vladimír

2017-04-01

The presented article deals with a side channel turbine, which can be used as a suitable substitute for a pressure reducing valve. Pressure reducing valves are a source of high hydraulic losses. The aim is to replace them by a side channel turbine. With that in mind, hydraulic losses can be replaced by a production of electrical energy at comparable characteristics of the reducing valve and the side channel turbine. The basis for the design is the loss characteristics of the pressure reducing valve. Thereby create a new kind of turbine valve with speed-controlled flow in dependence of the runner revolution. It is technical innovation and new renewable source of energy, which can be in future used in rehabilitation or projecting of pumped-storage power plants. It also increases the power of the power plant.

Calculated performance of a mercury-compressor-jet powered airplane using a nuclear reactor as an energy source

NASA Technical Reports Server (NTRS)

Doyle, R B

1951-01-01

An analysis was made at a flight Mach number of 1.5, an altitude of 45,000 feet, a turbine-inlet temperature of 1460 degrees R, of a mercury compressor-jet powered airplane using a nuclear reactor as an energy source. The calculations covered a range of turbine-exhaust and turbine-inlet pressures and condenser-inlet Mach numbers. For a turbine--inlet pressure of 40 pounds per square inch absolute, a turbine-exhaust pressure of 14 pounds per square inch absolute, and a condenser-inlet Mach number of 0.23 the calculated airplane gross weight required to carry a 20,000 pound payload was 322000 pounds and the reactor heat release per unit volume was 8.9 kilowatts per cubic inch. These do not represent optimum operating conditions.

Low-grade geothermal energy conversion by organic Rankine cycle turbine generator

NASA Astrophysics Data System (ADS)

Zarling, J. P.; Aspnes, J. D.

Results of a demonstration project which helped determine the feasibility of converting low-grade thermal energy in 49 C water into electrical energy via an organic Rankine cycle 2500 watt (electrical) turbine-generator are presented. The geothermal source which supplied the water is located in a rural Alaskan village. The reasons an organic Rankine cycle turbine-generator was investigated as a possible source of electric power in rural Alaska are: (1) high cost of operating diesel-electric units and their poor long-term reliability when high-quality maintenance is unavailable and (2) the extremely high level of long-term reliability reportedly attained by commercially available organic Rankine cycle turbines. Data is provided on the thermal and electrical operating characteristics of an experimental organic Rankine cycle turbine-generator operating at a uniquely low vaporizer temperature.

Aerodynamic and aeroacoustic for wind turbine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohamed, Maizi; Rabah, Dizene

2015-03-10

This paper describes a hybrid approach forpredicting noise radiated from the rotating Wind Turbine (HAWT) blades, where the sources are extracted from an unsteady Reynolds-Averaged-Navier Stocks (URANS) simulation, ANSYS CFX 11.0, was used to calculate The near-field flow parameters around the blade surface that are necessary for FW-H codes. Comparisons with NREL Phase II experimental results are presented with respect to the pressure distributions for validating a capacity of the solver to calculate the near-field flow on and around the wind turbine blades, The results show that numerical data have a good agreement with experimental. The acoustic pressure, presented asmore » a sum of thickness and loading noise components, is analyzed by means of a discrete fast Fourier transformation for the presentation of the time acoustic time histories in the frequency domain. The results convincingly show that dipole source noise is the dominant noise source for this wind turbine.« less

Wind Farm Facilities in Germany Kill Noctule Bats from Near and Far

PubMed Central

Lehnert, Linn S.; Kramer-Schadt, Stephanie; Schönborn, Sophia; Lindecke, Oliver; Niermann, Ivo; Voigt, Christian C.

2014-01-01

Over recent years, it became widely accepted that alternative, renewable energy may come at some risk for wildlife, for example, when wind turbines cause large numbers of bat fatalities. To better assess likely populations effects of wind turbine related wildlife fatalities, we studied the geographical origin of the most common bat species found dead below German wind turbines, the noctule bat (Nyctalus noctula). We measured stable isotope ratios of non-exchangeable hydrogen in fur keratin to separate migrants from local individuals, used a linear mixed-effects model to identify temporal, spatial and biological factors explaining the variance in measured stable isotope ratios and determined the geographical breeding provenance of killed migrants using isoscape origin models. We found that 72% of noctule bat casualties (n = 136) were of local origin, while 28% were long-distance migrants. These findings highlight that bat fatalities at German wind turbines may affect both local and distant populations. Our results indicated a sex and age-specific vulnerability of bats towards lethal accidents at turbines, i.e. a relatively high proportion of killed females were recorded among migratory individuals, whereas more juveniles than adults were recorded among killed bats of local origin. Migratory noctule bats were found to originate from distant populations in the Northeastern parts of Europe. The large catchment areas of German wind turbines and high vulnerability of female and juvenile noctule bats call for immediate action to reduce the negative cross-boundary effects of bat fatalities at wind turbines on local and distant populations. Further, our study highlights the importance of implementing effective mitigation measures and developing species and scale-specific conservation approaches on both national and international levels to protect source populations of bats. The efficacy of local compensatory measures appears doubtful, at least for migrant noctule bats, considering the large geographical catchment areas of German wind turbines for this species. PMID:25118805

Wind farm facilities in Germany kill noctule bats from near and far.

PubMed

Lehnert, Linn S; Kramer-Schadt, Stephanie; Schönborn, Sophia; Lindecke, Oliver; Niermann, Ivo; Voigt, Christian C

2014-01-01

Over recent years, it became widely accepted that alternative, renewable energy may come at some risk for wildlife, for example, when wind turbines cause large numbers of bat fatalities. To better assess likely populations effects of wind turbine related wildlife fatalities, we studied the geographical origin of the most common bat species found dead below German wind turbines, the noctule bat (Nyctalus noctula). We measured stable isotope ratios of non-exchangeable hydrogen in fur keratin to separate migrants from local individuals, used a linear mixed-effects model to identify temporal, spatial and biological factors explaining the variance in measured stable isotope ratios and determined the geographical breeding provenance of killed migrants using isoscape origin models. We found that 72% of noctule bat casualties (n = 136) were of local origin, while 28% were long-distance migrants. These findings highlight that bat fatalities at German wind turbines may affect both local and distant populations. Our results indicated a sex and age-specific vulnerability of bats towards lethal accidents at turbines, i.e. a relatively high proportion of killed females were recorded among migratory individuals, whereas more juveniles than adults were recorded among killed bats of local origin. Migratory noctule bats were found to originate from distant populations in the Northeastern parts of Europe. The large catchment areas of German wind turbines and high vulnerability of female and juvenile noctule bats call for immediate action to reduce the negative cross-boundary effects of bat fatalities at wind turbines on local and distant populations. Further, our study highlights the importance of implementing effective mitigation measures and developing species and scale-specific conservation approaches on both national and international levels to protect source populations of bats. The efficacy of local compensatory measures appears doubtful, at least for migrant noctule bats, considering the large geographical catchment areas of German wind turbines for this species.

A new class of actuator surface models for wind turbines

NASA Astrophysics Data System (ADS)

Yang, Xiaolei; Sotiropoulos, Fotis

2018-05-01

Actuator line model has been widely employed in wind turbine simulations. However, the standard actuator line model does not include a model for the turbine nacelle which can significantly impact turbine wake characteristics as shown in the literature. Another disadvantage of the standard actuator line model is that more geometrical features of turbine blades cannot be resolved on a finer mesh. To alleviate these disadvantages of the standard model, we develop a new class of actuator surface models for turbine blades and nacelle to take into account more geometrical details of turbine blades and include the effect of turbine nacelle. In the actuator surface model for blade, the aerodynamic forces calculated using the blade element method are distributed from the surface formed by the foil chords at different radial locations. In the actuator surface model for nacelle, the forces are distributed from the actual nacelle surface with the normal force component computed in the same way as in the direct forcing immersed boundary method and the tangential force component computed using a friction coefficient and a reference velocity of the incoming flow. The actuator surface model for nacelle is evaluated by simulating the flow over periodically placed nacelles. Both the actuator surface simulation and the wall-resolved large-eddy simulation are carried out. The comparison shows that the actuator surface model is able to give acceptable results especially at far wake locations on a very coarse mesh. It is noted that although this model is employed for the turbine nacelle in this work, it is also applicable to other bluff bodies. The capability of the actuator surface model in predicting turbine wakes is assessed by simulating the flow over the MEXICO (Model experiments in Controlled Conditions) turbine and a hydrokinetic turbine.

Robust Power Management Control for Stand-Alone Hybrid Power Generation System

NASA Astrophysics Data System (ADS)

Kamal, Elkhatib; Adouane, Lounis; Aitouche, Abdel; Mohammed, Walaa

2017-01-01

This paper presents a new robust fuzzy control of energy management strategy for the stand-alone hybrid power systems. It consists of two levels named centralized fuzzy supervisory control which generates the power references for each decentralized robust fuzzy control. Hybrid power systems comprises: a photovoltaic panel and wind turbine as renewable sources, a micro turbine generator and a battery storage system. The proposed control strategy is able to satisfy the load requirements based on a fuzzy supervisor controller and manage power flows between the different energy sources and the storage unit by respecting the state of charge and the variation of wind speed and irradiance. Centralized controller is designed based on If-Then fuzzy rules to manage and optimize the hybrid power system production by generating the reference power for photovoltaic panel and wind turbine. Decentralized controller is based on the Takagi-Sugeno fuzzy model and permits us to stabilize each photovoltaic panel and wind turbine in presence of disturbances and parametric uncertainties and to optimize the tracking reference which is given by the centralized controller level. The sufficient conditions stability are formulated in the format of linear matrix inequalities using the Lyapunov stability theory. The effectiveness of the proposed Strategy is finally demonstrated through a SAHPS (stand-alone hybrid power systems) to illustrate the effectiveness of the overall proposed method.

Reliability analysis of single crystal NiAl turbine blades

NASA Technical Reports Server (NTRS)

Salem, Jonathan; Noebe, Ronald; Wheeler, Donald R.; Holland, Fred; Palko, Joseph; Duffy, Stephen; Wright, P. Kennard

1995-01-01

As part of a co-operative agreement with General Electric Aircraft Engines (GEAE), NASA LeRC is modifying and validating the Ceramic Analysis and Reliability Evaluation of Structures algorithm for use in design of components made of high strength NiAl based intermetallic materials. NiAl single crystal alloys are being actively investigated by GEAE as a replacement for Ni-based single crystal superalloys for use in high pressure turbine blades and vanes. The driving force for this research lies in the numerous property advantages offered by NiAl alloys over their superalloy counterparts. These include a reduction of density by as much as a third without significantly sacrificing strength, higher melting point, greater thermal conductivity, better oxidation resistance, and a better response to thermal barrier coatings. The current drawback to high strength NiAl single crystals is their limited ductility. Consequently, significant efforts including the work agreement with GEAE are underway to develop testing and design methodologies for these materials. The approach to validation and component analysis involves the following steps: determination of the statistical nature and source of fracture in a high strength, NiAl single crystal turbine blade material; measurement of the failure strength envelope of the material; coding of statistically based reliability models; verification of the code and model; and modeling of turbine blades and vanes for rig testing.

Damage detection of rotating wind turbine blades using local flexibility method and long-gauge fiber Bragg grating sensors

NASA Astrophysics Data System (ADS)

Hsu, Ting-Yu; Shiao, Shen-Yuan; Liao, Wen-I.

2018-01-01

Wind turbines are a cost-effective alternative energy source; however, their blades are susceptible to damage. Therefore, damage detection of wind turbine blades is of great importance for condition monitoring of wind turbines. Many vibration-based structural damage detection techniques have been proposed in the last two decades. The local flexibility method, which can determine local stiffness variations of beam-like structures by using measured modal parameters, is one of the most promising vibration-based approaches. The local flexibility method does not require a finite element model of the structure. A few structural modal parameters identified from the ambient vibration signals both before and after damage are required for this method. In this study, we propose a damage detection approach for rotating wind turbine blades using the local flexibility method based on the dynamic macro-strain signals measured by long-gauge fiber Bragg grating (FBG)-based sensors. A small wind turbine structure was constructed and excited using a shaking table to generate vibration signals. The structure was designed to have natural frequencies as close as possible to those of a typical 1.5 MW wind turbine in real scale. The optical fiber signal of the rotating blades was transmitted to the data acquisition system through a rotary joint fixed inside the hollow shaft of the wind turbine. Reversible damage was simulated by aluminum plates attached to some sections of the wind turbine blades. The damaged locations of the rotating blades were successfully detected using the proposed approach, with the extent of damage somewhat over-estimated. Nevertheless, although the specimen of wind turbine blades cannot represent a real one, the results still manifest that FBG-based macro-strain measurement has potential to be employed to obtain the modal parameters of the rotating wind turbines and then locations of wind turbine segments with a change of rigidity can be estimated effectively by utilizing these identified parameters.

Introduction Wind farms in complex terrains: an introduction

PubMed Central

Alfredsson, P. H.; Segalini, A.

2017-01-01

Wind energy is one of the fastest growing sources of sustainable energy production. As more wind turbines are coming into operation, the best locations are already becoming occupied by turbines, and wind-farm developers have to look for new and still available areas—locations that may not be ideal such as complex terrain landscapes. In these locations, turbulence and wind shear are higher, and in general wind conditions are harder to predict. Also, the modelling of the wakes behind the turbines is more complicated, which makes energy-yield estimates more uncertain than under ideal conditions. This theme issue includes 10 research papers devoted to various fluid-mechanics aspects of using wind energy in complex terrains and illustrates recent progress and future developments in this important field. This article is part of the themed issue ‘Wind energy in complex terrains’. PMID:28265020

Photovoltaic-wind hybrid system for permanent magnet DC motor

NASA Astrophysics Data System (ADS)

Nasir, M. N. M.; Lada, M. Y.; Baharom, M. F.; Jaafar, H. I.; Ramani, A. N.; Sulaima, M. F.

2015-05-01

Hybrid system of Photovoltaic (PV) - Wind turbine (WT) generation has more advantages and reliable compared to PV or wind turbine system alone. The aim of this paper is to model and design hybrid system of PV-WT supplying 100W permanent-magnet dc motor. To achieve the objective, both of PV and WT are connected to converter in order to get the same source of DC supply. Then both sources were combined and straightly connected to 100W permanent magnet dc motor. All the works in this paper is only applied in circuit simulator by using Matlab Simulink. The output produced from each converter is expected to be suit to the motor specification. The output produced from each renewable energy system is as expected to be high as it can support the motor if one of them is breakdown

Cold Weather Wind Turbines: A Joint NASA/NSF/DOE Effort in Technology Transfer and Commercialization

NASA Technical Reports Server (NTRS)

Flynn, Michael; Bubenheim, David; Chiang, Erick; Goldman, Peter; Kohout, Lisa; Norton, Gary; Kliss, Mark (Technical Monitor)

1997-01-01

Renewable energy sources and their integration with other power sources to support remote communities is of interest for Mars applications as well as Earth communities. The National Science Foundation (NSF), NASA, and the Department of Energy (DOE) have been jointly supporting development of a 100 kW cold weather wind turbine through grants and SBIRs independently managed by each agency but coordinated by NASA. The NSF grant addressed issues associated with the South Pole application and a 3 kW direct drive unit is being tested there in anticipation of the 100 kW unit operation. The DOE-NREL contract focused on development of the 100 kW direct drive generator. The NASA SBIR focused on the development of the 100 kW direct drive wind turbine. The success of this effort has required coordination and team involvement of federal agencies and the industrial partners. Designs of the wind turbine and component performance testing results will be presented. Plans for field testing of wind turbines, based on this design, in village energy systems in Alaska and in energy production at the South Pole Station will be discussed. Also included will be a discussion of terrestrial and space use of hybrid energy systems, including renewable energy sources, such as the wind turbine, to support remote communities.

Experimental investigation of performance and dynamic loading of an axial-flow marine hydrokinetic turbine with comparison to predicted design values from BEM computations

NASA Astrophysics Data System (ADS)

van Ness, Katherine; Hill, Craig; Aliseda, Alberto; Polagye, Brian

2017-11-01

Experimental measurements of a 0.45-m diameter, variable-pitch marine hydrokinetic (MHK) turbine were collected in a tow tank at different tip speed ratios and blade pitch angles. The coefficients of power and thrust are computed from direct measurements of torque, force and angular speed at the hub level. Loads on individual blades were measured with a six-degree of freedom load cell mounted at the root of one of the turbine blades. This information is used to validate the performance predictions provided by blade element model (BEM) simulations used in the turbine design, specifically the open-source code WTPerf developed by the National Renewable Energy Lab (NREL). Predictions of blade and hub loads by NREL's AeroDyn are also validated for the first time for an axial-flow MHK turbine. The influence of design twist angle, combined with the variable pitch angle, on the flow separation and subsequent blade loading will be analyzed with the complementary information from simulations and experiments. Funding for this research was provided by the United States Naval Facilities Engineering Command.

Research on simulation of supercritical steam turbine system in large thermal power station

NASA Astrophysics Data System (ADS)

Zhou, Qiongyang

2018-04-01

In order to improve the stability and safety of supercritical steam turbine system operation in large thermal power station, the body of the steam turbine is modeled in this paper. And in accordance with the hierarchical modeling idea, the steam turbine body model, condensing system model, deaeration system model and regenerative system model are combined to build a simulation model of steam turbine system according to the connection relationship of each subsystem of steam turbine. Finally, the correctness of the model is verified by design and operation data of the 600MW supercritical unit. The results show that the maximum simulation error of the model is 2.15%, which meets the requirements of the engineering. This research provides a platform for the research on the variable operating conditions of the turbine system, and lays a foundation for the construction of the whole plant model of the thermal power plant.

Physical and Numerical Model Studies of Cross-flow Turbines Towards Accurate Parameterization in Array Simulations

NASA Astrophysics Data System (ADS)

Wosnik, M.; Bachant, P.

2014-12-01

Cross-flow turbines, often referred to as vertical-axis turbines, show potential for success in marine hydrokinetic (MHK) and wind energy applications, ranging from small- to utility-scale installations in tidal/ocean currents and offshore wind. As turbine designs mature, the research focus is shifting from individual devices to the optimization of turbine arrays. It would be expensive and time-consuming to conduct physical model studies of large arrays at large model scales (to achieve sufficiently high Reynolds numbers), and hence numerical techniques are generally better suited to explore the array design parameter space. However, since the computing power available today is not sufficient to conduct simulations of the flow in and around large arrays of turbines with fully resolved turbine geometries (e.g., grid resolution into the viscous sublayer on turbine blades), the turbines' interaction with the energy resource (water current or wind) needs to be parameterized, or modeled. Models used today--a common model is the actuator disk concept--are not able to predict the unique wake structure generated by cross-flow turbines. This wake structure has been shown to create "constructive" interference in some cases, improving turbine performance in array configurations, in contrast with axial-flow, or horizontal axis devices. Towards a more accurate parameterization of cross-flow turbines, an extensive experimental study was carried out using a high-resolution turbine test bed with wake measurement capability in a large cross-section tow tank. The experimental results were then "interpolated" using high-fidelity Navier--Stokes simulations, to gain insight into the turbine's near-wake. The study was designed to achieve sufficiently high Reynolds numbers for the results to be Reynolds number independent with respect to turbine performance and wake statistics, such that they can be reliably extrapolated to full scale and used for model validation. The end product of this work will be a cross-flow turbine actuator line model to be used as an extension to the OpenFOAM computational fluid dynamics (CFD) software framework, which will likely require modifications to commonly-used dynamic stall models, in consideration of the turbines' high angle of attack excursions during normal operation.

Potential climatic impacts and reliability of large-scale offshore wind farms

NASA Astrophysics Data System (ADS)

Wang, Chien; Prinn, Ronald G.

2011-04-01

The vast availability of wind power has fueled substantial interest in this renewable energy source as a potential near-zero greenhouse gas emission technology for meeting future world energy needs while addressing the climate change issue. However, in order to provide even a fraction of the estimated future energy needs, a large-scale deployment of wind turbines (several million) is required. The consequent environmental impacts, and the inherent reliability of such a large-scale usage of intermittent wind power would have to be carefully assessed, in addition to the need to lower the high current unit wind power costs. Our previous study (Wang and Prinn 2010 Atmos. Chem. Phys. 10 2053) using a three-dimensional climate model suggested that a large deployment of wind turbines over land to meet about 10% of predicted world energy needs in 2100 could lead to a significant temperature increase in the lower atmosphere over the installed regions. A global-scale perturbation to the general circulation patterns as well as to the cloud and precipitation distribution was also predicted. In the later study reported here, we conducted a set of six additional model simulations using an improved climate model to further address the potential environmental and intermittency issues of large-scale deployment of offshore wind turbines for differing installation areas and spatial densities. In contrast to the previous land installation results, the offshore wind turbine installations are found to cause a surface cooling over the installed offshore regions. This cooling is due principally to the enhanced latent heat flux from the sea surface to lower atmosphere, driven by an increase in turbulent mixing caused by the wind turbines which was not entirely offset by the concurrent reduction of mean wind kinetic energy. We found that the perturbation of the large-scale deployment of offshore wind turbines to the global climate is relatively small compared to the case of land-based installations. However, the intermittency caused by the significant seasonal wind variations over several major offshore sites is substantial, and demands further options to ensure the reliability of large-scale offshore wind power. The method that we used to simulate the offshore wind turbine effect on the lower atmosphere involved simply increasing the ocean surface drag coefficient. While this method is consistent with several detailed fine-scale simulations of wind turbines, it still needs further study to ensure its validity. New field observations of actual wind turbine arrays are definitely required to provide ultimate validation of the model predictions presented here.

A study on the power generation potential of mini wind turbine in east coast of Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Basrawi, Firdaus; Ismail, Izwan; Ibrahim, Thamir Khalil; Idris, Daing Mohamad Nafiz Daing; Anuar, Shahrani

2017-03-01

A small-scale wind turbine is an attractive renewable energy source, but its economic viability depends on wind speed. The aim of this study is to determine economic viability of small-scale wind turbine in East Coast of Peninsular Malaysia. The potential energy generated has been determined by wind speed data and power curved of. Hourly wind speed data of Kuantan throughout 2015 was collected as the input. Then, a model of wind turbine was developed based on a commercial a 300W mini wind turbine. It was found that power generation is 3 times higher during northeast monsoon season at 15 m elevation. This proved that the northeast monsoon season has higher potential in generating power by wind turbine in East Coast of Peninsular Malaysia. However, only a total of 153.4 kWh/year of power can be generated at this condition. The power generator utilization factor PGUI or capacity ratio was merely 0.06 and it is not technically viable. By increasing the height of wind turbine to 60 m elevation, power generation amount drastically increased to 344 kWh/year, with PGUI of 0.13. This is about two-thirds of PGUI for photovoltaic technology which is 0.21 at this site. If offshore condition was considered, power generation amount further increased to 1,328 kWh/year with PGUI of 0.51. Thus, for a common use of mini wind turbine that is usually installed on-site at low elevation, it has low power generation potential. But, if high elevation as what large wind turbine needed is implemented, it is technically viable option in East Coast of Peninsular Malaysia.

Sonic IR crack detection of aircraft turbine engine blades with multi-frequency ultrasound excitations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Ding; Han, Xiaoyan; Newaz, Golam

Effectively and accurately detecting cracks or defects in critical engine components, such as turbine engine blades, is very important for aircraft safety. Sonic Infrared (IR) Imaging is such a technology with great potential for these applications. This technology combines ultrasound excitation and IR imaging to identify cracks and flaws in targets. In general, failure of engine components, such as blades, begins with tiny cracks. Since the attenuation of the ultrasound wave propagation in turbine engine blades is small, the efficiency of crack detection in turbine engine blades can be quite high. The authors at Wayne State University have been developingmore » the technology as a reliable tool for the future field use in aircraft engines and engine parts. One part of the development is to use finite element modeling to assist our understanding of effects of different parameters on crack heating while experimentally hard to achieve. The development has been focused with single frequency ultrasound excitation and some results have been presented in a previous conference. We are currently working on multi-frequency excitation models. The study will provide results and insights of the efficiency of different frequency excitation sources to foster the development of the technology for crack detection in aircraft engine components.« less

SIGAR Quarterly Report to the United States Congress

DTIC Science & Technology

2016-07-30

electricity from sources such as mini-hydro turbines in streams, solar panels with battery storage, and wind turbines , but these are still a negligible...power, solar PV [photo-voltaic units], and wind turbines , is the most promising option for feasible, sustainable decentralized rural electrification...informed SIGAR that the installation of a third power-generating turbine at Kajaki Dam should be complete in September 2016—security conditions permitting

46 CFR 112.20-10 - Diesel or gas turbine driven emergency power source.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Diesel or gas turbine driven emergency power source. 112.20-10 Section 112.20-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Systems Having a Temporary and a Final Emergency...

46 CFR 112.20-10 - Diesel or gas turbine driven emergency power source.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Diesel or gas turbine driven emergency power source. 112.20-10 Section 112.20-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Systems Having a Temporary and a Final Emergency...

46 CFR 112.20-10 - Diesel or gas turbine driven emergency power source.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Diesel or gas turbine driven emergency power source. 112.20-10 Section 112.20-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Systems Having a Temporary and a Final Emergency...

14 CFR 121.344 - Digital flight data recorders for transport category airplanes.

Code of Federal Regulations, 2011 CFR

2011-01-01

... as provided in paragraph (l) of this section, no person may operate under this part a turbine-engine... (when an information source is installed); (38) Wind speed and direction (when an information source is... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

14 CFR 121.344 - Digital flight data recorders for transport category airplanes.

Code of Federal Regulations, 2014 CFR

2014-01-01

... as provided in paragraph (l) of this section, no person may operate under this part a turbine-engine... (when an information source is installed); (38) Wind speed and direction (when an information source is... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

14 CFR 121.344 - Digital flight data recorders for transport category airplanes.

Code of Federal Regulations, 2013 CFR

2013-01-01

... as provided in paragraph (l) of this section, no person may operate under this part a turbine-engine... (when an information source is installed); (38) Wind speed and direction (when an information source is... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

14 CFR 121.344 - Digital flight data recorders for transport category airplanes.

Code of Federal Regulations, 2010 CFR

2010-01-01

... as provided in paragraph (l) of this section, no person may operate under this part a turbine-engine... (when an information source is installed); (38) Wind speed and direction (when an information source is... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

14 CFR 121.344 - Digital flight data recorders for transport category airplanes.

Code of Federal Regulations, 2012 CFR

2012-01-01

... as provided in paragraph (l) of this section, no person may operate under this part a turbine-engine... (when an information source is installed); (38) Wind speed and direction (when an information source is... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

Bridging Scales: A Model-Based Assessment of the Technical Tidal-Stream Energy Resource off Massachusetts, USA

NASA Astrophysics Data System (ADS)

Cowles, G. W.; Hakim, A.; Churchill, J. H.

2016-02-01

Tidal in-stream energy conversion (TISEC) facilities provide a highly predictable and dependable source of energy. Given the economic and social incentives to migrate towards renewable energy sources there has been tremendous interest in the technology. Key challenges to the design process stem from the wide range of problem scales extending from device to array. In the present approach we apply a multi-model approach to bridge the scales of interest and select optimal device geometries to estimate the technical resource for several realistic sites in the coastal waters of Massachusetts, USA. The approach links two computational models. To establish flow conditions at site scales ( 10m), a barotropic setup of the unstructured grid ocean model FVCOM is employed. The model is validated using shipboard and fixed ADCP as well as pressure data. For device scale, the structured multiblock flow solver SUmb is selected. A large ensemble of simulations of 2D cross-flow tidal turbines is used to construct a surrogate design model. The surrogate model is then queried using velocity profiles extracted from the tidal model to determine the optimal geometry for the conditions at each site. After device selection, the annual technical yield of the array is evaluated with FVCOM using a linear momentum actuator disk approach to model the turbines. Results for several key Massachusetts sites including comparison with theoretical approaches will be presented.

Spatiotemporal structure of wind farm-atmospheric boundary layer interactions

NASA Astrophysics Data System (ADS)

Cervarich, Matthew; Baidya Roy, Somnath; Zhou, Liming

2013-04-01

Wind power is currently one of the fastest growing energy sources in the world. Most of the growth is in the utility sector consisting of large wind farms with numerous industrial-scale wind turbines. Wind turbines act as a sink of mean kinetic energy and a source of turbulent kinetic energy in the atmospheric boundary layer (ABL). In doing so, they modify the ABL profiles and land-atmosphere exchanges of energy, momentum, mass and moisture. This project explores theses interactions using remote sensing data and numerical model simulations. The domain is central Texas where 4 of the world's largest wind farms are located. A companion study of seasonally-averaged Land Surface Temperature data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on TERRA and AQUA satellites shows a warming signal at night and a mixed cooling/warming signal during the daytime within the wind farms. In the present study, wind farm-ABL interactions are simulated with the Weather Research and Forecasting (WRF) model. The simulations show that the model is capable of replicating the observed signal in land surface temperature. Moreover, similar warming/cooling effect, up to 1C, was observed in seasonal mean 2m air temperature as well. Further analysis show that enhanced turbulent mixing in the rotor wakes is responsible for the impacts on 2m and surface air temperatures. The mixing is due to 2 reasons: (i) turbulent momentum transport to compensate the momentum deficit in the wakes of the turbines and (ii) turbulence generated due to motion of turbine rotors. Turbulent mixing also alters vertical profiles of moisture. Changes in land-atmosphere temperature and moisture gradient and increase in turbulent mixing leads to more than 10% change in seasonal mean surface sensible and latent heat flux. Given the current installed capacity and the projected installation across the world, wind farms are likely becoming a major driver of anthropogenic land use change on Earth. Hence, understanding WF-ABL interactions and its effects is of significant scientific and societal importance.

Cross-flow turbines: progress report on physical and numerical model studies at large laboratory scale

NASA Astrophysics Data System (ADS)

Wosnik, Martin; Bachant, Peter

2016-11-01

Cross-flow turbines show potential in marine hydrokinetic (MHK) applications. A research focus is on accurately predicting device performance and wake evolution to improve turbine array layouts for maximizing overall power output, i.e., minimizing wake interference, or taking advantage of constructive wake interaction. Experiments were carried with large laboratory-scale cross-flow turbines D O (1 m) using a turbine test bed in a large cross-section tow tank, designed to achieve sufficiently high Reynolds numbers for the results to be Reynolds number independent with respect to turbine performance and wake statistics, such that they can be reliably extrapolated to full scale and used for model validation. Several turbines of varying solidity were employed, including the UNH Reference Vertical Axis Turbine (RVAT) and a 1:6 scale model of the DOE-Sandia Reference Model 2 (RM2) turbine. To improve parameterization in array simulations, an actuator line model (ALM) was developed to provide a computationally feasible method for simulating full turbine arrays inside Navier-Stokes models. Results are presented for the simulation of performance and wake dynamics of cross-flow turbines and compared with experiments and body-fitted mesh, blade-resolving CFD. Supported by NSF-CBET Grant 1150797, Sandia National Laboratories.

Wingtip vortex turbine investigation for vortex energy recovery

NASA Technical Reports Server (NTRS)

Abeyounis, William K.; Patterson, James C., Jr.; Stough, H. P., III; Wunschel, Alfred J.; Curran, Patrick D.

1990-01-01

A flight test investigation has been conducted to determine the performance of wingtip vortex turbines and their effect on aircraft performance. The turbines were designed to recover part of the large energy loss (induced drag) caused by the wingtip vortex. The turbine, driven by the vortex flow, reduces the strength of the vortex, resulting in an associated induced drag reduction. A four-blade turbine was mounted on each wingtip of a single-engine, T-tail, general aviation airplane. Two sets of turbine blades were tested, one with a 15' twist (washin) and one with no twist. Th power recovered by the turbine and the installed drag increment were measured. A trade-off between turbine power and induced drag reduction was found to be a function of turbine blade incidence angle. This test has demonstrated that the wingtip vortex turbine is an attractive alternate, as well as an emergency, power source.

An integrated modeling method for wind turbines

NASA Astrophysics Data System (ADS)

Fadaeinedjad, Roohollah

To study the interaction of the electrical, mechanical, and aerodynamic aspects of a wind turbine, a detailed model that considers all these aspects must be used. A drawback of many studies in the area of wind turbine simulation is that either a very simple mechanical model is used with a detailed electrical model, or vice versa. Hence the interactions between electrical and mechanical aspects of wind turbine operation are not accurately taken into account. In this research, it will be shown that a combination of different simulation packages, namely TurbSim, FAST, and Simulink can be used to model the aerodynamic, mechanical, and electrical aspects of a wind turbine in detail. In this thesis, after a review of some wind turbine concepts and software tools, a simulation structure is proposed for studying wind turbines that integrates the mechanical and electrical components of a wind energy conversion device. Based on the simulation structure, a comprehensive model for a three-bladed variable speed wind turbine with doubly-fed induction generator is developed. Using the model, the impact of a voltage sag on the wind turbine tower vibration is investigated under various operating conditions such as power system short circuit level, mechanical parameters, and wind turbine operating conditions. It is shown how an electrical disturbance can cause more sustainable tower vibrations under high speed and turbulent wind conditions, which may disrupt the operation of pitch control system. A similar simulation structure is used to model a two-bladed fixed speed wind turbine with an induction generator. An extension of the concept is introduced by adding a diesel generator system. The model is utilized to study the impact of the aeroelastic aspects of wind turbine (i.e. tower shadow, wind shears, yaw error, turbulence, and mechanical vibrations) on the power quality of a stand-alone wind-diesel system. Furthermore, an IEEE standard flickermeter model is implemented in a Simulink environment to study the flicker contribution of the wind turbine in the wind-diesel system. By using a new wind power plant representation method, a large wind farm (consisting of 96 fixed speed wind turbines) is modelled to study the power quality of wind power system. The flicker contribution of wind farm is also studied with different wind turbine numbers, using the flickermeter model. Keywords. Simulink, FAST, TurbSim, AreoDyn, wind energy, doubly-fed induction generator, variable speed wind turbine, voltage sag, tower vibration, power quality, flicker, fixed speed wind turbine, wind shear, tower shadow, and yaw error.

Valve exploiting the principle of a side channel turbine

NASA Astrophysics Data System (ADS)

Jandourek, Pavel; Habán, Vladimír; Pochylý, František; Fic, Miloslav

The article deals with a side channel turbine, which can be used as a suitable substitute for a pressure reducing valve. Reducing valves are a source of hydraulic losses. The aim is to replace them by a side channel turbine. With that in mind, hydraulic losses can be replaced by a production of electrical energy at comparable characteristics of the valve and the turbine. The basis for the design is the loss characteristics of the valve. Thereby creating a kind of turbine valve with speed-controlled flow in dependence of runner revolution.

Effects of Fuel and Nozzle Characteristics on Micro Gas Turbine System: A Review

NASA Astrophysics Data System (ADS)

Akasha Hashim, Muhammad; Khalid, Amir; Salleh, Hamidon; Sunar, Norshuhaila Mohamed

2017-08-01

For many decades, gas turbines have been used widely in the internal combustion engine industry. Due to the deficiency of fossil fuel and the concern of global warming, the used of bio-gas have been recognized as one of most clean fuels in the application of engine to improve performance of lean combustion and minimize the production of NOX and PM. This review paper is to understand the combustion performance using dual-fuel nozzle for a micro gas turbine that was basically designed as a natural gas fuelled engine, the nozzle characteristics of the micro gas turbine has been modelled and the effect of multi-fuel used were investigated. The used of biogas (hydrogen) as substitute for liquid fuel (methane) at constant fuel injection velocity, the flame temperature is increased, but the fuel low rate reduced. Applying the blended fuel at constant fuel rate will increased the flame temperature as the hydrogen percentages increased. Micro gas turbines which shows the uniformity of the flow distribution that can be improved without the increase of the pressure drop by applying the variable nozzle diameters into the fuel supply nozzle design. It also identifies the combustion efficiency, better fuel mixing in combustion chamber using duel fuel nozzle with the largest potential for the future. This paper can also be used as a reference source that summarizes the research and development activities on micro gas turbines.

RANS Simulation (Actuator Disk Model[ADM]) of the NREL Phase VI wind turbine modeled as MHK Turbine

DOE Data Explorer

Javaherchi, Teymour

2016-06-08

Attached are the .cas and .dat files for the Reynolds Averaged Navier-Stokes (RANS) simulation of a single lab-scaled DOE RM1 turbine implemented in ANSYS FLUENT CFD-package. In this case study the flow field around and in the wake of the NREL Phase VI wind turbine, modeled is MHK turbine, is simulated using Actuator Disk Model (a.k.a Porous Media) by solving RANS equations coupled with a turbulence closure model. It should be highlighted that in this simulation the actual geometry of the rotor blade is not modeled. The effect of turbine rotating blades are modeled using the Actuator Disk Theory (see the stated section of attached M.Sc. thesis for more details).

Health Effects Related to Wind Turbine Noise Exposure: A Systematic Review

PubMed Central

Schmidt, Jesper Hvass; Klokker, Mads

2014-01-01

Background Wind turbine noise exposure and suspected health-related effects thereof have attracted substantial attention. Various symptoms such as sleep-related problems, headache, tinnitus and vertigo have been described by subjects suspected of having been exposed to wind turbine noise. Objective This review was conducted systematically with the purpose of identifying any reported associations between wind turbine noise exposure and suspected health-related effects. Data Sources A search of the scientific literature concerning the health-related effects of wind turbine noise was conducted on PubMed, Web of Science, Google Scholar and various other Internet sources. Study Eligibility Criteria All studies investigating suspected health-related outcomes associated with wind turbine noise exposure were included. Results Wind turbines emit noise, including low-frequency noise, which decreases incrementally with increases in distance from the wind turbines. Likewise, evidence of a dose-response relationship between wind turbine noise linked to noise annoyance, sleep disturbance and possibly even psychological distress was present in the literature. Currently, there is no further existing statistically-significant evidence indicating any association between wind turbine noise exposure and tinnitus, hearing loss, vertigo or headache. Limitations Selection bias and information bias of differing magnitudes were found to be present in all current studies investigating wind turbine noise exposure and adverse health effects. Only articles published in English, German or Scandinavian languages were reviewed. Conclusions Exposure to wind turbines does seem to increase the risk of annoyance and self-reported sleep disturbance in a dose-response relationship. There appears, though, to be a tolerable level of around LAeq of 35 dB. Of the many other claimed health effects of wind turbine noise exposure reported in the literature, however, no conclusive evidence could be found. Future studies should focus on investigations aimed at objectively demonstrating whether or not measureable health-related outcomes can be proven to fluctuate depending on exposure to wind turbines. PMID:25474326

Investigation of the fluid-structure interaction of a high head Francis turbine using OpenFOAM and Code_Aster

NASA Astrophysics Data System (ADS)

Eichhorn, M.; Doujak, E.; Waldner, L.

2016-11-01

The increasing energy consumption and highly stressed power grids influence the operating conditions of turbines and pump turbines in the present situation. To provide or use energy as quick as possible, hydraulic turbines are operated more frequent and over longer periods of time in lower part load at off-design conditions. This leads to a more turbulent behavior and to higher requirements of the strength of stressed components (e.g. runner, guide or stay vanes). The modern advantages of computational capabilities regarding numerical investigations allow a precise prediction of appearing flow conditions and thereby induced strains in hydraulic machines. This paper focuses on the calculation of the unsteady pressure field of a high head Francis turbine with a specific speed of nq ≈ 24 min-1 and its impact on the structure at different operating conditions. In the first step, unsteady numerical flow simulations are performed with the open-source CFD software OpenFOAM. To obtain the appearing dynamic flow phenomena, the entire machine, consisting of the spiral casing, the stay vanes, the wicket gate, the runner and the draft tube, is taken into account. Additionally, a reduced model without the spiral casing and with a simplified inlet boundary is used. To evaluate the accuracy of the CFD simulations, operating parameters such as head and torque are compared with the results of site measurements carried out on the corresponding prototype machine. In the second part, the obtained pressure fields are used for a fluid-structure analysis with the open-source Finite Element software Code_Aster, to predict the static loads on the runner.

Blade number impact on pressure and performance of archimedes screw turbine using CFD

NASA Astrophysics Data System (ADS)

Maulana, Muhammad Ilham; Syuhada, Ahmad; Nawawi, Muhammad

2018-02-01

Many rivers in Indonesia can be used as source of mini/micro hydro power plant using low head turbine. The most suitable type of turbine used in fluid flow with low head is the Archimedes screw turbine. The Archimedes screw hydro turbine is a relative newcomer to the small-scale hydropower that can work efficiently on heads as low as 10 meter. In this study, the performance of Archimedes water turbines that has different blade numbers that are thoroughly evaluated to obtain proper blade configuration. For this purpose, numerical simulations are used to predict the pressure changes that occur along the turbine. The simulation results show that turbines with an amount of two blades have more sloping pressure distribution so that it has better stability.

Introduction Wind farms in complex terrains: an introduction.

PubMed

Alfredsson, P H; Segalini, A

2017-04-13

Wind energy is one of the fastest growing sources of sustainable energy production. As more wind turbines are coming into operation, the best locations are already becoming occupied by turbines, and wind-farm developers have to look for new and still available areas-locations that may not be ideal such as complex terrain landscapes. In these locations, turbulence and wind shear are higher, and in general wind conditions are harder to predict. Also, the modelling of the wakes behind the turbines is more complicated, which makes energy-yield estimates more uncertain than under ideal conditions. This theme issue includes 10 research papers devoted to various fluid-mechanics aspects of using wind energy in complex terrains and illustrates recent progress and future developments in this important field.This article is part of the themed issue 'Wind energy in complex terrains'. © 2017 The Author(s).

Investigation of Dynamic Aerodynamics and Control of Wind Turbine Sections Under Relevant Inflow/Blade Attitude Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naughton, Jonathan W.

2014-08-05

The growth of wind turbines has led to highly variable loading on the blades. Coupled with the relative reduced stiffness of longer blades, the need to control loading on the blades has become important. One method of controlling loads and maximizing energy extraction is local control of the flow on the wind turbine blades. The goal of the present work was to better understand the sources of the unsteady loading and then to control them. This is accomplished through an experimental effort to characterize the unsteadiness and the effect of a Gurney flap on the flow, as well as anmore » analytical effort to develop control approaches. It was planned to combine these two efforts to demonstrate control of a wind tunnel test model, but that final piece still remains to be accomplished.« less

Design of horizontal-axis wind turbine using blade element momentum method

NASA Astrophysics Data System (ADS)

Bobonea, Andreea; Pricop, Mihai Victor

2013-10-01

The study of mathematical models applied to wind turbine design in recent years, principally in electrical energy generation, has become significant due to the increasing use of renewable energy sources with low environmental impact. Thus, this paper shows an alternative mathematical scheme for the wind turbine design, based on the Blade Element Momentum (BEM) Theory. The results from the BEM method are greatly dependent on the precision of the lift and drag coefficients. The basic of BEM method assumes the blade can be analyzed as a number of independent element in spanwise direction. The induced velocity at each element is determined by performing the momentum balance for a control volume containing the blade element. The aerodynamic forces on the element are calculated using the lift and drag coefficient from the empirical two-dimensional wind tunnel test data at the geometric angle of attack (AOA) of the blade element relative to the local flow velocity.

Damage Detection Based on Static Strain Responses Using FBG in a Wind Turbine Blade.

PubMed

Tian, Shaohua; Yang, Zhibo; Chen, Xuefeng; Xie, Yong

2015-08-14

The damage detection of a wind turbine blade enables better operation of the turbines, and provides an early alert to the destroyed events of the blade in order to avoid catastrophic losses. A new non-baseline damage detection method based on the Fiber Bragg grating (FBG) in a wind turbine blade is developed in this paper. Firstly, the Chi-square distribution is proven to be an effective damage-sensitive feature which is adopted as the individual information source for the local decision. In order to obtain the global and optimal decision for the damage detection, the feature information fusion (FIF) method is proposed to fuse and optimize information in above individual information sources, and the damage is detected accurately through of the global decision. Then a 13.2 m wind turbine blade with the distributed strain sensor system is adopted to describe the feasibility of the proposed method, and the strain energy method (SEM) is used to describe the advantage of the proposed method. Finally results show that the proposed method can deliver encouraging results of the damage detection in the wind turbine blade.

Estimation of Acoustic Particle Motion and Source Bearing Using a Drifting Hydrophone Array Near a River Current Turbine to Assess Disturbances to Fish

NASA Astrophysics Data System (ADS)

Murphy, Paul G.

River hydrokinetic turbines may be an economical alternative to traditional energy sources for small communities on Alaskan rivers. However, there is concern that sound from these turbines could affect sockeye salmon (Oncorhynchus nerka), an important resource for small, subsistence based communities, commercial fisherman, and recreational anglers. The hearing sensitivity of sockeye salmon has not been quantified, but behavioral responses to sounds at frequencies less than a few hundred Hertz have been documented for Atlantic salmon (Salmo salar), and particle motion is thought to be the primary mode of stimulation. Methods of measuring acoustic particle motion are well-established, but have rarely been necessary in energetic areas, such as river and tidal current environments. In this study, the acoustic pressure in the vicinity of an operating river current turbine is measured using a freely drifting hydrophone array. Analysis of turbine sound reveals tones that vary in frequency and magnitude with turbine rotation rate, and that may sockeye salmon may sense. In addition to pressure, the vertical components of particle acceleration and velocity are estimated by calculating the finite difference of the pressure signals from the hydrophone array. A method of determining source bearing using an array of hydrophones is explored. The benefits and challenges of deploying drifting hydrophone arrays for marine renewable energy converter monitoring are discussed.

Foundations for offshore wind turbines.

PubMed

Byrne, B W; Houlsby, G T

2003-12-15

An important engineering challenge of today, and a vital one for the future, is to develop and harvest alternative sources of energy. This is a firm priority in the UK, with the government setting a target of 10% of electricity from renewable sources by 2010. A component central to this commitment will be to harvest electrical power from the vast energy reserves offshore, through wind turbines or current or wave power generators. The most mature of these technologies is that of wind, as much technology transfer can be gained from onshore experience. Onshore wind farms, although supplying 'green energy', tend to provoke some objections on aesthetic grounds. These objections can be countered by locating the turbines offshore, where it will also be possible to install larger capacity turbines, thus maximizing the potential of each wind farm location. This paper explores some civil-engineering problems encountered for offshore wind turbines. A critical component is the connection of the structure to the ground, and in particular how the load applied to the structure is transferred safely to the surrounding soil. We review previous work on the design of offshore foundations, and then present some simple design calculations for sizing foundations and structures appropriate to the wind-turbine problem. We examine the deficiencies in the current design approaches, and the research currently under way to overcome these deficiencies. Designs must be improved so that these alternative energy sources can compete economically with traditional energy suppliers.

Wind Energy Modeling and Simulation | Wind | NREL

Science.gov Websites

Wind Energy Modeling and Simulation Wind Turbine Modeling and Simulation Wind turbines are unique wind turbines. It enables the analysis of a range of wind turbine configurations, including: Two- or (SOWFA) employs computational fluid dynamics to allow users to investigate wind turbine and wind power

Systems Engineering Models and Tools | Wind | NREL

Science.gov Websites

(tm)) that provides wind turbine and plant engineering and cost models for holistic system analysis turbine/component models and wind plant analysis models that the systems engineering team produces. If you integrated modeling of wind turbines and plants. It provides guidance for overall wind turbine and plant

Location of aerodynamic noise sources from a 200 kW vertical-axis wind turbine

NASA Astrophysics Data System (ADS)

Ottermo, Fredric; Möllerström, Erik; Nordborg, Anders; Hylander, Jonny; Bernhoff, Hans

2017-07-01

Noise levels emitted from a 200 kW H-rotor vertical-axis wind turbine have been measured using a microphone array at four different positions, each at a hub-height distance from the tower. The microphone array, comprising 48 microphones in a spiral pattern, allows for directional mapping of the noise sources in the range of 500 Hz to 4 kHz. The produced images indicate that most of the noise is generated in a narrow azimuth-angle range, compatible with the location where increased turbulence is known to be present in the flow, as a result of the previous passage of a blade and its support arms. It is also shown that a semi-empirical model for inflow-turbulence noise seems to produce noise levels of the correct order of magnitude, based on the amount of turbulence that could be expected from power extraction considerations.

Experimental and numerical study of a 10MW TLP wind turbine in waves and wind

NASA Astrophysics Data System (ADS)

Pegalajar-Jurado, Antonio; Hansen, Anders M.; Laugesen, Robert; Mikkelsen, Robert F.; Borg, Michael; Kim, Taeseong; Heilskov, Nicolai F.; Bredmose, Henrik

2016-09-01

This paper presents tests on a 1:60 version of the DTU 10MW wind turbine mounted on a tension leg platform and their numerical reproduction. Both the experimental setup and the numerical model are Froude-scaled, and the dynamic response of the floating wind turbine to wind and waves is compared in terms of motion in the six degrees of freedom, nacelle acceleration and mooring line tension. The numerical model is implemented in the aero-elastic code Flex5, featuring the unsteady BEM method and the Morison equation for the modelling of aerodynamics and hydrodynamics, respectively. It was calibrated with the tests by matching key system features, namely the steady thrust curve and the decay tests in water. The calibrated model is used to reproduce the wind-wave climates in the laboratory, including regular and irregular waves, with and without wind. The model predictions are compared to the measured data, and a good agreement is found for surge and heave, while some discrepancies are observed for pitch, nacelle acceleration and line tension. The addition of wind generally improves the agreement with test results. The aerodynamic damping is identified in both tests and simulations. Finally, the sources of the discrepancies are discussed and some improvements in the numerical model are suggested in order to obtain a better agreement with the experiments.

Dynamic vibrations in wind energy systems: Application to vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Mabrouk, Imen Bel; El Hami, Abdelkhalak; Walha, Lassâad; Zghal, Bacem; Haddar, Mohamed

2017-02-01

Dynamic analysis of Darrieus turbine bevel spur gear subjected to transient aerodynamic loads is carried out in the present study. The aerodynamic torque is obtained by solving the two dimensional unsteady incompressible Navies Stocks equation with the k-ω shear stress transport turbulence model. The results are presented for several values of tip speed ratio. The two-dimensional Computational Fluid Dynamics model is validated with experimental results. The optimum tip speed ratio is achieved, giving the best overall performance. In this study, we developed a lamped mass dynamic model with 14 degrees of freedom. This model is excited by external and internal issues sources. The main factors of these excitations are the periodic fluctuations of the gear meshes' stiffness and the unsteady aerodynamic torque oscillations. The vibration responses are obtained in time and frequency domains. The originality of our work is the correlation between the complexity of the aerodynamic phenomenon and the non-stationary dynamics vibration of the mechanical gearing system. The effect of the rotational speed on the dynamic behavior of the Darrieus turbine is also discussed. The present study shows that the variation of rotor rotational speed directly affects the torque production. However, there is a small change in the dynamic vibration of the studied gearing system.

Broad band sound from wind turbine generators

NASA Technical Reports Server (NTRS)

Hubbard, H. H.; Shepherd, K. P.; Grosveld, F. W.

1981-01-01

Brief descriptions are given of the various types of large wind turbines and their sound characteristics. Candidate sources of broadband sound are identified and are rank ordered for a large upwind configuration wind turbine generator for which data are available. The rotor is noted to be the main source of broadband sound which arises from inflow turbulence and from the interactions of the turbulent boundary layer on the blade with its trailing edge. Sound is radiated about equally in all directions but the refraction effects of the wind produce an elongated contour pattern in the downwind direction.

Deterministic Stress Modeling of Hot Gas Segregation in a Turbine

NASA Technical Reports Server (NTRS)

Busby, Judy; Sondak, Doug; Staubach, Brent; Davis, Roger

1998-01-01

Simulation of unsteady viscous turbomachinery flowfields is presently impractical as a design tool due to the long run times required. Designers rely predominantly on steady-state simulations, but these simulations do not account for some of the important unsteady flow physics. Unsteady flow effects can be modeled as source terms in the steady flow equations. These source terms, referred to as Lumped Deterministic Stresses (LDS), can be used to drive steady flow solution procedures to reproduce the time-average of an unsteady flow solution. The goal of this work is to investigate the feasibility of using inviscid lumped deterministic stresses to model unsteady combustion hot streak migration effects on the turbine blade tip and outer air seal heat loads using a steady computational approach. The LDS model is obtained from an unsteady inviscid calculation. The LDS model is then used with a steady viscous computation to simulate the time-averaged viscous solution. Both two-dimensional and three-dimensional applications are examined. The inviscid LDS model produces good results for the two-dimensional case and requires less than 10% of the CPU time of the unsteady viscous run. For the three-dimensional case, the LDS model does a good job of reproducing the time-averaged viscous temperature migration and separation as well as heat load on the outer air seal at a CPU cost that is 25% of that of an unsteady viscous computation.

Modeling Hydrodynamic Changes Due to Marine Hydrokinetic Power Production: Community Outreach and Education

NASA Astrophysics Data System (ADS)

James, S. C.; Jones, C.; Roberts, J.

2013-12-01

Power generation with marine hydrokinetic (MHK) turbines is receiving growing global interest. Because of reasonable investment, maintenance, reliability, and environmental friendliness, this technology can contribute to national (and global) energy markets and is worthy of research investment. Furthermore, in remote areas, small-scale MHK energy from river, tidal, or ocean currents can provide a local power supply. The power-generating capacity of MHK turbines will depend, among other factors, upon the turbine type and number and the local flow velocities. There is an urgent need for deployment of practical, accessible tools and techniques to help the industry optimize MHK array layouts while establishing best sitting and design practices that minimize environmental impacts. Sandia National Laboratories (SNL) has modified the open-source flow and transport Environmental Fluid Dynamics Code (EFDC) to include the capability of simulating the effects of MHK power production. Upon removing energy (momentum) from the system, changes to the local and far-field flow dynamics can be estimated (e.g., flow speeds, tidal ranges, flushing rates, etc.). The effects of these changes on sediment dynamics and water quality can also be simulated using this model. Moreover, the model can be used to optimize MHK array layout to maximize power capture and minimize environmental impacts. Both a self-paced tutorial and in-depth training course have been developed as part of an outreach program to train academics, technology developers, and regulators in the use and application of this software. This work outlines SNL's outreach efforts using this modeling framework as applied to two specific sites where MHK turbines have been deployed.

Toward improved durability in advanced aircraft engine hot sections

NASA Technical Reports Server (NTRS)

Sokolowski, Daniel E. (Editor)

1989-01-01

The conference on durability improvement methods for advanced aircraft gas turbine hot-section components discussed NASA's Hot Section Technology (HOST) project, advanced high-temperature instrumentation for hot-section research, the development and application of combustor aerothermal models, and the evaluation of a data base and numerical model for turbine heat transfer. Also discussed are structural analysis methods for gas turbine hot section components, fatigue life-prediction modeling for turbine hot section materials, and the service life modeling of thermal barrier coatings for aircraft gas turbine engines.

A surface ice module for wind turbine dynamic response simulation using FAST

DOE PAGES

Yu, Bingbin; Karr, Dale G.; Song, Huimin; ...

2016-06-03

It is a fact that developing offshore wind energy has become more and more serious worldwide in recent years. Many of the promising offshore wind farm locations are in cold regions that may have ice cover during wintertime. The challenge of possible ice loads on offshore wind turbines raises the demand of modeling capacity of dynamic wind turbine response under the joint action of ice, wind, wave, and current. The simulation software FAST is an open source computer-aided engineering (CAE) package maintained by the National Renewable Energy Laboratory. In this paper, a new module of FAST for assessing the dynamicmore » response of offshore wind turbines subjected to ice forcing is presented. In the ice module, several models are presented which involve both prescribed forcing and coupled response. For conditions in which the ice forcing is essentially decoupled from the structural response, ice forces are established from existing models for brittle and ductile ice failure. For conditions in which the ice failure and the structural response are coupled, such as lock-in conditions, a rate-dependent ice model is described, which is developed in conjunction with a new modularization framework for FAST. In this paper, analytical ice mechanics models are presented that incorporate ice floe forcing, deformation, and failure. For lower speeds, forces slowly build until the ice strength is reached and ice fails resulting in a quasi-static condition. For intermediate speeds, the ice failure can be coupled with the structural response and resulting in coinciding periods of the ice failure and the structural response. A third regime occurs at high speeds of encounter in which brittle fracturing of the ice feature occurs in a random pattern, which results in a random vibration excitation of the structure. An example wind turbine response is simulated under ice loading of each of the presented models. This module adds to FAST the capabilities for analyzing the response of wind turbines subjected to forces resulting from ice impact on the turbine support structure. The conditions considered in this module are specifically addressed in the International Organization for Standardization (ISO) standard 19906:2010 for arctic offshore structures design consideration. Special consideration of lock-in vibrations is required due to the detrimental effects of such response with regard to fatigue and foundation/soil response. Finally, the use of FAST for transient, time domain simulation with the new ice module is well suited for such analyses.« less

Optimization of PV/WIND/DIESEL Hybrid Power System in HOMER for Rural Electrification

NASA Astrophysics Data System (ADS)

Hassan, Q.; Jaszczur, M.; Abdulateef, J.

2016-09-01

A large proportion of the world's population lives in remote rural areas that are geographically isolated and sparsely populated. The present study is based on modeling, computer simulation and optimization of hybrid power generation system in the rural area in Muqdadiyah district of Diyala state, Iraq. Two renewable resources, namely, solar photovoltaic (PV) and wind turbine (WT) are considered. The HOMER software is used to study and design the proposed hybrid energy system model. Based on simulation results, it has been found that renewable energy sources perhaps replace the conventional energy sources and would be a feasible solution for the generation of electric power at remote locations with a reasonable investment. The hybrid power system solution to electrify the selected area resulted in a least-cost combination of the hybrid power system that can meet the demand in a dependable manner at a cost about (0.321/kWh). If the wind resources in the study area at the lower stage, it's not economically viable for a wind turbine to generate the electricity.

Improving Wind Predictions in the Marine Atmospheric Boundary Layer through Parameter Estimation in a Single-Column Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Jared A.; Hacker, Joshua P.; Delle Monache, Luca

2016-12-14

A current barrier to greater deployment of offshore wind turbines is the poor quality of numerical weather prediction model wind and turbulence forecasts over open ocean. The bulk of development for atmospheric boundary layer (ABL) parameterization schemes has focused on land, partly due to a scarcity of observations over ocean. The 100-m FINO1 tower in the North Sea is one of the few sources worldwide of atmospheric profile observations from the sea surface to turbine hub height. These observations are crucial to developing a better understanding and modeling of physical processes in the marine ABL. In this study, we usemore » the WRF single column model (SCM), coupled with an ensemble Kalman filter from the Data Assimilation Research Testbed (DART), to create 100-member ensembles at the FINO1 location. The goal of this study is to determine the extent to which model parameter estimation can improve offshore wind forecasts.« less

Control of Air Pollution from Aviation: The Emission Standard Setting Process.

DTIC Science & Technology

1981-01-01

49 VIII-2 ORGANIC EMISSIONS FROM GAS TURBINE ENGINES .......... 64 VIII-3 THE REACTIVITY OF AIRCRAFT COMPARED WITH OTHER EMISSION SOURCES...SETTING PROCESS ............................................... 45 VIII-I GAS TURBINE POLLUTANT FORMATION AND DECOMPO- SITION...144 A-4-3 AIRCRAFT GAS TURBINE POLLUTION CONSIDERATIONS ....... 145 A-4-4 PRIMARY ZONE ENRICHMENT, DELAYED DILUTION, AND AIRBLAST

Shape Memory Alloy Actuator

NASA Technical Reports Server (NTRS)

Baumbick, Robert J. (Inventor)

2000-01-01

The present invention discloses and teaches a unique, remote optically controlled micro actuator particularly suitable for aerospace vehicle applications wherein hot gas, or in the alternative optical energy, is employed as the medium by which shape memory alloy elements are activated. In gas turbine powered aircraft the source of the hot gas may be the turbine engine compressor or turbine sections.

Shape Memory Alloy Actuator

NASA Technical Reports Server (NTRS)

Baumbick, Robert J. (Inventor)

2002-01-01

The present invention discloses and teaches a unique, remote optically controlled micro actuator particularly suitable for aerospace vehicle applications wherein hot gas, or in the alternative optical energy, is employed as the medium by which shape memory alloy elements are activated. In gas turbine powered aircraft the source of the hot gas may be the turbine engine compressor or turbine sections.

Numerical simulation of turbulence flow in a Kaplan turbine -Evaluation on turbine performance prediction accuracy-

NASA Astrophysics Data System (ADS)

Ko, P.; Kurosawa, S.

2014-03-01

The understanding and accurate prediction of the flow behaviour related to cavitation and pressure fluctuation in a Kaplan turbine are important to the design work enhancing the turbine performance including the elongation of the operation life span and the improvement of turbine efficiency. In this paper, high accuracy turbine and cavitation performance prediction method based on entire flow passage for a Kaplan turbine is presented and evaluated. Two-phase flow field is predicted by solving Reynolds-Averaged Navier-Stokes equations expressed by volume of fluid method tracking the free surface and combined with Reynolds Stress model. The growth and collapse of cavitation bubbles are modelled by the modified Rayleigh-Plesset equation. The prediction accuracy is evaluated by comparing with the model test results of Ns 400 Kaplan model turbine. As a result that the experimentally measured data including turbine efficiency, cavitation performance, and pressure fluctuation are accurately predicted. Furthermore, the cavitation occurrence on the runner blade surface and the influence to the hydraulic loss of the flow passage are discussed. Evaluated prediction method for the turbine flow and performance is introduced to facilitate the future design and research works on Kaplan type turbine.

Integrated Turbine Tip Clearance and Gas Turbine Engine Simulation

NASA Technical Reports Server (NTRS)

Chapman, Jeffryes W.; Kratz, Jonathan; Guo, Ten-Huei; Litt, Jonathan

2016-01-01

Gas turbine compressor and turbine blade tip clearance (i.e., the radial distance between the blade tip of an axial compressor or turbine and the containment structure) is a major contributing factor to gas path sealing, and can significantly affect engine efficiency and operational temperature. This paper details the creation of a generic but realistic high pressure turbine tip clearance model that may be used to facilitate active tip clearance control system research. This model uses a first principles approach to approximate thermal and mechanical deformations of the turbine system, taking into account the rotor, shroud, and blade tip components. Validation of the tip clearance model shows that the results are realistic and reflect values found in literature. In addition, this model has been integrated with a gas turbine engine simulation, creating a platform to explore engine performance as tip clearance is adjusted. Results from the integrated model explore the effects of tip clearance on engine operation and highlight advantages of tip clearance management.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Bingbin; Karr, Dale G.; Song, Huimin

It is a fact that developing offshore wind energy has become more and more serious worldwide in recent years. Many of the promising offshore wind farm locations are in cold regions that may have ice cover during wintertime. The challenge of possible ice loads on offshore wind turbines raises the demand of modeling capacity of dynamic wind turbine response under the joint action of ice, wind, wave, and current. The simulation software FAST is an open source computer-aided engineering (CAE) package maintained by the National Renewable Energy Laboratory. In this paper, a new module of FAST for assessing the dynamicmore » response of offshore wind turbines subjected to ice forcing is presented. In the ice module, several models are presented which involve both prescribed forcing and coupled response. For conditions in which the ice forcing is essentially decoupled from the structural response, ice forces are established from existing models for brittle and ductile ice failure. For conditions in which the ice failure and the structural response are coupled, such as lock-in conditions, a rate-dependent ice model is described, which is developed in conjunction with a new modularization framework for FAST. In this paper, analytical ice mechanics models are presented that incorporate ice floe forcing, deformation, and failure. For lower speeds, forces slowly build until the ice strength is reached and ice fails resulting in a quasi-static condition. For intermediate speeds, the ice failure can be coupled with the structural response and resulting in coinciding periods of the ice failure and the structural response. A third regime occurs at high speeds of encounter in which brittle fracturing of the ice feature occurs in a random pattern, which results in a random vibration excitation of the structure. An example wind turbine response is simulated under ice loading of each of the presented models. This module adds to FAST the capabilities for analyzing the response of wind turbines subjected to forces resulting from ice impact on the turbine support structure. The conditions considered in this module are specifically addressed in the International Organization for Standardization (ISO) standard 19906:2010 for arctic offshore structures design consideration. Special consideration of lock-in vibrations is required due to the detrimental effects of such response with regard to fatigue and foundation/soil response. Finally, the use of FAST for transient, time domain simulation with the new ice module is well suited for such analyses.« less

Wind turbines acoustic measurements

NASA Astrophysics Data System (ADS)

Trematerra, Amelia; Iannace, Gino

2017-07-01

The importance of wind turbines has increased over the last few years throughout the European Community. The European energy policy guidelines state that for the year 2020 20% of all energy must be produced by alternative energy sources. Wind turbines are an important type of energy production without petrol. A wind speed in a range from 2.5 m/s to 25.0 m/s is needed. One of the obstacles to the widespread diffusion of wind turbine is noise generation. This work presents some noise measurements of wind turbines in the South of Italy, and discusses the noise problems for the people living near wind farms.

Wind Energy Program Summary. Volume 2: Research summaries, fiscal year 1988

NASA Astrophysics Data System (ADS)

1989-04-01

Activities by the Federal Wind Energy program since the early 1980s have focused on developing a technology base necessary for industry to demonstrate the viability of wind energy as an alternative energy supply. The Federal Wind Energy Program's research has targeted the sciences of wind turbine dynamics and the development of advanced components and systems. These efforts have resulted in major advancements toward the development and commercialization of wind technology as an alternative energy source. The installation of more than 16,000 wind turbines in California by the end of 1987 provides evidence that commercial use of wind energy technology can be a viable source of electric power. Research in wind turbine sciences has focused on atmospheric fluid dynamics, aerodynamics, and structural dynamics. As outlines in the projects that are described in this document, advancements in atmospheric fluid dynamics have been made through the development and refinement of wind characterization models and wind/rotor interaction prediction codes. Recent gains in aerodynamics can be attributed to a better understanding of airfoil operations, using innovative research approaches such as flow-visualization techniques. Qualitative information and data from laboratory and field tests are being used to document fatigue damage processes. These data are being used to develop new theories and data bases for structural dynamics, and will help to achieve long-term unit life and lower capital and maintenance costs. Material characterization and modeling techniques have been improved to better analyze effects of stress and fatigue on system components.

HOMER: The Micropower Optimization Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2004-03-01

HOMER, the micropower optimization model, helps users to design micropower systems for off-grid and grid-connected power applications. HOMER models micropower systems with one or more power sources including wind turbines, photovoltaics, biomass power, hydropower, cogeneration, diesel engines, cogeneration, batteries, fuel cells, and electrolyzers. Users can explore a range of design questions such as which technologies are most effective, what size should components be, how project economics are affected by changes in loads or costs, and is the renewable resource adequate.

Assessment of arrays of in-stream tidal turbines in the Bay of Fundy.

PubMed

Karsten, Richard; Swan, Amanda; Culina, Joel

2013-02-28

Theories of in-stream turbines are adapted to analyse the potential electricity generation and impact of turbine arrays deployed in Minas Passage, Bay of Fundy. Linear momentum actuator disc theory (LMADT) is combined with a theory that calculates the flux through the passage to determine both the turbine power and the impact of rows of turbine fences. For realistically small blockage ratios, the theory predicts that extracting 2000-2500 MW of turbine power will result in a reduction in the flow of less than 5 per cent. The theory also suggests that there is little reason to tune the turbines if the blockage ratio remains small. A turbine array model is derived that extends LMADT by using the velocity field from a numerical simulation of the flow through Minas Passage and modelling the turbine wakes. The model calculates the resulting speed of the flow through and around a turbine array, allowing for the sequential positioning of turbines in regions of strongest flow. The model estimates that over 2000 MW of power is possible with only a 2.5 per cent reduction in the flow. If turbines are restricted to depths less than 50 m, the potential power generation is reduced substantially, down to 300 MW. For large turbine arrays, the blockage ratios remain small and the turbines can produce maximum power with a drag coefficient equal to the Betz-limit value.

Thermoelastic steam turbine rotor control based on neural network

NASA Astrophysics Data System (ADS)

Rzadkowski, Romuald; Dominiczak, Krzysztof; Radulski, Wojciech; Szczepanik, R.

2015-12-01

Considered here are Nonlinear Auto-Regressive neural networks with eXogenous inputs (NARX) as a mathematical model of a steam turbine rotor for controlling steam turbine stress on-line. In order to obtain neural networks that locate critical stress and temperature points in the steam turbine during transient states, an FE rotor model was built. This model was used to train the neural networks on the basis of steam turbine transient operating data. The training included nonlinearity related to steam turbine expansion, heat exchange and rotor material properties during transients. Simultaneous neural networks are algorithms which can be implemented on PLC controllers. This allows for the application neural networks to control steam turbine stress in industrial power plants.

Some Problems of Exploitation of Jet Turbine Aircraft Engines of Lot Polish Air Lines,

DTIC Science & Technology

1977-04-26

CI ‘AD~AOII6 221 FOREIGN TECHNOLOGY DIV WR IGHT—PATTERSON AFB OHIO F/I 21/5SOME PROBLEMS OF EXPLOITATION OF JET TURBINE AIRCRAFT ENGINES O—CTC(U...EXPLOITATION OF JET TURBINE AIRCRAFT ENGINES OF LOT POLISH AIR LINE S By: Andrzej Slodownik English pages: 1~ Source: Technika Lotnicza I Astronautyczna...SOME PROBLEMS OF EXPLOITATION OF JET TURBINE AIRCRAFT ENGINES OF LOT POLISH AIR LINES Andrzej Slodownik , M. Eng . FTD— ID ( RS) I— 0 1475 — 77 I

Measuring wind turbine wakes and unsteady loading in a micro wind farm model

NASA Astrophysics Data System (ADS)

Bossuyt, Juliaan; Meneveau, Charles; Meyers, Johan

2014-11-01

Very large wind farms, approximating the ``infinite'' asymptotic limit, are often studied with LES using periodic boundary conditions. In order to create an experimental realization of such large wind-turbine arrays in a wind tunnel experiment including over 100 turbines, a very small-scale turbine model based on a 3 cm diameter porous disk is designed. The porous disc matches a realistic thrust coefficient between 0.75--0.85, and the far wake flow characteristics of a rotating wind turbine. As a first step, we characterize the properties of a single model turbine. Hot-wire measurements are performed for uniform inflow conditions with different background turbulence intensity levels. Strain gage measurements are used to measure the mean value and power spectra of the thrust force, power output and wind velocity in front of the turbine. The dynamics of the wind turbine are modeled making it possible to measure force spectra at least up to the natural frequency of the model. This is shown by reproducing the -5/3 spectrum from the incoming flow and the vortex shedding signatures of an upstream obstruction. An array with a large number of these instrumented model turbines is placed in JHU's Corrsin wind tunnel, to study effects of farm layout on total power output and turbine loading. Work supported by ERC (ActiveWindFarms, Grant No: 306471), and by NSF (CBET-113380 and IIA-1243482).

Modelling tidal current energy extraction in large area using a three-dimensional estuary model

NASA Astrophysics Data System (ADS)

Chen, Yaling; Lin, Binliang; Lin, Jie

2014-11-01

This paper presents a three-dimensional modelling study for simulating tidal current energy extraction in large areas, with a momentum sink term being added into the momentum equations. Due to the limits of computational capacity, the grid size of the numerical model is generally much larger than the turbine rotor diameter. Two models, i.e. a local grid refinement model and a coarse grid model, are employed and an idealized estuary is set up. The local grid refinement model is constructed to simulate the power generation of an isolated turbine and its impacts on hydrodynamics. The model is then used to determine the deployment of turbine farm and quantify a combined thrust coefficient for multiple turbines located in a grid element of coarse grid model. The model results indicate that the performance of power extraction is affected by array deployment, with more power generation from outer rows than inner rows due to velocity deficit influence of upstream turbines. Model results also demonstrate that the large-scale turbine farm has significant effects on the hydrodynamics. The tidal currents are attenuated within the turbine swept area, and both upstream and downstream of the array. While the currents are accelerated above and below turbines, which is contributed to speeding up the wake mixing process behind the arrays. The water levels are heightened in both low and high water levels as the turbine array spanning the full width of estuary. The magnitude of water level change is found to increase with the array expansion, especially at the low water level.

Part 1 - Experimental study of the pressure fluctuations on propeller turbine runner blades during steady-state operation

NASA Astrophysics Data System (ADS)

Houde, S.; Fraser, R.; Ciocan, G. D.; Deschênes, C.

2012-11-01

A good evaluation of the unsteady pressure field on hydraulic turbine blades is critical in evaluating the turbine lifespan and its maintenance schedule. Low-head turbines such as Kaplan and Propeller, using a relatively low number of blades supported only at the hub, may also undergo significant deflections at the blade tips which will lead to higher amplitude vibration compared to Francis turbines. Furthermore, the precise evaluation of the unsteady pressure distribution on low-head turbines is still a challenge for computational fluid dynamics (CFD). Within the framework of an international research consortium on low-head turbines, a research project was instigated at the Hydraulic Machines Laboratory in Laval University (LAMH) to perform experimental measurements of the unsteady pressure field on propeller turbine model runner blades. The main objective of the project was to measure the pressure fluctuations on a wide band of frequencies, both in a blade-to-blade channel and on the pressure and suction side of the same blade, to provide validation data for CFD computations. To do so, a 32 channels telemetric data transmission system was used to extract the signal of 31 pressure transducers and two strain gages from the rotating part at an acquisition frequency of 5 KHz. The miniature piezoelectric pressure transducers were placed on two adjacent runner blades according to an estimated pressure distribution coming from flow simulations. Two suction sides and one pressure side were instrumented. The strain gages were mounted in full-bridge on both pressure and suction sides to measure the blade span wise deflection. In order to provide boundary conditions for flow simulations, the test bench conditions during the measurements were acquired. The measurements were made in different operating conditions ranging from part load, where a cavitating vortex occurs, to full load under different heads. The results enabled the identification and the quantification of the major known sources of pressure fluctuation as well as some unexpected ones. The paper first presents the experimental methodology discussing relevant topics such as telemetric system setup, transducers calibration and errors analysis. The main results are then presented to illustrate the relative amplitude of the main source of pressure fluctuations under different operating conditions. The discussion and conclusion addresses the important observations stemming from the data analysis and illustrates that most of the results can be correlated with the known behavior of hydraulic turbines while some require further investigation.

Development and Implementation of Mechanistic Terry Turbine Models in RELAP-7 to Simulate RCIC Normal Operation Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Haihua; Zou, Ling; Zhang, Hongbin

As part of the efforts to understand the unexpected “self-regulating” mode of the RCIC (Reactor Core Isolation Cooling) systems in Fukushima accidents and extend BWR RCIC and PWR AFW (Auxiliary Feed Water) operational range and flexibility, mechanistic models for the Terry turbine, based on Sandia’s original work [1], have been developed and implemented in the RELAP-7 code to simulate the RCIC system. In 2016, our effort has been focused on normal working conditions of the RCIC system. More complex off-design conditions will be pursued in later years when more data are available. In the Sandia model, the turbine stator inletmore » velocity is provided according to a reduced-order model which was obtained from a large number of CFD (computational fluid dynamics) simulations. In this work, we propose an alternative method, using an under-expanded jet model to obtain the velocity and thermodynamic conditions for the turbine stator inlet. The models include both an adiabatic expansion process inside the nozzle and a free expansion process outside of the nozzle to ambient pressure. The combined models are able to predict the steam mass flow rate and supersonic velocity to the Terry turbine bucket entrance, which are the necessary input information for the Terry turbine rotor model. The analytical models for the nozzle were validated with experimental data and benchmarked with CFD simulations. The analytical models generally agree well with the experimental data and CFD simulations. The analytical models are suitable for implementation into a reactor system analysis code or severe accident code as part of mechanistic and dynamical models to understand the RCIC behaviors. The newly developed nozzle models and modified turbine rotor model according to the Sandia’s original work have been implemented into RELAP-7, along with the original Sandia Terry turbine model. A new pump model has also been developed and implemented to couple with the Terry turbine model. An input model was developed to test the Terry turbine RCIC system, which generates reasonable results. Both the INL RCIC model and the Sandia RCIC model produce results matching major rated parameters such as the rotational speed, pump torque, and the turbine shaft work for the normal operation condition. The Sandia model is more sensitive to the turbine outlet pressure than the INL model. The next step will be further refining the Terry turbine models by including two-phase flow cases so that off-design conditions can be simulated. The pump model could also be enhanced with the use of the homologous curves.« less

Turbine disk cavity aerodynamics and heat transfer

NASA Technical Reports Server (NTRS)

Johnson, B. V.; Daniels, W. A.

1992-01-01

Experiments were conducted to define the nature of the aerodynamics and heat transfer for the flow within the disk cavities and blade attachments of a large-scale model, simulating the Space Shuttle Main Engine (SSME) turbopump drive turbines. These experiments of the aerodynamic driving mechanisms explored the following: (1) flow between the main gas path and the disk cavities; (2) coolant flow injected into the disk cavities; (3) coolant density; (4) leakage flows through the seal between blades; and (5) the role that each of these various flows has in determining the adiabatic recovery temperature at all of the critical locations within the cavities. The model and the test apparatus provide close geometrical and aerodynamic simulation of all the two-stage cavity flow regions for the SSME High Pressure Fuel Turbopump and the ability to simulate the sources and sinks for each cavity flow.

Turbine Sound May Influence the Metamorphosis Behaviour of Estuarine Crab Megalopae

PubMed Central

Pine, Matthew K.; Jeffs, Andrew G.; Radford, Craig A.

2012-01-01

It is now widely accepted that a shift towards renewable energy production is needed in order to avoid further anthropogenically induced climate change. The ocean provides a largely untapped source of renewable energy. As a result, harvesting electrical power from the wind and tides has sparked immense government and commercial interest but with relatively little detailed understanding of the potential environmental impacts. This study investigated how the sound emitted from an underwater tidal turbine and an offshore wind turbine would influence the settlement and metamorphosis of the pelagic larvae of estuarine brachyuran crabs which are ubiquitous in most coastal habitats. In a laboratory experiment the median time to metamorphosis (TTM) for the megalopae of the crabs Austrohelice crassa and Hemigrapsus crenulatus was significantly increased by at least 18 h when exposed to either tidal turbine or sea-based wind turbine sound, compared to silent control treatments. Contrastingly, when either species were subjected to natural habitat sound, observed median TTM decreased by approximately 21–31% compared to silent control treatments, 38–47% compared to tidal turbine sound treatments, and 46–60% compared to wind turbine sound treatments. A lack of difference in median TTM in A. crassa between two different source levels of tidal turbine sound suggests the frequency composition of turbine sound is more relevant in explaining such responses rather than sound intensity. These results show that estuarine mudflat sound mediates natural metamorphosis behaviour in two common species of estuarine crabs, and that exposure to continuous turbine sound interferes with this natural process. These results raise concerns about the potential ecological impacts of sound generated by renewable energy generation systems placed in the nearshore environment. PMID:23240063

Turbine sound may influence the metamorphosis behaviour of estuarine crab megalopae.

PubMed

Pine, Matthew K; Jeffs, Andrew G; Radford, Craig A

2012-01-01

It is now widely accepted that a shift towards renewable energy production is needed in order to avoid further anthropogenically induced climate change. The ocean provides a largely untapped source of renewable energy. As a result, harvesting electrical power from the wind and tides has sparked immense government and commercial interest but with relatively little detailed understanding of the potential environmental impacts. This study investigated how the sound emitted from an underwater tidal turbine and an offshore wind turbine would influence the settlement and metamorphosis of the pelagic larvae of estuarine brachyuran crabs which are ubiquitous in most coastal habitats. In a laboratory experiment the median time to metamorphosis (TTM) for the megalopae of the crabs Austrohelice crassa and Hemigrapsus crenulatus was significantly increased by at least 18 h when exposed to either tidal turbine or sea-based wind turbine sound, compared to silent control treatments. Contrastingly, when either species were subjected to natural habitat sound, observed median TTM decreased by approximately 21-31% compared to silent control treatments, 38-47% compared to tidal turbine sound treatments, and 46-60% compared to wind turbine sound treatments. A lack of difference in median TTM in A. crassa between two different source levels of tidal turbine sound suggests the frequency composition of turbine sound is more relevant in explaining such responses rather than sound intensity. These results show that estuarine mudflat sound mediates natural metamorphosis behaviour in two common species of estuarine crabs, and that exposure to continuous turbine sound interferes with this natural process. These results raise concerns about the potential ecological impacts of sound generated by renewable energy generation systems placed in the nearshore environment.

Tail Shape Design of Boat Wind Turbines

NASA Astrophysics Data System (ADS)

Singamsitty, Venkatesh

Wind energy is a standout among the most generally utilized sustainable power source assets. A great deal of research and improvements have been happening in the wind energy field. Wind turbines are mechanical devices that convert kinetic energy into electrical power. Boat wind turbines are for the small-scale generation of electric power. In order to catch wind energy effectively, boat wind turbines need to face wind direction. Tails are used in boat wind turbines to alter the wind turbine direction and receive the variation of the incoming direction of wind. Tails are used to change the performance of boat wind turbines in an effective way. They are required to generate a quick and steady response as per change in wind direction. Tails can have various shapes, and their effects on boat wind turbines are different. However, the effects of tail shapes on the performance of boat wind turbines are not thoroughly studied yet. In this thesis, five tail shapes were studied. Their effects on boat wind turbines were investigated. The power extracted by the turbines from the air and the force acting on the boat wind turbine tail were analyzed. The results of this thesis provide a guideline of tail shape design for boat wind turbines.

Combined cycle power plant incorporating coal gasification

DOEpatents

Liljedahl, Gregory N.; Moffat, Bruce K.

1981-01-01

A combined cycle power plant incorporating a coal gasifier as the energy source. The gases leaving the coal gasifier pass through a liquid couplant heat exchanger before being used to drive a gas turbine. The exhaust gases of the gas turbine are used to generate both high pressure and low pressure steam for driving a steam turbine, before being exhausted to the atmosphere.

The thermodynamic cycle models for geothermal power plants by considering the working fluid characteristic

NASA Astrophysics Data System (ADS)

Mulyana, Cukup; Adiprana, Reza; Saad, Aswad H.; M. Ridwan, H.; Muhammad, Fajar

2016-02-01

The scarcity of fossil energy accelerates the development of geothermal power plant in Indonesia. The main issue is how to minimize the energy loss from the geothermal working fluid so that the power generated can be increased. In some of geothermal power plant, the hot water which is resulted from flashing is flown to injection well, and steam out from turbine is condensed in condenser, while the temperature and pressure of the working fluid is still high. The aim of this research is how the waste energy can be re-used as energy source to generate electric power. The step of the research is started by studying the characteristics of geothermal fluid out from the well head. The temperature of fluid varies from 140°C - 250°C, the pressure is more than 7 bar and the fluid phase are liquid, gas, or mixing phase. Dry steam power plant is selected for vapor dominated source, single or multiple flash power plant is used for dominated water with temperature > 225°C, while the binary power plant is used for low temperature of fluid < 160°C. Theoretically, the process in the power plant can be described by thermodynamic cycle. Utilizing the heat loss of the brine and by considering the broad range of working fluid temperature, the integrated geothermal power plant has been developed. Started with two ordinary single flash power plants named unit 1 and unit 2, with the temperature 250°C resulting power is W1'+W2'. The power is enhanced by utilizing the steam that is out from first stage of the turbine by inputting the steam to the third stage, the power of the plant increase with W1''+W2" or 10% from the original power. By using flasher, the water from unit 1 and 2 is re-flashed at 200°C, and the steam is used to drive the turbine in unit 3, while the water is re-flashed at the temperature170°C and the steam is flown to the same turbine (unit 3) resulting the power of W3+W4. Using the fluid enthalpy, the calculated power of these double and triple flash power plant are 50% of W1+W2. At the last step, the steam out from the turbine of unit 3 with the temperature 150°C is used as a heat source for binary cycle power plant named unit 4, while the hot water from the flasher is used as a heat source for the other binary cycle named unit 5 resulted power W5+W6 or 15% of W1+W2. Using this integrated model the power increased 75% from the original one.

Damage Detection Based on Static Strain Responses Using FBG in a Wind Turbine Blade

PubMed Central

Tian, Shaohua; Yang, Zhibo; Chen, Xuefeng; Xie, Yong

2015-01-01

The damage detection of a wind turbine blade enables better operation of the turbines, and provides an early alert to the destroyed events of the blade in order to avoid catastrophic losses. A new non-baseline damage detection method based on the Fiber Bragg grating (FBG) in a wind turbine blade is developed in this paper. Firstly, the Chi-square distribution is proven to be an effective damage-sensitive feature which is adopted as the individual information source for the local decision. In order to obtain the global and optimal decision for the damage detection, the feature information fusion (FIF) method is proposed to fuse and optimize information in above individual information sources, and the damage is detected accurately through of the global decision. Then a 13.2 m wind turbine blade with the distributed strain sensor system is adopted to describe the feasibility of the proposed method, and the strain energy method (SEM) is used to describe the advantage of the proposed method. Finally results show that the proposed method can deliver encouraging results of the damage detection in the wind turbine blade. PMID:26287200

Investigation of the Impact of the Upstream Induction Zone on LIDAR Measurement Accuracy for Wind Turbine Control Applications using Large-Eddy Simulation

NASA Astrophysics Data System (ADS)

Simley, Eric; Y Pao, Lucy; Gebraad, Pieter; Churchfield, Matthew

2014-06-01

Several sources of error exist in lidar measurements for feedforward control of wind turbines including the ability to detect only radial velocities, spatial averaging, and wind evolution. This paper investigates another potential source of error: the upstream induction zone. The induction zone can directly affect lidar measurements and presents an opportunity for further decorrelation between upstream wind and the wind that interacts with the rotor. The impact of the induction zone is investigated using the combined CFD and aeroelastic code SOWFA. Lidar measurements are simulated upstream of a 5 MW turbine rotor and the true wind disturbances are found using a wind speed estimator and turbine outputs. Lidar performance in the absence of an induction zone is determined by simulating lidar measurements and the turbine response using the aeroelastic code FAST with wind inputs taken far upstream of the original turbine location in the SOWFA wind field. Results indicate that while measurement quality strongly depends on the amount of wind evolution, the induction zone has little effect. However, the optimal lidar preview distance and circular scan radius change slightly due to the presence of the induction zone.

Proposed Wind Turbine Aeroelasticity Studies Using Helicopter Systems Analysis

NASA Technical Reports Server (NTRS)

Ladkany, Samaan G.

1998-01-01

Advanced systems for the analysis of rotary wing aeroelastic structures (helicopters) are being developed at NASA Ames by the Rotorcraft Aeromechanics Branch, ARA. The research has recently been extended to the study of wind turbines, used for electric power generation Wind turbines play an important role in Europe, Japan & many other countries because they are non polluting & use a renewable source of energy. European countries such as Holland, Norway & France have been the world leaders in the design & manufacture of wind turbines due to their historical experience of several centuries, in building complex wind mill structures, which were used in water pumping, grain grinding & for lumbering. Fossil fuel cost in Japan & in Europe is two to three times higher than in the USA due to very high import taxes. High fuel cost combined with substantial governmental subsidies, allow wind generated power to be competitive with the more traditional sources of power generation. In the USA, the use of wind energy has been limited mainly because power production from wind is twice as expensive as from other traditional sources. Studies conducted at the National Renewable Energy Laboratories (NREL) indicate that the main cost in the production of wind turbines is due to the materials & the labor intensive processes used in the construction of turbine structures. Thus, for the US to assume world leadership in wind power generation, new lightweight & consequently very flexible wind turbines, that could be economically mass produced, would have to be developed [4,5]. This effort, if successful, would result in great benefit to the US & the developing nations that suffer from overpopulation & a very high cost of energy.

Mathematical modeling and characteristic analysis for over-under turbine based combined cycle engine

NASA Astrophysics Data System (ADS)

Ma, Jingxue; Chang, Juntao; Ma, Jicheng; Bao, Wen; Yu, Daren

2018-07-01

The turbine based combined cycle engine has become the most promising hypersonic airbreathing propulsion system for its superiority of ground self-starting, wide flight envelop and reusability. The simulation model of the turbine based combined cycle engine plays an important role in the research of performance analysis and control system design. In this paper, a turbine based combined cycle engine mathematical model is built on the Simulink platform, including a dual-channel air intake system, a turbojet engine and a ramjet. It should be noted that the model of the air intake system is built based on computational fluid dynamics calculation, which provides valuable raw data for modeling of the turbine based combined cycle engine. The aerodynamic characteristics of turbine based combined cycle engine in turbojet mode, ramjet mode and mode transition process are studied by the mathematical model, and the influence of dominant variables on performance and safety of the turbine based combined cycle engine is analyzed. According to the stability requirement of thrust output and the safety in the working process of turbine based combined cycle engine, a control law is proposed that could guarantee the steady output of thrust by controlling the control variables of the turbine based combined cycle engine in the whole working process.

Characterization of Deficiencies in the Frequency Domain Forced Response Analysis Technique for Supersonic Turbine Bladed Disks

NASA Technical Reports Server (NTRS)

Brown, Andrew M.; Schmauch, Preston

2012-01-01

Turbine blades in rocket and jet engine turbomachinery experience enormous harmonic loading conditions. These loads result from the integer number of upstream and downstream stator vanes as well as the other turbine stages. Assessing the blade structural integrity is a complex task requiring an initial characterization of whether resonance is possible and then performing a forced response analysis if that condition is met. The standard technique for forced response analysis in rocket engine turbines is to decompose a computational fluid dynamics (CFD).generated flow field into its harmonic components, and to then perform a frequency response analysis at the problematic natural frequencies using cyclically symmetric structural dynamic models. Recent CFD analysis and water-flow testing at NASA/MSFC, though, indicates that this technique may miss substantial harmonic and non ]harmonic excitation sources that become present in complex flows. This complex content can only be captured by a CFD flow field encompassing at least an entire revolution. A substantial development effort to create a series of software programs to enable application of the 360 degree forcing function in a frequency response analysis on cyclic symmetric models has been completed (to be described in a future paper), but the question still remains whether the frequency response analysis itself is capable of capturing the excitation content sufficiently. Two studies comparing frequency response analysis with transient response analysis, therefore, of bladed-disks undergoing this complex flow environment have been performed. The first is of a bladed disk with each blade modeled by simple beam elements and the disk modeled with plates (using the finite element code MSC/NASTRAN). The focus of this model is to be representative of response of realistic bladed disks, and so the dimensions are roughly equivalent to the new J2X rocket engine 1st stage fuel pump turbine. The simplicity of the model allows the CFD load to be able to be readily applied, along with analytical and experimental variations in both the temporal and spatial fourier components of the excitation. In addition, this model is a first step in identifying response differences between transient and frequency forced response analysis techniques. The second phase assesses this difference for a much more realistic solid model of a bladed-disk in order to evaluate the effect of the spatial variation in loading on blade dominated modes. Neither research on the accuracy of the frequency response method when used in this context or a comprehensive study of the effect of test-observed variation on blade forced response have been found in the literature, so this research is a new contribution to practical structural dynamic analysis of gas turbines. The primary excitation of the upstream nozzles interacts with the blades on fuel pump of the J2X causes the 5th Nodal diameter modes to be excited, as explained by Tyler and Sofrin1, so a modal analysis was first performed on the beam/plate model and the 5ND bladed-disk mode at 40167 hz was identified and chosen to be the one excited at resonance (see figure 1). The first forced response analysis with this model focuses on identifying differences between frequency and transient response analyses. A hypothesis going into the analysis was that perhaps the frequency response was enforcing a temporal periodicity that did not really exist, and so therefore it would overestimate the response. As high dynamic response was a considerable source of stress in the J2X, examining this concept could potentially be beneficial for the program.

Accuracy of the actuator disc-RANS approach for predicting the performance and wake of tidal turbines.

PubMed

Batten, W M J; Harrison, M E; Bahaj, A S

2013-02-28

The actuator disc-RANS model has widely been used in wind and tidal energy to predict the wake of a horizontal axis turbine. The model is appropriate where large-scale effects of the turbine on a flow are of interest, for example, when considering environmental impacts, or arrays of devices. The accuracy of the model for modelling the wake of tidal stream turbines has not been demonstrated, and flow predictions presented in the literature for similar modelled scenarios vary significantly. This paper compares the results of the actuator disc-RANS model, where the turbine forces have been derived using a blade-element approach, to experimental data measured in the wake of a scaled turbine. It also compares the results with those of a simpler uniform actuator disc model. The comparisons show that the model is accurate and can predict up to 94 per cent of the variation in the experimental velocity data measured on the centreline of the wake, therefore demonstrating that the actuator disc-RANS model is an accurate approach for modelling a turbine wake, and a conservative approach to predict performance and loads. It can therefore be applied to similar scenarios with confidence.

Water Tunnel Studies of Dynamic Wing Flap Effects

DTIC Science & Technology

2016-06-01

applications where dynamic flaps have been studied are in the active elevon rotor and wind turbines . Any analytical or computational study needs to be...observed here that most of these pertain to other applications such as rotorcraft and wind turbine flow control. At times, a Gurney flap has been for...the flap-slices used. Source: [12]. .......................14 Figure 6. NACA 2212 at wind tunnel section. Source: [8

Comparison of Standard Wind Turbine Models with Vendor Models for Power System Stability Analysis: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Honrubia-Escribano, A.; Gomez Lazaro, E.; Jimenez-Buendia, F.

The International Electrotechnical Commission Standard 61400-27-1 was published in February 2015. This standard deals with the development of generic terms and parameters to specify the electrical characteristics of wind turbines. Generic models of very complex technological systems, such as wind turbines, are thus defined based on the four common configurations available in the market. Due to its recent publication, the comparison of the response of generic models with specific vendor models plays a key role in ensuring the widespread use of this standard. This paper compares the response of a specific Gamesa dynamic wind turbine model to the corresponding genericmore » IEC Type III wind turbine model response when the wind turbine is subjected to a three-phase voltage dip. This Type III model represents the doubly-fed induction generator wind turbine, which is not only one of the most commonly sold and installed technologies in the current market but also a complex variable-speed operation implementation. In fact, active and reactive power transients are observed due to the voltage reduction. Special attention is given to the reactive power injection provided by the wind turbine models because it is a requirement of current grid codes. Further, the boundaries of the generic models associated with transient events that cannot be represented exactly are included in the paper.« less

Numerical simulations with a FSI-calibrated actuator disk model of wind turbines operating in stratified ABLs

NASA Astrophysics Data System (ADS)

Gohari, S. M. Iman; Sarkar, Sutanu; Korobenko, Artem; Bazilevs, Yuri

2017-11-01

Numerical simulations of wind turbines operating under different regimes of stability are performed using LES. A reduced model, based on the generalized actuator disk model (ADM), is implemented to represent the wind turbines within the ABL. Data from the fluid-solid interaction (FSI) simulations of wind turbines have been used to calibrate and validate the reduced model. The computational cost of this method to include wind turbines is affordable and incurs an overhead as low as 1.45%. Using this reduced model, we study the coupling of unsteady turbulent flow with the wind turbine under different ABL conditions: (i) A neutral ABL with zero heat-flux and inversion layer at 350m, in which the incoming wind has the maximum mean shear between the heights of upper-tip and lower-tip; (2) A shallow ABL with surface cooling rate of -1 K/hr wherein the low level jet occurs at the wind turbine hub height. We will discuss how the differences in the unsteady flow between the two ABL regimes impact the wind turbine performance.

Model tests of wind turbine with a vertical axis of rotation type Lenz 2

NASA Astrophysics Data System (ADS)

Zwierzchowski, Jaroslaw; Laski, Pawel Andrzej; Blasiak, Slawomir; Takosoglu, Jakub Emanuel; Pietrala, Dawid Sebastian; Bracha, Gabriel Filip; Nowakowski, Lukasz

A building design of vertical axis wind turbines (VAWT) was presented in the article. The construction and operating principle of a wind turbine were described therein. Two VAWT turbine models were compared, i.a. Darrieus and Lenz2, taking their strengths and weaknesses into consideration. 3D solid models of turbine components were presented with the use of SolidWorks software. Using CFD methods, the air flow on two aerodynamic fins, symmetrical and asymmetrical, at different angles of attack were tested. On the basis of flow simulation conducted in FlowSimulation, an asymmetrical fin was chosen as the one showing greater load bearing capacities. Due to the uncertainty of trouble-free operation of Darrieus turbine on construction elements creating the basis thereof, a 3D model of Lenz2 turbine was constructed, which is more reliable and makes turbine self-start possible. On the basis of the research, components were designed and technical docu mentation was compiled.

Windmill Noise Annoyance, Visual Aesthetics, and Attitudes towards Renewable Energy Sources.

PubMed

Klæboe, Ronny; Sundfør, Hanne Beate

2016-07-23

A small focused socio-acoustic after-study of annoyance from a windmill park was undertaken after local health officials demanded a health impact study to look into neighborhood complaints. The windmill park consists of 31 turbines and is located in the South of Norway where it affects 179 dwellings. Simple exposure-effect relationships indicate stronger reactions to windmills and wind turbine noise than shown internationally, with the caveat that the sample size is small (n = 90) and responses are colored by the existing local conflict. Pulsating swishing sounds and turbine engine hum are the main causes of noise annoyance. About 60 per cent of those who participated in the survey were of the opinion that windmills degrade the landscape aesthetically, and were far from convinced that land-based windmills are desirable as a renewable energy source (hydropower is an important alternative source of renewables in Norway). Attitudes play an important role in addition to visual aesthetics in determining the acceptance of windmills and the resulting noise annoyance. To compare results from different wind turbine noise studies it seems necessary to assess the impact of important modifying factors.

SINGLE PHASE ANALYTICAL MODELS FOR TERRY TURBINE NOZZLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Haihua; Zhang, Hongbin; Zou, Ling

All BWR RCIC (Reactor Core Isolation Cooling) systems and PWR AFW (Auxiliary Feed Water) systems use Terry turbine, which is composed of the wheel with turbine buckets and several groups of fixed nozzles and reversing chambers inside the turbine casing. The inlet steam is accelerated through the turbine nozzle and impacts on the wheel buckets, generating work to drive the RCIC pump. As part of the efforts to understand the unexpected “self-regulating” mode of the RCIC systems in Fukushima accidents and extend BWR RCIC and PWR AFW operational range and flexibility, mechanistic models for the Terry turbine, based on Sandiamore » National Laboratories’ original work, has been developed and implemented in the RELAP-7 code to simulate the RCIC system. RELAP-7 is a new reactor system code currently under development with the funding support from U.S. Department of Energy. The RELAP-7 code is a fully implicit code and the preconditioned Jacobian-free Newton-Krylov (JFNK) method is used to solve the discretized nonlinear system. This paper presents a set of analytical models for simulating the flow through the Terry turbine nozzles when inlet fluid is pure steam. The implementation of the models into RELAP-7 will be briefly discussed. In the Sandia model, the turbine bucket inlet velocity is provided according to a reduced-order model, which was obtained from a large number of CFD simulations. In this work, we propose an alternative method, using an under-expanded jet model to obtain the velocity and thermodynamic conditions for the turbine bucket inlet. The models include both adiabatic expansion process inside the nozzle and free expansion process out of the nozzle to reach the ambient pressure. The combined models are able to predict the steam mass flow rate and supersonic velocity to the Terry turbine bucket entrance, which are the necessary input conditions for the Terry Turbine rotor model. The nozzle analytical models were validated with experimental data and benchmarked with CFD simulations. The analytical models generally agree well with the experimental data and CFD simulations. The analytical models are suitable for implementation into a reactor system analysis code or severe accident code as part of mechanistic and dynamical models to understand the RCIC behaviors. The cases with two-phase flow at the turbine inlet will be pursued in future work.« less

Doubly fed induction generator wind turbines with fuzzy controller: a survey.

PubMed

Sathiyanarayanan, J S; Kumar, A Senthil

2014-01-01

Wind energy is one of the extraordinary sources of renewable energy due to its clean character and free availability. With the increasing wind power penetration, the wind farms are directly influencing the power systems. The majority of wind farms are using variable speed wind turbines equipped with doubly fed induction generators (DFIG) due to their advantages over other wind turbine generators (WTGs). Therefore, the analysis of wind power dynamics with the DFIG wind turbines has become a very important research issue, especially during transient faults. This paper presents fuzzy logic control of doubly fed induction generator (DFIG) wind turbine in a sample power system. Fuzzy logic controller is applied to rotor side converter for active power control and voltage regulation of wind turbine.

Modeling Smart Structure of Wind Turbine Blade

NASA Astrophysics Data System (ADS)

Qiao, Yin-hu; Han, Jiang; Zhang, Chun-yan; Chen, Jie-ping

2012-06-01

With the increasing size of wind turbine blades, the need for more sophisticated load control techniques has induced the interest for aerodynamic control systems with build-in intelligence on the blades. The paper aims to provide a way for modeling the adaptive wind turbine blades and analyze its ability for vibration suppress. It consists of the modeling of the adaptive wind turbine blades with the wire of piezoelectric material embedded in blade matrix, and smart sandwich structure of wind turbine blade. By using this model, an active vibration method which effectively suppresses the vibrations of the smart blade is designed.

Numerical modeling of wind turbine aerodynamic noise in the time domain.

PubMed

Lee, Seunghoon; Lee, Seungmin; Lee, Soogab

2013-02-01

Aerodynamic noise from a wind turbine is numerically modeled in the time domain. An analytic trailing edge noise model is used to determine the unsteady pressure on the blade surface. The far-field noise due to the unsteady pressure is calculated using the acoustic analogy theory. By using a strip theory approach, the two-dimensional noise model is applied to rotating wind turbine blades. The numerical results indicate that, although the operating and atmospheric conditions are identical, the acoustical characteristics of wind turbine noise can be quite different with respect to the distance and direction from the wind turbine.

Dynamics modeling and loads analysis of an offshore floating wind turbine

NASA Astrophysics Data System (ADS)

Jonkman, Jason Mark

The vast deepwater wind resource represents a potential to use offshore floating wind turbines to power much of the world with renewable energy. Many floating wind turbine concepts have been proposed, but dynamics models, which account for the wind inflow, aerodynamics, elasticity, and controls of the wind turbine, along with the incident waves, sea current, hydrodynamics, and platform and mooring dynamics of the floater, were needed to determine their technical and economic feasibility. This work presents the development of a comprehensive simulation tool for modeling the coupled dynamic response of offshore floating wind turbines, the verification of the simulation tool through model-to-model comparisons, and the application of the simulation tool to an integrated loads analysis for one of the promising system concepts. A fully coupled aero-hydro-servo-elastic simulation tool was developed with enough sophistication to address the limitations of previous frequency- and time-domain studies and to have the features required to perform loads analyses for a variety of wind turbine, support platform, and mooring system configurations. The simulation capability was tested using model-to-model comparisons. The favorable results of all of the verification exercises provided confidence to perform more thorough analyses. The simulation tool was then applied in a preliminary loads analysis of a wind turbine supported by a barge with catenary moorings. A barge platform was chosen because of its simplicity in design, fabrication, and installation. The loads analysis aimed to characterize the dynamic response and to identify potential loads and instabilities resulting from the dynamic couplings between the turbine and the floating barge in the presence of combined wind and wave excitation. The coupling between the wind turbine response and the barge-pitch motion, in particular, produced larger extreme loads in the floating turbine than experienced by an equivalent land-based turbine. Instabilities were also found in the system. The influence of conventional wind turbine blade-pitch control actions on the pitch damping of the floating turbine was also assessed. Design modifications for reducing the platform motions, improving the turbine response, and eliminating the instabilities are suggested. These suggestions are aimed at obtaining cost-effective designs that achieve favorable performance while maintaining structural integrity.

Numerical Simulations of Marine Hydrokinetic (MHK) Turbines Using the Blade Element Momentum Theory

NASA Astrophysics Data System (ADS)

Javaherchi, Teymour; Thulin, Oskar; Aliseda, Alberto

2011-11-01

Energy extraction from the available kinetic energy in tidal currents via Marine Hydrokinetic (MHK) turbines has recently attracted scientists' attention as a highly predictable source of renewable energy. The strongest tidal resources have a concentrated nature that require close turbine spacing in a farm of MHK turbines. This tight spacing, however, will lead to interaction of the downstream turbines with the turbulent wake generated by upstream turbines. This interaction can significantly reduce the power generated and possibly result in structural failure before the expected service life is completed. Development of a numerical methodology to study the turbine-wake interaction can provide a tool for optimization of turbine spacing to maximize the power generated in turbine arrays. In this work, we will present numerical simulations of the flow field in a farm of horizontal axis MHK turbines using the Blade Element Momentum Theory (BEMT). We compare the value of integral variables (i.e. efficiency, power, torque and etc.) calculated for each turbine in the farm for different arrangements with varying streamwise and lateral offsets between turbines. We find that BEMT provides accurate estimates of turbine efficiency under uniform flow conditions, but overpredicts the efficiency of downstream turbines when they are strongly affected by the wakes. Supported by DOE through the National Northwest Marine Renewable Energy Center.

Effects of incoming surface wind conditions on the wake characteristics and dynamic wind loads acting on a wind turbine model

NASA Astrophysics Data System (ADS)

Tian, Wei; Ozbay, Ahmet; Hu, Hui

2014-12-01

An experimental investigation was conducted to examine the effects of incoming surface wind conditions on the wake characteristics and dynamic wind loads acting on a wind turbine model. The experimental study was performed in a large-scale wind tunnel with a scaled three-blade Horizontal Axial Wind Turbine model placed in two different types of Atmospheric Boundary Layer (ABL) winds with distinct mean and turbulence characteristics. In addition to measuring dynamic wind loads acting on the model turbine by using a force-moment sensor, a high-resolution Particle Image Velocimetry system was used to achieve detailed flow field measurements to characterize the turbulent wake flows behind the model turbine. The measurement results reveal clearly that the discrepancies in the incoming surface winds would affect the wake characteristics and dynamic wind loads acting on the model turbine dramatically. The dynamic wind loads acting on the model turbine were found to fluctuate much more significantly, thereby, much larger fatigue loads, for the case with the wind turbine model sited in the incoming ABL wind with higher turbulence intensity levels. The turbulent kinetic energy and Reynolds stress levels in the wake behind the model turbine were also found to be significantly higher for the high turbulence inflow case, in comparison to those of the low turbulence inflow case. The flow characteristics in the turbine wake were found to be dominated by the formation, shedding, and breakdown of various unsteady wake vortices. In comparison with the case with relatively low turbulence intensities in the incoming ABL wind, much more turbulent and randomly shedding, faster dissipation, and earlier breakdown of the wake vortices were observed for the high turbulence inflow case, which would promote the vertical transport of kinetic energy by entraining more high-speed airflow from above to re-charge the wake flow and result in a much faster recovery of the velocity deficits in the turbine wake.

Wall modeled LES of wind turbine wakes with geometrical effects

NASA Astrophysics Data System (ADS)

Bricteux, Laurent; Benard, Pierre; Zeoli, Stephanie; Moureau, Vincent; Lartigue, Ghislain; Vire, Axelle

2017-11-01

This study focuses on prediction of wind turbine wakes when geometrical effects such as nacelle, tower, and built environment, are taken into account. The aim is to demonstrate the ability of a high order unstructured solver called YALES2 to perform wall modeled LES of wind turbine wake turbulence. The wind turbine rotor is modeled using an Actuator Line Model (ALM) while the geometrical details are explicitly meshed thanks to the use of an unstructured grid. As high Reynolds number flows are considered, sub-grid scale models as well as wall modeling are required. The first test case investigated concerns a wind turbine flow located in a wind tunnel that allows to validate the proposed methodology using experimental data. The second test case concerns the simulation of a wind turbine wake in a complex environment (e.g. a Building) using realistic turbulent inflow conditions.

A summary of computational experience at GE Aircraft Engines for complex turbulent flows in gas turbines

NASA Astrophysics Data System (ADS)

Zerkle, Ronald D.; Prakash, Chander

1995-03-01

This viewgraph presentation summarizes some CFD experience at GE Aircraft Engines for flows in the primary gaspath of a gas turbine engine and in turbine blade cooling passages. It is concluded that application of the standard k-epsilon turbulence model with wall functions is not adequate for accurate CFD simulation of aerodynamic performance and heat transfer in the primary gas path of a gas turbine engine. New models are required in the near-wall region which include more physics than wall functions. The two-layer modeling approach appears attractive because of its computational complexity. In addition, improved CFD simulation of film cooling and turbine blade internal cooling passages will require anisotropic turbulence models. New turbulence models must be practical in order to have a significant impact on the engine design process. A coordinated turbulence modeling effort between NASA centers would be beneficial to the gas turbine industry.

A summary of computational experience at GE Aircraft Engines for complex turbulent flows in gas turbines

NASA Technical Reports Server (NTRS)

Zerkle, Ronald D.; Prakash, Chander

1995-01-01

This viewgraph presentation summarizes some CFD experience at GE Aircraft Engines for flows in the primary gaspath of a gas turbine engine and in turbine blade cooling passages. It is concluded that application of the standard k-epsilon turbulence model with wall functions is not adequate for accurate CFD simulation of aerodynamic performance and heat transfer in the primary gas path of a gas turbine engine. New models are required in the near-wall region which include more physics than wall functions. The two-layer modeling approach appears attractive because of its computational complexity. In addition, improved CFD simulation of film cooling and turbine blade internal cooling passages will require anisotropic turbulence models. New turbulence models must be practical in order to have a significant impact on the engine design process. A coordinated turbulence modeling effort between NASA centers would be beneficial to the gas turbine industry.

Modeling Chilled-Water Storage System Components for Coupling to a Small Modular Reactor in a Nuclear Hybrid Energy System

NASA Astrophysics Data System (ADS)

Misenheimer, Corey Thomas

The intermittency of wind and solar power puts strain on electric grids, often forcing carbonbased and nuclear sources of energy to operate in a load-follow mode. Operating nuclear reactors in a load-follow fashion is undesirable due to the associated thermal and mechanical stresses placed on the fuel and other reactor components. Various Thermal Energy Storage (TES) elements and ancillary energy applications can be coupled to nuclear (or renewable) power sources to help absorb grid instabilities caused by daily electric demand changes and renewable intermittency, thereby forming the basis of a candidate Nuclear Hybrid Energy System (NHES). During the warmer months of the year in many parts of the country, facility air-conditioning loads are significant contributors to the increase in the daily peak electric demand. Previous research demonstrated that a stratified chilled-water storage tank can displace peak cooling loads to off-peak hours. Based on these findings, the objective of this work is to evaluate the prospect of using a stratified chilled-water storage tank as a potential TES reservoir for a nuclear reactor in a NHES. This is accomplished by developing time-dependent models of chilled-water system components, including absorption chillers, cooling towers, a storage tank, and facility cooling loads appropriate for a large office space or college campus, as a callable FORTRAN subroutine. The resulting TES model is coupled to a high-fidelity mPower-sized Small Modular Reactor (SMR) Simulator, with the goal of utilizing excess reactor capacity to operate several sizable chillers in order to keep reactor power constant. Chilled-water production via single effect, lithium bromide (LiBr) absorption chillers is primarily examined in this study, although the use of electric chillers is briefly explored. Absorption chillers use hot water or low-pressure steam to drive an absorption-refrigeration cycle. The mathematical framework for a high-fidelity dynamic absorption chiller model is presented. The transient FORTRAN model is grounded on time-dependent mass, species, and energy conservation equations. Due to the vast computational costs of the high-fidelity model, a low-fidelity absorption chiller model is formulated and calibrated to mimic the behavior of the high-fidelity model. Stratified chilled-water storage tank performance is characterized using Computational Fluid Dynamics (CFD). The geometry employed in the CFD model represents a 5-million-gallon storage tank currently in use at a North Carolina college campus. Simulation results reveal the laminar numerical model most closely aligns with actual tank charging and discharging data. A subsequent parametric study corroborates storage tank behavior documented throughout literature and industry. Two absorption chiller configurations are considered. The first involves bypassing lowpressure steam from the low-pressure turbine to absorption chillers during periods of excess reactor capacity in order to keep reactor power constant. Simulation results show steam conditions downstream of the turbine control valves are a strong function of turbine load, and absorption chiller performance is hindered by reduced turbine impulse pressures at reduced turbine demands. A more suitable configuration entails integrating the absorption chillers into a flash vessel system that is thermally coupled to a sensible heat storage system. The sensible heat storage system is able to maintain reactor thermal output constant at 100% and match turbine output with several different electric demand profiles. High-pressure condensate in the sensible heat storage system is dropped across a let-down orifice and flashed in an ideal separator. Generated steam is sent to a bank of absorption chillers. Simulation results show enough steam is available during periods of reduced turbine demand to power four large absorption chillers to charge a 5-million-gallon stratified chilled-water storage tank, which is used to offset cooling loads in an adjacent facility. The coupled TES systems operating in conjunction with an SMR comprise the foundation of a tightly coupled NHES.

Development of Iron Aluminides.

DTIC Science & Technology

1986-03-01

in the evolution of technology for the aerospace industry. This is particularly true for the gas turbine engine industry, where the requirements for...vulnerability of the U.S. gas turbine industry in terms of its heavy reliance upon non-domestic sources for much of its strategic metals requirements...superalloys used in gas turbine engines. The questionable future availability of chromium, for example, poses a potential serious threat to these applicacions

Shape design and CFD analysis on a 1MW-class horizontal axis tidal current turbine blade

NASA Astrophysics Data System (ADS)

Singh, P. M.; Choi, Y. D.

2013-12-01

This study aims to develop a 1MW-class horizontal axis tidal current turbine rotor blade which can be applied near the southwest island regions of South Korea. On the basis of actual tidal current conditions of southern region of Korea, configuration design of 1MW class turbine rotor blade is carried out by BEMT (Blade element momentum theory). The hydrodynamic performance including the lift and drag forces, is conducted with the variation of the angle of attack using an open source code of X-Foil. The purpose of the study is to study the shape of the hydrofoil used and how it affects the performance of the turbine. After a thorough study of many airfoils, a new hydrofoil is developed using the S814 and DU-91-W2- 250 airfoils, which show good performance for rough conditions. A combination of the upper and lower surface of the two hydrofoils is tested. Three dimensional models were developed and the optimized blade geometry is used for CFD (Computational Fluid Dynamics) analysis with hexahedral numerical grids. Power coefficient, pressure coefficient and velocity distributions are investigated according to Tip Speed Ratio by CFD analysis.

Design and Construction of a Hydroturbine Test Facility

NASA Astrophysics Data System (ADS)

Ayli, Ece; Kavurmaci, Berat; Cetinturk, Huseyin; Kaplan, Alper; Celebioglu, Kutay; Aradag, Selin; Tascioglu, Yigit; ETU Hydro Research Center Team

2014-11-01

Hydropower is one of the clean, renewable, flexible and efficient energy resources. Most of the developing countries invest on this cost-effective energy source. Hydroturbines for hydroelectric power plants are tailor-made. Each turbine is designed and constructed according to the properties, namely the head and flow rate values of the specific water source. Therefore, a center (ETU Hydro-Center for Hydro Energy Research) for the design, manufacturing and performance tests of hydraulic turbines is established at TOBB University of Economics and Technology to promote research in this area. CFD aided hydraulic and structural design, geometry optimization, manufacturing and performance tests of hydraulic turbines are the areas of expertise of this center. In this paper, technical details of the design and construction of this one of a kind test facility in Turkey, is explained. All the necessary standards of IEC (International Electrotechnical Commission) are met since the test facility will act as a certificated test center for hydraulic turbines.

The methodology of the gas turbine efficiency calculation

NASA Astrophysics Data System (ADS)

Kotowicz, Janusz; Job, Marcin; Brzęczek, Mateusz; Nawrat, Krzysztof; Mędrych, Janusz

2016-12-01

In the paper a calculation methodology of isentropic efficiency of a compressor and turbine in a gas turbine installation on the basis of polytropic efficiency characteristics is presented. A gas turbine model is developed into software for power plant simulation. There are shown the calculation algorithms based on iterative model for isentropic efficiency of the compressor and for isentropic efficiency of the turbine based on the turbine inlet temperature. The isentropic efficiency characteristics of the compressor and the turbine are developed by means of the above mentioned algorithms. The gas turbine development for the high compressor ratios was the main driving force for this analysis. The obtained gas turbine electric efficiency characteristics show that an increase of pressure ratio above 50 is not justified due to the slight increase in the efficiency with a significant increase of turbine inlet combustor outlet and temperature.

Materials for Advanced Turbine Engines. Volume 1; Power Metallurgy Rene 95 Rotating Turbine Engine Parts

NASA Technical Reports Server (NTRS)

Pfouts, W. R.; Shamblen, C. E.; Mosier, J. S.; Peebles, R. E.; Gorsler, R. W.

1979-01-01

An attempt was made to improve methods for producing powder metallurgy aircraft gas turbine engine parts from the nickel base superalloy known as Rene 95. The parts produced were the high pressure turbine aft shaft for the CF6-50 engine and the stages 5 through 9 compressor disk forgings for the CFM56/F101 engines. A 50% cost reduction was achieved as compared to conventional cast and wrought processing practices. An integrated effort involving several powder producers and a major forging source were included.

Evaluation of blade-strike models for estimating the biological performance of large Kaplan hydro turbines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Z.; Carlson, T. J.; Ploskey, G. R.

2005-11-01

Bio-indexing of hydro turbines has been identified as an important means to optimize passage conditions for fish by identifying operations for existing and new design turbines that minimize the probability of injury. Cost-effective implementation of bio-indexing requires the use of tools such as numerical and physical turbine models to generate hypotheses for turbine operations that can be tested at prototype scales using live fish. Blade strike has been proposed as an index variable for the biological performance of turbines. Report reviews an evaluation of the use of numerical blade-strike models as a means with which to predict the probability ofmore » blade strike and injury of juvenile salmon smolt passing through large Kaplan turbines on the mainstem Columbia River.« less

PIV study of the wake of a model wind turbine transitioning between operating set points

NASA Astrophysics Data System (ADS)

Houck, Dan; Cowen, Edwin (Todd)

2016-11-01

Wind turbines are ideally operated at their most efficient tip speed ratio for a given wind speed. There is increasing interest, however, in operating turbines at other set points to increase the overall power production of a wind farm. Specifically, Goit and Meyers (2015) used LES to examine a wind farm optimized by unsteady operation of its turbines. In this study, the wake of a model wind turbine is measured in a water channel using PIV. We measure the wake response to a change in operational set point of the model turbine, e.g., from low to high tip speed ratio or vice versa, to examine how it might influence a downwind turbine. A modified torque transducer after Kang et al. (2010) is used to calibrate in situ voltage measurements of the model turbine's generator operating across a resistance to the torque on the generator. Changes in operational set point are made by changing the resistance or the flow speed, which change the rotation rate measured by an encoder. Single camera PIV on vertical planes reveals statistics of the wake at various distances downstream as the turbine transitions from one set point to another. From these measurements, we infer how the unsteady operation of a turbine may affect the performance of a downwind turbine as its incoming flow. National Science Foundation and the Atkinson Center for a Sustainable Future.

A wind turbine hybrid simulation framework considering aeroelastic effects

NASA Astrophysics Data System (ADS)

Song, Wei; Su, Weihua

2015-04-01

In performing an effective structural analysis for wind turbine, the simulation of turbine aerodynamic loads is of great importance. The interaction between the wake flow and the blades may impact turbine blades loading condition, energy yield and operational behavior. Direct experimental measurement of wind flow field and wind profiles around wind turbines is very helpful to support the wind turbine design. However, with the growth of the size of wind turbines for higher energy output, it is not convenient to obtain all the desired data in wind-tunnel and field tests. In this paper, firstly the modeling of dynamic responses of large-span wind turbine blades will consider nonlinear aeroelastic effects. A strain-based geometrically nonlinear beam formulation will be used for the basic structural dynamic modeling, which will be coupled with unsteady aerodynamic equations and rigid-body rotations of the rotor. Full wind turbines can be modeled by using the multi-connected beams. Then, a hybrid simulation experimental framework is proposed to potentially address this issue. The aerodynamic-dominant components, such as the turbine blades and rotor, are simulated as numerical components using the nonlinear aeroelastic model; while the turbine tower, where the collapse of failure may occur under high level of wind load, is simulated separately as the physical component. With the proposed framework, dynamic behavior of NREL's 5MW wind turbine blades will be studied and correlated with available numerical data. The current work will be the basis of the authors' further studies on flow control and hazard mitigation on wind turbine blades and towers.

Development of methodology for horizontal axis wind turbine dynamic analysis

NASA Technical Reports Server (NTRS)

Dugundji, J.

1982-01-01

Horizontal axis wind turbine dynamics were studied. The following findings are summarized: (1) review of the MOSTAS computer programs for dynamic analysis of horizontal axis wind turbines; (2) review of various analysis methods for rotating systems with periodic coefficients; (3) review of structural dynamics analysis tools for large wind turbine; (4) experiments for yaw characteristics of a rotating rotor; (5) development of a finite element model for rotors; (6) development of simple models for aeroelastics; and (7) development of simple models for stability and response of wind turbines on flexible towers.

Numerical Modeling and Experimental Analysis of Scale Horizontal Axis Marine Hydrokinetic (MHK) Turbines

NASA Astrophysics Data System (ADS)

Javaherchi, Teymour; Stelzenmuller, Nick; Seydel, Joseph; Aliseda, Alberto

2013-11-01

We investigate, through a combination of scale model experiments and numerical simulations, the evolution of the flow field around the rotor and in the wake of Marine Hydrokinetic (MHK) turbines. Understanding the dynamics of this flow field is the key to optimizing the energy conversion of single devices and the arrangement of turbines in commercially viable arrays. This work presents a comparison between numerical and experimental results from two different case studies of scaled horizontal axis MHK turbines (45:1 scale). In the first case study, we investigate the effect of Reynolds number (Re = 40,000 to 100,000) and Tip Speed Ratio (TSR = 5 to 12) variation on the performance and wake structure of a single turbine. In the second case, we study the effect of the turbine downstream spacing (5d to 14d) on the performance and wake development in a coaxial configuration of two turbines. These results provide insights into the dynamics of Horizontal Axis Hydrokinetic Turbines, and by extension to Horizontal Axis Wind Turbines in close proximity to each other, and highlight the capabilities and limitations of the numerical models. Once validated at laboratory scale, the numerical model can be used to address other aspects of MHK turbines at full scale. Supported by DOE through the National Northwest Marine Renewable Energy Center.

Analysis of Control-Oriented Wake Modeling Tools Using Lidar Field Results

DOE PAGES

Annoni, Jennifer; Fleming, Paul; Scholbrock, Andrew; ...

2018-02-08

Wind turbines in a wind farm operate individually to maximize their own performance regardless of the impact of aerodynamic interactions on neighboring turbines. Wind farm controls can be used to increase power production or reduce overall structural loads by properly coordinating turbines. One wind farm control strategy that is addressed in literature is known as wake steering, wherein upstream turbines operate in yaw misaligned conditions to redirect their wakes away from downstream turbines. The National Renewable Energy Laboratory (NREL) in Golden, CO conducted a demonstration of wake steering on a single utility-scale turbine. In this study, the turbine was operatedmore » at various yaw misalignment setpoints while a lidar mounted on the nacelle scanned five downstream distances. The lidar measurements were combined with turbine data, as well as measurements of the inflow made by a highly instrumented meteorological mast upstream. The full-scale measurements are used to validate controls-oriented tools, including wind turbine wake models, used for wind farm controls and optimization. This paper presents a quantitative comparison of the lidar data and controls-oriented wake models under different atmospheric conditions and turbine operation. The results show good agreement between the lidar data and the models under these different conditions.« less

Analysis of Control-Oriented Wake Modeling Tools Using Lidar Field Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Annoni, Jennifer; Fleming, Paul; Scholbrock, Andrew

Wind turbines in a wind farm operate individually to maximize their own performance regardless of the impact of aerodynamic interactions on neighboring turbines. Wind farm controls can be used to increase power production or reduce overall structural loads by properly coordinating turbines. One wind farm control strategy that is addressed in literature is known as wake steering, wherein upstream turbines operate in yaw misaligned conditions to redirect their wakes away from downstream turbines. The National Renewable Energy Laboratory (NREL) in Golden, CO conducted a demonstration of wake steering on a single utility-scale turbine. In this study, the turbine was operatedmore » at various yaw misalignment setpoints while a lidar mounted on the nacelle scanned five downstream distances. The lidar measurements were combined with turbine data, as well as measurements of the inflow made by a highly instrumented meteorological mast upstream. The full-scale measurements are used to validate controls-oriented tools, including wind turbine wake models, used for wind farm controls and optimization. This paper presents a quantitative comparison of the lidar data and controls-oriented wake models under different atmospheric conditions and turbine operation. The results show good agreement between the lidar data and the models under these different conditions.« less

Simulations of an Offshore Wind Farm Using Large-Eddy Simulation and a Torque-Controlled Actuator Disc Model

NASA Astrophysics Data System (ADS)

Creech, Angus; Früh, Wolf-Gerrit; Maguire, A. Eoghan

2015-05-01

We present here a computational fluid dynamics (CFD) simulation of Lillgrund offshore wind farm, which is located in the Øresund Strait between Sweden and Denmark. The simulation combines a dynamic representation of wind turbines embedded within a large-eddy simulation CFD solver and uses hr-adaptive meshing to increase or decrease mesh resolution where required. This allows the resolution of both large-scale flow structures around the wind farm, and the local flow conditions at individual turbines; consequently, the response of each turbine to local conditions can be modelled, as well as the resulting evolution of the turbine wakes. This paper provides a detailed description of the turbine model which simulates the interaction between the wind, the turbine rotors, and the turbine generators by calculating the forces on the rotor, the body forces on the air, and instantaneous power output. This model was used to investigate a selection of key wind speeds and directions, investigating cases where a row of turbines would be fully aligned with the wind or at specific angles to the wind. Results shown here include presentations of the spin-up of turbines, the observation of eddies moving through the turbine array, meandering turbine wakes, and an extensive wind farm wake several kilometres in length. The key measurement available for cross-validation with operational wind farm data is the power output from the individual turbines, where the effect of unsteady turbine wakes on the performance of downstream turbines was a main point of interest. The results from the simulations were compared to the performance measurements from the real wind farm to provide a firm quantitative validation of this methodology. Having achieved good agreement between the model results and actual wind farm measurements, the potential of the methodology to provide a tool for further investigations of engineering and atmospheric science problems is outlined.

Thermal-economic optimisation of a CHP gas turbine system by applying a fit-problem genetic algorithm

NASA Astrophysics Data System (ADS)

Ferreira, Ana C. M.; Teixeira, Senhorinha F. C. F.; Silva, Rui G.; Silva, Ângela M.

2018-04-01

Cogeneration allows the optimal use of the primary energy sources and significant reductions in carbon emissions. Its use has great potential for applications in the residential sector. This study aims to develop a methodology for thermal-economic optimisation of small-scale micro-gas turbine for cogeneration purposes, able to fulfil domestic energy needs with a thermal power out of 125 kW. A constrained non-linear optimisation model was built. The objective function is the maximisation of the annual worth from the combined heat and power, representing the balance between the annual incomes and the expenditures subject to physical and economic constraints. A genetic algorithm coded in the java programming language was developed. An optimal micro-gas turbine able to produce 103.5 kW of electrical power with a positive annual profit (i.e. 11,925 €/year) was disclosed. The investment can be recovered in 4 years and 9 months, which is less than half of system lifetime expectancy.

Application of Thin-Film Thermocouples to Localized Heat Transfer Measurements

NASA Technical Reports Server (NTRS)

Lepicovsky, J.; Bruckner, R. J.; Smith, F. A.

1995-01-01

The paper describes a proof-of-concept experiment on thin-film thermocouples used for localized heat transfer measurements applicable to experiments on hot parts of turbine engines. The paper has three main parts. The first part describes the thin-film sensors and manufacturing procedures. Attention is paid to connections between thin-film thermocouples and lead wires, which has been a source of problems in the past. The second part addresses the test arrangement and facility used for the heat transfer measurements modeling the conditions for upcoming warm turbine tests at NASA LeRC. The paper stresses the advantages of a modular approach to the test rig design. Finally, we present the results of bulk and local heat flow rate measurements, as well as overall heat transfer coefficients obtained from measurements in a narrow passage with an aspect ratio of 11.8. The comparison of bulk and local heat flow rates confirms applicability of thin-film thermocouples to upcoming warm turbine tests.

Aerodynamic design and analysis of small horizontal axis wind turbine blades

NASA Astrophysics Data System (ADS)

Tang, Xinzi

This work investigates the aerodynamic design and analysis of small horizontal axis wind turbine blades via the blade element momentum (BEM) based approach and the computational fluid dynamics (CFD) based approach. From this research, it is possible to draw a series of detailed guidelines on small wind turbine blade design and analysis. The research also provides a platform for further comprehensive study using these two approaches. The wake induction corrections and stall corrections of the BEM method were examined through a case study of the NREL/NASA Phase VI wind turbine. A hybrid stall correction model was proposed to analyse wind turbine power performance. The proposed model shows improvement in power prediction for the validation case, compared with the existing stall correction models. The effects of the key rotor parameters of a small wind turbine as well as the blade chord and twist angle distributions on power performance were investigated through two typical wind turbines, i.e. a fixed-pitch variable-speed (FPVS) wind turbine and a fixed-pitch fixed-speed (FPFS) wind turbine. An engineering blade design and analysis code was developed in MATLAB to accommodate aerodynamic design and analysis of the blades.. The linearisation for radial profiles of blade chord and twist angle for the FPFS wind turbine blade design was discussed. Results show that, the proposed linearisation approach leads to reduced manufacturing cost and higher annual energy production (AEP), with minimal effects on the low wind speed performance. Comparative studies of mesh and turbulence models in 2D and 3D CFD modelling were conducted. The CFD predicted lift and drag coefficients of the airfoil S809 were compared with wind tunnel test data and the 3D CFD modelling method of the NREL/NASA Phase VI wind turbine were validated against measurements. Airfoil aerodynamic characterisation and wind turbine power performance as well as 3D flow details were studied. The detailed flow characteristics from the CFD modelling are quantitatively comparable to the measurements, such as blade surface pressure distribution and integrated forces and moments. It is confirmed that the CFD approach is able to provide a more detailed qualitative and quantitative analysis for wind turbine airfoils and rotors..

Computational simulation and aerodynamic sensitivity analysis of film-cooled turbines

NASA Astrophysics Data System (ADS)

Massa, Luca

A computational tool is developed for the time accurate sensitivity analysis of the stage performance of hot gas, unsteady turbine components. An existing turbomachinery internal flow solver is adapted to the high temperature environment typical of the hot section of jet engines. A real gas model and film cooling capabilities are successfully incorporated in the software. The modifications to the existing algorithm are described; both the theoretical model and the numerical implementation are validated. The accuracy of the code in evaluating turbine stage performance is tested using a turbine geometry typical of the last stage of aeronautical jet engines. The results of the performance analysis show that the predictions differ from the experimental data by less than 3%. A reliable grid generator, applicable to the domain discretization of the internal flow field of axial flow turbine is developed. A sensitivity analysis capability is added to the flow solver, by rendering it able to accurately evaluate the derivatives of the time varying output functions. The complex Taylor's series expansion (CTSE) technique is reviewed. Two of them are used to demonstrate the accuracy and time dependency of the differentiation process. The results are compared with finite differences (FD) approximations. The CTSE is more accurate than the FD, but less efficient. A "black box" differentiation of the source code, resulting from the automated application of the CTSE, generates high fidelity sensitivity algorithms, but with low computational efficiency and high memory requirements. New formulations of the CTSE are proposed and applied. Selective differentiation of the method for solving the non-linear implicit residual equation leads to sensitivity algorithms with the same accuracy but improved run time. The time dependent sensitivity derivatives are computed in run times comparable to the ones required by the FD approach.

Modeling of the dynamic response of a Francis turbine

NASA Astrophysics Data System (ADS)

Pennacchi, Paolo; Chatterton, Steven; Vania, Andrea

2012-05-01

The paper presents a detailed numerical model of the dynamic behaviour of a Francis turbine installed in a hydroelectric plant. The model considers in detail the Francis turbine with all the electromechanical subsystems, such as the main speed governor, the controller and the servo actuator of the turbine distributor, and the electrical generator. In particular, it reproduces the effects of pipeline elasticity in the penstock, the water inertia and the water compressibility on the turbine behaviour. The dynamics of the surge tank on low frequency pressure waves is also modelled together with the main governor speed loop and the position controllers of the distributor actuator and of the hydraulic electrovalve. Model validation has been made by means of experimental data of a 75 MW—470 m hydraulic head—Francis turbine acquired during some starting tests after a partial revamping, which also involved the control system of the distributor.

Doubly Fed Induction Generator Wind Turbines with Fuzzy Controller: A Survey

PubMed Central

Sathiyanarayanan, J. S.; Senthil Kumar, A.

2014-01-01

Wind energy is one of the extraordinary sources of renewable energy due to its clean character and free availability. With the increasing wind power penetration, the wind farms are directly influencing the power systems. The majority of wind farms are using variable speed wind turbines equipped with doubly fed induction generators (DFIG) due to their advantages over other wind turbine generators (WTGs). Therefore, the analysis of wind power dynamics with the DFIG wind turbines has become a very important research issue, especially during transient faults. This paper presents fuzzy logic control of doubly fed induction generator (DFIG) wind turbine in a sample power system. Fuzzy logic controller is applied to rotor side converter for active power control and voltage regulation of wind turbine. PMID:25028677

Infrasound and low frequency noise from wind turbines: exposure and health effects

NASA Astrophysics Data System (ADS)

Bolin, Karl; Bluhm, Gösta; Eriksson, Gabriella; Nilsson, Mats E.

2011-07-01

Wind turbines emit low frequency noise (LFN) and large turbines generally generate more LFN than small turbines. The dominant source of LFN is the interaction between incoming turbulence and the blades. Measurements suggest that indoor levels of LFN in dwellings typically are within recommended guideline values, provided that the outdoor level does not exceed corresponding guidelines for facade exposure. Three cross-sectional questionnaire studies show that annoyance from wind turbine noise is related to the immission level, but several explanations other than low frequency noise are probable. A statistically significant association between noise levels and self-reported sleep disturbance was found in two of the three studies. It has been suggested that LFN from wind turbines causes other, and more serious, health problems, but empirical support for these claims is lacking.

Can Fish Morphological Characteristics be Used to Re-design Hydroelectric Turbines?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cada, G. F.; Richmond, Marshall C.

2011-07-19

Safe fish passage affects not only migratory species, but also populations of resident fish by altering biomass, biodiversity, and gene flow. Consequently, it is important to estimate turbine passage survival of a wide range of susceptible fish. Although fish-friendly turbines show promise for reducing turbine passage mortality, experimental data on their beneficial effects are limited to only a few species, mainly salmon and trout. For thousands of untested species and sizes of fish, the particular causes of turbine passage mortality and the benefits of fish-friendly turbine designs remain unknown. It is not feasible to measure the turbine-passage survival of everymore » species of fish in every hydroelectric turbine design. We are attempting to predict fish mortality based on an improved understanding of turbine-passage stresses (pressure, shear stress, turbulence, strike) and information about the morphological, behavioral, and physiological characteristics of different fish taxa that make them susceptible to the stresses. Computational fluid dynamics and blade strike models of the turbine environment are re-examined in light of laboratory and field studies of fish passage effects. Comparisons of model-predicted stresses to measured injuries and mortalities will help identify fish survival thresholds and the aspects of turbines that are most in need of re-design. The coupled model and fish morphology evaluations will enable us to make predictions of turbine-passage survival among untested fish species, for both conventional and advanced turbines, and to guide the design of hydroelectric turbines to improve fish passage survival.« less

A local-circulation model for Darrieus vertical-axis wind turbines

NASA Astrophysics Data System (ADS)

Masse, B.

1986-04-01

A new computational model for the aerodynamics of the vertical-axis wind turbine is presented. Based on the local-circulation method generalized for curved blades, combined with a wake model for the vertical-axis wind turbine, it differs markedly from current models based on variations in the streamtube momentum and vortex models using the lifting-line theory. A computer code has been developed to calculate the loads and performance of the Darrieus vertical-axis wind turbine. The results show good agreement with experimental data and compare well with other methods.

CWEX (Crop/Wind-Energy Experiment): Measurements of the interaction between crop agriculture and wind power

NASA Astrophysics Data System (ADS)

Rajewski, Daniel Andrew

The current expansion of wind farms in the U.S. Midwest promotes an alternative renewable energy portfolio to conventional energy sources derived from fossil fuels. The construction of wind turbines and large wind farms within several millions of cropland acres creates a unique interaction between two unlike energy sources: electric generation by wind and bio-fuel production derived from crop grain and plant tissues. Wind turbines produce power by extracting mean wind speed and converting a portion of the flow to turbulence downstream of each rotor. Turbine-scale turbulence modifies fluxes of momentum, heat, moisture, and other gaseous constituents (e.g. carbon dioxide) between the crop canopy and the atmospheric boundary layer. Conversely, crop surfaces and tillage elements produce drag on the hub-height wind resource, and the release of sensible and latent heat flux from the canopy or soil influences the wind speed profile. The Crop-Wind Energy Experiment (CWEX) measured momentum, energy, and CO2 fluxes at several locations within the leading line of turbines in a large operational wind farm, and overall turbines promote canopy mixing of wind speed, temperature, moisture, and carbon dioxide in both the day and night. Turbine-generated perturbations of these fluxes are dependent on several factors influencing the turbine operation (e.g. wind speed, wind direction, stability, orientation of surrounding turbines within a wind park) and the cropland surface (e.g. crop type and cultivar, planting density, chemical application, and soil composition and drainage qualities). Additional strategies are proposed for optimizing the synergy between crop and wind power.

Australian DefenceScience. Volume 15, Number 3, Spring

DTIC Science & Technology

2007-01-01

ignition, high pressure sealing, ignitor and propellent design, and ballistics instrumentation . Validation of simulation models of internal ballistics...supplementing visual information obtained by sources such as radiography and scanning electron microscopy, revealing details about features that are not...otherwise visible. Hence, it can assist with the inspection of vital component parts that are subject to high stresses, like aircraft engine turbine

Markovian properties of wind turbine wakes within a 3x3 array

NASA Astrophysics Data System (ADS)

Melius, Matthew; Tutkun, Murat; Cal, Raúl Bayoán

2012-11-01

Wind turbine arrays have proven to be significant sources of renewable energy. Accurate projections of energy production is difficult to achieve because the wake of a wind turbine is highly intermittent and turbulent. Seeking to further the understanding of the downstream propagation of wind turbine wakes, a stochastic analysis of experimentally obtained turbulent flow data behind a wind turbine was performed. A 3x3 wind turbine array was constructed in the test section of a recirculating wind tunnel where X-wire anemometers were used to collect point velocity statistics. In this work, mathematics of the theory of Markovian processes are applied to obtain a statistical description of longitudinal velocity increments inside the turbine wake using conditional probability density functions. Our results indicate an existence of Markovian properties at scales on the order of the Taylor microscale, λ, which has also been observed and documented in different turbulent flows. This leads to characterization of the multi-point description of the wind turbine wakes using the most recent states of the flow.

Wind-tunnel experiments of scalar transport in aligned and staggered wind farms

NASA Astrophysics Data System (ADS)

Zhang, W.; Markfort, C. D.; Porté-Agel, F.

2012-04-01

Wind energy is the fastest growing renewable energy worldwide, and it is expected that many more large-scale wind farms will be built and will cover a significant portion of land and ocean surfaces. By extracting kinetic energy from the atmospheric boundary layer, wind farms may affect the exchange/transport of momentum, heat and moisture between the atmosphere and land surface. To ensure the long-term sustainability of wind energy, it is important to understand the influence of large-scale wind farms on land-atmosphere interaction. Knowledge of this impact will also be useful to improve parameterizations of wind farms in numerical prediction tools, such as large-scale weather models and large-eddy simulation. Here, we present wind-tunnel measurements of the surface scalar (heat) flux from model wind farms, consisting of more than 10 rows of wind turbines, in a turbulent boundary layer with a surface heat source. Spatially distributed surface heat flux was obtained in idealized aligned and staggered wind farm layouts, having the same turbine distribution density. Measurements, using surface-mounted heat flux sensors, were taken at the 11th out of 12 rows of wind turbines, where the mean flow achieves a quasi-equilibrium state. In the aligned farm, there exist two distinct regions of increased and decreased surface heat flux on either side of turbine columns. The regions are correlated with coherent wake rotation in the turbine-array. On the upwelling side there is decreased flux, while on the downwelling side cool air moves towards the surface causing increased flux. For the staggered farm, the surface heat flux exhibits a relatively uniform distribution and an overall reduction with respect to the boundary layer flow, except in the vicinity of the turbine tower. This observation is also supported by near-surface temperature and turbulent heat flux measured using a customized x-wire/cold-wire. The overall surface heat flux, relative to that of the boundary layer flow without wind turbines, is reduced by approximately 4% in the staggered wind farm and remains nearly the same in the aligned wind farm.

Experimental study of the thermal-acoustic efficiency in a long turbulent diffusion-flame burner

NASA Technical Reports Server (NTRS)

Mahan, J. R.

1983-01-01

A two-year study of noise production in a long tubular burner is described. The research was motivated by an interest in understanding and eventually reducing core noise in gas turbine engines. The general approach is to employ an acoustic source/propagation model to interpret the sound pressure spectrum in the acoustic far field of the burner in terms of the source spectrum that must have produced it. In the model the sources are assumed to be due uniquely to the unsteady component of combustion heat release; thus only direct combustion-noise is considered. The source spectrum is then the variation with frequency of the thermal-acoustic efficiency, defined as the fraction of combustion heat release which is converted into acoustic energy at a given frequency. The thrust of the research was to study the variation of the source spectrum with the design and operating parameters of the burner.

Three-dimensional modelling for assessment of far-field impact of tidal stream turbine: A case study at the Anglesey Coast, Wales, UK

NASA Astrophysics Data System (ADS)

Li, Xiaorong; Li, Ming; Wolf, Judith

2017-04-01

As a response to worldwide climate change, clean non-carbon renewable energy resources have been gaining significant attention. Among a range of renewable alternatives, tidal stream energy is considered very promising; due to its consistent predictability and availability. To investigate impacts of tidal stream devices on their surroundings, prototype experiments involving small scale laboratory studies have been implemented. Computational Flow Dynamics (CFD) modelling is also commonly applied to study turbine behaviours. However, these studies focus on impacts of the turbine in the near-field scale. As a result, in order to study and predict the far-field impacts caused by the operation of turbines, large scale 2D and 3D numerical oceanography models have been used, with routines added to reflect the impacts of turbines. In comparison to 2D models, 3D models are advantageous in providing complete prediction of vertical flow structures and hence mixing in the wake of a turbine. This research aims to deliver a thorough 3D tidal stream turbine simulation system, by considering major coastal processes, i.e. current, waves and sediment transport, based on a 3D wave-current-sediment fully coupled numerical oceanography model — the Unstructured Grid Finite Volume Community Ocean Model (FVCOM). The energy extraction of turbines is simulated by adding a body force to the momentum equations. Across the water depth, the coefficient related to the additional body force is given different values according to the turbine configuration and operation to reflect the vertical variation of the turbine's impacts on the passing flow. Three turbulence perturbation terms are added to the turbulence closure to simulate the turbine-induced turbulence generation, dissipation and interference for the turbulence length-scale. Impacts of turbine operation on surface waves are also considered by modification of wave energy flux across the device. A thorough validation study is carried out in which the developed model is tested; based on a combination of laboratory measured data and CFD simulated results. The developed turbine simulation system is then applied to the Anglesey coast, North Wales, UK for a case study. The validation study suggests that the developed turbine simulation system is able to accurately simulate both hydrodynamics and wave dynamics in the turbine wake. The case study with 18 turbines (diameter is 15 m) modelled individually in the waterway between the north-west Anglesey and the Skerries reveals impacts of the turbine farm on free surface elevation, flow field, turbulence kinetic energy (TKE), surface waves, bottom shear stress and suspended sediment transport. The wake is observable up to 4.5 km downstream of the device farm. Flow near the bed in the wake is accelerated, leading to enhanced bottom shear stress. The device farm has a strong influence on TKE and hence the vertical mixing of suspended sediment in the wake. Further, the eastwards directed residual sediment transport along the north coast of Anglesey is found to be weakened by the turbine farm.

Acoustic emission non-destructive testing of structures using source location techniques.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beattie, Alan G.

2013-09-01

The technology of acoustic emission (AE) testing has been advanced and used at Sandia for the past 40 years. AE has been used on structures including pressure vessels, fire bottles, wind turbines, gas wells, nuclear weapons, and solar collectors. This monograph begins with background topics in acoustics and instrumentation and then focuses on current acoustic emission technology. It covers the overall design and system setups for a test, with a wind turbine blade as the object. Test analysis is discussed with an emphasis on source location. Three test examples are presented, two on experimental wind turbine blades and one onmore » aircraft fire extinguisher bottles. Finally, the code for a FORTRAN source location program is given as an example of a working analysis program. Throughout the document, the stress is on actual testing of real structures, not on laboratory experiments.« less

LDV survey of cavitation and resonance effect on the precessing vortex rope dynamics in the draft tube of Francis turbines

NASA Astrophysics Data System (ADS)

Favrel, A.; Müller, A.; Landry, C.; Yamamoto, K.; Avellan, F.

2016-11-01

The large-scale penetration of the electrical grid by intermittent renewable energy sources requires a continuous operating range extension of hydropower plants. This causes the formation of unfavourable flow patterns in the draft tube of turbines and pump-turbines. At partial load operation, a precessing cavitation vortex rope is formed at the Francis turbine runner outlet, acting as an excitation source for the hydraulic system. In case of resonance, the resulting high-amplitude pressure pulsations can put at risk the stability of the machine and of the electrical grid to which it is connected. It is therefore crucial to understand and accurately simulate the underlying physical mechanisms in such conditions. However, the exact impact of cavitation and hydro-acoustic resonance on the flow velocity fluctuations in the draft tube remains to be established. The flow discharge pulsations expected to occur in the draft tube in resonance conditions have for instance never been verified experimentally. In this study, two-component Laser Doppler Velocimetry is used to investigate the axial and tangential velocity fluctuations at the runner outlet of a reduced scale physical model of a Francis turbine. The investigation is performed for a discharge equal to 64 % of the nominal value and three different pressure levels in the draft tube, including resonance and cavitation-free conditions. Based on the convective pressure fluctuations induced by the vortex precession, the periodical velocity fluctuations over one typical precession period are recovered by phase averaging. The impact of cavitation and hydro-acoustic resonance on both axial and tangential velocity fluctuations in terms of amplitude and phase shift is highlighted for the first time. It is shown that the occurrence of resonance does not have significant effects on the draft tube velocity fields, suggesting that the synchronous axial velocity fluctuations are surprisingly negligible compared to the velocity fluctuations induced by the vortex precession.

In situ measurements of wind and current speed and relationship between output power and turbulence

NASA Astrophysics Data System (ADS)

Duran Medina, Olmo; Schmitt, François G.; Sentchev, Alexei; Calif, Rudy

2015-04-01

In a context of energy transition, wind and tidal energy are sources of clean energy with the potential of partially satisfying the growing demand. The main problem of this type of energy, and other types of renewable energy remains the discontinuity of the electric power produced in different scales, inducing large fluctuations also called intermittency. This intermittency of wind and tidal energy is inherent to the turbulent nature of wind and marine currents. We consider this intermittent power production in strong relation with the turbulent intermittency of the resource. The turbulence theory is multifractal energy cascades models, a classic in physics of turbulence. From earlier studies in atmospheric sciences, we learn that wind speed and the aggregate power output are intermittent and multifractal over a wide range of scales [Calif and Schmitt 2014]. We want to extend this study to a marine current turbine and compare the scaling properties for those renewable energy sources. We consider here coupling between simultaneous velocity time series and output power from a wind turbine and a marine current turbine. Wind turbine data were obtained from Denmark and marine current data from Western Scheldt, Belgium where a prototype of a vertical and horizontal marine current turbines are tested. After an estimation of their Fourier density power spectra, we study their scaling properties in Kolmogorov's theory and the framework of fully developed turbulence. Hence, we employ a Hilbert-based methodology, namely arbitrary-order Hilbert spectral analysis [Calif et al. 2013a, 2013b] to characterize the intermittent property of the wind and marine current velocity in order to characterize the intermittent nature of the fluid. This method is used in order to obtain the spectrum and the corresponding power law for non-linear and non-stationary time series. The goal is to study the non-linear transfer characteristics in a multi-scale and multi-intensity framework.

Wake meandering of a model wind turbine operating in two different regimes

NASA Astrophysics Data System (ADS)

Foti, Daniel; Yang, Xiaolei; Campagnolo, Filippo; Maniaci, David; Sotiropoulos, Fotis

2018-05-01

The flow behind a model wind turbine under two different turbine operating regimes (region 2 for turbine operating at optimal condition with the maximum power coefficient and 1.4-deg pitch angle and region 3 for turbine operating at suboptimal condition with a lower power coefficient and 7-deg pitch angle) is investigated using wind tunnel experiments and numerical experiments using large-eddy simulation (LES) with actuator surface models for turbine blades and nacelle. Measurements from the model wind turbine experiment reveal that the power coefficient and turbine wake are affected by the operating regime. Simulations with and without a nacelle model are carried out for each operating condition to study the influence of the operating regime and nacelle on the formation of the hub vortex and wake meandering. Statistics and energy spectra of the simulated wakes are in good agreement with the measurements. For simulations with a nacelle model, the mean flow field is composed of an outer wake, caused by energy extraction by turbine blades, and an inner wake directly behind the nacelle, while for the simulations without a nacelle model, the central region of the wake is occupied by a jet. The simulations with the nacelle model reveal an unstable helical hub vortex expanding outward toward the outer wake, while the simulations without a nacelle model show a stable and columnar hub vortex. Because of the different interactions of the inner region of the wake with the outer region of the wake, a region with higher turbulence intensity is observed in the tip shear layer for the simulation with a nacelle model. The hub vortex for the turbine operating in region 3 remains in a tight helical spiral and intercepts the outer wake a few diameters further downstream than for the turbine operating in region 2. Wake meandering, a low-frequency large-scale motion of the wake, commences in the region of high turbulence intensity for all simulations with and without a nacelle model, indicating that neither a nacelle model nor an unstable hub vortex is a necessary requirement for the existence of wake meandering. However, further analysis of the wake meandering and instantaneous flow field using a filtering technique and dynamic mode decomposition show that the unstable hub vortex energizes the wake meandering. The turbine operating regime affects the shape and expansion of the hub vortex, altering the location of the onset of the wake meandering and wake meander oscillating intensity. Most important, the unstable hub vortex promotes a high-amplitude energetic meandering which cannot be predicted without a nacelle model.

Dynamic gas temperature measurement system

NASA Technical Reports Server (NTRS)

Elmore, D. L.; Robinson, W. W.; Watkins, W. B.

1983-01-01

A gas temperature measurement system with compensated frequency response of 1 KHz and capability to operate in the exhaust of a gas turbine combustor was developed. Environmental guidelines for this measurement are presented, followed by a preliminary design of the selected measurement method. Transient thermal conduction effects were identified as important; a preliminary finite-element conduction model quantified the errors expected by neglecting conduction. A compensation method was developed to account for effects of conduction and convection. This method was verified in analog electrical simulations, and used to compensate dynamic temperature data from a laboratory combustor and a gas turbine engine. Detailed data compensations are presented. Analysis of error sources in the method were done to derive confidence levels for the compensated data.

Energy Recovery

NASA Technical Reports Server (NTRS)

1987-01-01

The United States and other countries face the problem of waste disposal in an economical, environmentally safe manner. A widely applied solution adopted by Americans is "waste to energy," incinerating the refuse and using the steam produced by trash burning to drive an electricity producing generator. NASA's computer program PRESTO II, (Performance of Regenerative Superheated Steam Turbine Cycles), provides power engineering companies, including Blount Energy Resources Corporation of Alabama, with the ability to model such features as process steam extraction, induction and feedwater heating by external sources, peaking and high back pressure. Expansion line efficiency, exhaust loss, leakage, mechanical losses and generator losses are used to calculate the cycle heat rate. The generator output program is sufficiently precise that it can be used to verify performance quoted in turbine generator supplier's proposals.

Calculation of transient potential rise on the wind turbine struck by lightning.

PubMed

Xiaoqing, Zhang

2014-01-01

A circuit model is proposed in this paper for calculating the transient potential rise on the wind turbine struck by lightning. The model integrates the blade, sliding contact site, and tower and grounding system of the wind turbine into an equivalent circuit. The lightning current path from the attachment point to the ground can be fully described by the equivalent circuit. The transient potential responses are obtained in the different positions on the wind turbine by solving the circuit equations. In order to check the validity of the model, the laboratory measurement is made with a reduced-scale wind turbine. The measured potential waveform is compared with the calculated one and a better agreement is shown between them. The practical applicability of the model is also examined by a numerical example of a 2 MW Chinese-built wind turbine.

The effects of solarization on the performance of a gas turbine

NASA Astrophysics Data System (ADS)

Homann, Christiaan; van der Spuy, Johan; von Backström, Theodor

2016-05-01

Various hybrid solar gas turbine configurations exist. The Stellenbosch University Solar Power Thermodynamic (SUNSPOT) cycle consists of a heliostat field, solar receiver, primary Brayton gas turbine cycle, thermal storage and secondary Rankine steam cycle. This study investigates the effect of the solarization of a gas turbine on its performance and details the integration of a gas turbine into a solar power plant. A Rover 1S60 gas turbine was modelled in Flownex, a thermal-fluid system simulation and design code, and validated against a one-dimensional thermodynamic model at design input conditions. The performance map of a newly designed centrifugal compressor was created and implemented in Flownex. The effect of the improved compressor on the performance of the gas turbine was evident. The gas turbine cycle was expanded to incorporate different components of a CSP plant, such as a solar receiver and heliostat field. The solarized gas turbine model simulates the gas turbine performance when subjected to a typical variation in solar resource. Site conditions at the Helio100 solar field were investigated and the possibility of integrating a gas turbine within this system evaluated. Heat addition due to solar irradiation resulted in a decreased fuel consumption rate. The influence of the additional pressure drop over the solar receiver was evident as it leads to decreased net power output. The new compressor increased the overall performance of the gas turbine and compensated for pressure losses incurred by the addition of solar components. The simulated integration of the solarized gas turbine at Helio100 showed potential, although the solar irradiation is too little to run the gas turbine on solar heat alone. The simulation evaluates the feasibility of solarizing a gas turbine and predicts plant performance for such a turbine cycle.

Turbine Engine Mathematical Model Validation

DTIC Science & Technology

1976-12-01

AEDC-TR-76-90 ~Ec i ? Z985 TURBINE ENGINE MATHEMATICAL MODEL VALIDATION ENGINE TEST FACILITY ARNOLD ENGINEERING DEVELOPMENT CENTER AIR FORCE...i f n e c e s e a ~ ~ d i den t i f y by b l ock number) YJI01-GE-100 engine turbine engines mathematical models computations mathematical...report presents and discusses the results of an investigation to develop a rationale and technique for the validation of turbine engine steady-state

Computational study of the effects of shroud geometric variation on turbine performance in a 1.5-stage high-loaded turbine

NASA Astrophysics Data System (ADS)

Jia, Wei; Liu, Huoxing

2013-10-01

Generally speaking, main flow path of gas turbine is assumed to be perfect for standard 3D computation. But in real engine, the turbine annulus geometry is not completely smooth for the presence of the shroud and associated cavity near the end wall. Besides, shroud leakage flow is one of the dominant sources of secondary flow in turbomachinery, which not only causes a deterioration of useful work but also a penalty on turbine efficiency. It has been found that neglect shroud leakage flow makes the computed velocity profiles and loss distribution significantly different to those measured. Even so, the influence of shroud leakage flow is seldom taken into consideration during the routine of turbine design due to insufficient understanding of its impact on end wall flows and turbine performance. In order to evaluate the impact of tip shroud geometry on turbine performance, a 3D computational investigation for 1.5-stage turbine with shrouded blades was performed in this paper. The following geometry parameters were varied respectively: Inlet cavity length and exit cavity length

A Combined High and Low Cycle Fatigue Model for Life Prediction of Turbine Blades

PubMed Central

Yue, Peng; Yu, Zheng-Yong; Wang, Qingyuan

2017-01-01

Combined high and low cycle fatigue (CCF) generally induces the failure of aircraft gas turbine attachments. Based on the aero-engine load spectrum, accurate assessment of fatigue damage due to the interaction of high cycle fatigue (HCF) resulting from high frequency vibrations and low cycle fatigue (LCF) from ground-air-ground engine cycles is of critical importance for ensuring structural integrity of engine components, like turbine blades. In this paper, the influence of combined damage accumulation on the expected CCF life are investigated for turbine blades. The CCF behavior of a turbine blade is usually studied by testing with four load-controlled parameters, including high cycle stress amplitude and frequency, and low cycle stress amplitude and frequency. According to this, a new damage accumulation model is proposed based on Miner’s rule to consider the coupled damage due to HCF-LCF interaction by introducing the four load parameters. Five experimental datasets of turbine blade alloys and turbine blades were introduced for model validation and comparison between the proposed Miner, Manson-Halford, and Trufyakov-Kovalchuk models. Results show that the proposed model provides more accurate predictions than others with lower mean and standard deviation values of model prediction errors. PMID:28773064

A Combined High and Low Cycle Fatigue Model for Life Prediction of Turbine Blades.

PubMed

Zhu, Shun-Peng; Yue, Peng; Yu, Zheng-Yong; Wang, Qingyuan

2017-06-26

Combined high and low cycle fatigue (CCF) generally induces the failure of aircraft gas turbine attachments. Based on the aero-engine load spectrum, accurate assessment of fatigue damage due to the interaction of high cycle fatigue (HCF) resulting from high frequency vibrations and low cycle fatigue (LCF) from ground-air-ground engine cycles is of critical importance for ensuring structural integrity of engine components, like turbine blades. In this paper, the influence of combined damage accumulation on the expected CCF life are investigated for turbine blades. The CCF behavior of a turbine blade is usually studied by testing with four load-controlled parameters, including high cycle stress amplitude and frequency, and low cycle stress amplitude and frequency. According to this, a new damage accumulation model is proposed based on Miner's rule to consider the coupled damage due to HCF-LCF interaction by introducing the four load parameters. Five experimental datasets of turbine blade alloys and turbine blades were introduced for model validation and comparison between the proposed Miner, Manson-Halford, and Trufyakov-Kovalchuk models. Results show that the proposed model provides more accurate predictions than others with lower mean and standard deviation values of model prediction errors.

Cold flow testing of the Space Shuttle Main Engine alternate turbopump development high pressure fuel turbine model

NASA Technical Reports Server (NTRS)

Gaddis, Stephen W.; Hudson, Susan T.; Johnson, P. D.

1992-01-01

NASA's Marshall Space Flight Center has established a cold airflow turbine test program to experimentally determine the performance of liquid rocket engine turbopump drive turbines. Testing of the SSME alternate turbopump development (ATD) fuel turbine was conducted for back-to-back comparisons with the baseline SSME fuel turbine results obtained in the first quarter of 1991. Turbine performance, Reynolds number effects, and turbine diagnostics, such as stage reactions and exit swirl angles, were investigated at the turbine design point and at off-design conditions. The test data showed that the ATD fuel turbine test article was approximately 1.4 percent higher in efficiency and flowed 5.3 percent more than the baseline fuel turbine test article. This paper describes the method and results used to validate the ATD fuel turbine aerodynamic design. The results are being used to determine the ATD high pressure fuel turbopump (HPFTP) turbine performance over its operating range, anchor the SSME ATD steady-state performance model, and validate various prediction and design analyses.

Windmill Noise Annoyance, Visual Aesthetics, and Attitudes towards Renewable Energy Sources

PubMed Central

Klæboe, Ronny; Sundfør, Hanne Beate

2016-01-01

A small focused socio-acoustic after-study of annoyance from a windmill park was undertaken after local health officials demanded a health impact study to look into neighborhood complaints. The windmill park consists of 31 turbines and is located in the South of Norway where it affects 179 dwellings. Simple exposure-effect relationships indicate stronger reactions to windmills and wind turbine noise than shown internationally, with the caveat that the sample size is small (n = 90) and responses are colored by the existing local conflict. Pulsating swishing sounds and turbine engine hum are the main causes of noise annoyance. About 60 per cent of those who participated in the survey were of the opinion that windmills degrade the landscape aesthetically, and were far from convinced that land-based windmills are desirable as a renewable energy source (hydropower is an important alternative source of renewables in Norway). Attitudes play an important role in addition to visual aesthetics in determining the acceptance of windmills and the resulting noise annoyance. To compare results from different wind turbine noise studies it seems necessary to assess the impact of important modifying factors. PMID:27455301

Certification of alternative aviation fuels and blend components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson III, George R.; Edwards, Tim; Corporan, Edwin

2013-01-15

Aviation turbine engine fuel specifications are governed by ASTM International, formerly known as the American Society for Testing and Materials (ASTM) International, and the British Ministry of Defence (MOD). ASTM D1655 Standard Specification for Aviation Turbine Fuels and MOD Defence Standard 91-91 are the guiding specifications for this fuel throughout most of the world. Both of these documents rely heavily on the vast amount of experience in production and use of turbine engine fuels from conventional sources, such as crude oil, natural gas condensates, heavy oil, shale oil, and oil sands. Turbine engine fuel derived from these resources and meetingmore » the above specifications has properties that are generally considered acceptable for fuels to be used in turbine engines. Alternative and synthetic fuel components are approved for use to blend with conventional turbine engine fuels after considerable testing. ASTM has established a specification for fuels containing synthesized hydrocarbons under D7566, and the MOD has included additional requirements for fuels containing synthetic components under Annex D of DS91-91. New turbine engine fuel additives and blend components need to be evaluated using ASTM D4054, Standard Practice for Qualification and Approval of New Aviation Turbine Fuels and Fuel Additives. This paper discusses these specifications and testing requirements in light of recent literature claiming that some biomass-derived blend components, which have been used to blend in conventional aviation fuel, meet the requirements for aviation turbine fuels as specified by ASTM and the MOD. The 'Table 1' requirements listed in both D1655 and DS91-91 are predicated on the assumption that the feedstocks used to make fuels meeting these requirements are from approved sources. Recent papers have implied that commercial jet fuel can be blended with renewable components that are not hydrocarbons (such as fatty acid methyl esters). These are not allowed blend components for turbine engine fuels as discussed in this paper.« less

Wind flow characteristics in the wakes of large wind turbines. Volume 1: Analytical model development

NASA Technical Reports Server (NTRS)

Eberle, W. R.

1981-01-01

A computer program to calculate the wake downwind of a wind turbine was developed. Turbine wake characteristics are useful for determining optimum arrays for wind turbine farms. The analytical model is based on the characteristics of a turbulent coflowing jet with modification for the effects of atmospheric turbulence. The program calculates overall wake characteristics, wind profiles, and power recovery for a wind turbine directly in the wake of another turbine, as functions of distance downwind of the turbine. The calculation procedure is described in detail, and sample results are presented to illustrate the general behavior of the wake and the effects of principal input parameters.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Na, Ji Sung; Koo, Eunmo; Munoz-Esparza, Domingo

High-resolution large-eddy simulation of the flow over a large wind farm (64 wind turbines) is performed using the HIGRAD/FIRETEC-WindBlade model, which is a high-performance computing wind turbine–atmosphere interaction model that uses the Lagrangian actuator line method to represent rotating turbine blades. These high-resolution large-eddy simulation results are used to parameterize the thrust and power coefficients that contain information about turbine interference effects within the wind farm. Those coefficients are then incorporated into the WRF (Weather Research and Forecasting) model in order to evaluate interference effects in larger-scale models. In the high-resolution WindBlade wind farm simulation, insufficient distance between turbines createsmore » the interference between turbines, including significant vertical variations in momentum and turbulent intensity. The characteristics of the wake are further investigated by analyzing the distribution of the vorticity and turbulent intensity. Quadrant analysis in the turbine and post-turbine areas reveals that the ejection motion induced by the presence of the wind turbines is dominant compared to that in the other quadrants, indicating that the sweep motion is increased at the location where strong wake recovery occurs. Regional-scale WRF simulations reveal that although the turbulent mixing induced by the wind farm is partly diffused to the upper region, there is no significant change in the boundary layer depth. The velocity deficit does not appear to be very sensitive to the local distribution of turbine coefficients. However, differences of about 5% on parameterized turbulent kinetic energy were found depending on the turbine coefficient distribution. Furthermore, turbine coefficients that consider interference in the wind farm should be used in wind farm parameterization for larger-scale models to better describe sub-grid scale turbulent processes.« less

Turbulent kinetics of a large wind farm and their impact in the neutral boundary layer

DOE PAGES

Na, Ji Sung; Koo, Eunmo; Munoz-Esparza, Domingo; ...

2015-12-28

High-resolution large-eddy simulation of the flow over a large wind farm (64 wind turbines) is performed using the HIGRAD/FIRETEC-WindBlade model, which is a high-performance computing wind turbine–atmosphere interaction model that uses the Lagrangian actuator line method to represent rotating turbine blades. These high-resolution large-eddy simulation results are used to parameterize the thrust and power coefficients that contain information about turbine interference effects within the wind farm. Those coefficients are then incorporated into the WRF (Weather Research and Forecasting) model in order to evaluate interference effects in larger-scale models. In the high-resolution WindBlade wind farm simulation, insufficient distance between turbines createsmore » the interference between turbines, including significant vertical variations in momentum and turbulent intensity. The characteristics of the wake are further investigated by analyzing the distribution of the vorticity and turbulent intensity. Quadrant analysis in the turbine and post-turbine areas reveals that the ejection motion induced by the presence of the wind turbines is dominant compared to that in the other quadrants, indicating that the sweep motion is increased at the location where strong wake recovery occurs. Regional-scale WRF simulations reveal that although the turbulent mixing induced by the wind farm is partly diffused to the upper region, there is no significant change in the boundary layer depth. The velocity deficit does not appear to be very sensitive to the local distribution of turbine coefficients. However, differences of about 5% on parameterized turbulent kinetic energy were found depending on the turbine coefficient distribution. Furthermore, turbine coefficients that consider interference in the wind farm should be used in wind farm parameterization for larger-scale models to better describe sub-grid scale turbulent processes.« less

Evaluation of lightning accommodation systems for wind-driven turbine rotors

NASA Technical Reports Server (NTRS)

Bankaitis, H.

1982-01-01

Wind-driven turbine generators are being evaluated as an alternative source of electric energy. Areas of favorable location for the wind-driven turbines (high wind density) coincide with areas of high incidence of thunderstorm activity. These locations, coupled with the 30-m or larger diameter rotor blades, make the wind-driven turbine blades probable terminations for lightning strikes. Several candidate systems of lightning accommodation for composite-structural-material blades were designed and their effectiveness evaluated by submitting the systems to simulated lightning strikes. The test data were analyzed and system design were reviewed on the basis of the analysis.

Visualization techniques to experimentally model flow and heat transfer in turbine and aircraft flow passages

NASA Technical Reports Server (NTRS)

Russell, Louis M.; Hippensteele, Steven A.

1991-01-01

Increased attention to fuel economy and increased thrust requirements have increased the demand for higher aircraft gas turbine engine efficiency through the use of higher turbine inlet temperatures. These higher temperatures increase the importance of understanding the heat transfer patterns which occur throughout the turbine passages. It is often necessary to use a special coating or some form of cooling to maintain metal temperatures at a level which the metal can withstand for long periods of time. Effective cooling schemes can result in significant fuel savings through higher allowable turbine inlet temperatures and can increase engine life. Before proceeding with the development of any new turbine it is economically desirable to create both mathematical and experimental models to study and predict flow characteristics and temperature distributions. Some of the methods are described used to physically model heat transfer patterns, cooling schemes, and other complex flow patterns associated with turbine and aircraft passages.

Indirect combustion noise of auxiliary power units

NASA Astrophysics Data System (ADS)

Tam, Christopher K. W.; Parrish, Sarah A.; Xu, Jun; Schuster, Bill

2013-08-01

Recent advances in noise suppression technology have significantly reduced jet and fan noise from commercial jet engines. This leads many investigators in the aeroacoustics community to suggest that core noise could well be the next aircraft noise barrier. Core noise consists of turbine noise and combustion noise. There is direct combustion noise generated by the combustion processes, and there is indirect combustion noise generated by the passage of combustion hot spots, or entropy waves, through constrictions in an engine. The present work focuses on indirect combustion noise. Indirect combustion noise has now been found in laboratory experiments. The primary objective of this work is to investigate whether indirect combustion noise is also generated in jet and other engines. In a jet engine, there are numerous noise sources. This makes the identification of indirect combustion noise a formidable task. Here, our effort concentrates exclusively on auxiliary power units (APUs). This choice is motivated by the fact that APUs are relatively simple engines with only a few noise sources. It is, therefore, expected that the chance of success is higher. Accordingly, a theoretical model study of the generation of indirect combustion noise in an Auxiliary Power Unit (APU) is carried out. The cross-sectional areas of an APU from the combustor to the turbine exit are scaled off to form an equivalent nozzle. A principal function of a turbine in an APU is to extract mechanical energy from the flow stream through the exertion of a resistive force. Therefore, the turbine is modeled by adding a negative body force to the momentum equation. This model is used to predict the ranges of frequencies over which there is a high probability for indirect combustion noise generation. Experimental spectra of internal pressure fluctuations and far-field noise of an RE220 APU are examined to identify anomalous peaks. These peaks are possible indirection combustion noise. In the case of the APU RE220, such peaks are identified. The frequency ranges of these peaks are found to overlap those predicted by the model theory. Based on this agreement, a tentative conclusion is drawn that there is good reason to believe that APUs do generate measurable indirect combustion noise. This paper is dedicated to the memory of Prof. Phil Doak for his numerous contributions to Aeroacoustics and the Journal of Sound and Vibration.

Improving Energy Security for Air Force Installations

DTIC Science & Technology

2015-09-01

Wind power is a mature technology, with wind turbines first being used for electricity in the late 19th century. The Air Force operates two wind ...company, and the military unit receives energy credits back on its bill. Two concepts are important when considering the turbine size for a wind ...generation and consumption must remain balanced for a grid, so wind turbines are rarely used as a sole energy source since power is only generated

Analysis of Operational Data: A Proof of Concept for Assessing Electrical Infrastructure Impact

DTIC Science & Technology

2015-11-01

cogeneration, solar, wind , geothermal, etc.) or by prime mover (i.e., steam turbine , water turbine , gas turbine , etc.). Power plants are typically...and Time SDR Sensor Data Record TRADOC U.S. Army Training and Doctrine Command UTC Coordinated Universal Time VCM VIIRS Cloud Mask VIIRS Visible...power, and other natural sources (water or wind ). The generating facilities or power plants can run by fuel (e.g., fossil fuel, hydroelectric, nuclear

Modeling Improvements and Users Manual for Axial-flow Turbine Off-design Computer Code AXOD

NASA Technical Reports Server (NTRS)

Glassman, Arthur J.

1994-01-01

An axial-flow turbine off-design performance computer code used for preliminary studies of gas turbine systems was modified and calibrated based on the experimental performance of large aircraft-type turbines. The flow- and loss-model modifications and calibrations are presented in this report. Comparisons are made between computed performances and experimental data for seven turbines over wide ranges of speed and pressure ratio. This report also serves as the users manual for the revised code, which is named AXOD.

A Free Wake Numerical Simulation for Darrieus Vertical Axis Wind Turbine Performance Prediction

NASA Astrophysics Data System (ADS)

Belu, Radian

2010-11-01

In the last four decades, several aerodynamic prediction models have been formulated for the Darrieus wind turbine performances and characteristics. We can identified two families: stream-tube and vortex. The paper presents a simplified numerical techniques for simulating vertical axis wind turbine flow, based on the lifting line theory and a free vortex wake model, including dynamic stall effects for predicting the performances of a 3-D vertical axis wind turbine. A vortex model is used in which the wake is composed of trailing stream-wise and shedding span-wise vortices, whose strengths are equal to the change in the bound vortex strength as required by the Helmholz and Kelvin theorems. Performance parameters are computed by application of the Biot-Savart law along with the Kutta-Jukowski theorem and a semi-empirical stall model. We tested the developed model with an adaptation of the earlier multiple stream-tube performance prediction model for the Darrieus turbines. Predictions by using our method are shown to compare favorably with existing experimental data and the outputs of other numerical models. The method can predict accurately the local and global performances of a vertical axis wind turbine, and can be used in the design and optimization of wind turbines for built environment applications.

Calculation of Transient Potential Rise on the Wind Turbine Struck by Lightning

PubMed Central

Xiaoqing, Zhang

2014-01-01

A circuit model is proposed in this paper for calculating the transient potential rise on the wind turbine struck by lightning. The model integrates the blade, sliding contact site, and tower and grounding system of the wind turbine into an equivalent circuit. The lightning current path from the attachment point to the ground can be fully described by the equivalent circuit. The transient potential responses are obtained in the different positions on the wind turbine by solving the circuit equations. In order to check the validity of the model, the laboratory measurement is made with a reduced-scale wind turbine. The measured potential waveform is compared with the calculated one and a better agreement is shown between them. The practical applicability of the model is also examined by a numerical example of a 2 MW Chinese-built wind turbine. PMID:25254231

NREL Leads Wind Farm Modeling Research - Continuum Magazine | NREL

Science.gov Websites

ten 2-MW Bonus wind turbines. Photo provided by HC Sorensen, Middelgrunden Wind Turbine Cooperative ) has created complex computer modeling tools to improve wind turbine design and overall wind farm activity surrounding a multi-megawatt wind turbine. In addition to its work with Doppler LIDAR, the

Microscale air quality impacts of distributed power generation facilities.

PubMed

Olaguer, Eduardo P; Knipping, Eladio; Shaw, Stephanie; Ravindran, Satish

2016-08-01

The electric system is experiencing rapid growth in the adoption of a mix of distributed renewable and fossil fuel sources, along with increasing amounts of off-grid generation. New operational regimes may have unforeseen consequences for air quality. A three-dimensional microscale chemical transport model (CTM) driven by an urban wind model was used to assess gaseous air pollutant and particulate matter (PM) impacts within ~10 km of fossil-fueled distributed power generation (DG) facilities during the early afternoon of a typical summer day in Houston, TX. Three types of DG scenarios were considered in the presence of motor vehicle emissions and a realistic urban canopy: (1) a 25-MW natural gas turbine operating at steady state in either simple cycle or combined heating and power (CHP) mode; (2) a 25-MW simple cycle gas turbine undergoing a cold startup with either moderate or enhanced formaldehyde emissions; and (3) a data center generating 10 MW of emergency power with either diesel or natural gas-fired backup generators (BUGs) without pollution controls. Simulations of criteria pollutants (NO2, CO, O3, PM) and the toxic pollutant, formaldehyde (HCHO), were conducted assuming a 2-hr operational time period. In all cases, NOx titration dominated ozone production near the source. The turbine scenarios did not result in ambient concentration enhancements significantly exceeding 1 ppbv for gaseous pollutants or over 1 µg/m(3) for PM after 2 hr of emission, assuming realistic plume rise. In the case of the datacenter with diesel BUGs, ambient NO2 concentrations were enhanced by 10-50 ppbv within 2 km downwind of the source, while maximum PM impacts in the immediate vicinity of the datacenter were less than 5 µg/m(3). Plausible scenarios of distributed fossil generation consistent with the electricity grid's transformation to a more flexible and modernized system suggest that a substantial amount of deployment would be required to significantly affect air quality on a localized scale. In particular, natural gas turbines typically used in distributed generation may have minor effects. Large banks of diesel backup generators such as those used by data centers, on the other hand, may require pollution controls or conversion to natural gas-fired reciprocal internal combustion engines to decrease nitrogen dioxide pollution.

Francis-99: Transient CFD simulation of load changes and turbine shutdown in a model sized high-head Francis turbine

NASA Astrophysics Data System (ADS)

Mössinger, Peter; Jester-Zürker, Roland; Jung, Alexander

2017-01-01

With increasing requirements for hydropower plant operation due to intermittent renewable energy sources like wind and solar, numerical simulations of transient operations in hydraulic turbo machines become more important. As a continuation of the work performed for the first workshop which covered three steady operating conditions, in the present paper load changes and a shutdown procedure are investigated. The findings of previous studies are used to create a 360° model and compare measurements with simulation results for the operating points part load, high load and best efficiency. A mesh motion procedure is introduced, allowing to represent moving guide vanes for load changes from best efficiency to part load and high load. Additionally an automated re-mesh procedure is added for turbine shutdown to ensure reliable mesh quality during guide vane closing. All three transient operations are compared to PIV velocity measurements in the draft tube and pressure signals in the vaneless space. Simulation results of axial velocity distributions for all three steady operation points, during both load changes and for the shutdown correlated well with the measurement. An offset at vaneless space pressure is found to be a result of guide vane corrections for the simulation to ensure similar velocity fields. Short-time Fourier transformation indicating increasing amplitudes and frequencies at speed-no load conditions. Further studies will discuss the already measured start-up procedure and investigate the necessity to consider the hydraulic system dynamics upstream of the turbine by means of a 1D3D coupling between the 3D flow field and a 1D system model.

Sound propagation from a ridge wind turbine across a valley.

PubMed

Van Renterghem, Timothy

2017-04-13

Sound propagation outdoors can be strongly affected by ground topography. The existence of hills and valleys between a source and receiver can lead to the shielding or focusing of sound waves. Such effects can result in significant variations in received sound levels. In addition, wind speed and air temperature gradients in the atmospheric boundary layer also play an important role. All of the foregoing factors can become especially important for the case of wind turbines located on a ridge overlooking a valley. Ridges are often selected for wind turbines in order to increase their energy capture potential through the wind speed-up effects often experienced in such locations. In this paper, a hybrid calculation method is presented to model such a case, relying on an analytical solution for sound diffraction around an impedance cylinder and the conformal mapping (CM) Green's function parabolic equation (GFPE) technique. The various aspects of the model have been successfully validated against alternative prediction methods. Example calculations with this hybrid analytical-CM-GFPE model show the complex sound pressure level distribution across the valley and the effect of valley ground type. The proposed method has the potential to include the effect of refraction through the inclusion of complex wind and temperature fields, although this aspect has been highly simplified in the current simulations.This article is part of the themed issue 'Wind energy in complex terrains'. © 2017 The Author(s).

Wake Flow Simulation of a Vertical Axis Wind Turbine Under the Influence of Wind Shear

NASA Astrophysics Data System (ADS)

Mendoza, Victor; Goude, Anders

2017-05-01

The current trend of the wind energy industry aims for large scale turbines installed in wind farms. This brings a renewed interest in vertical axis wind turbines (VAWTs) since they have several advantages over the traditional Horizontal Axis Wind Tubines (HAWTs) for mitigating the new challenges. However, operating VAWTs are characterized by complex aerodynamics phenomena, presenting considerable challenges for modeling tools. An accurate and reliable simulation tool for predicting the interaction between the obtained wake of an operating VAWT and the flow in atmospheric open sites is fundamental for optimizing the design and location of wind energy facility projects. The present work studies the wake produced by a VAWT and how it is affected by the surface roughness of the terrain, without considering the effects of the ambient turbulence intensity. This study was carried out using an actuator line model (ALM), and it was implemented using the open-source CFD library OpenFOAM to solve the governing equations and to compute the resulting flow fields. An operational H-shaped VAWT model was tested, for which experimental activity has been performed at an open site north of Uppsala-Sweden. Different terrains with similar inflow velocities have been evaluated. Simulated velocity and vorticity of representative sections have been analyzed. Numerical results were validated using normal forces measurements, showing reasonable agreement.

Wind Turbine Modeling Overview for Control Engineers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moriarty, P. J.; Butterfield, S. B.

2009-01-01

Accurate modeling of wind turbine systems is of paramount importance for controls engineers seeking to reduce loads and optimize energy capture of operating turbines in the field. When designing control systems, engineers often employ a series of models developed in the different disciplines of wind energy. The limitations and coupling of each of these models is explained to highlight how these models might influence control system design.

Analysis of a pico tubular-type hydro turbine performance by runner blade shape using CFD

NASA Astrophysics Data System (ADS)

Park, J. H.; Lee, N. J.; Wata, J. V.; Hwang, Y. C.; Kim, Y. T.; Lee, Y. H.

2012-11-01

There has been a considerable interest recently in the topic of renewable energy. This is primarily due to concerns about environmental impacts of fossil fuels. Moreover, fluctuating and rising oil prices, increase in demand, supply uncertainties and other factors have led to increased calls for alternative energy sources. Small hydropower, among other renewable energy sources, has been evaluated to have adequate development value because it is a clean, renewable and abundant energy resource. In addition, small hydropower has the advantage of low cost development by using rivers, agricultural reservoirs, sewage treatment plants, waterworks and water resources. The main concept of the tubular-type hydro turbine is based on the difference in water pressure levels in pipe lines, where the energy which was initially wasted by using a reducing valve at the pipeline of waterworks, is collected by turbine in the hydro power generator. In this study, in order to acquire the performance data of a pico tubular-type hydro turbine, the output power, head and efficiency characteristics by different runner blade shapes are examined. The pressure and velocity distributions with the variation of guide vane and runner vane angle on turbine performance are investigated by using a commercial CFD code.

Testing and Modeling of a 3-MW Wind Turbine Using Fully Coupled Simulation Codes (Poster)

DOE Office of Scientific and Technical Information (OSTI.GOV)

LaCava, W.; Guo, Y.; Van Dam, J.

This poster describes the NREL/Alstom Wind testing and model verification of the Alstom 3-MW wind turbine located at NREL's National Wind Technology Center. NREL,in collaboration with ALSTOM Wind, is studying a 3-MW wind turbine installed at the National Wind Technology Center(NWTC). The project analyzes the turbine design using a state-of-the-art simulation code validated with detailed test data. This poster describes the testing and the model validation effort, and provides conclusions about the performance of the unique drive train configuration used in this wind turbine. The 3-MW machine has been operating at the NWTC since March 2011, and drive train measurementsmore » will be collected through the spring of 2012. The NWTC testing site has particularly turbulent wind patterns that allow for the measurement of large transient loads and the resulting turbine response. This poster describes the 3-MW turbine test project, the instrumentation installed, and the load cases captured. The design of a reliable wind turbine drive train increasingly relies on the use of advanced simulation to predict structural responses in a varying wind field. This poster presents a fully coupled, aero-elastic and dynamic model of the wind turbine. It also shows the methodology used to validate the model, including the use of measured tower modes, model-to-model comparisons of the power curve, and mainshaft bending predictions for various load cases. The drivetrain is designed to only transmit torque to the gearbox, eliminating non-torque moments that are known to cause gear misalignment. Preliminary results show that the drivetrain is able to divert bending loads in extreme loading cases, and that a significantly smaller bending moment is induced on the mainshaft compared to a three-point mounting design.« less

77 FR 52553 - Standards of Performance for Stationary Gas Turbines; Standards of Performance for Stationary...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-29

...The EPA is proposing to amend the new source performance standards (NSPS) for stationary gas turbines and stationary combustion turbines. These amendments are primarily in response to issues raised by the regulated community. On July 6, 2006, the EPA promulgated amendments to the new source performance standards for stationary combustion turbines. On September 5, 2006, the Utility Air Regulatory Group filed a petition for reconsideration of certain aspects of the promulgated standards. The EPA is proposing to amend specific provisions in the NSPS to resolve issues and questions raised by the petition for reconsideration, and to address other technical and editorial issues. In addition, this proposed rule would amend the location and wording of existing paragraphs for clarity. The proposed amendments would increase the environmental benefits of the existing requirements because the emission standards would apply at all times. The proposed amendments would also promote efficiency by recognizing the environmental benefit of combined heat and power and the beneficial use of low energy content gases.

Wind tunnel validation of AeroDyn within LIFES50+ project: imposed Surge and Pitch tests

NASA Astrophysics Data System (ADS)

Bayati, I.; Belloli, M.; Bernini, L.; Zasso, A.

2016-09-01

This paper presents the first set of results of the steady and unsteady wind tunnel tests, performed at Politecnico di Milano wind tunnel, on a 1/75 rigid scale model of the DTU 10 MW wind turbine, within the LIFES50+ project. The aim of these tests is the validation of the open source code AeroDyn developed at NREL. Numerical and experimental steady results are compared in terms of thrust and torque coefficients, showing good agreement, as well as for unsteady measurements gathered with a 2 degree-of-freedom test rig, capable of imposing the displacements at the base of the model, and providing the surge and pitch motion of the floating offshore wind turbine (FOWT) scale model. The measurements of the unsteady test configuration are compared with AeroDyn/Dynin module results, implementing the generalized dynamic wake (GDW) model. Numerical and experimental comparison showed similar behaviours in terms of non linear hysteresis, however some discrepancies are herein reported and need further data analysis and interpretations about the aerodynamic integral quantities, with a special attention to the physics of the unsteady phenomenon.

Analyzing hydro abrasive erosion in Kaplan turbine: A case study from India

NASA Astrophysics Data System (ADS)

Rai, Anant Kr.; Kumar, Arun

2016-10-01

Sediment flow through hydro turbine causes erosion of hydraulic components resulting in drop of turbine efficiency, particularly in hydropower plants of the Himalayan region. The measurement of erosion and monitoring of sediment flow in turbine are major concerns in erosion study. Attempts have been made to study erosion mainly in Pelton and Francis turbines. In this study, a simple and effective method has been presented to measure erosion in a Kaplan turbine of a run-of-river scheme Chilla hydropower plant in foothills of Himalaya. Recent techniques were used to measure sediment parameters like concentration, size, shape and mineral content. A standard erosion model is applied to estimate the erosion in Kaplan turbine blade, runner chamber and draft tube cone. A calibration factor has been proposed to apply the erosion model for site specific conditions. It has been found that the outer trailing edges of the turbine blade and upper runner chamber are most erosion prone zones. Sediment analysis revealed that effective operation can reduce erosion in turbine components. The estimated erosion values from model are found to be consistent with measured values. Finally, suggestions for design improvements and effective operation of erosion affected hydropower plants are given.

Systems Engineering 2010 Workshop | Wind | NREL

Science.gov Websites

turbine aeroelastic model, inflow turbulence model, wind plan layout and interactions, resource model, O on the approach to wind turbine design, choice, and deployment 2:40 Break Computer Science perspective) International Laboratories 3:20 Bernard Bulder, ECN Integral Wind Turbine Design with Focus-6 3

Validation of Simplified Load Equations through Loads Measurement and Modeling of a Small Horizontal-Axis Wind Turbine Tower; NREL (National Renewable Energy Laboratory)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dana, S.; Damiani, R.; vanDam, J.

As part of an ongoing effort to improve the modeling and prediction of small wind turbine dynamics, NREL tested a small horizontal axis wind turbine in the field at the National Wind Technology Center (NWTC). The test turbine was a 2.1-kW downwind machine mounted on an 18-meter multi-section fiberglass composite tower. The tower was instrumented and monitored for approximately 6 months. The collected data were analyzed to assess the turbine and tower loads and further validate the simplified loads equations from the International Electrotechnical Commission (IEC) 61400-2 design standards. Field-measured loads were also compared to the output of an aeroelasticmore » model of the turbine. Ultimate loads at the tower base were assessed using both the simplified design equations and the aeroelastic model output. The simplified design equations in IEC 61400-2 do not accurately model fatigue loads. In this project, we compared fatigue loads as measured in the field, as predicted by the aeroelastic model, and as calculated using the simplified design equations.« less

Investigation of heat transfer and flow using ribs within gas turbine blade cooling passage: Experimental and hybrid LES/RANS modeling

NASA Astrophysics Data System (ADS)

Kumar, Sourabh

Gas turbines are extensively used for aircraft propulsion, land based power generation and various industrial applications. Developments in innovative gas turbine cooling technology enhance the efficiency and power output, with an increase in turbine rotor inlet temperatures. These advancements of turbine cooling have allowed engine design to exceed normal material temperature limits. For internal cooling design, techniques for heat extraction from the surfaces exposed to hot stream are based on the increase of heat transfer areas and on promotion of turbulence of the cooling flow. In this study, it is obtained by casting repeated continuous V and broken V shaped ribs on one side of the two pass square channel into the core of blade. Despite extensive research on ribs, only few papers have validated the numerical data with experimental results in two pass channel. In the present study, detailed experimental investigation is carried out for two pass square channels with 180° turn. Detailed heat transfer distribution occurring in the ribbed passage is reported for steady state experiment. Four different combinations of 60° and Broken 60° V ribs in channel are considered. Thermocouples are used to obtain the temperature on the channel surface and local heat transfer coefficients are obtained for various Reynolds numbers, within the turbulent flow regime. Area averaged data are calculated in order to compare the overall performance of the tested ribbed surface and to evaluate the degree of heat transfer enhancement induced by the ribs with. Flow within the channels is characterized by heat transfer enhancing ribs, bends, rotation and buoyancy effects. Computational Fluid Dynamics (CFD) simulations were carried out for the same geometries using different turbulence models such as k-o Shear stress transport (SST) and Reynolds stress model (RSM). These CFD simulations were based on advanced computing in order to improve the accuracy of three dimensional metal temperature prediction which can be applied routinely in the design stage of turbine cooled vanes and blades. This study presents an attempt to collect information about Nusselt number inside the ribbed duct and a series of measurement is performed in steady state eliminating the error sources inherently connected with transient method. A Large Eddy Simulation (LES) is carried out on the best V and Broken V rib arrangements to analyze the flow pattern inside the channel. A novel method is devised to analyze the results obtained from CFD simulation. Hybrid LES/Reynolds Averaged Navier Strokes (RANS) modeling is used to modify Reynolds stresses using Algebraic Stress Model (ASM).

Pump for spawning channels includes a turbine and motor. Turbine ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Pump for spawning channels includes a turbine and motor. Turbine is Berkeley H-17500, model 8C2PH, Serial No. 2889, B.M. No. 4886 - Berkeley Pump Co. The Motor is G.E. Induction Motor, model 5K4256XA3YI, serial no. GAJ728337, Tri-Clad. View looking northeast. - Prairie Creek Fish Hatchery, Hwy. 101, Orick, Humboldt County, CA

Basic investigation of turbine erosion phenomena

NASA Technical Reports Server (NTRS)

Pouchot, W. D.; Kothmann, R. E.; Fentress, W. K.; Heymann, F. J.; Varljen, T. C.; Chi, J. W. H.; Milton, J. D.; Glassmire, C. M.; Kyslinger, J. A.; Desai, K. A.

1971-01-01

An analytical-empirical model is presented of turbine erosion that fits and explains experience in both steam and metal vapor turbines. Because of the complexities involved in analyzing turbine problems, in a pure scientific sense, it is obvious that this goal can be only partially realized. Therefore, emphasis is placed on providing a useful model for preliminary erosion estimates for given configurations, fluids, and flow conditions.

Guide to the evaluation of human exposure to noise from large wind turbines

NASA Technical Reports Server (NTRS)

Stephens, D. G.; Shepherd, K. P.; Hubbard, H. H.; Grosveld, F.

1982-01-01

Guidance for evaluating human exposure to wind turbine noise is provided and includes consideration of the source characteristics, the propagation to the receiver location, and the exposure of the receiver to the noise. The criteria for evaluation of human exposure are based on comparisons of the noise at the receiver location with the human perception thresholds for wind turbine noise and noise-induced building vibrations in the presence of background noise.

Sustainability Logistics Basing - Science and Technology Objective - Demonstration; Demonstration #1 - 50 Person Camp Demo

DTIC Science & Technology

2017-08-17

sources: solar panels, two wind turbines , JP8/diesel genset, and alternating current (AC) shore power. The system can be towed by a High Mobility...energy. The project office shipped two REDUCE units to the demonstration, one with wind turbines and one without. For the demonstration, the team...operated and collected data from the system without wind turbines due to the greater reliability of its integrated genset. The system with wind

Fluid-structure coupling for wind turbine blade analysis using OpenFOAM

NASA Astrophysics Data System (ADS)

Dose, Bastian; Herraez, Ivan; Peinke, Joachim

2015-11-01

Modern wind turbine rotor blades are designed increasingly large and flexible. This structural flexibility represents a problem for the field of Computational Fluid Dynamics (CFD), which is used for accurate load calculations and detailed investigations of rotor aerodynamics. As the blade geometries within CFD simulations are considered stiff, the effect of blade deformation caused by aerodynamic loads cannot be captured by the common CFD approach. Coupling the flow solver with a structural solver can overcome this restriction and enables the investigation of flexible wind turbine blades. For this purpose, a new Finite Element (FE) solver was implemented into the open source CFD code OpenFOAM. Using a beam element formulation based on the Geometrically Exact Beam Theory (GEBT), the structural model can capture geometric non-linearities such as large deformations. Coupled with CFD solvers of the OpenFOAM package, the new framework represents a powerful tool for aerodynamic investigations. In this work, we investigated the aerodynamic performance of a state of the art wind turbine. For different wind speeds, aerodynamic key parameters are evaluated and compared for both, rigid and flexible blade geometries. The present work is funded within the framework of the joint project Smart Blades (0325601D) by the German Federal Ministry for Economic Affairs and Energy (BMWi) under decision of the German Federal Parliament.

A Probabilistic Model for Hydrokinetic Turbine Collision Risks: Exploring Impacts on Fish

PubMed Central

Hammar, Linus; Eggertsen, Linda; Andersson, Sandra; Ehnberg, Jimmy; Arvidsson, Rickard; Gullström, Martin; Molander, Sverker

2015-01-01

A variety of hydrokinetic turbines are currently under development for power generation in rivers, tidal straits and ocean currents. Because some of these turbines are large, with rapidly moving rotor blades, the risk of collision with aquatic animals has been brought to attention. The behavior and fate of animals that approach such large hydrokinetic turbines have not yet been monitored at any detail. In this paper, we conduct a synthesis of the current knowledge and understanding of hydrokinetic turbine collision risks. The outcome is a generic fault tree based probabilistic model suitable for estimating population-level ecological risks. New video-based data on fish behavior in strong currents are provided and models describing fish avoidance behaviors are presented. The findings indicate low risk for small-sized fish. However, at large turbines (≥5 m), bigger fish seem to have high probability of collision, mostly because rotor detection and avoidance is difficult in low visibility. Risks can therefore be substantial for vulnerable populations of large-sized fish, which thrive in strong currents. The suggested collision risk model can be applied to different turbine designs and at a variety of locations as basis for case-specific risk assessments. The structure of the model facilitates successive model validation, refinement and application to other organism groups such as marine mammals. PMID:25730314

Toward Development of a Stochastic Wake Model: Validation Using LES and Turbine Loads

DOE PAGES

Moon, Jae; Manuel, Lance; Churchfield, Matthew; ...

2017-12-28

Wind turbines within an array do not experience free-stream undisturbed flow fields. Rather, the flow fields on internal turbines are influenced by wakes generated by upwind unit and exhibit different dynamic characteristics relative to the free stream. The International Electrotechnical Commission (IEC) standard 61400-1 for the design of wind turbines only considers a deterministic wake model for the design of a wind plant. This study is focused on the development of a stochastic model for waked wind fields. First, high-fidelity physics-based waked wind velocity fields are generated using Large-Eddy Simulation (LES). Stochastic characteristics of these LES waked wind velocity field,more » including mean and turbulence components, are analyzed. Wake-related mean and turbulence field-related parameters are then estimated for use with a stochastic model, using Multivariate Multiple Linear Regression (MMLR) with the LES data. To validate the simulated wind fields based on the stochastic model, wind turbine tower and blade loads are generated using aeroelastic simulation for utility-scale wind turbine models and compared with those based directly on the LES inflow. The study's overall objective is to offer efficient and validated stochastic approaches that are computationally tractable for assessing the performance and loads of turbines operating in wakes.« less

Toward Development of a Stochastic Wake Model: Validation Using LES and Turbine Loads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moon, Jae; Manuel, Lance; Churchfield, Matthew

Wind turbines within an array do not experience free-stream undisturbed flow fields. Rather, the flow fields on internal turbines are influenced by wakes generated by upwind unit and exhibit different dynamic characteristics relative to the free stream. The International Electrotechnical Commission (IEC) standard 61400-1 for the design of wind turbines only considers a deterministic wake model for the design of a wind plant. This study is focused on the development of a stochastic model for waked wind fields. First, high-fidelity physics-based waked wind velocity fields are generated using Large-Eddy Simulation (LES). Stochastic characteristics of these LES waked wind velocity field,more » including mean and turbulence components, are analyzed. Wake-related mean and turbulence field-related parameters are then estimated for use with a stochastic model, using Multivariate Multiple Linear Regression (MMLR) with the LES data. To validate the simulated wind fields based on the stochastic model, wind turbine tower and blade loads are generated using aeroelastic simulation for utility-scale wind turbine models and compared with those based directly on the LES inflow. The study's overall objective is to offer efficient and validated stochastic approaches that are computationally tractable for assessing the performance and loads of turbines operating in wakes.« less

A probabilistic model for hydrokinetic turbine collision risks: exploring impacts on fish.

PubMed

Hammar, Linus; Eggertsen, Linda; Andersson, Sandra; Ehnberg, Jimmy; Arvidsson, Rickard; Gullström, Martin; Molander, Sverker

2015-01-01

A variety of hydrokinetic turbines are currently under development for power generation in rivers, tidal straits and ocean currents. Because some of these turbines are large, with rapidly moving rotor blades, the risk of collision with aquatic animals has been brought to attention. The behavior and fate of animals that approach such large hydrokinetic turbines have not yet been monitored at any detail. In this paper, we conduct a synthesis of the current knowledge and understanding of hydrokinetic turbine collision risks. The outcome is a generic fault tree based probabilistic model suitable for estimating population-level ecological risks. New video-based data on fish behavior in strong currents are provided and models describing fish avoidance behaviors are presented. The findings indicate low risk for small-sized fish. However, at large turbines (≥5 m), bigger fish seem to have high probability of collision, mostly because rotor detection and avoidance is difficult in low visibility. Risks can therefore be substantial for vulnerable populations of large-sized fish, which thrive in strong currents. The suggested collision risk model can be applied to different turbine designs and at a variety of locations as basis for case-specific risk assessments. The structure of the model facilitates successive model validation, refinement and application to other organism groups such as marine mammals.

Physical Model Study of the Fully Developed Wind Turbine Array Boundary Layer in the UNH Flow Physics Facility

NASA Astrophysics Data System (ADS)

Turner, John; Wosnik, Martin

2015-11-01

Results from an experimental study of an array of up to 100 model wind turbines with 0.25 m diameter are reported. The study was conducted in the UNH Flow Physics Facility (FPF), which has test section dimensions of 6.0 m wide, 2.7 m high and 72.0 m long. For a given configuration (spacing, initial conditions, etc.), the model wind farm reaches a ``fully developed'' condition, in which turbulence statistics remain the same from one row to the next within and above the wind turbine array. Of interest is the transport of kinetic energy within the wind turbine array boundary layer (WTABL). Model wind farms of up to 20 rows are possible in the FPF at the wind turbine scale used. The present studies in the FPF are able to achieve the fully developed WTABL condition, which can provide valuable insight to the optimization of wind farm energy production. The FPF can achieve a boundary layer height on the order of 1 m at the beginning of the wind turbine array. The wind turbine array was constructed of porous disks, which where drag (thrust) matched to wind turbines at typical operating conditions and therefore act as momentum sinks similar to wind turbines. The flow in the WTABL was measured with constant temperature anemometry using an X-wire.

Cooling system with compressor bleed and ambient air for gas turbine engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marsh, Jan H.; Marra, John J.

A cooling system for a turbine engine for directing cooling fluids from a compressor to a turbine blade cooling fluid supply and from an ambient air source to the turbine blade cooling fluid supply to supply cooling fluids to one or more airfoils of a rotor assembly is disclosed. The cooling system may include a compressor bleed conduit extending from a compressor to the turbine blade cooling fluid supply that provides cooling fluid to at least one turbine blade. The compressor bleed conduit may include an upstream section and a downstream section whereby the upstream section exhausts compressed bleed airmore » through an outlet into the downstream section through which ambient air passes. The outlet of the upstream section may be generally aligned with a flow of ambient air flowing in the downstream section. As such, the compressed air increases the flow of ambient air to the turbine blade cooling fluid supply.« less

Coastal Ohio Wind Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorsevski, Peter; Afjeh, Abdollah; Jamali, Mohsin

The Coastal Ohio Wind Project intends to address problems that impede deployment of wind turbines in the coastal and offshore regions of Northern Ohio. The project evaluates different wind turbine designs and the potential impact of offshore turbines on migratory and resident birds by developing multidisciplinary research, which involves wildlife biology, electrical and mechanical engineering, and geospatial science. Firstly, the project conducts cost and performance studies of two- and three-blade wind turbines using a turbine design suited for the Great Lakes. The numerical studies comprised an analysis and evaluation of the annual energy production of two- and three-blade wind turbinesmore » to determine the levelized cost of energy. This task also involved wind tunnel studies of model wind turbines to quantify the wake flow field of upwind and downwind wind turbine-tower arrangements. The experimental work included a study of a scaled model of an offshore wind turbine platform in a water tunnel. The levelized cost of energy work consisted of the development and application of a cost model to predict the cost of energy produced by a wind turbine system placed offshore. The analysis found that a floating two-blade wind turbine presents the most cost effective alternative for the Great Lakes. The load effects studies showed that the two-blade wind turbine model experiences less torque under all IEC Standard design load cases considered. Other load effects did not show this trend and depending on the design load cases, the two-bladed wind turbine showed higher or lower load effects. The experimental studies of the wake were conducted using smoke flow visualization and hot wire anemometry. Flow visualization studies showed that in the downwind turbine configuration the wake flow was insensitive to the presence of the blade and was very similar to that of the tower alone. On the other hand, in the upwind turbine configuration, increasing the rotor blade angle of attack reduced the wake size and enhanced the vortices in the flow downstream of the turbine-tower compared with the tower alone case. Mean and rms velocity distributions from hot wire anemometer data confirmed that in a downwind configuration, the wake of the tower dominates the flow, thus the flow fields of a tower alone and tower-turbine combinations are nearly the same. For the upwind configuration, the mean velocity shows a narrowing of the wake compared with the tower alone case. The downwind configuration wake persisted longer than that of an upwind configuration; however, it was not possible to quantify this difference because of the size limitation of the wind tunnel downstream of the test section. The water tunnel studies demonstrated that the scale model studies could be used to adequately produce accurate motions to model the motions of a wind turbine platform subject to large waves. It was found that the important factors that affect the platform is whether the platform is submerged or surface piercing. In the former, the loads on the platform will be relatively reduced whereas in the latter case, the structure pierces the wave free surface and gains stiffness and stability. The other important element that affects the movement of the platform is depth of the sea in which the wind turbine will be installed. Furthermore, the wildlife biology component evaluated migratory patterns by different monitoring systems consisting of marine radar, thermal IR camera and acoustic recorders. The types of radar used in the project are weather surveillance radar and marine radar. The weather surveillance radar (1988 Doppler), also known as Next Generation Radar (NEXRAD), provides a network of weather stations in the US. Data generated from this network were used to understand general migratory patterns, migratory stopover habitats, and other patterns caused by the effects of weather conditions. At a local scale our marine radar was used to complement the datasets from NEXRAD and to collect additional monitoring parameters such as passage rates, flight paths, flight directions, and flight altitudes of nocturnal migrating species. Our work focused on the design and development of custom built marine radar that used t-bar and parabolic dish antennas. The marine radar used in the project was Furuno (XANK250) which was coupled with a XIR3000B digitizing card from Russell Technologies for collection of the radar data. The radar data was processed by open source radR processing software using different computational techniques and methods. Additional data from thermal IR imaging cameras were collected to detect heat emitted from objects and provide information on movements of birds and bats, data which we used for different animal flight behavior analysis. Lastly, the data from the acoustic recorders were used to provide the number of bird calls for assessing patterns and peak passage rates during migration. The development of the geospatial database included collection of different data sources that are used to support offshore wind turbine development. Many different data sets were collected and organized using initial version of web-based repository software tools that can accommodate distribution of rectified pertinent data sets such as the lake depth, lake bottom engineering parameters, extent of ice, navigation pathways, wind speed, important bird habitats, fish efforts and other layers that are relevant for supporting robust offshore wind turbine developments. Additional geospatial products developed during the project included few different prototypes for offshore wind farm suitability which can involve different stakeholders and participants for solving complex planning problems and building consensus. Some of the prototypes include spatial decision support system (SDSS) for collaborative decision making, a web-based Participatory Geographic Information System (PGIS) framework for evaluating importance of different decision alternatives using different evaluation criteria, and an Android application for collection of field data using mobile and tablet devices . In summary, the simulations of two- and three-blade wind turbines suggested that two-bladed machines could produce comparable annual energy as the three-blade wind turbines but have a lighter tower top weight, which leads to lower cost of energy. In addition, the two-blade rotor configuration potentially costs 20% less than a three blade configuration that produces the same power at the same site. The cost model analysis predicted a potential cost savings of approximately 15% for offshore two-blade wind turbines. The foundation design for a wind turbine in Lake Erie is likely to be driven by ice loads based on the currently available ice data and ice mechanics models. Hence, for Lake Eire, the cost savings will be somewhat smaller than the other lakes in the Great Lakes. Considering the size of cranes and vessels currently available in the Great Lakes, the cost optimal wind turbine size should be 3 MW, not larger. The surveillance data from different monitoring systems suggested that bird and bat passage rates per hour were comparable during heavy migrations in both spring and fall seasons while passage rates were significantly correlated to wind directions and wind speeds. The altitude of migration was higher during heavy migrations and higher over water relative to over land. Notable portions of migration on some spring nights occurred parallel the shoreline, often moving perpendicular to southern winds. The birds approaching the Western basin have a higher propensity to cross than birds approaching the Central basin of Lake Erie and as such offshore turbine development might be a better option further east towards Cleveland than in the Western basin. The high stopover density was more strongly associated with migration volume the following night rather than the preceding night. The processed mean scalar wind speeds with temporal resolutions as fine as 10-minute intervals near turbine height showed that August is the month with the weakest winds while December is the month, which typically has the strongest winds. The ice data suggests that shallow western basin of Lake Erie has higher ice cover duration many times exceeding 90 days during some winters.« less

Energy justice: Participation promotes acceptance

NASA Astrophysics Data System (ADS)

Baxter, Jamie

2017-08-01

Wind turbines have been a go-to technology for addressing climate change, but they are increasingly a source of frustration for all stakeholders. While community ownership is often lauded as a panacea for maximizing turbine acceptance, a new study suggests that decision-making involvement — procedural fairness — matters most.

14 CFR 125.226 - Digital flight data recorders.

Code of Federal Regulations, 2014 CFR

2014-01-01

... this section, no person may operate under this part a turbine-engine-powered transport category... selection; (37) Drift angle (when an information source is installed); (38) Wind speed and direction (when... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

14 CFR 125.226 - Digital flight data recorders.

Code of Federal Regulations, 2010 CFR

2010-01-01

... this section, no person may operate under this part a turbine-engine-powered transport category... selection; (37) Drift angle (when an information source is installed); (38) Wind speed and direction (when... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

14 CFR 125.226 - Digital flight data recorders.

Code of Federal Regulations, 2013 CFR

2013-01-01

... this section, no person may operate under this part a turbine-engine-powered transport category... selection; (37) Drift angle (when an information source is installed); (38) Wind speed and direction (when... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

14 CFR 125.226 - Digital flight data recorders.

Code of Federal Regulations, 2012 CFR

2012-01-01

... this section, no person may operate under this part a turbine-engine-powered transport category... selection; (37) Drift angle (when an information source is installed); (38) Wind speed and direction (when... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

14 CFR 125.226 - Digital flight data recorders.

Code of Federal Regulations, 2011 CFR

2011-01-01

... this section, no person may operate under this part a turbine-engine-powered transport category... selection; (37) Drift angle (when an information source is installed); (38) Wind speed and direction (when... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

Analytical Model for Mean Flow and Fluxes of Momentum and Energy in Very Large Wind Farms

NASA Astrophysics Data System (ADS)

Markfort, Corey D.; Zhang, Wei; Porté-Agel, Fernando

2018-01-01

As wind-turbine arrays continue to be installed and the array size continues to grow, there is an increasing need to represent very large wind-turbine arrays in numerical weather prediction models, for wind-farm optimization, and for environmental assessment. We propose a simple analytical model for boundary-layer flow in fully-developed wind-turbine arrays, based on the concept of sparsely-obstructed shear flows. In describing the vertical distribution of the mean wind speed and shear stress within wind farms, our model estimates the mean kinetic energy harvested from the atmospheric boundary layer, and determines the partitioning between the wind power captured by the wind turbines and that absorbed by the underlying land or water. A length scale based on the turbine geometry, spacing, and performance characteristics, is able to estimate the asymptotic limit for the fully-developed flow through wind-turbine arrays, and thereby determine if the wind-farm flow is fully developed for very large turbine arrays. Our model is validated using data collected in controlled wind-tunnel experiments, and its usefulness for the prediction of wind-farm performance and optimization of turbine-array spacing are described. Our model may also be useful for assessing the extent to which the extraction of wind power affects the land-atmosphere coupling or air-water exchange of momentum, with implications for the transport of heat, moisture, trace gases such as carbon dioxide, methane, and nitrous oxide, and ecologically important oxygen.

Study on the glaze ice accretion of wind turbine with various chord lengths

NASA Astrophysics Data System (ADS)

Liang, Jian; Liu, Maolian; Wang, Ruiqi; Wang, Yuhang

2018-02-01

Wind turbine icing often occurs in winter, which changes the aerodynamic characteristics of the blades and reduces the work efficiency of the wind turbine. In this paper, the glaze ice model is established for horizontal-axis wind turbine in 3-D. The model contains the grid generation, two-phase simulation, heat and mass transfer. Results show that smaller wind turbine suffers from more serious icing problem, which reflects on a larger ice thickness. Both the collision efficiency and heat transfer coefficient increase under smaller size condition.

Sources and potential application of waste heat utilization at a gas processing facility

NASA Astrophysics Data System (ADS)

Alshehhi, Alyas Ali

Waste heat recovery (WHR) has the potential to significantly improve the efficiency of oil and gas plants, chemical and other processing facilities, and reduce their environmental impact. In this Thesis a comprehensive energy audit at Abu Dhabi Gas Industries Ltd. (GASCO) ASAB gas processing facilities is undertaken to identify sources of waste heat and evaluate their potential for on-site recovery. Two plants are considered, namely ASAB0 and ASAB1. Waste heat evaluation criteria include waste heat grade (i.e., temperature), rate, accessibility (i.e., proximity) to potential on-site waste heat recovery applications, and potential impact of recovery on installation performance and safety. The operating parameters of key waste heat source producing equipment are compiled, as well as characteristics of the waste heat streams. In addition, potential waste heat recovery applications and strategies are proposed, focusing on utilities, i.e., enhancement of process cooling/heating, electrical/mechanical power generation, and steam production. The sources of waste heat identified at ASAB facilities consist of gas turbine and gas generator exhaust gases, flared gases, excess propane cooling capacity, excess process steam, process gas air-cooler heat dissipation, furnace exhaust gases and steam turbine outlet steam. Of the above waste heat sources, exhaust gases from five gas turbines and one gas generator at ASAB0 plant, as well as from four gas turbines at ASAB1 plant, were found to meet the rate (i.e., > 1 MW), grade (i.e., > 180°C), accessibility (i.e., < 50 m from potential on-site WHR applications) and minimal impact criteria on the performance and safety of existing installations, for potential waste heat recovery. The total amount of waste heat meeting these criteria were estimated at 256 MW and 289 MW at ASAB0 and ASAB1 plants, respectively, both of which are substantial. Of the 289 MW waste generated at ASAB1, approximately 173 MW are recovered by waste heat recovery steam generators (WHRSGs), leaving 116 MW unutilized. The following strategies were developed to recover the above waste heat. At ASAB0, it is proposed that exhaust gases from all five gas turbines be used to power a WHRSG. The steam generated by the WHRSG would both i) drive an absorption refrigeration unit for gas turbine inlet air cooling, which would result in additional electric or mechanical power generation, and pre-cooling of process gas, which could reduce the need for or eliminate air coolers, as well as reduce propane chiller load, and ii) serve for heating of lean gas, which would reduce furnace load. At ASAB1, it is proposed that exhaust gases from all four gas turbines be used to generate steam in WHRSG that would drive an absorption refrigeration unit for either gas turbine inlet air cooling for additional electric or mechanical power generation, or pre-cooling of process gas to eliminate air-coolers and reduce propane chiller cooling load. Considering the smaller amount of waste heat available at ASAB1 (116 MW) relative to ASAB0 (237 MW), these above two recovery options could not be implemented simultaneously at ASAB0. To permit the detailed design and techno-economic feasibility evaluation of the proposed waste heat recovery strategies in a subsequent study, the cooling loads and associated electric power consumption of ASAB0 process gas air-coolers were estimated at 21 MW and 1.9 MW, respectively, and 67 MW and 2.2 MW, respectively for ASAB1 plant. In addition, the heating loads and fuel consumption of ASAB0 furnaces used for lean gas re-generation were estimated at 24 MW and 0.0653 MMSCMD, respectively. In modeling work undertaken in parallel with this study at the Petroleum Institute, the waste heat recovery strategies proposed here were found to be thermodynamically and economically feasible, and to lead to substantial energy and cost savings, hence environmental benefits.

A wind tunnel study on the effects of complex topography on wind turbine performance

NASA Astrophysics Data System (ADS)

Howard, Kevin; Hu, Stephen; Chamorro, Leonardo; Guala, Michele

2012-11-01

A set of wind tunnel experiments were conducted to study the response of a wind turbine under flow conditions typically observed at the wind farm scale, in complex terrain. A scale model wind turbine was placed in a fully developed turbulent boundary layer flow obtained in the SAFL Wind Tunnel. Experiments focused on the performance of a turbine model, under the effects induced by a second upwind turbine or a by three-dimensional, sinusoidal hill, peaking at the turbine hub height. High frequency measurements of fluctuating streamwise and wall normal velocities were obtained with a X-wire anemometer simultaneously with the rotor angular velocity and the turbine(s) voltage output. Velocity measurements in the wake of the first turbine and of the hill were used to determine the inflow conditions for the downwind test turbine. Turbine performance was inferred by the mean and fluctuating voltage statistics. Specific experiments were devoted to relate the mean voltage to the mean hub velocity, and the fluctuating voltage to the unsteadiness in the rotor kinematics induced by the perturbed (hill or turbine) or unperturbed (boundary layer) large scales of the incoming turbulent flow. Results show that the voltage signal can be used to assess turbine performance in complex flows.

A Reduced Model for Prediction of Thermal and Rotational Effects on Turbine Tip Clearance

NASA Technical Reports Server (NTRS)

Kypuros, Javier A.; Melcher, Kevin J.

2003-01-01

This paper describes a dynamic model that was developed to predict changes in turbine tip clearance the radial distance between the end of a turbine blade and the abradable tip seal. The clearance is estimated by using a first principles approach to model the thermal and mechanical effects of engine operating conditions on the turbine sub-components. These effects are summed to determine the resulting clearance. The model is demonstrated via a ground idle to maximum power transient and a lapse-rate takeoff transient. Results show the model demonstrates the expected pinch point behavior. The paper concludes by identifying knowledge gaps and suggesting additional research to improve the model.

IEA Wind Task 37: Systems Modeling Framework and Ontology for Wind Turbines and Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dykes, Katherine L; Zahle, Frederik; Merz, Karl

This presentation will provide an overview of progress to date in the development of a system modeling framework and ontology for wind turbines and plants as part of the larger IEA Wind Task 37 on wind energy systems engineering. The goals of the effort are to create a set of guidelines for a common conceptual architecture for wind turbines and plants so that practitioners can more easily share descriptions of wind turbines and plants across multiple parties and reduce the effort for translating descriptions between models; integrate different models together and collaborate on model development; and translate models among differentmore » levels of fidelity in the system.« less

On the performance of a high head Francis turbine at design and off-design conditions

NASA Astrophysics Data System (ADS)

Aakti, B.; Amstutz, O.; Casartelli, E.; Romanelli, G.; Mangani, L.

2015-01-01

In the present paper, fully 360 degrees transient and steady-state simulations of a Francis turbine were performed at three operating conditions, namely at part load (PL), best efficiency point (BEP), and high load (HL), using different numerical approaches for the pressure-velocity coupling. The simulation domain includes the spiral casing with stay and guide vanes, the runner and the draft tube. The main target of the investigations is the numerical prediction of the overall performance of the high head Francis turbine model as well as local and integral quantities of the complete machine in different operating conditions. All results were compared with experimental data published by the workshop organization. All CFD simulations were performed at model scale with a new in-house, 3D, unstructured, object-oriented finite volume code within the framework of the open source OpenFOAM library. The novel fully coupled pressure-based solver is designed to solve the incompressible RANS- Equations and is capable of handling multiple references of frame (MRF). The obtained results show that the overall performance is well captured by the simulations. Regarding the local flow distributions within the inlet section of the draft-tube, the axial velocity is better estimated than the circumferential component.

A review of damage detection methods for wind turbine blades

NASA Astrophysics Data System (ADS)

Li, Dongsheng; Ho, Siu-Chun M.; Song, Gangbing; Ren, Liang; Li, Hongnan

2015-03-01

Wind energy is one of the most important renewable energy sources and many countries are predicted to increase wind energy portion of their whole national energy supply to about twenty percent in the next decade. One potential obstacle in the use of wind turbines to harvest wind energy is the maintenance of the wind turbine blades. The blades are a crucial and costly part of a wind turbine and over their service life can suffer from factors such as material degradation and fatigue, which can limit their effectiveness and safety. Thus, the ability to detect damage in wind turbine blades is of great significance for planning maintenance and continued operation of the wind turbine. This paper presents a review of recent research and development in the field of damage detection for wind turbine blades. Specifically, this paper reviews frequently employed sensors including fiber optic and piezoelectric sensors, and four promising damage detection methods, namely, transmittance function, wave propagation, impedance and vibration based methods. As a note towards the future development trend for wind turbine sensing systems, the necessity for wireless sensing and energy harvesting is briefly presented. Finally, existing problems and promising research efforts for online damage detection of turbine blades are discussed.

Failures in large gas turbines due to liquid-metal embrittlement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cameron, D.W.

1994-07-01

The failures of three gas turbine components, attributed to liquid-metal embrittlement or solid-metal-induced embrittlement, are described. High temperatures inherent in the gas turbine can aggravate these phenomenon if the necessary conditions are present. Examples chosen include a power transmission shaft, flange bolts from a cooling steam line, and a turbine rotor bolt. The respective material couples involved are 17-4PH stainless steel-copper, AISI 4130-cadmium, and IN 718-cadmium. Each case includes information on the source of the aggressive material and relevant operating environment. The implications of the failures with regard to the general failure mechanism are briefly discussed.

Unsteady aerodynamic analysis for offshore floating wind turbines under different wind conditions.

PubMed

Xu, B F; Wang, T G; Yuan, Y; Cao, J F

2015-02-28

A free-vortex wake (FVW) model is developed in this paper to analyse the unsteady aerodynamic performance of offshore floating wind turbines. A time-marching algorithm of third-order accuracy is applied in the FVW model. Owing to the complex floating platform motions, the blade inflow conditions and the positions of initial points of vortex filaments, which are different from the fixed wind turbine, are modified in the implemented model. A three-dimensional rotational effect model and a dynamic stall model are coupled into the FVW model to improve the aerodynamic performance prediction in the unsteady conditions. The effects of floating platform motions in the simulation model are validated by comparison between calculation and experiment for a small-scale rigid test wind turbine coupled with a floating tension leg platform (TLP). The dynamic inflow effect carried by the FVW method itself is confirmed and the results agree well with the experimental data of a pitching transient on another test turbine. Also, the flapping moment at the blade root in yaw on the same test turbine is calculated and compares well with the experimental data. Then, the aerodynamic performance is simulated in a yawed condition of steady wind and in an unyawed condition of turbulent wind, respectively, for a large-scale wind turbine coupled with the floating TLP motions, demonstrating obvious differences in rotor performance and blade loading from the fixed wind turbine. The non-dimensional magnitudes of loading changes due to the floating platform motions decrease from the blade root to the blade tip. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Unsteady aerodynamic analysis for offshore floating wind turbines under different wind conditions

PubMed Central

Xu, B. F.; Wang, T. G.; Yuan, Y.; Cao, J. F.

2015-01-01

A free-vortex wake (FVW) model is developed in this paper to analyse the unsteady aerodynamic performance of offshore floating wind turbines. A time-marching algorithm of third-order accuracy is applied in the FVW model. Owing to the complex floating platform motions, the blade inflow conditions and the positions of initial points of vortex filaments, which are different from the fixed wind turbine, are modified in the implemented model. A three-dimensional rotational effect model and a dynamic stall model are coupled into the FVW model to improve the aerodynamic performance prediction in the unsteady conditions. The effects of floating platform motions in the simulation model are validated by comparison between calculation and experiment for a small-scale rigid test wind turbine coupled with a floating tension leg platform (TLP). The dynamic inflow effect carried by the FVW method itself is confirmed and the results agree well with the experimental data of a pitching transient on another test turbine. Also, the flapping moment at the blade root in yaw on the same test turbine is calculated and compares well with the experimental data. Then, the aerodynamic performance is simulated in a yawed condition of steady wind and in an unyawed condition of turbulent wind, respectively, for a large-scale wind turbine coupled with the floating TLP motions, demonstrating obvious differences in rotor performance and blade loading from the fixed wind turbine. The non-dimensional magnitudes of loading changes due to the floating platform motions decrease from the blade root to the blade tip. PMID:25583859

Cold flow testing of the Space Shuttle Main Engine high pressure fuel turbine model

NASA Technical Reports Server (NTRS)

Hudson, Susan T.; Gaddis, Stephen W.; Johnson, P. D.; Boynton, James L.

1991-01-01

In order to experimentally determine the performance of the Space Shuttle Main Engine (SSME) High Pressure Fuel Turbopump (HPFTP) turbine, a 'cold' air flow turbine test program was established at NASA's Marshall Space Flight Center. As part of this test program, a baseline test of Rocketdyne's HPFTP turbine has been completed. The turbine performance and turbine diagnostics such as airfoil surface static pressure distributions, static pressure drops through the turbine, and exit swirl angles were investigated at the turbine design point, over its operating range, and at extreme off-design points. The data was compared to pretest predictions with good results. The test data has been used to improve meanline prediction codes and is now being used to validate various three-dimensional codes. The data will also be scaled to engine conditions and used to improve the SSME steady-state performance model.

Adaptive Control of a Utility-Scale Wind Turbine Operating in Region 3

NASA Technical Reports Server (NTRS)

Frost, Susan A.; Balas, Mark J.; Wright, Alan D.

2009-01-01

Adaptive control techniques are well suited to nonlinear applications, such as wind turbines, which are difficult to accurately model and which have effects from poorly known operating environments. The turbulent and unpredictable conditions in which wind turbines operate create many challenges for their operation. In this paper, we design an adaptive collective pitch controller for a high-fidelity simulation of a utility scale, variable-speed horizontal axis wind turbine. The objective of the adaptive pitch controller in Region 3 is to regulate generator speed and reject step disturbances. The control objective is accomplished by collectively pitching the turbine blades. We use an extension of the Direct Model Reference Adaptive Control (DMRAC) approach to track a reference point and to reject persistent disturbances. The turbine simulation models the Controls Advanced Research Turbine (CART) of the National Renewable Energy Laboratory in Golden, Colorado. The CART is a utility-scale wind turbine which has a well-developed and extensively verified simulator. The adaptive collective pitch controller for Region 3 was compared in simulations with a bas celliansesical Proportional Integrator (PI) collective pitch controller. In the simulations, the adaptive pitch controller showed improved speed regulation in Region 3 when compared with the baseline PI pitch controller and it demonstrated robustness to modeling errors.

Probabilistic analysis of mean-response along-wind induced vibrations on wind turbine towers using wireless network data sensors

NASA Astrophysics Data System (ADS)

Velazquez, Antonio; Swartz, Raymond A.

2011-04-01

Wind turbine systems are attracting considerable attention due to concerns regarding global energy consumption as well as sustainability. Advances in wind turbine technology promote the tendency to improve efficiency in the structure that support and produce this renewable power source, tending toward more slender and larger towers, larger gear boxes, and larger, lighter blades. The structural design optimization process must account for uncertainties and nonlinear effects (such as wind-induced vibrations, unmeasured disturbances, and material and geometric variabilities). In this study, a probabilistic monitoring approach is developed that measures the response of the turbine tower to stochastic loading, estimates peak demand, and structural resistance (in terms of serviceability). The proposed monitoring system can provide a real-time estimate of the probability of exceedance of design serviceability conditions based on data collected in-situ. Special attention is paid to wind and aerodynamic characteristics that are intrinsically present (although sometimes neglected in health monitoring analysis) and derived from observations or experiments. In particular, little attention has been devoted to buffeting, usually non-catastrophic but directly impacting the serviceability of the operating wind turbine. As a result, modal-based analysis methods for the study and derivation of flutter instability, and buffeting response, have been successfully applied to the assessment of the susceptibility of high-rise slender structures, including wind turbine towers. A detailed finite element model has been developed to generate data (calibrated to published experimental and analytical results). Risk assessment is performed for the effects of along wind forces in a framework of quantitative risk analysis. Both structural resistance and wind load demands were considered probabilistic with the latter assessed by dynamic analyses.

A numerical study of automotive turbocharger mixed flow turbine inlet geometry for off design performance

NASA Astrophysics Data System (ADS)

Leonard, T.; Spence, S.; Early, J.; Filsinger, D.

2013-12-01

Mixed flow turbines represent a potential solution to the increasing requirement for high pressure, low velocity ratio operation in turbocharger applications. While literature exists for the use of these turbines at such operating conditions, there is a lack of detailed design guidance for defining the basic geometry of the turbine, in particular, the cone angle - the angle at which the inlet of the mixed flow turbine is inclined to the axis. This investigates the effect and interaction of such mixed flow turbine design parameters. Computational Fluids Dynamics was initially used to investigate the performance of a modern radial turbine to create a baseline for subsequent mixed flow designs. Existing experimental data was used to validate this model. Using the CFD model, a number of mixed flow turbine designs were investigated. These included studies varying the cone angle and the associated inlet blade angle. The results of this analysis provide insight into the performance of a mixed flow turbine with respect to cone and inlet blade angle.

76 FR 19903 - Special Conditions: Diamond Aircraft Industry Model DA-40NG; Diesel Cycle Engine

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-11

... DA-40NG the Austro Engine GmbH model E4 aircraft diesel engine (ADE) using turbine (jet) fuel. This... engine utilizing turbine (jet) fuel. The applicable airworthiness regulations do not contain adequate or...: Installation of the Austro Engine GmbH Model E4 ADE diesel engine utilizing turbine (jet) fuel. Discussion...

A reward semi-Markov process with memory for wind speed modeling

NASA Astrophysics Data System (ADS)

Petroni, F.; D'Amico, G.; Prattico, F.

2012-04-01

The increasing interest in renewable energy leads scientific research to find a better way to recover most of the available energy. Particularly, the maximum energy recoverable from wind is equal to 59.3% of that available (Betz law) at a specific pitch angle and when the ratio between the wind speed in output and in input is equal to 1/3. The pitch angle is the angle formed between the airfoil of the blade of the wind turbine and the wind direction. Old turbine and a lot of that actually marketed, in fact, have always the same invariant geometry of the airfoil. This causes that wind turbines will work with an efficiency that is lower than 59.3%. New generation wind turbines, instead, have a system to variate the pitch angle by rotating the blades. This system able the wind turbines to recover, at different wind speed, always the maximum energy, working in Betz limit at different speed ratios. A powerful system control of the pitch angle allows the wind turbine to recover better the energy in transient regime. A good stochastic model for wind speed is then needed to help both the optimization of turbine design and to assist the system control to predict the value of the wind speed to positioning the blades quickly and correctly. The possibility to have synthetic data of wind speed is a powerful instrument to assist designer to verify the structures of the wind turbines or to estimate the energy recoverable from a specific site. To generate synthetic data, Markov chains of first or higher order are often used [1,2,3]. In particular in [1] is presented a comparison between a first-order Markov chain and a second-order Markov chain. A similar work, but only for the first-order Markov chain, is conduced by [2], presenting the probability transition matrix and comparing the energy spectral density and autocorrelation of real and synthetic wind speed data. A tentative to modeling and to join speed and direction of wind is presented in [3], by using two models, first-order Markov chain with different number of states, and Weibull distribution. All this model use Markov chains to generate synthetic wind speed time series but the search for a better model is still open. Approaching this issue, we applied new models which are generalization of Markov models. More precisely we applied semi-Markov models to generate synthetic wind speed time series. The primary goal of this analysis is the study of the time history of the wind in order to assess its reliability as a source of power and to determine the associated storage levels required. In order to assess this issue we use a probabilistic model based on indexed semi-Markov process [4] to which a reward structure is attached. Our model is used to calculate the expected energy produced by a given turbine and its variability expressed by the variance of the process. Our results can be used to compare different wind farms based on their reward and also on the risk of missed production due to the intrinsic variability of the wind speed process. The model is used to generate synthetic time series for wind speed by means of Monte Carlo simulations and backtesting procedure is used to compare results on first and second oder moments of rewards between real and synthetic data. [1] A. Shamshad, M.A. Bawadi, W.M.W. Wan Hussin, T.A. Majid, S.A.M. Sanusi, First and second order Markov chain models for synthetic gen- eration of wind speed time series, Energy 30 (2005) 693-708. [2] H. Nfaoui, H. Essiarab, A.A.M. Sayigh, A stochastic Markov chain model for simulating wind speed time series at Tangiers, Morocco, Re- newable Energy 29 (2004) 1407-1418. [3] F. Youcef Ettoumi, H. Sauvageot, A.-E.-H. Adane, Statistical bivariate modeling of wind using first-order Markov chain and Weibull distribu- tion, Renewable Energy 28 (2003) 1787-1802. [4]F. Petroni, G. D'Amico, F. Prattico, Indexed semi-Markov process for wind speed modeling. To be submitted.

The 3-D CFD modeling of gas turbine combustor-integral bleed flow interaction

NASA Technical Reports Server (NTRS)

Chen, D. Y.; Reynolds, R. S.

1993-01-01

An advanced 3-D Computational Fluid Dynamics (CFD) model was developed to analyze the flow interaction between a gas turbine combustor and an integral bleed plenum. In this model, the elliptic governing equations of continuity, momentum and the k-e turbulence model were solved on a boundary-fitted, curvilinear, orthogonal grid system. The model was first validated against test data from public literature and then applied to a gas turbine combustor with integral bleed. The model predictions agreed well with data from combustor rig testing. The model predictions also indicated strong flow interaction between the combustor and the integral bleed. Integral bleed flow distribution was found to have a great effect on the pressure distribution around the gas turbine combustor.

Ejector-turbine studies and experimental data. Final report, August 1, 1979-October 31, 1982

DOE Office of Scientific and Technical Information (OSTI.GOV)

Minardi, J.E.; Lawson, M.O.; Krolak, R.V.

1982-11-01

An innovative low-power Rankine turbine concept is described which promises competitive efficiencies, low cost, significant reduction in rpm, low maintenance, and long-life operation over similarly rated turbines. The cycle uses a highly efficient two-fluid ejector which greatly lowers the turbine inlet pressure and temperature. The two-fluid ejector cycle is shown by theoretical studies to be capable of transferring energy at efficiencies in excess of 90% from a high-power flux fluid medium to a low-power flux fluid medium. The volume flow of the thermodynamic fluid can be augmented by as much as one-hundred fold. For very low-power turbine applications this couldmore » result in far-more-favorable turbine sizes and rpm. One major application for this type turbine is the heating and cooling with heat pumps. The concept permits engine cycles that cover an extremely broad range of peak temperatures, including those corresponding to stoichiometric combustion of hydrocarbon fuels, waste heat sources, and solar. Actual test data indicated ejector efficiencies as high as 85%. A two-fluid, ejector turbine was designed and tested. The turbine achieved 94% of design power. Additional data indicated that the ejector attached to the turbine operated on the supersonic branch.« less

Efficiency of the DOMUS 750 vertical-axis wind turbine

NASA Astrophysics Data System (ADS)

Hallock, Kyle; Rasch, Tyler; Ju, Guoqiang; Alonso-Marroquin, Fernando

2017-06-01

The aim of this paper is to present some preliminary results on the efficiency of a wind turbine for an off-grid housing unit. To generate power, the unit uses a photovoltaic solar array and a vertical-axis wind turbine (VAWT). The existing VAWT was analysed to improve efficiency and increase power generation. There were found to be two main sources of inefficiency: 1. the 750W DC epicyclic generator performed poorly in low winds, and 2. the turbine blades wobbled, allowing for energy loss due to off-axis rotation. A 12V DC permanent magnet alternator was chosen that met the power requirements of the housing unit and would generate power at lower wind speeds. A support bracket was designed to prevent the turbine blades from wobbling.

Survey of techniques for reduction of wind turbine blade trailing edge noise.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barone, Matthew Franklin

2011-08-01

Aerodynamic noise from wind turbine rotors leads to constraints in both rotor design and turbine siting. The primary source of aerodynamic noise on wind turbine rotors is the interaction of turbulent boundary layers on the blades with the blade trailing edges. This report surveys concepts that have been proposed for trailing edge noise reduction, with emphasis on concepts that have been tested at either sub-scale or full-scale. These concepts include trailing edge serrations, low-noise airfoil designs, trailing edge brushes, and porous trailing edges. The demonstrated noise reductions of these concepts are cited, along with their impacts on aerodynamic performance. Anmore » assessment is made of future research opportunities in trailing edge noise reduction for wind turbine rotors.« less

Health effects and wind turbines: a review of the literature.

PubMed

Knopper, Loren D; Ollson, Christopher A

2011-09-14

Wind power has been harnessed as a source of power around the world. Debate is ongoing with respect to the relationship between reported health effects and wind turbines, specifically in terms of audible and inaudible noise. As a result, minimum setback distances have been established world-wide to reduce or avoid potential complaints from, or potential effects to, people living in proximity to wind turbines. People interested in this debate turn to two sources of information to make informed decisions: scientific peer-reviewed studies published in scientific journals and the popular literature and internet. The purpose of this paper is to review the peer-reviewed scientific literature, government agency reports, and the most prominent information found in the popular literature. Combinations of key words were entered into the Thomson Reuters Web of KnowledgeSM and the internet search engine Google. The review was conducted in the spirit of the evaluation process outlined in the Cochrane Handbook for Systematic Reviews of Interventions. Conclusions of the peer reviewed literature differ in some ways from those in the popular literature. In peer reviewed studies, wind turbine annoyance has been statistically associated with wind turbine noise, but found to be more strongly related to visual impact, attitude to wind turbines and sensitivity to noise. To date, no peer reviewed articles demonstrate a direct causal link between people living in proximity to modern wind turbines, the noise they emit and resulting physiological health effects. If anything, reported health effects are likely attributed to a number of environmental stressors that result in an annoyed/stressed state in a segment of the population. In the popular literature, self-reported health outcomes are related to distance from turbines and the claim is made that infrasound is the causative factor for the reported effects, even though sound pressure levels are not measured. What both types of studies have in common is the conclusion that wind turbines can be a source of annoyance for some people. The difference between both types is the reason for annoyance. While it is acknowledged that noise from wind turbines can be annoying to some and associated with some reported health effects (e.g., sleep disturbance), especially when found at sound pressure levels greater than 40 db(A), given that annoyance appears to be more strongly related to visual cues and attitude than to noise itself, self reported health effects of people living near wind turbines are more likely attributed to physical manifestation from an annoyed state than from wind turbines themselves. In other words, it appears that it is the change in the environment that is associated with reported health effects and not a turbine-specific variable like audible noise or infrasound. Regardless of its cause, a certain level of annoyance in a population can be expected (as with any number of projects that change the local environment) and the acceptable level is a policy decision to be made by elected officials and their government representatives where the benefits of wind power are weighted against their cons. Assessing the effects of wind turbines on human health is an emerging field and conducting further research into the effects of wind turbines (and environmental changes) on human health, emotional and physical, is warranted.

Health effects and wind turbines: A review of the literature

PubMed Central

2011-01-01

Background Wind power has been harnessed as a source of power around the world. Debate is ongoing with respect to the relationship between reported health effects and wind turbines, specifically in terms of audible and inaudible noise. As a result, minimum setback distances have been established world-wide to reduce or avoid potential complaints from, or potential effects to, people living in proximity to wind turbines. People interested in this debate turn to two sources of information to make informed decisions: scientific peer-reviewed studies published in scientific journals and the popular literature and internet. Methods The purpose of this paper is to review the peer-reviewed scientific literature, government agency reports, and the most prominent information found in the popular literature. Combinations of key words were entered into the Thomson Reuters Web of KnowledgeSM and the internet search engine Google. The review was conducted in the spirit of the evaluation process outlined in the Cochrane Handbook for Systematic Reviews of Interventions. Results Conclusions of the peer reviewed literature differ in some ways from those in the popular literature. In peer reviewed studies, wind turbine annoyance has been statistically associated with wind turbine noise, but found to be more strongly related to visual impact, attitude to wind turbines and sensitivity to noise. To date, no peer reviewed articles demonstrate a direct causal link between people living in proximity to modern wind turbines, the noise they emit and resulting physiological health effects. If anything, reported health effects are likely attributed to a number of environmental stressors that result in an annoyed/stressed state in a segment of the population. In the popular literature, self-reported health outcomes are related to distance from turbines and the claim is made that infrasound is the causative factor for the reported effects, even though sound pressure levels are not measured. Conclusions What both types of studies have in common is the conclusion that wind turbines can be a source of annoyance for some people. The difference between both types is the reason for annoyance. While it is acknowledged that noise from wind turbines can be annoying to some and associated with some reported health effects (e.g., sleep disturbance), especially when found at sound pressure levels greater than 40 db(A), given that annoyance appears to be more strongly related to visual cues and attitude than to noise itself, self reported health effects of people living near wind turbines are more likely attributed to physical manifestation from an annoyed state than from wind turbines themselves. In other words, it appears that it is the change in the environment that is associated with reported health effects and not a turbine-specific variable like audible noise or infrasound. Regardless of its cause, a certain level of annoyance in a population can be expected (as with any number of projects that change the local environment) and the acceptable level is a policy decision to be made by elected officials and their government representatives where the benefits of wind power are weighted against their cons. Assessing the effects of wind turbines on human health is an emerging field and conducting further research into the effects of wind turbines (and environmental changes) on human health, emotional and physical, is warranted. PMID:21914211

Experimental Study on New Multi-Column Tension-Leg-Type Floating Wind Turbine

NASA Astrophysics Data System (ADS)

Zhao, Yong-sheng; She, Xiao-he; He, Yan-ping; Yang, Jian-min; Peng, Tao; Kou, Yu-feng

2018-04-01

Deep-water regions often have winds favorable for offshore wind turbines, and floating turbines currently show the greatest potential to exploit such winds. This work established proper scaling laws for model tests, which were then implemented in the construction of a model wind turbine with optimally designed blades. The aerodynamic, hydrodynamic, and elastic characteristics of the proposed new multi-column tension-leg-type floating wind turbine (WindStar TLP system) were explored in the wave tank testing of a 1:50 scale model at the State Key Laboratory of Ocean Engineering at Shanghai Jiao Tong University. Tests were conducted under conditions of still water, white noise waves, irregular waves, and combined wind, wave, and current loads. The results established the natural periods of the motion, damping, motion response amplitude operators, and tendon tensions of the WindStar TLP system under different environmental conditions, and thus could serve as a reference for further research. Key words: floating wind turbine, model test, WindStar TLP, dynamic response

Total Energy Concepts as Applied to Universities.

ERIC Educational Resources Information Center

Gudgeon, R.L.

A comprehensive discussion of single fuel source generation of power and heating requirements is presented. Definition and explanation of system concepts includes--(1) heat pumps, (2) steam turbines, (3) gas turbines, and (4) gas and diesel engines. Concept cost evaluation factors described are--(1) load pattern, (2) campus configuration, (3) fuel…

ADVANCED COMBUSTION SYSTEMS FOR STATIONARY GAS TURBINE ENGINES: VOLUME I. REVIEW AND PRELIMINARY EVALUATION

EPA Science Inventory

The reports describe an exploratory development program to identify, evaluate, and demonstrate dry techniques for significantly reducing NOx from thermal and fuel-bound sources in stationary gas turbine engines. Volume 1 covers Phase I of the four-phase effort. In Phase I, duty c...

Multi-dimensional modelling of gas turbine combustion using a flame sheet model in KIVA II

NASA Technical Reports Server (NTRS)

Cheng, W. K.; Lai, M.-C.; Chue, T.-H.

1991-01-01

A flame sheet model for heat release is incorporated into a multi-dimensional fluid mechanical simulation for gas turbine application. The model assumes that the chemical reaction takes place in thin sheets compared to the length scale of mixing, which is valid for the primary combustion zone in a gas turbine combustor. In this paper, the details of the model are described and computational results are discussed.

Optimization of Wind Turbine Airfoils/Blades and Wind Farm Layouts

NASA Astrophysics Data System (ADS)

Chen, Xiaomin

Shape optimization is widely used in the design of wind turbine blades. In this dissertation, a numerical optimization method called Genetic Algorithm (GA) is applied to address the shape optimization of wind turbine airfoils and blades. In recent years, the airfoil sections with blunt trailing edge (called flatback airfoils) have been proposed for the inboard regions of large wind-turbine blades because they provide several structural and aerodynamic performance advantages. The FX, DU and NACA 64 series airfoils are thick airfoils widely used for wind turbine blade application. They have several advantages in meeting the intrinsic requirements for wind turbines in terms of design point, off-design capabilities and structural properties. This research employ both single- and multi-objective genetic algorithms (SOGA and MOGA) for shape optimization of Flatback, FX, DU and NACA 64 series airfoils to achieve maximum lift and/or maximum lift to drag ratio. The commercially available software FLUENT is employed for calculation of the flow field using the Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with a two-equation Shear Stress Transport (SST) turbulence model and a three equation k-kl-o turbulence model. The optimization methodology is validated by an optimization study of subsonic and transonic airfoils (NACA0012 and RAE 2822 airfoils). In this dissertation, we employ DU 91-W2-250, FX 66-S196-V1, NACA 64421, and Flat-back series of airfoils (FB-3500-0050, FB-3500-0875, and FB-3500-1750) and compare their performance with S809 airfoil used in NREL Phase II and III wind turbines; the lift and drag coefficient data for these airfoils sections are available. The output power of the turbine is calculated using these airfoil section blades for a given B and lambda and is compared with the original NREL Phase II and Phase III turbines using S809 airfoil section. It is shown that by a suitable choice of airfoil section of HAWT blade, the power generated by the turbine can be significantly increased. Parametric studies are also conducted by varying the turbine diameter. In addition, a simplified dynamic inflow model is integrated into the BEM theory. It is shown that the improved BEM theory has superior performance in capturing the instantaneous behavior of wind turbines due to the existence of wind turbine wake or temporal variations in wind velocity. The dissertation also considers the Wind Farm layout optimization problem using a genetic algorithm. Both the Horizontal --Axis Wind Turbines (HAWT) and Vertical-Axis Wind Turbines (VAWT) are considered. The goal of the optimization problem is to optimally position the turbines within the wind farm such that the wake effects are minimized and the power production is maximized. The reasonably accurate modeling of the turbine wake is critical in determination of the optimal layout of the turbines and the power generated. For HAWT, two wake models are considered; both are found to give similar answers. For VAWT, a very simple wake model is employed. Finally, some preliminary investigation of shape optimization of 3D wind turbine blades at low Reynolds numbers is conducted. The optimization employs a 3D straight untapered wind turbine blade with cross section of NACA 0012 airfoils as the geometry of baseline blade. The optimization objective is to achieve maximum Cl/Cd as well as maximum Cl. The multi-objective genetic algorithm is employed together with the commercially available software FLUENT for calculation of the flow field using the Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with a one-equation Sparlart-Allmaras turbulence model. The results show excellent performance of the optimized wind turbine blade and indicate the feasibility of optimization on real wind turbine blades with more complex shapes in the future. (Abstract shortened by UMI.)

A theoretical prediction of the acoustic pressure generated by turbulence-flame front interactions

NASA Technical Reports Server (NTRS)

Huff, R. G.

1984-01-01

The equations of momentum annd continuity are combined and linearized yielding the one dimensional nonhomogeneous acoustic wave equation. Three terms in the non-homogeneous equation act as acoustic sources and are taken to be forcing functions acting on the homogeneous wave equation. The three source terms are: fluctuating entropy, turbulence gradients, and turbulence-flame interactions. Each source term is discussed. The turbulence-flame interaction source is used as the basis for computing the source acoustic pressure from the Fourier transformed wave equation. Pressure fluctuations created in turbopump gas generators and turbines may act as a forcing function for turbine and propellant tube vibrations in Earth to orbit space propulsion systems and could reduce their life expectancy. A preliminary assessment of the acoustic pressure fluctuations in such systems is presented.

A theoretical prediction of the acoustic pressure generated by turbulence-flame front interactions

NASA Technical Reports Server (NTRS)

Huff, R. G.

1984-01-01

The equations of momentum and continuity are combined and linearized yielding the one dimensional nonhomogeneous acoustic wave equation. Three terms in the non-homogeneous equation act as acoustic sources and are taken to be forcing functions acting on the homogeneous wave equation. The three source terms are: fluctuating entropy, turbulence gradients, and turbulence-flame interactions. Each source term is discussed. The turbulence-flame interaction source is used as the basis for computing the source acoustic pressure from the Fourier transformed wave equation. Pressure fluctuations created in turbopump gas generators and turbines may act as a forcing function for turbine and propellant tube vibrations in earth to orbit space propulsion systems and could reduce their life expectancy. A preliminary assessment of the acoustic pressure fluctuations in such systems is presented.

Darrieus wind-turbine and pump performance for low-lift irrigation pumping

NASA Astrophysics Data System (ADS)

Hagen, L. J.; Sharif, M.

1981-10-01

In the Great Plains about 15 percent of the irrigation water pumped on farms comes from surface water sources; for the United States as a whole, the figure is about 22 percent. Because of forecast fuel shortages, there is a need to develop alternative energy sources such as wind power for surface water pumping. Specific objectives of this investigation were to: design and assemble a prototype wind powered pumping system for low lift irrigation pumping; determine performance of the prototype system; design and test an irrigation system using the wind powered prototype in a design and test an farm application; and determine the size combinations of wind turbines, tailwater pits, and temporary storage reservoirs needed for successful farm application of wind powered tailwater pumping systems in western Kansas. The power source selected was a two bladed, 6 m diameter, 9 m tall Darrieus vertical axis wind turbine with 0.10 solidity and 36.1 M(2) swept area.

Analytical model for local scour prediction around hydrokinetic turbine foundations

NASA Astrophysics Data System (ADS)

Musa, M.; Heisel, M.; Hill, C.; Guala, M.

2017-12-01

Marine and Hydrokinetic renewable energy is an emerging sustainable and secure technology which produces clean energy harnessing water currents from mostly tidal and fluvial waterways. Hydrokinetic turbines are typically anchored at the bottom of the channel, which can be erodible or non-erodible. Recent experiments demonstrated the interactions between operating turbines and an erodible surface with sediment transport, resulting in a remarkable localized erosion-deposition pattern significantly larger than those observed by static in-river construction such as bridge piers, etc. Predicting local scour geometry at the base of hydrokinetic devices is extremely important during foundation design, installation, operation, and maintenance (IO&M), and long-term structural integrity. An analytical modeling framework is proposed applying the phenomenological theory of turbulence to the flow structures that promote the scouring process at the base of a turbine. The evolution of scour is directly linked to device operating conditions through the turbine drag force, which is inferred to locally dictate the energy dissipation rate in the scour region. The predictive model is validated using experimental data obtained at the University of Minnesota's St. Anthony Falls Laboratory (SAFL), covering two sediment mobility regimes (clear water and live bed), different turbine designs, hydraulic parameters, grain size distribution and bedform types. The model is applied to a potential prototype scale deployment in the lower Mississippi River, demonstrating its practical relevance and endorsing the feasibility of hydrokinetic energy power plants in large sandy rivers. Multi-turbine deployments are further studied experimentally by monitoring both local and non-local geomorphic effects introduced by a twelve turbine staggered array model installed in a wide channel at SAFL. Local scour behind each turbine is well captured by the theoretical predictive model. However, multi-turbine configurations introduce subtle large-scale effects that deepen local scour within the first two rows of the array and develop spatially as a two-dimensional oscillation of the mean bed downstream of the entire array.

Wind Plant Power Optimization and Control under Uncertainty

NASA Astrophysics Data System (ADS)

Jha, Pankaj; Ulker, Demet; Hutchings, Kyle; Oxley, Gregory

2017-11-01

The development of optimized cooperative wind plant control involves the coordinated operation of individual turbines co-located within a wind plant to improve the overall power production. This is typically achieved by manipulating the trajectory and intensity of wake interactions between nearby turbines, thereby reducing wake losses. However, there are various types of uncertainties involved, such as turbulent inflow and microscale and turbine model input parameters. In a recent NREL-Envision collaboration, a controller that performs wake steering was designed and implemented for the Longyuan Rudong offshore wind plant in Jiangsu, China. The Rudong site contains 25 Envision EN136-4 MW turbines, of which a subset was selected for the field test campaign consisting of the front two rows for the northeasterly wind direction. In the first row, a turbine was selected as the reference turbine, providing comparison power data, while another was selected as the controlled turbine. This controlled turbine wakes three different turbines in the second row depending on the wind direction. A yaw misalignment strategy was designed using Envision's GWCFD, a multi-fidelity plant-scale CFD tool based on SOWFA with a generalized actuator disc (GAD) turbine model, which, in turn, was used to tune NREL's FLORIS model used for wake steering and yaw control optimization. The presentation will account for some associated uncertainties, such as those in atmospheric turbulence and wake profile.

Simulation of pump-turbine prototype fast mode transition for grid stability support

NASA Astrophysics Data System (ADS)

Nicolet, C.; Braun, O.; Ruchonnet, N.; Hell, J.; Béguin, A.; Avellan, F.

2017-04-01

The paper explores the additional services that Full Size Frequency Converter, FSFC, solution can provide for the case of an existing pumped storage power plant of 2x210 MW, for which conversion from fixed speed to variable speed is investigated with a focus on fast mode transition. First, reduced scale model tests experiments of fast transition of Francis pump-turbine which have been performed at the ANDRITZ HYDRO Hydraulic Laboratory in Linz Austria are presented. The tests consist of linear speed transition from pump to turbine and vice versa performed with constant guide vane opening. Then existing pumped storage power plant with pump-turbine quasi homologous to the reduced scale model is modelled using the simulation software SIMSEN considering the reservoirs, penstocks, the two Francis pump-turbines, the two downstream surge tanks, and the tailrace tunnel. For the electrical part, an FSFC configuration is considered with a detailed electrical model. The transitions from turbine to pump and vice versa are simulated, and similarities between prototype simulation results and reduced scale model experiments are highlighted.

Flow Simulation of Modified Duct System Wind Turbines Installed on Vehicle

NASA Astrophysics Data System (ADS)

Rosly, N.; Mohd, S.; Zulkafli, M. F.; Ghafir, M. F. Abdul; Shamsudin, S. S.; Muhammad, W. N. A. Wan

2017-10-01

This study investigates the characteristics of airflow with a flow guide installed and output power generated by wind turbine system being installed on a pickup truck. The wind turbine models were modelled by using SolidWorks 2015 software. In order to investigate the characteristic of air flow inside the wind turbine system, a computer simulation (by using ANSYS Fluent software) is used. There were few models being designed and simulated, one without the rotor installed and another two with rotor installed in the wind turbine system. Three velocities being used for the simulation which are 16.7 m/s (60 km/h), 25 m/s (90 km/h) and 33.33 m/s (120 km/h). The study proved that the flow guide did give an impact to the output power produced by the wind turbine system. The predicted result from this study is the velocity of the air inside the ducting system of the present model is better that reference model. Besides, the flow guide implemented in the ducting system gives a big impact on the characteristics of the air flow.

Computational Analysis of a Wells Turbine with Flexible Trailing Edges

NASA Astrophysics Data System (ADS)

Kincaid, Kellis; Macphee, David

2017-11-01

The Wells turbine is often used to produce a net positive power from an oscillating air column excited by ocean waves. It has been parametrically studied quite thoroughly in the past, both experimentally and numerically. The effects of various characteristics such as blade count and profile, solidity, and tip gap are well known. Several three-dimensional computational studies have been carried out using commercial code to investigate many phenomena detected in experiments: hysteresis, tip-gap drag, and post-stall behavior for example. In this work, the open-source code Foam-Extend is used to examine the effect of flexible blades on the performance of the Wells turbine. A new solver is created to integrate fluid-structure interaction into the code, allowing an accurate solution for both the solid and fluid domains. Reynolds-averaged governing equations are employed in a fully transient solution model. The elastic modulus of the flexible portion of the blade and the tip-gap width are varied, and the resulting flow fields are investigated to determine the cause of any performance differences. NSF Grant EEC 1659710.

A study of the optimization method used in the NAVY/NASA gas turbine engine computer code

NASA Technical Reports Server (NTRS)

Horsewood, J. L.; Pines, S.

1977-01-01

Sources of numerical noise affecting the convergence properties of the Powell's Principal Axis Method of Optimization in the NAVY/NASA gas turbine engine computer code were investigated. The principal noise source discovered resulted from loose input tolerances used in terminating iterations performed in subroutine CALCFX to satisfy specified control functions. A minor source of noise was found to be introduced by an insufficient number of digits in stored coefficients used by subroutine THERM in polynomial expressions of thermodynamic properties. Tabular results of several computer runs are presented to show the effects on program performance of selective corrective actions taken to reduce noise.

Damped gyroscopic effects and axial-flexural-torsional coupling using spinning finite elements for wind-turbine blades characterization

NASA Astrophysics Data System (ADS)

Velazquez, Antonio; Swartz, R. Andrew

2013-04-01

Renewable energy sources like wind are important technologies, useful to alleviate for the current fossil-fuel crisis. Capturing wind energy in a more efficient way has resulted in the emergence of more sophisticated designs of wind turbines, particularly Horizontal-Axis Wind Turbines (HAWTs). To promote efficiency, traditional finite element methods have been widely used to characterize the aerodynamics of these types of multi-body systems and improve their design. Given their aeroelastic behavior, tapered-swept blades offer the potential to optimize energy capture and decrease fatigue loads. Nevertheless, modeling special complex geometries requires huge computational efforts necessitating tradeoffs between faster computation times at lower cost, and reliability and numerical accuracy. Indeed, the computational cost and the numerical effort invested, using traditional FE methods, to reproduce dependable aerodynamics of these complex-shape beams are sometimes prohibitive. A condensed Spinning Finite Element (SFE) method scheme is presented in this study aimed to alleviate this issue by means of modeling wind-turbine rotor blades properly with tapered-swept cross-section variations of arbitrary order via Lagrangian equations. Axial-flexural-torsional coupling is carried out on axial deformation, torsion, in-plane bending and out-of-plane bending using super-convergent elements. In this study, special attention is paid for the case of damped yaw effects, expressed within the described skew-symmetric damped gyroscopic matrix. Dynamics of the model are analyzed by achieving modal analysis with complex-number eigen-frequencies. By means of mass, damped gyroscopic, and stiffness (axial-flexural-torsional coupling) matrix condensation (order reduction), numerical analysis is carried out for several prototypes with different tapered, swept, and curved variation intensities, and for a practical range of spinning velocities at different rotation angles. A convergence study for the resulting natural frequencies is performed to evaluate the dynamic collateral effects of tapered-swept blade profiles in spinning motion using this new model. Stability analysis in boundary conditions of the postulated model is achieved to test the convergence and integrity of the mathematical model. The proposed framework presumes to be particularly suitable to characterize models with complex-shape cross-sections at low computation cost.

Real-Time Digital Simulation of Inertial Response with Hardware-in-the-Loop Implementation on the CART3 Wind Turbine at the National Wind Technology Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Wenzhong; Wang, Xiao; Muljadi, Eduard

With increasing penetrations of wind power on electric grids, the stability and reliability of interconnected power systems may be impacted. In some countries that have developed renewable energy sources and systems, grid codes have been revised to require wind power plants (WPPs) to provide ancillary services to support the power system frequency in case of severe grid events. To do this, wind turbine generators (WTGs) should be deloaded to reserve a certain amount of active power for primary frequency response; however, deloading curtails annual energy production, and the market for this type of service needs to be further developed. Inmore » this report, we focus on the temporary frequency support provided by WTGs through inertial response. WTGs have potential to provide inertial response, but appropriate control methods should be implemented. With the implemented inertial control methods, wind turbines are capable of increasing their active power output by releasing some of their stored kinetic energy when a frequency excursion occurs. Active power can be temporarily boosted above the maximum power points, after which the rotor speed decelerates, and subsequently an active power output reduction restores the kinetic energy. In this report, we develop two types of models for wind power systems: the first is common, based on the wind power aerodynamic equation, and the power coefficient can be regressed using nonlinear functions; the second is much more complicated, wherein the wind turbine system is modeled using the Fatigue, Aerodynamics, Structures, and Turbulence Modeling (FAST) tool with several degrees of freedoms. A nine-bus test power system is built in Simulink and the Real-Time Digital Simulator, respectively, which are used to evaluate the frequency support performance of the WPPs. We implement two distinct types of inertial control methods in the modeled wind turbines: frequency-based inertial control (FBIC) and stepwise inertial control (SIC). We compare the performances of the two methods in terms of their frequency nadirs, rates of change of frequency, and recovery times. We conclude the results under various wind speeds and penetration cases, which provide insight into designing the inertial response of WTGs. Further, we discuss the impact of the parameters on the performance of the inertial control methods. We evaluate both the scaling factors for the FBIC method and the slope values for the TLIC methods. The simulation work shows the characteristics of different inertial responses compared to conventional synchronous generators. Based on the simulation results, we modify, improve, and test the inertial control methods under a more realistic wind turbine model based on FAST. We then validate the inertial responses under highly turbulent wind conditions generated by TurbSim, and we examine their influences on the turbine mechanical components. The extensive simulation proves the effectiveness of the proposed inertial control methods as well as the nine-bus test power system. We then reconsider the parameters. We rebuild the same test power system using Real time Simulator Computer Aided Design (RSCAD), and we implement the inertial control methods in the real Controls Advanced Research Turbine (CART3), which is prepared for the hardware-in-the-loop field-test simulation. After the setups for the hardware and software hybrid simulation platform are complete, the inertial response is further tested on a real wind turbine for the first time, in which CART3 release the controlled inertial response against the emulated frequency excursion, provided by the real-time simulated power system test bed in RTDS.« less

Evaluation of different inertial control methods for variable-speed wind turbines simulated by fatigue, aerodynamic, structures and turbulence (FAST)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Xiao; Gao, Wenzhong; Scholbrock, Andrew

To mitigate the degraded power system inertia and undesirable primary frequency response caused by large-scale wind power integration, the frequency support capabilities of variable-speed wind turbines is studied in this work. This is made possible by controlled inertial response, which is demonstrated on a research turbine - controls advanced research turbine, 3-bladed (CART3). Two distinct inertial control (IC) methods are analysed in terms of their impacts on the grids and the response of the turbine itself. The released kinetic energy in the IC methods are determined by the frequency measurement or shaped active power reference in the turbine speed-power plane.more » The wind turbine model is based on the high-fidelity turbine simulator fatigue, aerodynamic, structures and turbulence, which constitutes the aggregated wind power plant model with the simplified power converter model. The IC methods are implemented over the baseline CART3 controller, evaluated in the modified 9-bus and 14-bus testing power grids considering different wind speeds and different wind power penetration levels. The simulation results provide various insights on designing such kinds of ICs. The authors calculate the short-term dynamic equivalent loads and give a discussion about the turbine structural loadings related to the inertial response.« less

Modelling the far field hydro-environmental impacts of tidal farms - A focus on tidal regime, inter-tidal zones and flushing

NASA Astrophysics Data System (ADS)

Nash, S.; O'Brien, N.; Olbert, A.; Hartnett, M.

2014-10-01

The introduction of tidal stream turbines into water bodies can have an impact on the environment due to changes in the hydrodynamic flow fields resulting from the extraction of energy by the tidal turbines. Water levels, tidal currents and flushing characteristics could potentially be significantly altered with the introduction of tidal turbine farms, which could lead to possible loss of habitat and a change in the tidal regime. Therefore, planning of tidal turbines field deployments must take into account possible hydro-environmental impacts. This paper describes research undertaken by the authors in the Shannon Estuary to predict changes in the tidal regime and flushing characteristics, with the introduction of tidal turbine farms of different array configurations. The model was simulated using a 2D hydrodynamic model that was modified to incorporate the effects of tidal turbine fields. Water levels are shown to have been affected with the inclusion of turbines, especially in areas upstream of the turbine farm where inter-tidal zones could become predominately inundated resulting in loss of habitat in the estuary. Flushing parameters were also shown to be altered with the inclusion of turbines, with residence time shown to be increased, which could change pollutant transport in the region.

Review of fluid and control technology of hydraulic wind turbines

NASA Astrophysics Data System (ADS)

Cai, Maolin; Wang, Yixuan; Jiao, Zongxia; Shi, Yan

2017-09-01

This study examines the development of the fluid and control technology of hydraulic wind turbines. The current state of hydraulic wind turbines as a new technology is described, and its basic fluid model and typical control method are expounded by comparing various study results. Finally, the advantages of hydraulic wind turbines are enumerated. Hydraulic wind turbines are expected to become the main development direction of wind turbines.

Analysis of axial-induction-based wind plant control using an engineering and a high-order wind plant model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Annoni, Jennifer; Gebraad, Pieter M. O.; Scholbrock, Andrew K.

2015-08-14

Wind turbines are typically operated to maximize their performance without considering the impact of wake effects on nearby turbines. Wind plant control concepts aim to increase overall wind plant performance by coordinating the operation of the turbines. This paper focuses on axial-induction-based wind plant control techniques, in which the generator torque or blade pitch degrees of freedom of the wind turbines are adjusted. The paper addresses discrepancies between a high-order wind plant model and an engineering wind plant model. Changes in the engineering model are proposed to better capture the effects of axial-induction-based control shown in the high-order model.

A Comprehensive Structural Study of Offshore Wind Turbine Foundation and Non-Model Based Damage Detection using Effective Mass with Application to Small Components/ Cables and a Truss Wind Turbine Tower

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Scott A.

This research has two areas of focus. The first area is to investigate offshore wind turbine (OWT) designs, for use in the Maryland offshore wind area (MOWA), using intensive modeling techniques. The second focus area is to investigate a way to detect damage in wind turbine towers and small electrical components.

Simplified hydrodynamic analysis on the general shape of the hill charts of Francis turbines using shroud-streamline modeling

NASA Astrophysics Data System (ADS)

Iliev, I.; Trivedi, C.; Dahlhaug, O. G.

2018-06-01

The paper presents a simplified one-dimensional calculation of the efficiency hill-chart for Francis turbines, based on the velocity triangles at the inlet and outlet of the runner’s blade. Calculation is done for one streamline, namely the shroud streamline in the meridional section, where an efficiency model is established and iteratively approximated in order to satisfy the Euler equation for turbomachines at a wide operating range around the best efficiency point (BEP). Using the presented method, hill charts are calculated for one splitter-bladed Francis turbine runner and one Reversible Pump-Turbine (RPT) runner operated in the turbine mode. Both turbines have similar and relatively low specific speeds of nsQ = 23.3 and nsQ = 27, equal inlet and outlet diameters and are designed to fit in the same turbine rig for laboratory measurements (i.e. spiral casing and draft tube are the same). Calculated hill charts are compared against performance data obtained experimentally from model tests according to IEC standards for both turbines. Good agreement between theoretical and experimental results is observed when comparing the shapes of the efficiency contours in the hill-charts. The simplified analysis identifies the design parameters that defines the general shape and inclination of the turbine’s hill charts and, with some additional improvements in the loss models used, it can be used for quick assessment of the performance at off-design conditions during the design process of hydraulic turbines.

Developments in Marine Current Turbine Research at the United States Naval Academy (Invited)

NASA Astrophysics Data System (ADS)

Flack, K. A.; Luznik, L.

2013-12-01

A series of tests have been performed on a 1/25th scale model of a two bladed horizontal axis marine current turbine. The tests were conducted in a large tow tank facility at the United States Naval Academy. The turbine model has a 0.8 m diameter (D) rotor with a NACA 63-618 cross section, which is Reynolds number independent with respect to the lift coefficient in the operating range of Rec ≈ 4 x 105. Baseline test were conducted to obtain torque, thrust and rotational speed at a range of tip speed ratios (TSR) from 5 < TSR < 11. The power and thrust coefficients for the model turbine match expected results from blade-element-momentum theory. The lift and drag curves for the numerical model were obtained by testing a 2D NACA 63-618 airfoil in a wind tunnel. Additional tests were performed at two rotor depths (1.3D and 2.25D) in the presence of intermediate and deep water waves. The average values for power and thrust coefficient are weakly dependent on turbine depth. The waves yield a small increase in turbine performance which can be explained by Stokes drift velocity. Phase averaged results indicate that the oscillatory wave velocity results in significant variations in measured turbine torque and rotational speed as a function of wave phase. The turbine rotation speed, power, and thrust reach a maximum with the passing of the wave crest and a minimum with the passing of the wave trough. The torque appears dependent on vertical velocity, which lags the horizontal velocity by 90° of wave phase. Variations of the performance parameters are of the same order of magnitude as the average value, especially when the turbine is near the mean free surface and in the presence of high energy waves. These results demonstrate the impact of surface gravity waves on power production and structural loading. Future tests will focus on measuring and modeling the wake of the turbine for unsteady flow conditions. Model Turbine Power Coefficient vs, Tip Speed Ratio

A Robust Design Approach to Cost Estimation: Solar Energy for Marine Corps Expeditionary Operations

DTIC Science & Technology

2014-07-14

solutions in such areas as photovoltaic arrays for power harvesting, light emitting diodes (LED) for decreased energy consumption, and improved battery...generation and conversion system that allows Marines to power systems with solar energy. Each GREENS is comprised of eight photovoltaic array panels...renewable power sources such as photovoltaic arrays and wind turbines. The HOMER model has been utilized for years by organizations and companies

Validation of Simplified Load Equations Through Loads Measurement and Modeling of a Small Horizontal-Axis Wind Turbine Tower

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dana, Scott; Van Dam, Jeroen J; Damiani, Rick R

As part of an ongoing effort to improve the modeling and prediction of small wind turbine dynamics, the National Renewable Energy Laboratory (NREL) tested a small horizontal-axis wind turbine in the field at the National Wind Technology Center. The test turbine was a 2.1-kW downwind machine mounted on an 18-m multi-section fiberglass composite tower. The tower was instrumented and monitored for approximately 6 months. The collected data were analyzed to assess the turbine and tower loads and further validate the simplified loads equations from the International Electrotechnical Commission (IEC) 61400-2 design standards. Field-measured loads were also compared to the outputmore » of an aeroelastic model of the turbine. In particular, we compared fatigue loads as measured in the field, predicted by the aeroelastic model, and calculated using the simplified design equations. Ultimate loads at the tower base were assessed using both the simplified design equations and the aeroelastic model output. The simplified design equations in IEC 61400-2 do not accurately model fatigue loads and a discussion about the simplified design equations is discussed.« less

Modelling the failure behaviour of wind turbines

NASA Astrophysics Data System (ADS)

Faulstich, S.; Berkhout, V.; Mayer, J.; Siebenlist, D.

2016-09-01

Modelling the failure behaviour of wind turbines is an essential part of offshore wind farm simulation software as it leads to optimized decision making when specifying the necessary resources for the operation and maintenance of wind farms. In order to optimize O&M strategies, a thorough understanding of a wind turbine's failure behaviour is vital and is therefore being developed at Fraunhofer IWES. Within this article, first the failure models of existing offshore O&M tools are presented to show the state of the art and strengths and weaknesses of the respective models are briefly discussed. Then a conceptual framework for modelling different failure mechanisms of wind turbines is being presented. This framework takes into account the different wind turbine subsystems and structures as well as the failure modes of a component by applying several influencing factors representing wear and break failure mechanisms. A failure function is being set up for the rotor blade as exemplary component and simulation results have been compared to a constant failure rate and to empirical wind turbine fleet data as a reference. The comparison and the breakdown of specific failure categories demonstrate the overall plausibility of the model.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Churchfield, M. J.; Moriarty, P. J.; Hao, Y.

The focus of this work is the comparison of the dynamic wake meandering model and large-eddy simulation with field data from the Egmond aan Zee offshore wind plant composed of 36 3-MW turbines. The field data includes meteorological mast measurements, SCADA information from all turbines, and strain-gauge data from two turbines. The dynamic wake meandering model and large-eddy simulation are means of computing unsteady wind plant aerodynamics, including the important unsteady meandering of wakes as they convect downstream and interact with other turbines and wakes. Both of these models are coupled to a turbine model such that power and mechanicalmore » loads of each turbine in the wind plant are computed. We are interested in how accurately different types of waking (e.g., direct versus partial waking), can be modeled, and how background turbulence level affects these loads. We show that both the dynamic wake meandering model and large-eddy simulation appear to underpredict power and overpredict fatigue loads because of wake effects, but it is unclear that they are really in error. This discrepancy may be caused by wind-direction uncertainty in the field data, which tends to make wake effects appear less pronounced.« less

Vibration Based Wind Turbine Tower Foundation Design Utilizing Soil-Foundation-Structure Interaction

NASA Astrophysics Data System (ADS)

Al Satari, P. E. Mohamed; Hussain, S. E. Saif

2008-07-01

Wind turbines have been used to generate electricity as an alternative energy source to conventional fossil fuels. This case study is for multiple wind towers located at different villages in Alaska where severe arctic weather conditions exist. The towers are supported by two different types of foundations; large mat or deep piles foundations. Initially, a Reinforced Concrete (RC) mat foundation was utilized to provide the system with vertical and lateral support. Where soil conditions required it, a pile foundation solution was devised utilizing a 30″ thick RC mat containing an embedded steel grillage of W18 beams supported by 20″-24″ grouted or un-grouted piles. The mixing and casting of concrete in-situ has become the major source of cost and difficulty of construction at these remote Alaska sites. An all-steel foundation was proposed for faster installation and lower cost, but was found to impact the natural frequencies of the structural system by significantly softening the foundation system. The tower-foundation support structure thus became near-resonant with the operational frequencies of the wind turbine leading to a likelihood of structural instability or even collapse. A detailed 3D Finite-Element model of the original tower-foundation-pile system with RC foundation was created using SAP2000. Soil springs were included in the model based on soil properties obtained from the geotechnical consultant. The natural frequency from the model was verified against the tower manufacturer analytical and the experimental values. Where piles were used, numerous iterations were carried out to eliminate the need for the RC and optimize the design. An optimized design was achieved with enough separation between the natural and operational frequencies to prevent damage to the structural system eliminating the need for any RC encasement to the steel foundation or grouting to the piles.

Simulating Turbulent Wind Fields for Offshore Turbines in Hurricane-Prone Regions (Poster)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Y.; Damiani, R.; Musial, W.

Extreme wind load cases are one of the most important external conditions in the design of offshore wind turbines in hurricane prone regions. Furthermore, in these areas, the increase in load with storm return-period is higher than in extra-tropical regions. However, current standards have limited information on the appropriate models to simulate wind loads from hurricanes. This study investigates turbulent wind models for load analysis of offshore wind turbines subjected to hurricane conditions. Suggested extreme wind models in IEC 61400-3 and API/ABS (a widely-used standard in oil and gas industry) are investigated. The present study further examines the wind turbinemore » response subjected to Hurricane wind loads. Three-dimensional wind simulator, TurbSim, is modified to include the API wind model. Wind fields simulated using IEC and API wind models are used for an offshore wind turbine model established in FAST to calculate turbine loads and response.« less

Wind Plant Power Optimization through Yaw Control using a Parametric Model for Wake Effects -- A CFD Simulation Study

DOE PAGES

Gebraad, P. M. O.; Teeuwisse, F. W.; van Wingerden, J. W.; ...

2016-01-01

This article presents a wind plant control strategy that optimizes the yaw settings of wind turbines for improved energy production of the whole wind plant by taking into account wake effects. The optimization controller is based on a novel internal parametric model for wake effects, called the FLOw Redirection and Induction in Steady-state (FLORIS) model. The FLORIS model predicts the steady-state wake locations and the effective flow velocities at each turbine, and the resulting turbine electrical energy production levels, as a function of the axial induction and the yaw angle of the different rotors. The FLORIS model has a limitedmore » number of parameters that are estimated based on turbine electrical power production data. In high-fidelity computational fluid dynamics simulations of a small wind plant, we demonstrate that the optimization control based on the FLORIS model increases the energy production of the wind plant, with a reduction of loads on the turbines as an additional effect.« less

Feasible application of offshore wind turbines in Labuan Island, Sabah for energy complementary

NASA Astrophysics Data System (ADS)

Salleh, Nur Farahin; Chew, Boon Cheong; Hamid, Syaiful Rizal

2017-03-01

Nowadays, the world energy requirements are increasing at an alarming rate and the power demand is running ahead of supply. It is widely recognized that the fossil fuels such as coal, petroleum and natural gas are presently being used for electricity generation. Therefore, in future it may not be sufficient to keep pace with ever increasing demand of the electrical energy of the world. The renewable energy can provide clean sources of energy which is reliable and secure to society. This paper analyzed renewable energy adoption, focusing on offshore wind turbines. In this case study, Labuan, Sabah has been selected and suggested as the location to install the offshore wind turbines because of geographical advantage of the South China Sea. The technology is expected to provide great power energy with least environment impact and high sustainability as it is located within the windy area with no terrain features, buildings or other obstruction. This study used qualitative methods for both data collection and data analysis. This study proved the feasible application of offshore wind turbines in the South China Sea, Sabah produced the complementary energy to fossil fuels. Hence, the offshore wind turbines might become one of main energy sources in Sabah. The application of the offshore wind turbines to Sabah residential area develops a lot of benefit and support Malaysian government goal which is to be more competitive in renewable energy generation while sustaining national economic growth.

A new vertical axis wind turbine design for urban areas

NASA Astrophysics Data System (ADS)

Frunzulica, Florin; Cismilianu, Alexandru; Boros, Alexandru; Dumitrache, Alexandru; Suatean, Bogdan

2016-06-01

In this paper we aim at developing the model of a Vertical Axis Wind Turbine (VAWT) with the short-term goal of physically realising this turbine to operate at a maximmum power of 5 kW. The turbine is designed for household users in the urban or rural areas and remote or isolated residential areas (hardly accsessible). The proposed model has a biplane configuration on each arm of the VAWT (3 × 2 = 6 blades), allowing for increased performance of the turbine at TSR between 2 and 2.5 (urban area operation) compared to the classic vertical axis turbines. Results that validate the proposed configuration as well as passive control methods to increase the performance of the classic VAWTs are presented.

Finite difference time domain modeling of steady state scattering from jet engines with moving turbine blades

NASA Technical Reports Server (NTRS)

Ryan, Deirdre A.; Langdon, H. Scott; Beggs, John H.; Steich, David J.; Luebbers, Raymond J.; Kunz, Karl S.

1992-01-01

The approach chosen to model steady state scattering from jet engines with moving turbine blades is based upon the Finite Difference Time Domain (FDTD) method. The FDTD method is a numerical electromagnetic program based upon the direct solution in the time domain of Maxwell's time dependent curl equations throughout a volume. One of the strengths of this method is the ability to model objects with complicated shape and/or material composition. General time domain functions may be used as source excitations. For example, a plane wave excitation may be specified as a pulse containing many frequencies and at any incidence angle to the scatterer. A best fit to the scatterer is accomplished using cubical cells in the standard cartesian implementation of the FDTD method. The material composition of the scatterer is determined by specifying its electrical properties at each cell on the scatterer. Thus, the FDTD method is a suitable choice for problems with complex geometries evaluated at multiple frequencies. It is assumed that the reader is familiar with the FDTD method.

Maximum wind energy extraction strategies using power electronic converters

NASA Astrophysics Data System (ADS)

Wang, Quincy Qing

2003-10-01

This thesis focuses on maximum wind energy extraction strategies for achieving the highest energy output of variable speed wind turbine power generation systems. Power electronic converters and controls provide the basic platform to accomplish the research of this thesis in both hardware and software aspects. In order to send wind energy to a utility grid, a variable speed wind turbine requires a power electronic converter to convert a variable voltage variable frequency source into a fixed voltage fixed frequency supply. Generic single-phase and three-phase converter topologies, converter control methods for wind power generation, as well as the developed direct drive generator, are introduced in the thesis for establishing variable-speed wind energy conversion systems. Variable speed wind power generation system modeling and simulation are essential methods both for understanding the system behavior and for developing advanced system control strategies. Wind generation system components, including wind turbine, 1-phase IGBT inverter, 3-phase IGBT inverter, synchronous generator, and rectifier, are modeled in this thesis using MATLAB/SIMULINK. The simulation results have been verified by a commercial simulation software package, PSIM, and confirmed by field test results. Since the dynamic time constants for these individual models are much different, a creative approach has also been developed in this thesis to combine these models for entire wind power generation system simulation. An advanced maximum wind energy extraction strategy relies not only on proper system hardware design, but also on sophisticated software control algorithms. Based on literature review and computer simulation on wind turbine control algorithms, an intelligent maximum wind energy extraction control algorithm is proposed in this thesis. This algorithm has a unique on-line adaptation and optimization capability, which is able to achieve maximum wind energy conversion efficiency through continuously improving the performance of wind power generation systems. This algorithm is independent of wind power generation system characteristics, and does not need wind speed and turbine speed measurements. Therefore, it can be easily implemented into various wind energy generation systems with different turbine inertia and diverse system hardware environments. In addition to the detailed description of the proposed algorithm, computer simulation results are presented in the thesis to demonstrate the advantage of this algorithm. As a final confirmation of the algorithm feasibility, the algorithm has been implemented inside a single-phase IGBT inverter, and tested with a wind simulator system in research laboratory. Test results were found consistent with the simulation results. (Abstract shortened by UMI.)

Advanced Modeling System for Optimization of Wind Farm Layout and Wind Turbine Sizing Using a Multi-Level Extended Pattern Search Algorithm

DOE Office of Scientific and Technical Information (OSTI.GOV)

DuPont, Bryony; Cagan, Jonathan; Moriarty, Patrick

This paper presents a system of modeling advances that can be applied in the computational optimization of wind plants. These modeling advances include accurate cost and power modeling, partial wake interaction, and the effects of varying atmospheric stability. To validate the use of this advanced modeling system, it is employed within an Extended Pattern Search (EPS)-Multi-Agent System (MAS) optimization approach for multiple wind scenarios. The wind farm layout optimization problem involves optimizing the position and size of wind turbines such that the aerodynamic effects of upstream turbines are reduced, which increases the effective wind speed and resultant power at eachmore » turbine. The EPS-MAS optimization algorithm employs a profit objective, and an overarching search determines individual turbine positions, with a concurrent EPS-MAS determining the optimal hub height and rotor diameter for each turbine. Two wind cases are considered: (1) constant, unidirectional wind, and (2) three discrete wind speeds and varying wind directions, each of which have a probability of occurrence. Results show the advantages of applying the series of advanced models compared to previous application of an EPS with less advanced models to wind farm layout optimization, and imply best practices for computational optimization of wind farms with improved accuracy.« less

A New Energy-Critical Plane Damage Parameter for Multiaxial Fatigue Life Prediction of Turbine Blades.

PubMed

Yu, Zheng-Yong; Zhu, Shun-Peng; Liu, Qiang; Liu, Yunhan

2017-05-08

As one of fracture critical components of an aircraft engine, accurate life prediction of a turbine blade to disk attachment is significant for ensuring the engine structural integrity and reliability. Fatigue failure of a turbine blade is often caused under multiaxial cyclic loadings at high temperatures. In this paper, considering different failure types, a new energy-critical plane damage parameter is proposed for multiaxial fatigue life prediction, and no extra fitted material constants will be needed for practical applications. Moreover, three multiaxial models with maximum damage parameters on the critical plane are evaluated under tension-compression and tension-torsion loadings. Experimental data of GH4169 under proportional and non-proportional fatigue loadings and a case study of a turbine disk-blade contact system are introduced for model validation. Results show that model predictions by Wang-Brown (WB) and Fatemi-Socie (FS) models with maximum damage parameters are conservative and acceptable. For the turbine disk-blade contact system, both of the proposed damage parameters and Smith-Watson-Topper (SWT) model show reasonably acceptable correlations with its field number of flight cycles. However, life estimations of the turbine blade reveal that the definition of the maximum damage parameter is not reasonable for the WB model but effective for both the FS and SWT models.

A New Energy-Critical Plane Damage Parameter for Multiaxial Fatigue Life Prediction of Turbine Blades

PubMed Central

Yu, Zheng-Yong; Zhu, Shun-Peng; Liu, Qiang; Liu, Yunhan

2017-01-01

As one of fracture critical components of an aircraft engine, accurate life prediction of a turbine blade to disk attachment is significant for ensuring the engine structural integrity and reliability. Fatigue failure of a turbine blade is often caused under multiaxial cyclic loadings at high temperatures. In this paper, considering different failure types, a new energy-critical plane damage parameter is proposed for multiaxial fatigue life prediction, and no extra fitted material constants will be needed for practical applications. Moreover, three multiaxial models with maximum damage parameters on the critical plane are evaluated under tension-compression and tension-torsion loadings. Experimental data of GH4169 under proportional and non-proportional fatigue loadings and a case study of a turbine disk-blade contact system are introduced for model validation. Results show that model predictions by Wang-Brown (WB) and Fatemi-Socie (FS) models with maximum damage parameters are conservative and acceptable. For the turbine disk-blade contact system, both of the proposed damage parameters and Smith-Watson-Topper (SWT) model show reasonably acceptable correlations with its field number of flight cycles. However, life estimations of the turbine blade reveal that the definition of the maximum damage parameter is not reasonable for the WB model but effective for both the FS and SWT models. PMID:28772873

Robust 1550-nm single-frequency all-fiber ns-pulsed fiber amplifier for wind-turbine predictive control by wind lidar

NASA Astrophysics Data System (ADS)

Beier, F.; de Vries, O.; Schreiber, T.; Eberhardt, R.; Tünnermann, A.; Bollig, C.; Hofmeister, P. G.; Schmidt, J.; Reuter, R.

2013-02-01

Scaling of the power yield of offshore wind farms relies on the capacity of the individual wind turbines. This results in a trend to very large rotor diameters, which are difficult to control. It is crucial to monitor the inhomogeneous wind field in front of the wind turbines at different distances to ensure reliable operation and a long lifetime at high output levels. In this contribution, we demonstrate an all-fiber ns-pulsed fiber amplifier based on cost-efficient commercially available components. The amplifier is a suitable source for coherent Doppler lidar pulses making a predictive control of the turbine operation feasible.

Comparative study on the wake deflection behind yawed wind turbine models

NASA Astrophysics Data System (ADS)

Schottler, Jannik; Mühle, Franz; Bartl, Jan; Peinke, Joachim; Adaramola, Muyiwa S.; Sætran, Lars; Hölling, Michael

2017-05-01

In this wind tunnel campaign, detailed wake measurements behind two different model wind turbines in yawed conditions were performed. The wake deflections were quantified by estimating the rotor-averaged available power within the wake. By using two different model wind turbines, the influence of the rotor design and turbine geometry on the wake deflection caused by a yaw misalignment of 30° could be judged. It was found that the wake deflections three rotor diameters downstream were equal while at six rotor diameters downstream insignificant differences were observed. The results compare well with previous experimental and numerical studies.

NREL Software Aids Offshore Wind Turbine Designs (Fact Sheet)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2013-10-01

NREL researchers are supporting offshore wind power development with computer models that allow detailed analyses of both fixed and floating offshore wind turbines. While existing computer-aided engineering (CAE) models can simulate the conditions and stresses that a land-based wind turbine experiences over its lifetime, offshore turbines require the additional considerations of variations in water depth, soil type, and wind and wave severity, which also necessitate the use of a variety of support-structure types. NREL's core wind CAE tool, FAST, models the additional effects of incident waves, sea currents, and the foundation dynamics of the support structures.

40 CFR 63.9983 - Are any EGUs not subject to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

..., recirculated flue gases or exhaust gases from other sources (such as stationary gas turbines, internal... subject to this subpart. (a) Any unit designated as a stationary combustion turbine, other than an... utility steam generating unit that is not a coal- or oil-fired EGU and combusts natural gas for more than...

40 CFR 63.9983 - Are any EGUs not subject to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

..., recirculated flue gases or exhaust gases from other sources (such as stationary gas turbines, internal... subject to this subpart. (a) Any unit designated as a stationary combustion turbine, other than an... utility steam generating unit that is not a coal- or oil-fired EGU and combusts natural gas for more than...

40 CFR 63.9983 - Are any EGUs not subject to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

..., recirculated flue gases or exhaust gases from other sources (such as stationary gas turbines, internal... subject to this subpart. (a) Any unit designated as a stationary combustion turbine, other than an... utility steam generating unit that is not a coal- or oil-fired EGU and combusts natural gas for more than...

14 CFR 121.360 - Ground proximity warning-glide slope deviation alerting system.

Code of Federal Regulations, 2010 CFR

2010-01-01

... person may operate a turbine-powered airplane unless it is equipped with a ground proximity warning... system incorporates a Mode 4 flap warning inhibition control; and (2) An outline of all input sources... turbine-powered airplane unless it is equipped with a ground proximity warning/glide slope deviation...

14 CFR 121.360 - Ground proximity warning-glide slope deviation alerting system.

Code of Federal Regulations, 2011 CFR

2011-01-01

... person may operate a turbine-powered airplane unless it is equipped with a ground proximity warning... system incorporates a Mode 4 flap warning inhibition control; and (2) An outline of all input sources... turbine-powered airplane unless it is equipped with a ground proximity warning/glide slope deviation...

Real-time neutron imaging of gas turbines

NASA Astrophysics Data System (ADS)

Stewart, P. A. E.

1987-06-01

The current status of real-time neutron radiography imaging is briefly reviewed, and results of tests carried out on cold neutron sources are reported. In particular, attention is given to demonstrations of neutron radiography on a running gas turbine engine. The future role of real-time neutron imaging in engineering diagnostics is briefly discussed.

Ambient air cooling arrangement having a pre-swirler for gas turbine engine blade cooling

DOEpatents

Lee, Ching-Pang; Tham, Kok-Mun; Schroeder, Eric; Meeroff, Jamie; Miller, Jr., Samuel R; Marra, John J

2015-01-06

A gas turbine engine including: an ambient-air cooling circuit (10) having a cooling channel (26) disposed in a turbine blade (22) and in fluid communication with a source (12) of ambient air: and an pre-swirler (18), the pre-swirler having: an inner shroud (38); an outer shroud (56); and a plurality of guide vanes (42), each spanning from the inner shroud to the outer shroud. Circumferentially adjacent guide vanes (46, 48) define respective nozzles (44) there between. Forces created by a rotation of the turbine blade motivate ambient air through the cooling circuit. The pre-swirler is configured to impart swirl to ambient air drawn through the nozzles and to direct the swirled ambient air toward a base of the turbine blade. The end walls (50, 54) of the pre-swirler may be contoured.

Blade Surface Pressure Distributions in a Rocket Engine Turbine: Experimental Work With On-Blade Pressure Transducers

NASA Technical Reports Server (NTRS)

Hudson, Susan T.; Zoladz, Thomas F.; Griffin, Lisa W.; Turner, James E. (Technical Monitor)

2000-01-01

Understanding the unsteady aspects of turbine rotor flowfields is critical to successful future turbine designs. A technology program was conducted at NASA's Marshall Space Flight Center to increase the understanding of unsteady environments for rocket engine turbines. The experimental program involved instrumenting turbine rotor blades with surface-mounted high frequency response pressure transducers. The turbine model was then tested to measure the unsteady pressures on the rotor blades. The data obtained from the experimental program is unique in three respects. First, much more unsteady data was obtained (several minutes per set point) than has been possible in the past. Also, two independent unsteady data acquisition systems and fundamental signal processing approaches were used. Finally, an extensive steady performance database existed for the turbine model. This allowed an evaluation of the effect of the on-blade instrumentation on the turbine's performance. This unique data set, the lessons learned for acquiring this type of data, and the improvements made to the data analysis and prediction tools will contribute to future turbine programs such as those for reusable launch vehicles.

Materials for Wind Turbine Blades: An Overview.

PubMed

Mishnaevsky, Leon; Branner, Kim; Petersen, Helga Nørgaard; Beauson, Justine; McGugan, Malcolm; Sørensen, Bent F

2017-11-09

A short overview of composite materials for wind turbine applications is presented here. Requirements toward the wind turbine materials, loads, as well as available materials are reviewed. Apart from the traditional composites for wind turbine blades (glass fibers/epoxy matrix composites), natural composites, hybrid and nanoengineered composites are discussed. Manufacturing technologies for wind turbine composites, as well their testing and modelling approaches are reviewed.

Numerical investigation of flow motion and performance of a horizontal axis tidal turbine subjected to a steady current

NASA Astrophysics Data System (ADS)

Li, Lin-juan; Zheng, Jin-hai; Peng, Yu-xuan; Zhang, Ji-sheng; Wu, Xiu-guang

2015-04-01

Horizontal axis tidal turbines have attracted more and more attentions nowadays, because of their convenience and low expense in construction and high efficiency in extracting tidal energy. The present study numerically investigates the flow motion and performance of a horizontal axis tidal turbine with a supporting vertical cylinder under steady current. In the numerical model, the continuous equation and incompressible Reynolds-averaged Navier-Stokes equations are solved, and the volume of fluid method is employed to track free surface motion. The RNG k- ɛ model is adopted to calculate turbulence transport while the fractional area/volume obstacle representation method is used to describe turbine characteristics and movement. The effects of installation elevation of tidal turbine and inlet velocity on the water elevation, and current velocity, rotating speed and resultant force on turbine are discussed. Based on the comparison of the numerical results, a better understanding of flow structure around horizontal axis tidal turbine and turbine performance is achieved.

Reduction of gas flow nonuniformity in gas turbine engines by means of gas-dynamic methods

NASA Astrophysics Data System (ADS)

Matveev, V.; Baturin, O.; Kolmakova, D.; Popov, G.

2017-08-01

Gas flow nonuniformity is one of the main sources of rotor blade vibrations in the gas turbine engines. Usually, the flow circumferential nonuniformity occurs near the annular frames, located in the flow channel of the engine. This leads to the increased dynamic stresses in blades and as a consequence to the blade damage. The goal of the research was to find an acceptable method of reducing the level of gas flow nonuniformity as the source of dynamic stresses in the rotor blades. Two different methods were investigated during this research. Thus, this study gives the ideas about methods of improving the flow structure in gas turbine engine. On the basis of existing conditions (under development or existing engine) it allows the selection of the most suitable method for reducing gas flow nonuniformity.

Radar-cross-section reduction of wind turbines. part 1.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brock, Billy C.; Loui, Hung; McDonald, Jacob J.

2012-03-05

In recent years, increasing deployment of large wind-turbine farms has become an issue of growing concern for the radar community. The large radar cross section (RCS) presented by wind turbines interferes with radar operation, and the Doppler shift caused by blade rotation causes problems identifying and tracking moving targets. Each new wind-turbine farm installation must be carefully evaluated for potential disruption of radar operation for air defense, air traffic control, weather sensing, and other applications. Several approaches currently exist to minimize conflict between wind-turbine farms and radar installations, including procedural adjustments, radar upgrades, and proper choice of low-impact wind-farm sites,more » but each has problems with limited effectiveness or prohibitive cost. An alternative approach, heretofore not technically feasible, is to reduce the RCS of wind turbines to the extent that they can be installed near existing radar installations. This report summarizes efforts to reduce wind-turbine RCS, with a particular emphasis on the blades. The report begins with a survey of the wind-turbine RCS-reduction literature to establish a baseline for comparison. The following topics are then addressed: electromagnetic model development and validation, novel material development, integration into wind-turbine fabrication processes, integrated-absorber design, and wind-turbine RCS modeling. Related topics of interest, including alternative mitigation techniques (procedural, at-the-radar, etc.), an introduction to RCS and electromagnetic scattering, and RCS-reduction modeling techniques, can be found in a previous report.« less

Collecting Currents with Water Turbines

NASA Astrophysics Data System (ADS)

Allen, J.; Allen, S.

2017-12-01

Our science poster is inspired by Florida Atlantic University's recent program to develop three types of renewable energy. They are using water turbines and the Gulf Stream Current to produce a renewable energy source. Wave, tidal and current driven energy. Our poster is called "Collecting Currents with Water Turbines". In our science poster, the purpose was to see which turbine design could produce the most power. We tested three different variables, the number of blades (four, six, and eight), the material of the blades and the shape of the blades. To test which number of blades produced the most power we cut slits into a cork. We used plastic from a soda bottle to make the blades and then we put the blades in the cork to make the turbines. We observed each blade and how much time it took for the water turbines to pull up 5 pennies. Currently water turbines are used in dams to make hydroelectric energy. But with FAU we could understand how to harness the Gulf Stream current off Florida's coast we could soon have new forms of renewable energy.

SOURCEBOOK: NOX CONTROL TECHNOLOGY DATA

EPA Science Inventory

The report, a compilation of available information on the control of nitrogen oxide (NOx) emissions from stationary sources, is provided to assist new source permitting activities by regulatory agencies. he sources covered are combustion turbines, internal combustion engines, non...

Augmented Adaptive Control of a Wind Turbine in the Presence of Structural Modes

NASA Technical Reports Server (NTRS)

Frost, Susan A.; Balas, Mark J.; Wright, Alan D.

2010-01-01

Wind turbines operate in highly turbulent environments resulting in aerodynamic loads that can easily excite turbine structural modes, potentially causing component fatigue and failure. Two key technology drivers for turbine manufacturers are increasing turbine up time and reducing maintenance costs. Since the trend in wind turbine design is towards larger, more flexible turbines with lower frequency structural modes, manufacturers will want to develop methods to operate in the presence of these modes. Accurate models of the dynamic characteristics of new wind turbines are often not available due to the complexity and expense of the modeling task, making wind turbines ideally suited to adaptive control. In this paper, we develop theory for adaptive control with rejection of disturbances in the presence of modes that inhibit the controller. We use this method to design an adaptive collective pitch controller for a high-fidelity simulation of a utility-scale, variable-speed wind turbine operating in Region 3. The objective of the adaptive pitch controller is to regulate generator speed, accommodate wind gusts, and reduce the interference of certain structural modes in feedback. The control objective is accomplished by collectively pitching the turbine blades. The adaptive pitch controller for Region 3 is compared in simulations with a baseline classical Proportional Integrator (PI) collective pitch controller.

3D Lagrangian VPM: simulations of the near-wake of an actuator disc and horizontal axis wind turbine

NASA Astrophysics Data System (ADS)

Berdowski, T.; Ferreira, C.; Walther, J.

2016-09-01

The application of a 3-dimensional Lagrangian vortex particle method has been assessed for modelling the near-wake of an axisymmetrical actuator disc and 3-bladed horizontal axis wind turbine with prescribed circulation from the MEXICO (Model EXperiments In COntrolled conditions) experiment. The method was developed in the framework of the open- source Parallel Particle-Mesh library for handling the efficient data-parallelism on a CPU (Central Processing Unit) cluster, and utilized a O(N log N)-type fast multipole method for computational acceleration. Simulations with the actuator disc resulted in a wake expansion, velocity deficit profile, and induction factor that showed a close agreement with theoretical, numerical, and experimental results from literature. Also the shear layer expansion was present; the Kelvin-Helmholtz instability in the shear layer was triggered due to the round-off limitations of a numerical method, but this instability was delayed to beyond 1 diameter downstream due to the particle smoothing. Simulations with the 3-bladed turbine demonstrated that a purely 3-dimensional flow representation is challenging to model with particles. The manifestation of local complex flow structures of highly stretched vortices made the simulation unstable, but this was successfully counteracted by the application of a particle strength exchange scheme. The axial and radial velocity profile over the near wake have been compared to that of the original MEXICO experiment, which showed close agreement between results.

Gas Dynamic Modernization of Axial Uncooled Turbine by Means of CFD and Optimization Software

NASA Astrophysics Data System (ADS)

Marchukov, E. Yu; Egorov, I. N.

2018-01-01

The results of multicriteria optimization of three-stage low-pressure turbine are described in the paper. The aim of the optimization is to improve turbine operation process by three criteria: turbine outlet flow angle, value of residual swirl at the turbine outlet, and turbine efficiency. Full reprofiling of all blade rows is carried out while solving optimization problem. Reprofiling includes a change in both shape of flat blade sections (profiles) and three-dimensional shape of the blades. The study is carried out with 3D numerical models of turbines.

An improved computer model for prediction of axial gas turbine performance losses

NASA Technical Reports Server (NTRS)

Jenkins, R. M.

1984-01-01

The calculation model performs a rapid preliminary pitchline optimization of axial gas turbine annular flowpath geometry, as well as an initial estimate of blade profile shapes, given only a minimum of thermodynamic cycle requirements. No geometric parameters need be specified. The following preliminary design data are determined: (1) the optimum flowpath geometry, within mechanical stress limits; (2) initial estimates of cascade blade shapes; and (3) predictions of expected turbine performance. The model uses an inverse calculation technique whereby blade profiles are generated by designing channels to yield a specified velocity distribution on the two walls. Velocity distributions are then used to calculate the cascade loss parameters. Calculated blade shapes are used primarily to determine whether the assumed velocity loadings are physically realistic. Model verification is accomplished by comparison of predicted turbine geometry and performance with an array of seven NASA single-stage axial gas turbine configurations.

Nonlinear modeling and dynamic analysis of a hydro-turbine governing system in the process of sudden load increase transient

NASA Astrophysics Data System (ADS)

Li, Huanhuan; Chen, Diyi; Zhang, Hao; Wang, Feifei; Ba, Duoduo

2016-12-01

In order to study the nonlinear dynamic behaviors of a hydro-turbine governing system in the process of sudden load increase transient, we establish a novel nonlinear dynamic model of the hydro-turbine governing system which considers the elastic water-hammer model of the penstock and the second-order model of the generator. The six nonlinear dynamic transfer coefficients of the hydro-turbine are innovatively proposed by utilizing internal characteristics and analyzing the change laws of the characteristic parameters of the hydro-turbine governing system. Moreover, from the point of view of engineering, the nonlinear dynamic behaviors of the above system are exhaustively investigated based on bifurcation diagrams and time waveforms. More importantly, all of the above analyses supply theoretical basis for allowing a hydropower station to maintain a stable operation in the process of sudden load increase transient.

Optimization of CCGT power plant and performance analysis using MATLAB/Simulink with actual operational data.

PubMed

Hasan, Naimul; Rai, Jitendra Nath; Arora, Bharat Bhushan

2014-01-01

In the Modern scenario, the naturally available resources for power generation are being depleted at an alarming rate; firstly due to wastage of power at consumer end, secondly due to inefficiency of various power system components. A Combined Cycle Gas Turbine (CCGT) integrates two cycles- Brayton cycle (Gas Turbine) and Rankine cycle (Steam Turbine) with the objective of increasing overall plant efficiency. This is accomplished by utilising the exhaust of Gas Turbine through a waste-heat recovery boiler to run a Steam Turbine. The efficiency of a gas turbine which ranges from 28% to 33% can hence be raised to about 60% by recovering some of the low grade thermal energy from the exhaust gas for steam turbine process. This paper is a study for the modelling of CCGT and comparing it with actual operational data. The performance model for CCGT plant was developed in MATLAB/Simulink.

Analysis of S Characteristics and Pressure Pulsations in a Pump-Turbine With Misaligned Guide Vanes.

PubMed

Sun, Hui; Xiao, Ruofu; Liu, Weichao; Wang, Fujun

2013-05-01

Growing environmental concerns and the need for better power balancing and frequency control have increased attention in renewable energy sources such as the reversible pump-turbine which can provide both power generation and energy storage. Pump-turbine operation along the S-shaped curve can lead to difficulties in loading the rejection process with unusual increases in water pressure, which lead to machine vibrations. Pressure fluctuations are the primary reason for unstable operation of pump-turbines. Misaligned guide vanes (MGVs) are widely used to control the stability in the S region. There have been experimental investigations and computational fluid dynamics (CFD) simulations of scale models with aligned guide vanes and MGVs with spectral analyses of the S curve characteristics and the pressure pulsations in the frequency and time-frequency domains at runaway conditions. The course of the S characteristic is related to the centrifugal force and the large incident angle at low flow conditions with large vortices forming between the guide vanes and the blade inlets and strong flow recirculation inside the vaneless space as the main factors that lead to the S-shaped characteristics. Preopening some of the guide vanes enables the pump-turbine to avoid the influence of the S characteristic. However, the increase of the flow during runaway destroys the flow symmetry in the runner leading to all asymmetry forces on the runner that leads to hydraulic system oscillations. The MGV technique also increases the pressure fluctuations in the draft tube and has a negative impact on stable operation of the unit.

Specific features of the flow structure in a reactive type turbine stage

NASA Astrophysics Data System (ADS)

Chernikov, V. A.; Semakina, E. Yu.

2017-04-01

The results of experimental studies of the gas dynamics for a reactive type turbine stage are presented. The objective of the studies is the measurement of the 3D flow fields in reference cross sections, experimental determination of the stage characteristics, and analysis of the flow structure for detecting the sources of kinetic energy losses. The integral characteristics of the studied stage are obtained by averaging the results of traversing the 3D flow over the area of the reference cross sections before and behind the stage. The averaging is performed using the conservation equations for mass, total energy flux, angular momentum with respect to the axis z of the turbine, entropy flow, and the radial projection of the momentum flux equation. The flow parameter distributions along the channel height behind the stage are obtained in the same way. More thorough analysis of the flow structure is performed after interpolation of the experimentally measured point parameter values and 3D flow velocities behind the stage. The obtained continuous velocity distributions in the absolute and relative coordinate systems are presented in the form of vector fields. The coordinates of the centers and the vectors of secondary vortices are determined using the results of point measurements of velocity vectors in the cross section behind the turbine stage and their subsequent interpolation. The approach to analysis of experimental data on aerodynamics of the turbine stage applied in this study allows one to find the detailed space structure of the working medium flow, including secondary coherent vortices at the root and peripheral regions of the air-gas part of the stage. The measured 3D flow parameter fields and their interpolation, on the one hand, point to possible sources of increased power losses, and, on the other hand, may serve as the basis for detailed testing of CFD models of the flow using both integral and local characteristics. The comparison of the numerical and experimental results, as regards local characteristics, using statistical methods yields the quantitative estimate of their agreement.

Design of LPV fault-tolerant controller for pitch system of wind turbine

NASA Astrophysics Data System (ADS)

Wu, Dinghui; Zhang, Xiaolin

2017-07-01

To address failures of wind turbine pitch-angle sensors, traditional wind turbine linear parameter varying (LPV) model is transformed into a double-layer convex polyhedron LPV model. On the basis of this model, when the plurality of the sensor undergoes failure and details of the failure are inconvenient to obtain, each sub-controller is designed using distributed thought and gain scheduling method. The final controller is obtained using all of the sub-controllers by a convex combination. The design method corrects the errors of the linear model, improves the linear degree of the system, and solves the problem of multiple pitch angle faults to ensure stable operation of the wind turbine.

Turbine Powered Simulator Calibration and Testing for Hybrid Wing Body Powered Airframe Integration

NASA Technical Reports Server (NTRS)

Shea, Patrick R.; Flamm, Jeffrey D.; Long, Kurtis R.; James, Kevin D.; Tompkins, Daniel M.; Beyar, Michael D.

2016-01-01

Propulsion airframe integration testing on a 5.75% scale hybrid wing body model us- ing turbine powered simulators was completed at the National Full-Scale Aerodynamics Complex 40- by 80-foot test section. Four rear control surface con gurations including a no control surface de ection con guration were tested with the turbine powered simulator units to investigate how the jet exhaust in uenced the control surface performance as re- lated to the resultant forces and moments on the model. Compared to ow-through nacelle testing on the same hybrid wing body model, the control surface e ectiveness was found to increase with the turbine powered simulator units operating. This was true for pitching moment, lift, and drag although pitching moment was the parameter of greatest interest for this project. With the turbine powered simulator units operating, the model pitching moment was seen to increase when compared to the ow-through nacelle con guration indicating that the center elevon and vertical tail control authority increased with the jet exhaust from the turbine powered simulator units.

Modeling of the UAE Wind Turbine for Refinement of FAST{_}AD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jonkman, J. M.

The Unsteady Aerodynamics Experiment (UAE) research wind turbine was modeled both aerodynamically and structurally in the FAST{_}AD wind turbine design code, and its response to wind inflows was simulated for a sample of test cases. A study was conducted to determine why wind turbine load magnitude discrepancies-inconsistencies in aerodynamic force coefficients, rotor shaft torque, and out-of-plane bending moments at the blade root across a range of operating conditions-exist between load predictions made by FAST{_}AD and other modeling tools and measured loads taken from the actual UAE wind turbine during the NASA-Ames wind tunnel tests. The acquired experimental test data representmore » the finest, most accurate set of wind turbine aerodynamic and induced flow field data available today. A sample of the FAST{_}AD model input parameters most critical to the aerodynamics computations was also systematically perturbed to determine their effect on load and performance predictions. Attention was focused on the simpler upwind rotor configuration, zero yaw error test cases. Inconsistencies in input file parameters, such as aerodynamic performance characteristics, explain a noteworthy fraction of the load prediction discrepancies of the various modeling tools.« less

Predictive model for local scour downstream of hydrokinetic turbines in erodible channels

NASA Astrophysics Data System (ADS)

Musa, Mirko; Heisel, Michael; Guala, Michele

2018-02-01

A modeling framework is derived to predict the scour induced by marine hydrokinetic turbines installed on fluvial or tidal erodible bed surfaces. Following recent advances in bridge scour formulation, the phenomenological theory of turbulence is applied to describe the flow structures that dictate the equilibrium scour depth condition at the turbine base. Using scaling arguments, we link the turbine operating conditions to the flow structures and scour depth through the drag force exerted by the device on the flow. The resulting theoretical model predicts scour depth using dimensionless parameters and considers two potential scenarios depending on the proximity of the turbine rotor to the erodible bed. The model is validated at the laboratory scale with experimental data comprising the two sediment mobility regimes (clear water and live bed), different turbine configurations, hydraulic settings, bed material compositions, and migrating bedform types. The present work provides future developers of flow energy conversion technologies with a physics-based predictive formula for local scour depth beneficial to feasibility studies and anchoring system design. A potential prototype-scale deployment in a large sandy river is also considered with our model to quantify how the expected scour depth varies as a function of the flow discharge and rotor diameter.

Cycle of a closed gas-turbine plant with a gas-dynamic energy-separation device

NASA Astrophysics Data System (ADS)

Leontiev, A. I.; Burtsev, S. A.

2017-09-01

The efficiency of closed gas-turbine space-based plants is analyzed. The weight-size characteristics of closed gas-turbine plants are shown in many respects as determined by the refrigerator-radiator parameters. The scheme of closed gas-turbine plants with a gas-dynamic temperature-stratification device is proposed, and a calculation model is developed. This model shows that the cycle efficiency decreases by 2% in comparison with that of the closed gas-turbine plants operating by the traditional scheme with increasing temperature at the output from the refrigerator-radiator by 28 K and decreasing its area by 13.7%.

On controllability and system constraints of the linear models of proton exchange membrane and solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Radisavljevic, Verica

2011-10-01

In this paper we first show that the linear models of proton exchange membrane (polymer electrolyte membrane, PEM) and solid oxide (SO) fuel cells, commonly used in power and energy literature, are not controllable. The source of uncontrollability is the equation for pressure of the water vapor that is only affected by the fuel cell current, which in fact is a disturbance in this system and cannot be controlled by the given model inputs: inlet molar flow rates of hydrogen and oxygen. Being uncontrollable these models are not good candidates for studying control of dynamic processes in PEM and SO fuel cells. However, due to their simplicity, they can be used in hybrid configurations with other energy producing devices such as photovoltaic (solar) cells, wind turbine, micro gas turbine, battery (ultra capacitor) to demonstrate some other phenomena, but not for control purposes unless the hybrid models formed in such hybrid configurations are controllable. Testing controllability of such hybrid models is mandatory. Secondly, we introduce some algebraic constraints that follow from the model dynamics and the Nernst open-loop fuel cell voltage formula. These constraints must be satisfied in simulation of considered fuel cell modes, for example, via MATLAB/Simulink or any other computer software package.

Improved reliability of wind turbine towers with active tuned mass dampers (ATMDs)

NASA Astrophysics Data System (ADS)

Fitzgerald, Breiffni; Sarkar, Saptarshi; Staino, Andrea

2018-04-01

Modern multi-megawatt wind turbines are composed of slender, flexible, and lightly damped blades and towers. These components exhibit high susceptibility to wind-induced vibrations. As the size, flexibility and cost of the towers have increased in recent years, the need to protect these structures against damage induced by turbulent aerodynamic loading has become apparent. This paper combines structural dynamic models and probabilistic assessment tools to demonstrate improvements in structural reliability when modern wind turbine towers are equipped with active tuned mass dampers (ATMDs). This study proposes a multi-modal wind turbine model for wind turbine control design and analysis. This study incorporates an ATMD into the tower of this model. The model is subjected to stochastically generated wind loads of varying speeds to develop wind-induced probabilistic demand models for towers of modern multi-megawatt wind turbines under structural uncertainty. Numerical simulations have been carried out to ascertain the effectiveness of the active control system to improve the structural performance of the wind turbine and its reliability. The study constructs fragility curves, which illustrate reductions in the vulnerability of towers to wind loading owing to the inclusion of the damper. Results show that the active controller is successful in increasing the reliability of the tower responses. According to the analysis carried out in this paper, a strong reduction of the probability of exceeding a given displacement at the rated wind speed has been observed.

Development of a 5 MW reference gearbox for offshore wind turbines: 5 MW reference gearbox

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nejad, Amir Rasekhi; Guo, Yi; Gao, Zhen

2015-07-27

This paper presents detailed descriptions, modeling parameters and technical data of a 5MW high-speed gearbox developed for the National Renewable Energy Laboratory offshore 5MW baseline wind turbine. The main aim of this paper is to support the concept studies and research for large offshore wind turbines by providing a baseline gearbox model with detailed modeling parameters. This baseline gearbox follows the most conventional design types of those used in wind turbines. It is based on the four-point supports: two main bearings and two torque arms. The gearbox consists of three stages: two planetary and one parallel stage gears. The gearmore » ratios among the stages are calculated in a way to obtain the minimum gearbox weight. The gearbox components are designed and selected based on the offshore wind turbine design codes and validated by comparison to the data available from large offshore wind turbine prototypes. All parameters required to establish the dynamic model of the gearbox are then provided. Moreover, a maintenance map indicating components with high to low probability of failure is shown. The 5 MW reference gearbox can be used as a baseline for research on wind turbine gearboxes and comparison studies. It can also be employed in global analysis tools to represent a more realistic model of a gearbox in a coupled analysis.« less

Predicted Turbine Heat Transfer for a Range of Test Conditions

NASA Technical Reports Server (NTRS)

Boyle, R. J.; Lucci, B. L.

1996-01-01

Comparisons are shown between predictions and experimental data for blade and endwall heat transfer. The comparisons of computational domain parisons are given for both vane and rotor geometries over an extensive range of Reynolds and Mach numbers. Comparisons are made with experimental data from a variety of sources. A number of turbulence models are available for predicting blade surface heat transfer, as well as aerodynamic performance. The results of an investigation to determine the turbulence model which gives the best agreement with experimental data over a wide range of test conditions are presented.

Small Wind Research Turbine: Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Corbus, D.; Meadors, M.

2005-10-01

The Small Wind Research Turbine (SWRT) project was initiated to provide reliable test data for model validation of furling wind turbines and to help understand small wind turbine loads. This report will familiarize the user with the scope of the SWRT test and support the use of these data. In addition to describing all the testing details and results, the report presents an analysis of the test data and compares the SWRT test data to simulation results from the FAST aeroelastic simulation model.

New airfoil sections for straight bladed turbine

NASA Astrophysics Data System (ADS)

Boumaza, B.

1987-07-01

A theoretical investigation of aerodynamic performance for vertical axis Darrieus wind turbine with new airfoils sections is carried out. The blade section aerodynamics characteristics are determined from turbomachines cascade model. The model is also adapted to the vertical Darrieus turbine for the performance prediction of the machine. In order to choose appropriate value of zero-lift-drag coefficient in calculation, an analytical expression is introduced as function of chord-radius ratio and Reynolds numbers. New airfoils sections are proposed and analyzed for straight-bladed turbine.

Aerodynamic potpourri

NASA Technical Reports Server (NTRS)

Wilson, R. E.

1981-01-01

Aerodynamic developments for vertical axis and horizontal axis wind turbines are given that relate to the performance and aerodynamic loading of these machines. Included are: (1) a fixed wake aerodynamic model of the Darrieus vertical axis wind turbine; (2) experimental results that suggest the existence of a laminar flow Darrieus vertical axis turbine; (3) a simple aerodynamic model for the turbulent windmill/vortex ring state of horizontal axis rotors; and (4) a yawing moment of a rigid hub horizontal axis wind turbine that is related to blade coning.

Industrial wind turbines and adverse health effects.

PubMed

Jeffery, Roy D; Krogh, Carmen M E; Horner, Brett

2014-01-01

Some people living in the environs of industrial wind turbines (IWTs) report experiencing adverse health and socioeconomic effects. This review considers the hypothesis that annoyance from audible IWTs is the cause of these adverse health effects. We searched PubMed and Google Scholar for articles published since 2000 that included the terms "wind turbine health," "wind turbine infrasound," "wind turbine annoyance," "noise annoyance" or "low frequency noise" in the title or abstract. Industrial wind turbines produce sound that is perceived to be more annoying than other sources of sound. Reported effects from exposure to IWTs are consistent with well-known stress effects from persistent unwanted sound. If placed too close to residents, IWTs can negatively affect the physical, mental and social well-being of people. There is sufficient evidence to support the conclusion that noise from audible IWTs is a potential cause of health effects. Inaudible low-frequency noise and infrasound from IWTs cannot be ruled out as plausible causes of health effects.

Advanced Issues of Wind Turbine Modelling and Control

NASA Astrophysics Data System (ADS)

Simani, Silvio

2015-11-01

The motivation for this paper comes from a real need to have an overview about the challenges of modelling and control for very demanding systems, such as wind turbine systems, which require reliability, availability, maintainability, and safety over power conversion efficiency. These issues have begun to stimulate research and development in the wide control community particularly for these installations that need a high degree of “sustainability”. Note that this topic represents a key point mainly for offshore wind turbines with very large rotors, since they are characterised by challenging modelling and control problems, as well as expensive and safety critical maintenance works. In this case, a clear conflict exists between ensuring a high degree of availability and reducing maintenance times, which affect the final energy cost. On the other hand, wind turbines have highly nonlinear dynamics, with a stochastic and uncontrollable driving force as input in the form of wind speed, thus representing an interesting challenge also from the modelling point of view. Suitable control methods can provide a sustainable optimisation of the energy conversion efficiency over wider than normally expected working conditions. Moreover, a proper mathematical description of the wind turbine system should be able to capture the complete behaviour of the process under monitoring, thus providing an important impact on the control design itself. In this way, the control scheme could guarantee prescribed performance, whilst also giving a degree of “tolerance” to possible deviation of characteristic properties or system parameters from standard conditions, if properly included in the wind turbine model itself. The most important developments in advanced controllers for wind turbines are addressed, and open problems in the areas of modelling of wind turbines are also outlined.

Compressor and Turbine Models of Brayton Units for Space Nuclear Power Systems

NASA Astrophysics Data System (ADS)

Gallo, Bruno M.; El-Genk, Mohamed S.; Tournier, Jean-Michel

2007-01-01

Closed Brayton Cycles with centrifugal flow, single-shaft turbo-machines are being considered, with gas cooled nuclear reactors, to provide 10's to 100's of electrical power to support future space exploration missions and Lunar and Mars outposts. Such power system analysis is typically based on the cycle thermodynamics, for given operating pressures and temperatures and assumed polytropic efficiencies of the compressor and turbine of the Brayton energy conversion units. Thus the analysis results not suitable for modeling operation transients such as startup and changes in the electric load. To simulate these transients, accurate models of the turbine and compressor in the Brayton rotating unit, which calculate the changes in the compressor and turbine efficiencies with system operation are needed. This paper presents flow models that account for the design and dimensions of the compressor impeller and diffuser, and the turbine stator and rotor blades. These models calculate the various enthalpy losses and the polytropic efficiencies along with the pressure ratios of the turbine and compressor. The predictions of these models compare well with reported performance data of actual hardware. In addition, the results of a parametric analysis to map the operations of the compressor and turbine, as functions of the rotating shaft speed and inlet Mach number of the gas working fluid, are presented and discussed. The analysis used a binary mixture of He-Xe with a molecular weight of 40 g/mole as the working fluid.

Large HAWT wake measurement and analysis

NASA Technical Reports Server (NTRS)

Miller, A. H.; Wegley, H. L.; Buck, J. W.

1995-01-01

From the theoretical fluid dynamics point of view, the wake region of a large horizontal-axis wind turbine has been defined and described, and numerical models of wake behavior have been developed. Wind tunnel studies of single turbine wakes and turbine array wakes have been used to verify the theory and further refine the numerical models. However, the effects of scaling, rotor solidity, and topography on wake behavior are questions that remain unanswered. In the wind tunnel studies, turbines were represented by anything from scaled models to tea strainers or wire mesh disks whose solidity was equivalent to that of a typical wind turbine. The scale factor compensation for the difference in Reynolds number between the scale model and an actual turbine is complex, and not typically accounted for. Though it is wise to study the simpler case of wakes in flat topography, which can be easily duplicated in the wind tunnel, current indications are that wind turbine farm development is actually occurring in somewhat more complex terrain. Empirical wake studies using large horizontal-axis wind turbines have not been thoroughly composited, and, therefore, the results have not been applied to the well-developed theory of wake structure. The measurement programs have made use of both in situ sensor systems, such as instrumented towers, and remote sensors, such as kites and tethered, balloonborne anemometers. We present a concise overview of the work that has been performed, including our own, which is based on the philosophy that the MOD-2 turbines are probably their own best detector of both the momentum deficit and the induced turbulence effect downwind. Only the momentum deficit aspects of the wake/machine interactions have been addressed. Both turbine power output deficits and wind energy deficits as measured by the onsite meteorological towers have been analyzed from a composite data set. The analysis has also evidenced certain topographic influences on the operation of spatially diverse wind turbines.

Large HAWT wake measurement and analysis

NASA Astrophysics Data System (ADS)

Miller, A. H.; Wegley, H. L.; Buck, J. W.

1995-05-01

From the theoretical fluid dynamics point of view, the wake region of a large horizontal-axis wind turbine has been defined and described, and numerical models of wake behavior have been developed. Wind tunnel studies of single turbine wakes and turbine array wakes have been used to verify the theory and further refine the numerical models. However, the effects of scaling, rotor solidity, and topography on wake behavior are questions that remain unanswered. In the wind tunnel studies, turbines were represented by anything from scaled models to tea strainers or wire mesh disks whose solidity was equivalent to that of a typical wind turbine. The scale factor compensation for the difference in Reynolds number between the scale model and an actual turbine is complex, and not typically accounted for. Though it is wise to study the simpler case of wakes in flat topography, which can be easily duplicated in the wind tunnel, current indications are that wind turbine farm development is actually occurring in somewhat more complex terrain. Empirical wake studies using large horizontal-axis wind turbines have not been thoroughly composited, and, therefore, the results have not been applied to the well-developed theory of wake structure. The measurement programs have made use of both in situ sensor systems, such as instrumented towers, and remote sensors, such as kites and tethered, balloonborne anemometers. We present a concise overview of the work that has been performed, including our own, which is based on the philosophy that the MOD-2 turbines are probably their own best detector of both the momentum deficit and the induced turbulence effect downwind. Only the momentum deficit aspects of the wake/machine interactions have been addressed. Both turbine power output deficits and wind energy deficits as measured by the onsite meteorological towers have been analyzed from a composite data set. The analysis has also evidenced certain topographic influences on the operation of spatially diverse wind turbines.

A comparative study of various inflow boundary conditions and turbulence models for wind turbine wake predictions

NASA Astrophysics Data System (ADS)

Tian, Lin-Lin; Zhao, Ning; Song, Yi-Lei; Zhu, Chun-Ling

2018-05-01

This work is devoted to perform systematic sensitivity analysis of different turbulence models and various inflow boundary conditions in predicting the wake flow behind a horizontal axis wind turbine represented by an actuator disc (AD). The tested turbulence models are the standard k-𝜀 model and the Reynolds Stress Model (RSM). A single wind turbine immersed in both uniform flows and in modeled atmospheric boundary layer (ABL) flows is studied. Simulation results are validated against the field experimental data in terms of wake velocity and turbulence intensity.

Numerical investigation of interactions between marine atmospheric boundary layer and offshore wind farm

NASA Astrophysics Data System (ADS)

Lyu, Pin; Chen, Wenli; Li, Hui; Shen, Lian

2017-11-01

In recent studies, Yang, Meneveau & Shen (Physics of Fluids, 2014; Renewable Energy, 2014) developed a hybrid numerical framework for simulation of offshore wind farm. The framework consists of simulation of nonlinear surface waves using a high-order spectral method, large-eddy simulation of wind turbulence on a wave-surface-fitted curvilinear grid, and an actuator disk model for wind turbines. In the present study, several more precise wind turbine models, including the actuator line model, actuator disk model with rotation, and nacelle model, are introduced into the computation. Besides offshore wind turbines on fixed piles, the new computational framework has the capability to investigate the interaction among wind, waves, and floating wind turbines. In this study, onshore, offshore fixed pile, and offshore floating wind farms are compared in terms of flow field statistics and wind turbine power extraction rate. The authors gratefully acknowledge financial support from China Scholarship Council (No. 201606120186) and the Institute on the Environment of University of Minnesota.

An LES study of vertical-axis wind turbine wakes aerodynamics

NASA Astrophysics Data System (ADS)

Abkar, Mahdi; Dabiri, John O.

2016-11-01

In this study, large-eddy simulation (LES) combined with a turbine model is used to investigate the structure of the wake behind a vertical-axis wind turbine (VAWT). In the simulations, a recently developed minimum dissipation model is used to parameterize the subgrid-scale stress tensor, while the turbine-induced forces are modeled with an actuator-line technique. The LES framework is first tested in the simulation of the wake behind a model straight-bladed VAWT placed in the water channel, and then used to study the wake structure downwind of a full-scale VAWT sited in the atmospheric boundary layer. In particular, the self-similarity of the wake is examined, and it is found that the wake velocity deficit is well characterized by a two-dimensional elliptical Gaussian distribution. By assuming a self-similar Gaussian distribution of the velocity deficit, and applying mass and momentum conservation, an analytical model is developed and tested to predict the maximum velocity deficit downwind of the turbine.

Water Injected Turbomachinery

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Shouse, D. T.; Roquemore, W. M.

2005-01-01

From antiquity, water has been a source of cooling, lubrication, and power for energy transfer devices. More recent applications in gas turbines demonstrate an added facet, emissions control. Fogging gas turbine inlets or direct injection of water into gas turbine combustors, decreases NOx and increases power. Herein we demonstrate that injection of water into the air upstream of the combustor reduces NOx by factors up to three in a natural gas fueled Trapped Vortex Combustor (TVC) and up to two in a liquid JP-8 fueled (TVC) for a range in water/fuel and fuel/air ratios.

Spectral Discrete Probability Density Function of Measured Wind Turbine Noise in the Far Field

PubMed Central

Ashtiani, Payam; Denison, Adelaide

2015-01-01

Of interest is the spectral character of wind turbine noise at typical residential set-back distances. In this paper, a spectral statistical analysis has been applied to immission measurements conducted at three locations. This method provides discrete probability density functions for the Turbine ONLY component of the measured noise. This analysis is completed for one-third octave sound levels, at integer wind speeds, and is compared to existing metrics for measuring acoustic comfort as well as previous discussions on low-frequency noise sources. PMID:25905097

Wind turbine acoustics research bibliography with selected annotation

NASA Technical Reports Server (NTRS)

Hubbard, Harvey H.; Shepherd, Kevin P.

1988-01-01

Citations of documents are included, which represent the state-of-the-art of technology in each of the following acoustics subject areas: Prediction of Wind Turbine Noise; Acoustic Measurements for Wind Tunnels; Effect of Wind Turbine Noise on Building Structures, People and Communities; Atmospheric Propagation; and Measurement Technology Including Wind Screens. Documents are listed in chronological order in each section of the paper, with key documents and associated annotation listed first. The sources are given along with acquisition numbers, when available, to expedite the acquisition of copies of the documents.

Materials for Wind Turbine Blades: An Overview

PubMed Central

Branner, Kim; Petersen, Helga Nørgaard; Beauson, Justine; McGugan, Malcolm; Sørensen, Bent F.

2017-01-01

A short overview of composite materials for wind turbine applications is presented here. Requirements toward the wind turbine materials, loads, as well as available materials are reviewed. Apart from the traditional composites for wind turbine blades (glass fibers/epoxy matrix composites), natural composites, hybrid and nanoengineered composites are discussed. Manufacturing technologies for wind turbine composites, as well their testing and modelling approaches are reviewed. PMID:29120396

Computational modelling of an operational wind turbine and validation with LIDAR

NASA Astrophysics Data System (ADS)

Creech, Angus; Fruh, Wolf-Gerrit; Clive, Peter

2010-05-01

We present a computationally efficient method to model the interaction of wind turbines with the surrounding flow, where the interaction provides information on the power generation of the turbine and the generated wake behind the turbine. The turbine representation is based on the principle of an actuator volume, whereby the energy extraction and balancing forces on the fluids are formulated as body forces which avoids the extremely high computational costs of boundary conditions and forces. Depending on the turbine information available, those forces can be derived either from published turbine performance specifications or from their rotor and blade design. This turbine representation is then coupled to a Computational Fluid Dynamics package, in this case the hr-adaptive Finite-Element code Fluidity from Imperial College, London. Here we present a simulation of an operational 950kW NEG Micon NM54 wind turbine installed in the west of Scotland. The calculated wind is compared with LIDAR measurements using a Galion LIDAR from SgurrEnergy. The computational domain extends over an area of 6km by 6km and a height of 750m, centred on the turbine. The lower boundary includes the orography of the terrain and surface roughness values representing the vegetation - some forested areas and some grassland. The boundary conditions on the sides are relaxed Dirichlet conditions, relaxed to an observed prevailing wind speed and direction. Within instrumental errors and model limitations, the overall flow field in general and the wake behind the turbine in particular, show a very high degree of agreement, demonstrating the validity and value of this approach. The computational costs of this approach are such that it is possible to extend this single-turbine example to a full wind farm, as the number of required mesh nodes is given by the domain and then increases only linearly with the number of turbines

40 CFR 1042.670 - Special provisions for gas turbine engines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... AND VESSELS Special Compliance Provisions § 1042.670 Special provisions for gas turbine engines. The provisions of this section apply for gas turbine engines. (a) Implementation schedule. The requirements of this part do not apply for gas turbine engines below 600 kW before the 2014 model year. The...

40 CFR 1042.670 - Special provisions for gas turbine engines.

Code of Federal Regulations, 2011 CFR

2011-07-01

... AND VESSELS Special Compliance Provisions § 1042.670 Special provisions for gas turbine engines. The provisions of this section apply for gas turbine engines. (a) Implementation schedule. The requirements of this part do not apply for gas turbine engines below 600 kW before the 2014 model year. The...

Analysis of the pump-turbine S characteristics using the detached eddy simulation method

NASA Astrophysics Data System (ADS)

Sun, Hui; Xiao, Ruofu; Wang, Fujun; Xiao, Yexiang; Liu, Weichao

2015-01-01

Current research on pump-turbine units is focused on the unstable operation at off-design conditions, with the characteristic curves in generating mode being S-shaped. Unlike in the traditional water turbines, pump-turbine operation along the S-shaped curve can lead to difficulties during load rejection with unusual increases in the water pressure, which leads to machine vibrations. This paper describes both model tests and numerical simulations. A reduced scale model of a low specific speed pump-turbine was used for the performance tests, with comparisons to computational fluid dynamics(CFD) results. Predictions using the detached eddy simulation(DES) turbulence model, which is a combined Reynolds averaged Naviers-Stokes(RANS) and large eddy simulation(LES) model, are compared with the two-equation turbulence mode results. The external characteristics as well as the internal flow are for various guide vane openings to understand the unsteady flow along the so called S characteristics of a pump-turbine. Comparison of the experimental data with the CFD results for various conditions and times shows that DES model gives better agreement with experimental data than the two-equation turbulence model. For low flow conditions, the centrifugal forces and the large incident angle create large vortices between the guide vanes and the runner inlet in the runner passage, which is the main factor leading to the S-shaped characteristics. The turbulence model used here gives more accurate simulations of the internal flow characteristics of the pump-turbine and a more detailed force analysis which shows the mechanisms controlling of the S characteristics.

40 CFR 98.30 - Definition of the source category.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., boilers, simple and combined-cycle combustion turbines, engines, incinerators, and process heaters. (b... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING General Stationary Fuel Combustion Sources § 98.30 Definition...

Turbine Vane External Heat Transfer. Volume 2. Numerical Solutions of the Navier-stokes Equations for Two- and Three-dimensional Turbine Cascades with Heat Transfer

NASA Technical Reports Server (NTRS)

Yang, R. J.; Weinberg, B. C.; Shamroth, S. J.; Mcdonald, H.

1985-01-01

The application of the time-dependent ensemble-averaged Navier-Stokes equations to transonic turbine cascade flow fields was examined. In particular, efforts focused on an assessment of the procedure in conjunction with a suitable turbulence model to calculate steady turbine flow fields using an O-type coordinate system. Three cascade configurations were considered. Comparisons were made between the predicted and measured surface pressures and heat transfer distributions wherever available. In general, the pressure predictions were in good agreement with the data. Heat transfer calculations also showed good agreement when an empirical transition model was used. However, further work in the development of laminar-turbulent transitional models is indicated. The calculations showed most of the known features associated with turbine cascade flow fields. These results indicate the ability of the Navier-Stokes analysis to predict, in reasonable amounts of computation time, the surface pressure distribution, heat transfer rates, and viscous flow development for turbine cascades operating at realistic conditions.

A full three dimensional Navier-Stokes numerical simulation of flow field inside a power plant Kaplan turbine using some model test turbine hill chart points

NASA Astrophysics Data System (ADS)

Hosseinalipour, S. M.; Raja, A.; Hajikhani, S.

2012-06-01

A full three dimensional Navier - Stokes numerical simulation has been performed for performance analysis of a Kaplan turbine which is installed in one of the Irans south dams. No simplifications have been enforced in the simulation. The numerical results have been evaluated using some integral parameters such as the turbine efficiency via comparing the results with existing experimental data from the prototype Hill chart. In part of this study the numerical simulations were performed in order to calculate the prototype turbine efficiencies in some specific points which comes from the scaling up of the model efficiency that are available in the model experimental Hill chart. The results are very promising which shows the good ability of the numerical techniques for resolving the flow characteristics in these kind of complex geometries. A parametric study regarding the evaluation of turbine performance in three different runner angles of the prototype is also performed and the results are cited in this paper.

Hydraulic development of high specific-speed pump-turbines by means of an inverse design method, numerical flow-simulation (CFD) and model testing

NASA Astrophysics Data System (ADS)

Kerschberger, P.; Gehrer, A.

2010-08-01

In recent years an increased interest in pump-turbines has been recognized in the market. The rapid availability of pumped storage schemes and the benefits to the power system by peak lopping, providing reserve and rapid response for frequency control are becoming of growing advantage. In that context it is requested to develop pump-turbines that reliably stand dynamic operation modes, fast changes of the discharge rate by adjusting the variable diffuser vanes as well as fast changes from pump to turbine operation. Within the present study various flow patterns linked to the operation of a pump-turbine system are discussed. In that context pump and turbine mode are presented separately and different load cases at both operation modes are shown. In order to achieve modern, competitive pump-turbine designs it is further explained which design challenges should be considered during the geometry definition of a pump-turbine impeller. Within the present study a runner-blade profile for a low head pump-turbine has been developed. For the initial hydraulic runner-blade design, an inverse design method has been applied. Within this design procedure, a first blade geometry is generated by imposing the pressure loading-distribution and by means of an inverse 3D potential-flow-solution. The hydraulic behavior of both, pump-mode and turbine-mode is then evaluated by solving the full 3D Navier-Stokes equations in combination with a robust turbulence model. Based on this initial design the blade profile has been further optimized and redesigned considering various hydraulic pump-turbine requirements. Finally, the progress in hydraulic design is demonstrated by model test results which show a significant improvement in hydraulic performance compared to an existing reference design.

Numerical Modeling of Hydrokinetic Turbines and their Environmental Effects

NASA Astrophysics Data System (ADS)

Javaherchi, T.; Seydel, J.; Aliseda, A.

2010-12-01

The search for predictable renewable energy has led research into marine hydrokinetic energy. Electricity can be generated from tidally-induced currents through turbines located in regions of high current speed and relatively low secondary flow intensity. Although significant technological challenges exist, the main obstacle in the development and commercial deployment of marine hydrokinetic (MHK) turbines is the uncertainty in the environmental effect of devices. The velocity deficit in the turbulent wake of the turbine might enhance the sedimentation process of suspended particles in the water column and lead to deposition into artificial patterns that alter the benthic ecosystem. Pressure fluctuations across turbine blades and in blade tip vortices can damage internal organs of marine species as they swim through the device. These are just a few examples of the important potential environmental effects of MHK turbines that need to be addressed and investigated a priori before pilot and large scale deployment. We have developed a hierarchy of numerical models to simulate the turbulent wake behind a well characterized two bladed turbine. The results from these models (Sliding Mesh, Rotating Reference Frame, Virtual Blade Model and Actuator Disk Model) have been validated and are been used to investigate the efficiency and physical changes introduced in the environment by single or multiple MHK turbines. We will present results from sedimenting particles and model juvenile fish, with relative densities of 1.2 and 0.95, respectively. The settling velocity and terminal location on the bottom of the tidal channel is computed and compared to the simulated flow in a channel without turbines. We have observed an enhanced sedimentation, and we will quantify the degree of enhancement and the parameter range within which it is significant. For the slightly buoyant particles representing fish, the pressure history is studied statistically with particular attention to the high magnitudes of pressure fluctuation occurring over short periods of time. These high impulse conditions are correlated with damage thresholds obtained from laboratory experiments in the literature. *Supported by DOE through the National Northwest Marine Renewable Energy Center Top view of the channel with turbine hub located at (0,0). Particle sedimentation is enhanced closer to the turbine location and effect of hub can be seen at the end of the channel.

Enhancing BEM simulations of a stalled wind turbine using a 3D correction model

NASA Astrophysics Data System (ADS)

Bangga, Galih; Hutomo, Go; Syawitri, Taurista; Kusumadewi, Tri; Oktavia, Winda; Sabila, Ahmad; Setiadi, Herlambang; Faisal, Muhamad; Hendranata, Yongki; Lastomo, Dwi; Putra, Louis; Kristiadi, Stefanus; Bumi, Ilmi

2018-03-01

Nowadays wind turbine rotors are usually employed with pitch control mechanisms to avoid deep stall conditions. Despite that, wind turbines often operate under pitch fault situation causing massive flow separation to occur. Pure Blade Element Momentum (BEM) approaches are not designed for this situation and inaccurate load predictions are already expected. In the present studies, BEM predictions are improved through the inclusion of a stall delay model for a wind turbine rotor operating under pitch fault situation of -2.3° towards stall. The accuracy of the stall delay model is assessed by comparing the results with available Computational Fluid Dynamics (CFD) simulations data.

Aeronautical Engineering. A Continuing Bibliography with Indexes

DTIC Science & Technology

1987-09-01

engines 482 01 AERONAUTICS (GENERAL) i-10 aircraft equipped with turbine engine ...rate adaptive control with applications to lateral Statistics on aircraft gas turbine engine rotor failures Unified model for the calculation of blade ...PUMPS p 527 A87-35669 to test data for a composite prop-tan model Gas turbine combustor and engine augmentor tube GENERAL AVIATION AIRCRAFT

Wind turbine rotor simulation using the actuator disk and actuator line methods

NASA Astrophysics Data System (ADS)

Tzimas, M.; Prospathopoulos, J.

2016-09-01

The present paper focuses on wind turbine rotor modeling for loads and wake flow prediction. Two steady-state models based on the actuator disk approach are considered, using either a uniform thrust or a blade element momentum calculation of the wind turbine loads. A third model is based on the unsteady-state actuator line approach. Predictions are compared with measurements in wind tunnel experiments and in atmospheric environment and the capabilities and weaknesses of the different models are addressed.

75 FR 22439 - Advance Notice of Proposed Rulemaking on Lead Emissions From Piston-Engine Aircraft Using Leaded...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-28

... fuel that is used in commercial aircraft, most military aircraft, or other turbine-engine powered... largely converted to jet turbine-engine propelled aircraft. However, the use of avgas containing 4 grams... or group of sources are the sole or even the major part of an air pollution problem. Moreover...

Aquantis Ocean Current Turbine Development Project Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleming, Alex J.

2014-08-23

The Aquantis® Current Plane (“C-Plane”) technology developed by Dehlsen Associates, LLC (DA) and Aquantis, Inc. is an ocean current turbine designed to extract kinetic energy from ocean currents. The technology is capable of achieving competitively priced base-load, continuous, and reliable power generation from a source of renewable energy not before possible in this scale or form.

Simulation modelling for new gas turbine fuel controller creation.

NASA Astrophysics Data System (ADS)

Vendland, L. E.; Pribylov, V. G.; Borisov, Yu A.; Arzamastsev, M. A.; Kosoy, A. A.

2017-11-01

State of the art gas turbine fuel flow control systems are based on throttle principle. Major disadvantage of such systems is that they require high pressure fuel intake. Different approach to fuel flow control is to use regulating compressor. And for this approach because of controller and gas turbine interaction a specific regulating compressor is required. Difficulties emerge as early as the requirement definition stage. To define requirements for new object, his properties must be known. Simulation modelling helps to overcome these difficulties. At the requirement definition stage the most simplified mathematical model is used. Mathematical models will get more complex and detailed as we advance in planned work. If future adjusting of regulating compressor physical model to work with virtual gas turbine and physical control system is planned.

AN INVESTIGATION INTO THE MECHANICS OF SINGLE CRYSTAL TURBINE BLADES WITH A VIEW TOWARDS ENHANCING GAS TURBINE EFFICIENCY

DOE Office of Scientific and Technical Information (OSTI.GOV)

K.R. Rajagopal; I.J. Rao

The demand for increased efficiency of gas turbines used in power generation and aircraft applications has fueled research into advanced materials for gas turbine blades that can withstand higher temperatures in that they have excellent resistance to creep. The term ''Superalloys'' describes a group of alloys developed for applications that require high performance at elevated temperatures. Superalloys have a load bearing capacity up to 0.9 times their melting temperature. The objective of the investigation was to develop a thermodynamic model that can be used to describe the response of single crystal superalloys that takes into account the microstructure of themore » alloy within the context of a continuum model. Having developed the model, its efficacy was to be tested by corroborating the predictions of the model with available experimental data. Such a model was developed and it is implemented in the finite element software ABAQUS/STANDARD through a user subroutine (UMAT) so that the model can be used in realistic geometries that correspond to turbine blades.« less

Experimental validation of a numerical 3-D finite model applied to wind turbines design under vibration constraints: TREVISE platform

NASA Astrophysics Data System (ADS)

Sellami, Takwa; Jelassi, Sana; Darcherif, Abdel Moumen; Berriri, Hanen; Mimouni, Med Faouzi

2018-04-01

With the advancement of wind turbines towards complex structures, the requirement of trusty structural models has become more apparent. Hence, the vibration characteristics of the wind turbine components, like the blades and the tower, have to be extracted under vibration constraints. Although extracting the modal properties of blades is a simple task, calculating precise modal data for the whole wind turbine coupled to its tower/foundation is still a perplexing task. In this framework, this paper focuses on the investigation of the structural modeling approach of modern commercial micro-turbines. Thus, the structural model a complex designed wind turbine, which is Rutland 504, is established based on both experimental and numerical methods. A three-dimensional (3-D) numerical model of the structure was set up based on the finite volume method (FVM) using the academic finite element analysis software ANSYS. To validate the created model, experimental vibration tests were carried out using the vibration test system of TREVISE platform at ECAM-EPMI. The tests were based on the experimental modal analysis (EMA) technique, which is one of the most efficient techniques for identifying structures parameters. Indeed, the poles and residues of the frequency response functions (FRF), between input and output spectra, were calculated to extract the mode shapes and the natural frequencies of the structure. Based on the obtained modal parameters, the numerical designed model was up-dated.

Off-design performance loss model for radial turbines with pivoting, variable-area stators

NASA Technical Reports Server (NTRS)

Meitner, P. L.; Glassman, A. J.

1980-01-01

An off-design performance loss model was developed for variable stator (pivoted vane), radial turbines through analytical modeling and experimental data analysis. Stator loss is determined by a viscous loss model; stator vane end-clearance leakage effects are determined by a clearance flow model. Rotor loss coefficient were obtained by analyzing the experimental data from a turbine rotor previously tested with six stators having throat areas from 20 to 144 percent of design area and were correlated with stator-to-rotor throat area ratio. An incidence loss model was selected to obtain best agreement with experimental results. Predicted turbine performance is compared with experimental results for the design rotor as well as with results for extended and cutback versions of the rotor. Sample calculations were made to show the effects of stator vane end-clearance leakage.

Characterization of Deficiencies in the Frequency Domain Forced Response Analysis Technique for Turbine Bladed Disks

NASA Technical Reports Server (NTRS)

Brown, Andrew M.; Schmauch, Preston

2012-01-01

Turbine blades in rocket and jet engine turbomachinery experience enormous harmonic loading conditions. These loads result from the integer number of upstream and downstream stator vanes as well as the other turbine stages. The standard technique for forced response analysis to assess structural integrity is to decompose a CFD generated flow field into its harmonic components, and to then perform a frequency response analysis at the problematic natural frequencies. Recent CFD analysis and water-flow testing at NASA/MSFC, though, indicates that this technique may miss substantial harmonic and non-harmonic excitation sources that become present in complex flows. These complications suggest the question of whether frequency domain analysis is capable of capturing the excitation content sufficiently. Two studies comparing frequency response analysis with transient response analysis, therefore, have been performed. The first is of a bladed disk with each blade modeled by simple beam elements. It was hypothesized that the randomness and other variation from the standard harmonic excitation would reduce the blade structural response, but the results showed little reduction. The second study was of a realistic model of a bladed-disk excited by the same CFD used in the J2X engine program. The results showed that the transient analysis results were up to 10% higher for "clean" nodal diameter excitations and six times larger for "messy" excitations, where substantial Fourier content around the main harmonic exists.

Development turbine blade for ultramicro hydro power generation by 3D printer system

NASA Astrophysics Data System (ADS)

Kamimura, T.; Itoh, H.; Sugiura, K.

2017-11-01

We have developed micro generation system for effective use of unutilized energy and the spread of a self-controlled dispersion energy supply system. The turbine blade was designed for achieving high performance by special shape. The turbine type was called quasi-Peace turbine type. Turbine with a diameter of 30cm is made of metal, it was created by the 5-axis milling machine. The experimental apparatus was fabricated by the 3D printer. An experiment was carried out in the scale down model. The specific speed of this turbine was much lower than that of existing turbines.

46 CFR 112.25-3 - Normal source for emergency loads.

Code of Federal Regulations, 2014 CFR

2014-10-01

....25-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Systems Having an Automatic Starting Diesel Engine or Gas Turbine Driven Emergency Power Source as the Sole Emergency Power Source § 112.25-3 Normal source for...

46 CFR 112.25-3 - Normal source for emergency loads.

Code of Federal Regulations, 2013 CFR

2013-10-01

....25-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Systems Having an Automatic Starting Diesel Engine or Gas Turbine Driven Emergency Power Source as the Sole Emergency Power Source § 112.25-3 Normal source for...

46 CFR 112.25-3 - Normal source for emergency loads.

Code of Federal Regulations, 2010 CFR

2010-10-01

....25-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Systems Having an Automatic Starting Diesel Engine or Gas Turbine Driven Emergency Power Source as the Sole Emergency Power Source § 112.25-3 Normal source for...

46 CFR 112.25-3 - Normal source for emergency loads.

Code of Federal Regulations, 2011 CFR

2011-10-01

....25-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Systems Having an Automatic Starting Diesel Engine or Gas Turbine Driven Emergency Power Source as the Sole Emergency Power Source § 112.25-3 Normal source for...

46 CFR 112.25-3 - Normal source for emergency loads.

Code of Federal Regulations, 2012 CFR

2012-10-01

....25-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Systems Having an Automatic Starting Diesel Engine or Gas Turbine Driven Emergency Power Source as the Sole Emergency Power Source § 112.25-3 Normal source for...

Physics-based model for predicting the performance of a miniature wind turbine

NASA Astrophysics Data System (ADS)

Xu, F. J.; Hu, J. Z.; Qiu, Y. P.; Yuan, F. G.

2011-04-01

A comprehensive physics-based model for predicting the performance of the miniature wind turbine (MWT) for power wireless sensor systems was proposed in this paper. An approximation of the power coefficient of the turbine rotor was made after the turbine rotor performance was measured. Incorporation of the approximation with the equivalent circuit model which was proposed according to the principles of the MWT, the overall system performance of the MWT was predicted. To demonstrate the prediction, the MWT system comprised of a 7.6 cm thorgren plastic propeller as turbine rotor and a DC motor as generator was designed and its performance was tested experimentally. The predicted output voltage, power and system efficiency are matched well with the tested results, which imply that this study holds promise in estimating and optimizing the performance of the MWT.

Identification of Dynamic Simulation Models for Variable Speed Pumped Storage Power Plants

NASA Astrophysics Data System (ADS)

Moreira, C.; Fulgêncio, N.; Silva, B.; Nicolet, C.; Béguin, A.

2017-04-01

This paper addresses the identification of reduced order models for variable speed pump-turbine plants, including the representation of the dynamic behaviour of the main components: hydraulic system, turbine governors, electromechanical equipment and power converters. A methodology for the identification of appropriated reduced order models both for turbine and pump operating modes is presented and discussed. The methodological approach consists of three main steps: 1) detailed pumped-storage power plant modelling in SIMSEN; 2) reduced order models identification and 3) specification of test conditions for performance evaluation.

78 FR 2423 - Draft Environmental Impact Statement (DEIS) for the Proposed Shu'luuk Wind Project on the Campo...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-11

... turbines installed by Invenergy. The manufacturer and model of the wind turbines have not yet been selected... to 85 3-MW wind turbines. Each turbine would have a hub height up to 309 feet, rotor diameter up to... to 80 2-MW wind turbines (totaling 160 MW from wind) in combination with up to 40 1-MW solar...

Removable inner turbine shell with bucket tip clearance control

DOEpatents

Sexton, Brendan F.; Knuijt, Hans M.; Eldrid, Sacheverel Q.; Myers, Albert; Coneybeer, Kyle E.; Johnson, David Martin; Kellock, Iain R.

2000-01-01

A turbine includes a plurality of inner shell sections mounting first and second stage nozzle and shroud portions. The inner shell sections are pinned to an outer containment shell formed of sections to preclude circumferential movement of the inner shell relative to the outer shell and enable thermal expansion and contraction of the inner shell relative to the outer shell. Positive bucket tip clearance control is afforded by passing a thermal medium about the inner shell in heat transfer relation with the shrouds about the first and second stage bucket tips, the thermal medium being provided from a source of heating/cooling fluid independent of the turbine. Access is provided to the rotor and turbine buckets by removing the outer and inner shell sections.

Rocket Engine Turbine Blade Surface Pressure Distributions Experiment and Computations

NASA Technical Reports Server (NTRS)

Hudson, Susan T.; Zoladz, Thomas F.; Dorney, Daniel J.; Turner, James (Technical Monitor)

2002-01-01

Understanding the unsteady aspects of turbine rotor flow fields is critical to successful future turbine designs. A technology program was conducted at NASA's Marshall Space Flight Center to increase the understanding of unsteady environments for rocket engine turbines. The experimental program involved instrumenting turbine rotor blades with miniature surface mounted high frequency response pressure transducers. The turbine model was then tested to measure the unsteady pressures on the rotor blades. The data obtained from the experimental program is unique in two respects. First, much more unsteady data was obtained (several minutes per set point) than has been possible in the past. Also, an extensive steady performance database existed for the turbine model. This allowed an evaluation of the effect of the on-blade instrumentation on the turbine's performance. A three-dimensional unsteady Navier-Stokes analysis was also used to blindly predict the unsteady flow field in the turbine at the design operating conditions and at +15 degrees relative incidence to the first-stage rotor. The predicted time-averaged and unsteady pressure distributions show good agreement with the experimental data. This unique data set, the lessons learned for acquiring this type of data, and the improvements made to the data analysis and prediction tools are contributing significantly to current Space Launch Initiative turbine airflow test and blade surface pressure prediction efforts.

A large-eddy simulation study of wake propagation and power production in an array of tidal-current turbines.

PubMed

Churchfield, Matthew J; Li, Ye; Moriarty, Patrick J

2013-02-28

This paper presents our initial work in performing large-eddy simulations of tidal turbine array flows. First, a horizontally periodic precursor simulation is performed to create turbulent flow data. Then those data are used as inflow into a tidal turbine array two rows deep and infinitely wide. The turbines are modelled using rotating actuator lines, and the finite-volume method is used to solve the governing equations. In studying the wakes created by the turbines, we observed that the vertical shear of the inflow combined with wake rotation causes lateral wake asymmetry. Also, various turbine configurations are simulated, and the total power production relative to isolated turbines is examined. We found that staggering consecutive rows of turbines in the simulated configurations allows the greatest efficiency using the least downstream row spacing. Counter-rotating consecutive downstream turbines in a non-staggered array shows a small benefit. This work has identified areas for improvement. For example, using a larger precursor domain would better capture elongated turbulent structures, and including salinity and temperature equations would account for density stratification and its effect on turbulence. Additionally, the wall shear stress modelling could be improved, and more array configurations could be examined.

Using Reconstructed POD Modes as Turbulent Inflow for LES Wind Turbine Simulations

NASA Astrophysics Data System (ADS)

Nielson, Jordan; Bhaganagar, Kiran; Juttijudata, Vejapong; Sirisup, Sirod

2016-11-01

Currently, in order to get realistic atmospheric effects of turbulence, wind turbine LES simulations require computationally expensive precursor simulations. At times, the precursor simulation is more computationally expensive than the wind turbine simulation. The precursor simulations are important because they capture turbulence in the atmosphere and as stated above, turbulence impacts the power production estimation. On the other hand, POD analysis has been shown to be capable of capturing turbulent structures. The current study was performed to determine the plausibility of using lower dimension models from POD analysis of LES simulations as turbulent inflow to wind turbine LES simulations. The study will aid the wind energy community by lowering the computational cost of full scale wind turbine LES simulations, while maintaining a high level of turbulent information and being able to quickly apply the turbulent inflow to multi turbine wind farms. This will be done by comparing a pure LES precursor wind turbine simulation with simulations that use reduced POD mod inflow conditions. The study shows the feasibility of using lower dimension models as turbulent inflow of LES wind turbine simulations. Overall the power production estimation and velocity field of the wind turbine wake are well captured with small errors.

Modeling the Control Systems of Gas-Turbines to Ensure Their Reliable Parallel Operation in the UPS of Russia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vinogradov, A. Yu., E-mail: vinogradov-a@ntcees.ru; Gerasimov, A. S.; Kozlov, A. V.

Consideration is given to different approaches to modeling the control systems of gas turbines as a component of CCPP and GTPP to ensure their reliable parallel operation in the UPS of Russia. The disadvantages of the approaches to the modeling of combined-cycle units in studying long-term electromechanical transients accompanied by power imbalance are pointed out. Examples are presented to support the use of more detailed models of gas turbines in electromechanical transient calculations. It is shown that the modern speed control systems of gas turbines in combination with relatively low equivalent inertia have a considerable effect on electromechanical transients, includingmore » those caused by disturbances not related to power imbalance.« less

The acoustic field of a point source in a uniform boundary layer over an impedance plane

NASA Technical Reports Server (NTRS)

Zorumski, W. E.; Willshire, W. L., Jr.

1986-01-01

The acoustic field of a point source in a boundary layer above an impedance plane is investigated anatytically using Obukhov quasi-potential functions, extending the normal-mode theory of Chunchuzov (1984) to account for the effects of finite ground-plane impedance and source height. The solution is found to be asymptotic to the surface-wave term studies by Wenzel (1974) in the limit of vanishing wind speed, suggesting that normal-mode theory can be used to model the effects of an atmospheric boundary layer on infrasonic sound radiation. Model predictions are derived for noise-generation data obtained by Willshire (1985) at the Medicine Bow wind-turbine facility. Long-range downwind propagation is found to behave as a cylindrical wave, with attention proportional to the wind speed, the boundary-layer displacement thickness, the real part of the ground admittance, and the square of the frequency.

Dynamics of the precessing vortex rope and its interaction with the system at Francis turbines part load operating conditions

NASA Astrophysics Data System (ADS)

Favrel, A.; Müller, A.; Landry, C.; Gomes, J.; Yamamoto, K.; Avellan, F.

2017-04-01

At part load conditions, Francis turbines experience the formation of a cavitation vortex rope at the runner outlet whose precession acts as a pressure excitation source for the hydraulic circuit. This can lead to hydro-acoustic resonances characterized by high pressure pulsations, as well as torque and output power fluctuations. This study highlights the influence of the discharge factor on both the vortex parameters and the pressure excitation source by performing Particle Image Velocimetry (PIV) and pressure measurements. Moreover, it is shown that the occurrence of hydro-acoustic resonances in cavitation conditions mainly depend on the swirl degree of the flow independently of the speed factor. Empirical laws linking both natural and precession frequencies with the operating parameters of the machine are, then, derived, enabling the prediction of resonance conditions on the complete part load operating range of the turbine.

Wind power live! An interactive exhibit and related programs about wind generated energy at the Science Museum of Minnesota. Final performance report, February 1, 1995--September 30, 1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamilton, P.

The final performance report for the Wind Power Live! museum exhibit summarizes the goals and outcomes for the project. Project goals included: (1) help museum visitors understand why wind is being considered as a significant energy source; (2) enable visualization of the dynamics and power output of turbines; (3) exhibit a working wind turbine; (4) showcase wind as a technological success story; (5) consider the environmental costs and benefits of wind energy; (6) examine the economics of wind power, and (7) explain some of the limits to wind power as a commercial energy source. The methods of meeting the projectmore » goals through the museum exhibit are briefly outlined in the report. Goal number three, to introduce a working wind turbine, was dropped from the final project.« less

Simulation of Mechanical Behavior and Damage of a Large Composite Wind Turbine Blade under Critical Loads

NASA Astrophysics Data System (ADS)

Tarfaoui, M.; Nachtane, M.; Khadimallah, H.; Saifaoui, D.

2018-04-01

Issues such as energy generation/transmission and greenhouse gas emissions are the two energy problems we face today. In this context, renewable energy sources are a necessary part of the solution essentially winds power, which is one of the most profitable sources of competition with new fossil energy facilities. This paper present the simulation of mechanical behavior and damage of a 48 m composite wind turbine blade under critical wind loads. The finite element analysis was performed by using ABAQUS code to predict the most critical damage behavior and to apprehend and obtain knowledge of the complex structural behavior of wind turbine blades. The approach developed based on the nonlinear FE analysis using mean values for the material properties and the failure criteria of Tsai-Hill to predict failure modes in large structures and to identify the sensitive zones.

Enthalpy restoration in geothermal energy processing system

DOEpatents

Matthews, Hugh B.

1983-01-01

A geothermal deep well energy extraction system is provided of the general type in which solute-bearing hot water is pumped to the earth's surface from a relatively low temperature geothermal source by transferring thermal energy from the hot water to a working fluid for driving a primary turbine-motor and a primary electrical generator at the earth's surface. The superheated expanded exhaust from the primary turbine motor is conducted to a bubble tank where it bubbles through a layer of sub-cooled working fluid that has been condensed. The superheat and latent heat from the expanded exhaust of the turbine transfers thermal energy to the sub-cooled condensate. The desuperheated exhaust is then conducted to the condenser where it is condensed and sub-cooled, whereupon it is conducted back to the bubble tank via a barometric storage tank. The novel condensing process of this invention makes it possible to exploit geothermal sources which might otherwise be non-exploitable.

Aerodynamic optimization of wind turbine rotor using CFD/AD method

NASA Astrophysics Data System (ADS)

Cao, Jiufa; Zhu, Weijun; Wang, Tongguang; Ke, Shitang

2018-05-01

The current work describes a novel technique for wind turbine rotor optimization. The aerodynamic design and optimization of wind turbine rotor can be achieved with different methods, such as the semi-empirical engineering methods and more accurate computational fluid dynamic (CFD) method. The CFD method often provides more detailed aerodynamics features during the design process. However, high computational cost limits the application, especially for rotor optimization purpose. In this paper, a CFD-based actuator disc (AD) model is used to represent turbulent flow over a wind turbine rotor. The rotor is modeled as a permeable disc of equivalent area where the forces from the blades are distributed on the circular disc. The AD model is coupled with a Reynolds Averaged Navier-Stokes (RANS) solver such that the thrust and power are simulated. The design variables are the shape parameters comprising the chord, the twist and the relative thickness of the wind turbine rotor blade. The comparative aerodynamic performance is analyzed between the original and optimized reference wind turbine rotor. The results showed that the optimization framework can be effectively and accurately utilized in enhancing the aerodynamic performance of the wind turbine rotor.

Hydrodynamics and sediment transport in a meandering channel with a model axial-flow hydrokinetic turbine

NASA Astrophysics Data System (ADS)

Hill, Craig; Kozarek, Jessica; Sotiropoulos, Fotis; Guala, Michele

2016-02-01

An investigation into the interactions between a model axial-flow hydrokinetic turbine (rotor diameter, dT = 0.15 m) and the complex hydrodynamics and sediment transport processes within a meandering channel was carried out in the Outdoor StreamLab research facility at the University of Minnesota St. Anthony Falls Laboratory. This field-scale meandering stream with bulk flow and sediment discharge control provided a location for high spatiotemporally resolved measurements of bed and water surface elevations around the model turbine. The device was installed within an asymmetric, erodible channel cross section under migrating bed form and fixed outer bank conditions. A comparative analysis between velocity and topographic measurements, with and without the turbine installed, highlights the local and nonlocal features of the turbine-induced scour and deposition patterns. In particular, it shows how the cross-section geometry changes, how the bed form characteristics are altered, and how the mean flow field is distorted both upstream and downstream of the turbine. We further compare and discuss how current energy conversion deployments in meander regions would result in different interactions between the turbine operation and the local and nonlocal bathymetry compared to straight channels.

Towards reduced order modelling for predicting the dynamics of coherent vorticity structures within wind turbine wakes

NASA Astrophysics Data System (ADS)

Debnath, M.; Santoni, C.; Leonardi, S.; Iungo, G. V.

2017-03-01

The dynamics of the velocity field resulting from the interaction between the atmospheric boundary layer and a wind turbine array can affect significantly the performance of a wind power plant and the durability of wind turbines. In this work, dynamics in wind turbine wakes and instabilities of helicoidal tip vortices are detected and characterized through modal decomposition techniques. The dataset under examination consists of snapshots of the velocity field obtained from large-eddy simulations (LES) of an isolated wind turbine, for which aerodynamic forcing exerted by the turbine blades on the atmospheric boundary layer is mimicked through the actuator line model. Particular attention is paid to the interaction between the downstream evolution of the helicoidal tip vortices and the alternate vortex shedding from the turbine tower. The LES dataset is interrogated through different modal decomposition techniques, such as proper orthogonal decomposition and dynamic mode decomposition. The dominant wake dynamics are selected for the formulation of a reduced order model, which consists in a linear time-marching algorithm where temporal evolution of flow dynamics is obtained from the previous temporal realization multiplied by a time-invariant operator. This article is part of the themed issue 'Wind energy in complex terrains'.

Effect of RANS-Type Turbulence Models on Adiabatic Film Cooling Effectiveness over a Scaled Up Gas Turbine Blade Leading Edge Surface

NASA Astrophysics Data System (ADS)

Yepuri, Giridhara Babu; Talanki Puttarangasetty, Ashok Babu; Kolke, Deepak Kumar; Jesuraj, Felix

2016-06-01

Increasing the gas turbine inlet temperature is one of the key technologies in raising gas turbine engine power output. Film cooling is one of the efficient cooling techniques to cool the hot section components of a gas turbine engines in turn the turbine inlet temperature can be increased. This study aims at investigating the effect of RANS-type turbulence models on adiabatic film cooling effectiveness over a scaled up gas turbine blade leading edge surfaces. For the evaluation, five different two equation RANS-type turbulent models have been taken in consideration, which are available in the ANSYS-Fluent. For this analysis, the gas turbine blade leading edge configuration is generated using Solid Works. The meshing is done using ANSYS-Workbench Mesh and ANSYS-Fluent is used as a solver to solve the flow field. The considered gas turbine blade leading edge model is having five rows of film cooling circular holes, one at stagnation line and the two each on either side of stagnation line at 30° and 60° respectively. Each row has the five holes with the hole diameter of 4 mm, pitch of 21 mm arranged in staggered manner and has the hole injection angle of 30° in span wise direction. The experiments are carried in a subsonic cascade tunnel facility at heat transfer lab of CSIR-National Aerospace Laboratory with a Reynolds number of 1,00,000 based on leading edge diameter. From the Computational Fluid Dynamics (CFD) evaluation it is found that K-ɛ Realizable model gives more acceptable results with the experimental values, compared to the other considered turbulence models for this type of geometries. Further the CFD evaluated results, using K-ɛ Realizable model at different blowing ratios are compared with the experimental results.

Structural Health Monitoring challenges on the 10-MW offshore wind turbine model

NASA Astrophysics Data System (ADS)

Di Lorenzo, E.; Kosova, G.; Musella, U.; Manzato, S.; Peeters, B.; Marulo, F.; Desmet, W.

2015-07-01

The real-time structural damage detection on large slender structures has one of its main application on offshore Horizontal Axis Wind Turbines (HAWT). The renewable energy market is continuously pushing the wind turbine sizes and performances. This is the reason why nowadays offshore wind turbines concepts are going toward a 10 MW reference wind turbine model. The aim of the work is to perform operational analyses on the 10-MW reference wind turbine finite element model using an aeroelastic code in order to obtain long-time-low- cost simulations. The aeroelastic code allows simulating the damages in several ways: by reducing the edgewise/flapwise blades stiffness, by adding lumped masses or considering a progressive mass addiction (i.e. ice on the blades). The damage detection is then performed by means of Operational Modal Analysis (OMA) techniques. Virtual accelerometers are placed in order to simulate real measurements and to estimate the modal parameters. The feasibility of a robust damage detection on the model has been performed on the HAWT model in parked conditions. The situation is much more complicated in case of operating wind turbines because the time periodicity of the structure need to be taken into account. Several algorithms have been implemented and tested in the simulation environment. They are needed in order to carry on a damage detection simulation campaign and develop a feasible real-time damage detection method. In addition to these algorithms, harmonic removal tools are needed in order to dispose of the harmonics due to the rotation.

Optimisation and evaluation of pre-design models for offshore wind turbines with jacket support structures and their influence on integrated load simulations

NASA Astrophysics Data System (ADS)

Schafhirt, S.; Kaufer, D.; Cheng, P. W.

2014-12-01

In recent years many advanced load simulation tools, allowing an aero-servo-hydroelastic analyses of an entire offshore wind turbine, have been developed and verified. Nowadays, even an offshore wind turbine with a complex support structure such as a jacket can be analysed. However, the computational effort rises significantly with an increasing level of details. This counts especially for offshore wind turbines with lattice support structures, since those models do naturally have a higher number of nodes and elements than simpler monopile structures. During the design process multiple load simulations are demanded to obtain an optimal solution. In the view of pre-design tasks it is crucial to apply load simulations which keep the simulation quality and the computational effort in balance. The paper will introduce a reference wind turbine model consisting of the REpower5M wind turbine and a jacket support structure with a high level of detail. In total twelve variations of this reference model are derived and presented. Main focus is to simplify the models of the support structure and the foundation. The reference model and the simplified models are simulated with the coupled simulation tool Flex5-Poseidon and analysed regarding frequencies, fatigue loads, and ultimate loads. A model has been found which reaches an adequate increase of simulation speed while holding the results in an acceptable range compared to the reference results.

Advanced inflow forecasting for a hydropower plant in an Alpine hydropower regulated catchment - coupling of operational and hydrological forecasts

NASA Astrophysics Data System (ADS)

Tilg, Anna-Maria; Schöber, Johannes; Huttenlau, Matthias; Messner, Jakob; Achleitner, Stefan

2017-04-01

Hydropower is a renewable energy source which can help to stabilize fluctuations in the volatile energy market. Especially pumped-storage infrastructures in the European Alps play an important role within the European energy grid system. Today, the runoff of rivers in the Alps is often influenced by cascades of hydropower infrastructures where the operational procedures are triggered by energy market demands, water deliveries and flood control aspects rather than by hydro-meteorological variables. An example for such a highly hydropower regulated river is the catchment of the river Inn in the Eastern European Alps, originating in the Engadin (Switzerland). A new hydropower plant is going to be built as transboundary project at the boarder of Switzerland and Austria using the water of the Inn River. For the operation, a runoff forecast to the plant is required. The challenge in this case is that a high proportion of runoff is turbine water from an upstream situated hydropower cascade. The newly developed physically based hydrological forecasting system is mainly capable to cover natural hydrological runoff processes caused by storms and snow melt but can model only a small degree of human impact. These discontinuous parts of the runoff downstream of the pumped storage are described by means of an additional statistical model which has been developed. The main goal of the statistical model is to forecast the turbine water up to five days in advance. The lead time of the data driven model exceeds the lead time of the used energy production forecast. Additionally, the amount of turbine water is linked to the need of electricity production and the electricity price. It has been shown that especially the parameters day-ahead prognosis of the energy production and turbine inflow of the previous week are good predictors and are therefore used as input parameters for the model. As the data is restricted due to technical conditions, so-called Tobit models have been used to develop a linear regression for the runoff forecast. Although the day-ahead prognosis cannot always be kept, the regression model delivers, especially during office hours, very reasonable results. In the remaining hours the error between measurement and the forecast increases. Overall, the inflow forecast can be substantially improved by the implementation of the developed regression in the hydrological modelling system.

Modelling of the impact of biofouling on hydrodynamics downstream of a tidal turbine

NASA Astrophysics Data System (ADS)

Bennis, A. C.; Rivier, A.; Dauvin, J. C.

2016-02-01

Biological organisms, like barnacles, mussels or bryozoans, colonize rapidly an immersed surface and could form a thickness until several centimeters on it. This biofouling could modify hydrodynamics around tidal turbine by increasing drag and hence resistance and could be detrimental to the performance of turbine (e.g. Orme et al., 2001; Khor and Xiao, 2011). Our work focuses on modifications of vortices downstream of a tidal turbine due to biofouling using CFD. Fixed biological organisms are solved explicitly by the model and are considered by modifying the blade profile. Firstly an airfoil colonized by barnacles is modelled for various fouling height and spacing and results are compared to experimental and simulated data (Orme et al., 2001; Khor and Xiao, 2011) in order to assess the capacity of the model to reproduce the flow around a blade with biofouling. Then a Darrieus vertical axis tidal turbine is modelled using a dynamic mesh. Configuration with smooth clean blades is assessed by comparison with experiments and simulations made by Roa (2011) and Bossard (2012). Biological organisms with various heights, spacing and shapes are fixed on blades and wakes downstream of clean and colonized tidal turbine are compared. Vorticity fields around the tidal turbine are clearly modified when blades are colonized. Samples will be taken from location where farms are planned to be built (Alderney Race/Raz Blanchard) to characterize more precisely the characteristics of species which are liable to fix on tidal turbine.Reference:Bossard (2012). Doctoral dissertation, Université de Grenoble.Khor & Xiao. (2011). Ocean Eng, 38(10), 1065-1079. Orme et al. (2001). Marine Renewable Energy Conference, Newcastle.Roa (2011).Doctoral dissertation, Université de Grenoble.

Annoyance, detection and recognition of wind turbine noise.

PubMed

Van Renterghem, Timothy; Bockstael, Annelies; De Weirt, Valentine; Botteldooren, Dick

2013-07-01

Annoyance, recognition and detection of noise from a single wind turbine were studied by means of a two-stage listening experiment with 50 participants with normal hearing abilities. In-situ recordings made at close distance from a 1.8-MW wind turbine operating at 22 rpm were mixed with road traffic noise, and processed to simulate indoor sound pressure levels at LAeq 40 dBA. In a first part, where people were unaware of the true purpose of the experiment, samples were played during a quiet leisure activity. Under these conditions, pure wind turbine noise gave very similar annoyance ratings as unmixed highway noise at the same equivalent level, while annoyance by local road traffic noise was significantly higher. In a second experiment, listeners were asked to identify the sample containing wind turbine noise in a paired comparison test. The detection limit of wind turbine noise in presence of highway noise was estimated to be as low as a signal-to-noise ratio of -23 dBA. When mixed with local road traffic, such a detection limit could not be determined. These findings support that noticing the sound could be an important aspect of wind turbine noise annoyance at the low equivalent levels typically observed indoors in practice. Participants that easily recognized wind-turbine(-like) sounds could detect wind turbine noise better when submersed in road traffic noise. Recognition of wind turbine sounds is also linked to higher annoyance. Awareness of the source is therefore a relevant aspect of wind turbine noise perception which is consistent with previous research. Copyright © 2013 Elsevier B.V. All rights reserved.

Numerical Simulations and Experimental Measurements of Scale-Model Horizontal Axis Hydrokinetic Turbines (HAHT) Arrays

NASA Astrophysics Data System (ADS)

Javaherchi, Teymour; Stelzenmuller, Nick; Seydel, Joseph; Aliseda, Alberto

2014-11-01

The performance, turbulent wake evolution and interaction of multiple Horizontal Axis Hydrokinetic Turbines (HAHT) is analyzed in a 45:1 scale model setup. We combine experimental measurements with different RANS-based computational simulations that model the turbines with sliding-mesh, rotating reference frame and blame element theory strategies. The influence of array spacing and Tip Speed Ratio on performance and wake velocity structure is investigated in three different array configurations: Two coaxial turbines at different downstream spacing (5d to 14d), Three coaxial turbines with 5d and 7d downstream spacing, and Three turbines with lateral offset (0.5d) and downstream spacing (5d & 7d). Comparison with experimental measurements provides insights into the dynamics of HAHT arrays, and by extension to closely packed HAWT arrays. The experimental validation process also highlights the influence of the closure model used (k- ω SST and k- ɛ) and the flow Reynolds number (Re=40,000 to 100,000) on the computational predictions of devices' performance and characteristics of the flow field inside the above-mentioned arrays, establishing the strengths and limitations of existing numerical models for use in industrially-relevant settings (computational cost and time). Supported by DOE through the National Northwest Marine Renewable Energy Center (NNMREC).

Field Research Validation Sites | Wind | NREL

Science.gov Websites

, independent pitch control of the Controls Advanced Research Turbine (CART) blades Variable-speed or constant CART2 600-kW Turbine Model: Westinghouse Blades: 2 Hub height: 36.6 m Rotor diameter: 42.6 m Extensively instrumented CART3 600-kW Turbine Model: Westinghouse Blades: 3 Hub height: 36.6 m Rotor diameter: 42.6 m

@NWTC Newsletter: Summer 2014 | Wind | NREL

Science.gov Websites

, Developmental Role in Major Wind Journal Boosting Wind Plant Power Output by 4%-5% through Coordinated Turbine . Part 2: Wind Farm Wake Models New Framework Transforms FAST Wind Turbine Modeling Tool (Fact Sheet ) Sensitivity Analysis of Wind Plant Performance to Key Turbine Design Parameters: A Systems Engineering

Cavitation study of a pump-turbine at turbine mode with critical cavitation coefficient condition

NASA Astrophysics Data System (ADS)

Wang, J.; Yang, D.; Xu, J. W.; Liu, J. T.; Jiao, L.

2016-05-01

To study the cavitation phenomenon of a pump-turbine at turbine mode when it ran at the critical cavitation coefficient condition, a high-head model pump-turbine was disperse using hexahedron grid. Three dimensional, steady cavitating flow was numerically studied using SST k-ω model. It is confirmed that ZGB cavitation model and SST k-ω model are useful ways to study the two-phase cavitation flow in pump-turbine. Mass flow inlet and pressure outlet were specified at the casing inlet and draft tube outlet, respectively. The static pressure was set according to the cavitation coefficient. The steady cavitating flows at critical cavitation coefficient condition were analysed. The cavitation area in the runner was investigated. It was found that the pressure of the suction on the blade surface was decreasing gradually with the decrease of the cavitation coefficient. In addition, the vortex flow in the draft tube was observed at the critical cavitation coefficient. It was found that the vortex flow appeared at the center of the draft tube inlet with the decreasing of the cavitation coefficient. Compared with the experimental data, the simulation results show reasonable agreement with the experimental data.

Phase Resolved Angular Velocity Control of Cross Flow Turbines

NASA Astrophysics Data System (ADS)

Strom, Benjamin; Brunton, Steven; Polagye, Brian

2015-11-01

Cross flow turbines have a number of operational advantages for the conversion of kinetic energy in marine or fluvial currents, but they are often less efficient than axial flow devices. Here a control scheme is presented in which the angular velocity of a cross flow turbine with two straight blades is prescribed as a function of azimuthal blade position, altering the time-varying effective angle of attack. Flume experiments conducted with a scale model turbine show approximately an 80% increase in turbine efficiency versus optimal constant angular velocity and constant resistive torque control schemes. Torque, drag, and lateral forces on one- and two-bladed turbines are analyzed and interpreted with bubble flow visualization to develop a simple model that describes the hydrodynamics responsible for the observed increase in mean efficiency. Challenges associated with implementing this control scheme on commercial-scale devices are discussed. If solutions are found, the performance increase presented here may impact the future development of cross flow turbines.

Advanced ceramic coating development for industrial/utility gas turbine applications

NASA Technical Reports Server (NTRS)

Andersson, C. A.; Lau, S. K.; Bratton, R. J.; Lee, S. Y.; Rieke, K. L.; Allen, J.; Munson, K. E.

1982-01-01

The effects of ceramic coatings on the lifetimes of metal turbine components and on the performance of a utility turbine, as well as of the turbine operational cycle on the ceramic coatings were determined. When operating the turbine under conditions of constant cooling flow, the first row blades run 55K cooler, and as a result, have 10 times the creep rupture life, 10 times the low cycle fatigue life and twice the corrosion life with only slight decreases in both specific power and efficiency. When operating the turbine at constant metal temperature and reduced cooling flow, both specific power and efficiency increases, with no change in component lifetime. The most severe thermal transient of the turbine causes the coating bond stresses to approach 60% of the bond strengths. Ceramic coating failures was studied. Analytic models based on fracture mechanics theories, combined with measured properties quantitatively assessed both single and multiple thermal cycle failures which allowed the prediction of coating lifetime. Qualitative models for corrosion failures are also presented.

Low order physical models of vertical axis wind turbines

NASA Astrophysics Data System (ADS)

Craig, Anna; Dabiri, John; Koseff, Jeffrey

2016-11-01

In order to examine the ability of low-order physical models of vertical axis wind turbines to accurately reproduce key flow characteristics, experiments were conducted on rotating turbine models, rotating solid cylinders, and stationary porous flat plates (of both uniform and non-uniform porosities). From examination of the patterns of mean flow, the wake turbulence spectra, and several quantitative metrics, it was concluded that the rotating cylinders represent a reasonably accurate analog for the rotating turbines. In contrast, from examination of the patterns of mean flow, it was found that the porous flat plates represent only a limited analog for rotating turbines (for the parameters examined). These findings have implications for both laboratory experiments and numerical simulations, which have previously used analogous low order models in order to reduce experimental/computational costs. NSF GRF and SGF to A.C; ONR N000141211047 and the Gordon and Betty Moore Foundation Grant GBMF2645 to J.D.; and the Bob and Norma Street Environmental Fluid Mechanics Laboratory at Stanford University.

Design and aero-acoustic analysis of a counter-rotating wind turbine

NASA Astrophysics Data System (ADS)

Agrawal, Vineesh V.

Wind turbines have become an integral part of the energy business because they are one of the most economical and reliable sources of renewable energy. Conventional wind turbines are capable of capturing less than half of the energy present in the wind. Hence, to make the wind turbines more efficient, it is important to increase their performance. A horizontal axis wind turbine with multiple rotors is one concept that can achieve a higher power conversion rate. Also, a concern for wind energy is the noise generated by wind turbines. Hence, an investigation into the acoustic behavior of a multi-rotor horizontal axis wind turbine is required. In response to the need of a wind turbine design with higher power coefficient, a unique design of a counter-rotating horizontal axis wind turbine (CR-HAWT) is proposed. The Blade Element Momentum (BEM) theory is used to aerodynamically design the blades of the two rotors. Modifications are made to the BEM theory to accommodate the interaction of the two rotors. The tower effect on the noise generation of the downwind rotor is investigated. Predictions are made for the total noise generated by the wind turbine at its design operating conditions. A total power coefficient of 65.2% is predicted for the proposed CR-HAWT design. A low tip speed ratio is chosen to minimize the noise generation. The aeroacoustic analysis of the CR-HAWT shows that the noise generated at its design operating conditions is within an acceptable range. Thus, the CR-HAWT is predicted to be a quiet wind turbine with a high power coefficient, making it highly desirable for small wind turbine applications.

Performance Evaluation, Emulation, and Control of Cross-Flow Hydrokinetic Turbines

NASA Astrophysics Data System (ADS)

Cavagnaro, Robert J.

Cross-flow hydrokinetic turbines are a promising option for effectively harvesting energy from fast-flowing streams or currents. This work describes the dynamics of such turbines, analyzes techniques used to scale turbine properties for prototyping, determines and demonstrates the limits of stability for cross-flow rotors, and discusses means and objectives of turbine control. Novel control strategies are under development to utilize low-speed operation (slower than at maximum power point) as a means of shedding power under rated conditions. However, operation in this regime may be unstable. An experiment designed to characterize the stability of a laboratory-scale cross-flow turbine operating near a critically low speed yields evidence that system stall (complete loss of ability to rotate) occurs due, in part, to interactions with turbulent decreases in flow speed. The turbine is capable of maintaining 'stable' operation at critical speed for short duration (typically less than 10 s), as described by exponential decay. The presence of accelerated 'bypass' flow around the rotor and decelerated 'induction' region directly upstream of the rotor, both predicted by linear momentum theory, are observed and quantified with particle image velocimetry (PIV) measurements conducted upstream of the turbine. Additionally, general agreement is seen between PIV inflow measurements and those obtained by an advection-corrected acoustic Doppler velocimeter (ADV) further upstream. Performance of a turbine at small (prototype) geometric scale may be prone to undesirable effects due to operation at low Reynolds number and in the presence of high channel blockage. Therefore, testing at larger scale, in open water is desirable. A cross-flow hydrokinetic turbine with a projected area (product of blade span and rotor diameter) of 0.7 m2 is evaluated in open-water tow trials at three inflow speeds ranging from 1.0 m/s to 2.1 m/s. Measurements of the inflow velocity, the rotor mechanical power, and electrical power output of a complete power take-off (PTO) system are utilized to determine the rotor hydrodynamic efficiency (maximum of 17%) and total system efficiency (maximum of 9%). A lab-based dynamometry method yields individual component and total PTO efficiencies, shown to have high variability and strong influence on total system efficiency. Dynamic efficiencies of PTO components can effect the overall efficiency of a turbine system, a result from field characterization. Thus, the ability to evaluate such components and their potential effects on turbine performance prior to field deployment is desirable. Before attempting control experiments with actual turbines, hardware-in-the-loop testing on controllable motor-generator sets or electromechanical emulation machines (EEMs) are explored to better understand power take-off response. The emulator control dynamic equations are presented, methods for scaling turbine parameters are developed and evaluated, and experimental results are presented from three EEMs programmed to emulate the same cross-flow turbine. Although hardware platforms and control implementations varied, results show that each EEM is successful in emulating the turbine model at different power levels, thus demonstrating the general feasibility of the approach. However, performance of motor control under torque command, current command, or speed command differed; torque methods required accurate characterization of the motors while speed methods utilized encoder feedback and more accurately tracked turbine dynamics. In a demonstration of an EEM for evaluating a hydrokinetic turbine implementation, a controller is used to track the maximum power-point of the turbine in response to turbulence. Utilizing realistic inflow conditions and control laws, the emulator dynamic speed response is shown to agree well at low frequencies with simulation but to deviate at high frequencies. The efficacy of an electromechanical emulator as an accurate representation of a fielded turbine is evaluated. A commercial horizontally-oriented cross-flow turbine is dynamically emulated on hardware to investigate control strategies and grid integration. A representative inflow time-series with a mean of 2 m/s is generated from high-resolution flow measurements of a riverine site and is used to drive emulation. Power output during emulation under similar input and loading conditions yields agreement with field measurements to within 3% at high power, near-optimal levels. Constant tip-speed ratio and constant speed proportional plus integral control schemes are compared to optimal nonlinear control and constant resistance regulation. All controllers yield similar results in terms of overall system efficiency. The emulated turbine is more responsive to turbulent inflow than the field turbine, as the model utilized to drive emulation does not account for a smoothing effect of turbulent fluctuations over the span of the fielded turbine's rotors. The turbine has a lower inertia than the demand of an isolated grid, indicating a secondary source of power with a similar frequency response is necessary if a single turbine cannot meet the entire demand. (Abstract shortened by UMI.).

High-resolution computational algorithms for simulating offshore wind turbines and farms: Model development and validation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calderer, Antoni; Yang, Xiaolei; Angelidis, Dionysios

2015-10-30

The present project involves the development of modeling and analysis design tools for assessing offshore wind turbine technologies. The computational tools developed herein are able to resolve the effects of the coupled interaction of atmospheric turbulence and ocean waves on aerodynamic performance and structural stability and reliability of offshore wind turbines and farms. Laboratory scale experiments have been carried out to derive data sets for validating the computational models.

Numerical investigation of the flow in axial water turbines and marine propellers with scale-resolving simulations

NASA Astrophysics Data System (ADS)

Morgut, Mitja; Jošt, Dragica; Nobile, Enrico; Škerlavaj, Aljaž

2015-11-01

The accurate prediction of the performances of axial water turbines and naval propellers is a challenging task, of great practical relevance. In this paper a numerical prediction strategy, based on the combination of a trusted CFD solver and a calibrated mass transfer model, is applied to the turbulent flow in axial turbines and around a model scale naval propeller, under non-cavitating and cavitating conditions. Some selected results for axial water turbines and a marine propeller, and in particular the advantages, in terms of accuracy and fidelity, of ScaleResolving Simulations (SRS), like SAS (Scale Adaptive Simulation) and Zonal-LES (ZLES) compared to standard RANS approaches, are presented. Efficiency prediction for a Kaplan and a bulb turbine was significantly improved by use of the SAS SST model in combination with the ZLES in the draft tube. Size of cavitation cavity and sigma break curve for Kaplan turbine were successfully predicted with SAS model in combination with robust high resolution scheme, while for mass transfer the Zwart model with calibrated constants were used. The results obtained for a marine propeller in non-uniform inflow, under cavitating conditions, compare well with available experimental measurements, and proved that a mass transfer model, previously calibrated for RANS (Reynolds Averaged Navier Stokes), can be successfully applied also within the SRS approaches.

Wind Power Curve Modeling Using Statistical Models: An Investigation of Atmospheric Input Variables at a Flat and Complex Terrain Wind Farm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wharton, S.; Bulaevskaya, V.; Irons, Z.

The goal of our FY15 project was to explore the use of statistical models and high-resolution atmospheric input data to develop more accurate prediction models for turbine power generation. We modeled power for two operational wind farms in two regions of the country. The first site is a 235 MW wind farm in Northern Oklahoma with 140 GE 1.68 turbines. Our second site is a 38 MW wind farm in the Altamont Pass Region of Northern California with 38 Mitsubishi 1 MW turbines. The farms are very different in topography, climatology, and turbine technology; however, both occupy high wind resourcemore » areas in the U.S. and are representative of typical wind farms found in their respective areas.« less

Coordinated Control of Cross-Flow Turbines

NASA Astrophysics Data System (ADS)

Strom, Benjamin; Brunton, Steven; Polagye, Brian

2016-11-01

Cross-flow turbines, also known as vertical-axis turbines, have several advantages over axial-flow turbines for a number of applications including urban wind power, high-density arrays, and marine or fluvial currents. By controlling the angular velocity applied to the turbine as a function of angular blade position, we have demonstrated a 79 percent increase in cross-flow turbine efficiency over constant-velocity control. This strategy uses the downhill simplex method to optimize control parameter profiles during operation of a model turbine in a recirculating water flume. This optimization method is extended to a set of two turbines, where the blade motions and position of the downstream turbine are optimized to beneficially interact with the coherent structures in the wake of the upstream turbine. This control scheme has the potential to enable high-density arrays of cross-flow turbines to operate at cost-effective efficiency. Turbine wake and force measurements are analyzed for insight into the effect of a coordinated control strategy.

Computational examination of utility scale wind turbine wake interactions

DOE PAGES

Okosun, Tyamo; Zhou, Chenn Q.

2015-07-14

We performed numerical simulations of small, utility scale wind turbine groupings to determine how wakes generated by upstream turbines affect the performance of the small turbine group as a whole. Specifically, various wind turbine arrangements were simulated to better understand how turbine location influences small group wake interactions. The minimization of power losses due to wake interactions certainly plays a significant role in the optimization of wind farms. Since wind turbines extract kinetic energy from the wind, the air passing through a wind turbine decreases in velocity, and turbines downstream of the initial turbine experience flows of lower energy, resultingmore » in reduced power output. Our study proposes two arrangements of turbines that could generate more power by exploiting the momentum of the wind to increase velocity at downstream turbines, while maintaining low wake interactions at the same time. Furthermore, simulations using Computational Fluid Dynamics are used to obtain results much more quickly than methods requiring wind tunnel models or a large scale experimental test.« less

Multi-source energy harvester to power sensing hardware on rotating structures

NASA Astrophysics Data System (ADS)

Schlichting, Alexander; Ouellette, Scott; Carlson, Clinton; Farinholt, Kevin M.; Park, Gyuhae; Farrar, Charles R.

2010-04-01

The U.S. Department of Energy (DOE) proposes to meet 20% of the nation's energy needs through wind power by the year 2030. To accomplish this goal, the industry will need to produce larger (>100m diameter) turbines to increase efficiency and maximize energy production. It will be imperative to instrument the large composite structures with onboard sensing to provide structural health monitoring capabilities to understand the global response and integrity of these systems as they age. A critical component in the deployment of such a system will be a robust power source that can operate for the lifespan of the wind turbine. In this paper we consider the use of discrete, localized power sources that derive energy from the ambient (solar, thermal) or operational (kinetic) environment. This approach will rely on a multi-source configuration that scavenges energy from photovoltaic and piezoelectric transducers. Each harvester is first characterized individually in the laboratory and then they are combined through a multi-source power conditioner that is designed to combine the output of each harvester in series to power a small wireless sensor node that has active-sensing capabilities. The advantages/disadvantages of each approach are discussed, along with the proposed design for a field ready energy harvester that will be deployed on a small-scale 19.8m diameter wind turbine.

Wind Farm Flow Modeling using an Input-Output Reduced-Order Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Annoni, Jennifer; Gebraad, Pieter; Seiler, Peter

Wind turbines in a wind farm operate individually to maximize their own power regardless of the impact of aerodynamic interactions on neighboring turbines. There is the potential to increase power and reduce overall structural loads by properly coordinating turbines. To perform control design and analysis, a model needs to be of low computational cost, but retains the necessary dynamics seen in high-fidelity models. The objective of this work is to obtain a reduced-order model that represents the full-order flow computed using a high-fidelity model. A variety of methods, including proper orthogonal decomposition and dynamic mode decomposition, can be used tomore » extract the dominant flow structures and obtain a reduced-order model. In this paper, we combine proper orthogonal decomposition with a system identification technique to produce an input-output reduced-order model. This technique is used to construct a reduced-order model of the flow within a two-turbine array computed using a large-eddy simulation.« less

Design of low noise wind turbine blades using Betz and Joukowski concepts

NASA Astrophysics Data System (ADS)

Shen, W. Z.; Hrgovan, I.; Okulov, V.; Zhu, W. J.; Madsen, J.

2014-06-01

This paper presents the aerodynamic design of low noise wind turbine blades using Betz and Joukowski concepts. The aerodynamic model is based on Blade Element Momentum theory whereas the aeroacoustic prediction model is based on the BPM model. The investigation is started with a 3MW baseline/reference turbine rotor with a diameter of 80 m. To reduce the noise emission from the baseline rotor, the rotor is reconstructed with the low noise CQU-DTU-LN1 series of airfoils which has been tested in the acoustic wind tunnel located at Virginia Tech. Finally, 3MW low noise turbine rotors are designed using the concepts of Betz and Joukowski, and the CQU-DTU-LN1 series of airfoils. Performance analysis shows that the newly designed turbine rotors can achieve an overall noise reduction of 6 dB and 1.5 dB(A) with a similar power output as compared to the reference rotor.

Dynamics analysis of the fast-slow hydro-turbine governing system with different time-scale coupling

NASA Astrophysics Data System (ADS)

Zhang, Hao; Chen, Diyi; Wu, Changzhi; Wang, Xiangyu

2018-01-01

Multi-time scales modeling of hydro-turbine governing system is crucial in precise modeling of hydropower plant and provides support for the stability analysis of the system. Considering the inertia and response time of the hydraulic servo system, the hydro-turbine governing system is transformed into the fast-slow hydro-turbine governing system. The effects of the time-scale on the dynamical behavior of the system are analyzed and the fast-slow dynamical behaviors of the system are investigated with different time-scale. Furthermore, the theoretical analysis of the stable regions is presented. The influences of the time-scale on the stable region are analyzed by simulation. The simulation results prove the correctness of the theoretical analysis. More importantly, the methods and results of this paper provide a perspective to multi-time scales modeling of hydro-turbine governing system and contribute to the optimization analysis and control of the system.

Turbine Internal and Film Cooling Modeling For 3D Navier-Stokes Codes

NASA Technical Reports Server (NTRS)

DeWitt, Kenneth; Garg Vijay; Ameri, Ali

2005-01-01

The aim of this research project is to make use of NASA Glenn on-site computational facilities in order to develop, validate and apply aerodynamic, heat transfer, and turbine cooling models for use in advanced 3D Navier-Stokes Computational Fluid Dynamics (CFD) codes such as the Glenn-" code. Specific areas of effort include: Application of the Glenn-HT code to specific configurations made available under Turbine Based Combined Cycle (TBCC), and Ultra Efficient Engine Technology (UEET) projects. Validating the use of a multi-block code for the time accurate computation of the detailed flow and heat transfer of cooled turbine airfoils. The goal of the current research is to improve the predictive ability of the Glenn-HT code. This will enable one to design more efficient turbine components for both aviation and power generation. The models will be tested against specific configurations provided by NASA Glenn.

A Computational Fluid Dynamics Study of Transitional Flows in Low-Pressure Turbines under a Wide Range of Operating Conditions

NASA Technical Reports Server (NTRS)

Suzen, Y. B.; Huang, P. G.; Ashpis, D. E.; Volino, R. J.; Corke, T. C.; Thomas, F. O.; Huang, J.; Lake, J. P.; King, P. I.

2007-01-01

A transport equation for the intermittency factor is employed to predict the transitional flows in low-pressure turbines. The intermittent behavior of the transitional flows is taken into account and incorporated into computations by modifying the eddy viscosity, mu(sub p) with the intermittency factor, gamma. Turbulent quantities are predicted using Menter's two-equation turbulence model (SST). The intermittency factor is obtained from a transport equation model which can produce both the experimentally observed streamwise variation of intermittency and a realistic profile in the cross stream direction. The model had been previously validated against low-pressure turbine experiments with success. In this paper, the model is applied to predictions of three sets of recent low-pressure turbine experiments on the Pack B blade to further validate its predicting capabilities under various flow conditions. Comparisons of computational results with experimental data are provided. Overall, good agreement between the experimental data and computational results is obtained. The new model has been shown to have the capability of accurately predicting transitional flows under a wide range of low-pressure turbine conditions.

Preliminary Two-Phase Terry Turbine Nozzle Models for RCIC Off-Design Operation Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Haihua; O'Brien, James

This report presents the effort to extend the single-phase analytical Terry turbine model to cover two-phase off-design conditions. The work includes: (1) adding well-established two-phase choking models – the Isentropic Homogenous Equilibrium Model (IHEM) and Moody’s model, and (2) theoretical development and implementation of a two-phase nozzle expansion model. The two choking models provide bounding cases for the two-phase choking mass flow rate. The new two-phase Terry turbine model uses the choking models to calculate the mass flow rate, the critical pressure at the nozzle throat, and steam quality. In the divergent stage, we only consider the vapor phase withmore » a similar model for the single-phase case by assuming that the liquid phase would slip along the wall with a much slower speed and will not contribute the impulse on the rotor. We also modify the stagnation conditions according to two-phase choking conditions at the throat and the cross-section areas for steam flow at the nozzle throat and at the nozzle exit. The new two-phase Terry turbine model was benchmarked with the same steam nozzle test as for the single-phase model. Better agreement with the experimental data is observed than from the single-phase model. We also repeated the Terry turbine nozzle benchmark work against the Sandia CFD simulation results with the two-phase model for the pure steam inlet nozzle case. The RCIC start-up tests were simulated and compared with the single-phase model. Similar results are obtained. Finally, we designed a new RCIC system test case to simulate the self-regulated Terry turbine behavior observed in Fukushima accidents. In this test, a period inlet condition for the steam quality varying from 1 to 0 is applied. For the high quality inlet period, the RCIC system behaves just like the normal operation condition with a high pump injection flow rate and a nominal steam release rate through the turbine, with the net addition of water to the primary system; for the low quality inlet period, the RCIC turbine shaft work dramatically decreases and results in a much reduced pump injection flow rate, and the mixture flow rate through the turbine increases due to the high liquid phase flow rate. The net effect for this period is net removal of coolant from the primary loop. With the periodic addition and removal of coolant to the primary loop, the self-regulation mode of the RCIC system can be maintained for a quite long time. Both the IHEM and Moody’s models generate similar phenomena; however noticeable differences can be observed.« less

Literature Reviews on Wind Turbines and Health: Are They Enough?

ERIC Educational Resources Information Center

Horner, Brett; Jeffery, Roy D.; Krogh, Carmen M. E.

2011-01-01

Industrial wind turbines (IWTs) are a new source of community noise to which relatively few people have yet been exposed. IWTs are being erected at a rapid pace in proximity to human habitation. Some people report experiencing adverse health effects as a result of living in the environs of IWTs. In order to address public concerns and assess the…

78 FR 30901 - Record of Decision and Wetland/Floodplain Statement of Findings for the W.A. Parish Post...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-23

... W.A. Parish Plant in Fort Bend County, Texas. A new 80-MW natural gas-fired turbine, currently under... the CO 2 capture facility, the combustion turbine and heat recovery steam generator (CT/HRSG) area... maintenance power sources or by new metered service from a local retail provider. Potential construction...

Impacts | Wind | NREL

Science.gov Websites

in hard hats standing on top of a large wind turbine overlooking several other wind turbines in the Framework Transforms FAST Wind Turbine Modeling Tool NREL Assesses National Design Standards for Offshore Wind Resource NREL Identifies Investments for Wind Turbine Drivetrain Technologies Awards R&D 100

Guidelines for reducing dynamic loads in two-bladed teetering-hub downwind wind turbines

NASA Astrophysics Data System (ADS)

Wright, A. D.; Bir, G. S.; Butterfield, C. D.

1995-06-01

A major goal of the federal Wind Energy Program is the rapid development and validation of structural models to determine loads and response for a wide variety of different wind turbine configurations operating under extreme conditions. Such codes are crucial to the successful design of future advanced wind turbines. In previous papers the authors described steps they took to develop a model of a two-bladed teetering-hub downwind wind turbine using ADAMS (Automatic Dynamic Analysis of Mechanical Systems), as well as comparison of model predictions to test data. In this paper they show the use of this analytical model to study the influence of various turbine parameters on predicted system loads. They concentrate their study on turbine response in the frequency range of six to ten times the rotor rotational frequency (6P to 10P). Their goal is to identify the most important parameters which influence the response of this type of machine in this frequency range and give turbine designers some general design guidelines for designing two-bladed teetering-hub machines to be less susceptible to vibration. They study the effects of such parameters as blade edgewise and flapwise stiffness, tower top stiffness, blade tip-brake mass, low-speed shaft stiffness, nacelle mass momenta of inertia, and rotor speed. They show which parameters can be varied in order to make the turbine less responsive to such atmospheric inputs as wind shear and tower shadow. They then give designers a set of design guidelines in order to show how these machines can be designed to be less responsive to these inputs.

Ground noise measurements during static and flyby operations of the Cessna 02-T turbine powered airplane

NASA Technical Reports Server (NTRS)

Hilton, D. A.; Henderson, H. R.; Lawton, B. W.

1975-01-01

The field noise measurements on the Cessna 02-T turbine powered propeller aircraft are presented. The objective of the study was to obtain the basic noise characteristics of the aircraft during static ground runs and flyover tests, to identify the sources of the noise, and to correlate the noises with the aircraft operating conditions. The results are presented in the form of a overall noise levels, radiation patterns, and frequency spectra. The noise characteristics of the turbine powered aircraft are compared with those of the reciprocating engine powered aircraft.

Analysis and improvement of gas turbine blade temperature measurement error

NASA Astrophysics Data System (ADS)

Gao, Shan; Wang, Lixin; Feng, Chi; Daniel, Ketui

2015-10-01

Gas turbine blade components are easily damaged; they also operate in harsh high-temperature, high-pressure environments over extended durations. Therefore, ensuring that the blade temperature remains within the design limits is very important. In this study, measurement errors in turbine blade temperatures were analyzed, taking into account detector lens contamination, the reflection of environmental energy from the target surface, the effects of the combustion gas, and the emissivity of the blade surface. In this paper, each of the above sources of measurement error is discussed, and an iterative computing method for calculating blade temperature is proposed.

Comparing model-based predictions of a wind turbine wake to LiDAR measurements in complex terrain

NASA Astrophysics Data System (ADS)

Kay, Andrew; Jones, Paddy; Boyce, Dean; Bowman, Neil

2013-04-01

The application of remote sensing techniques to the measurement of wind characteristics offers great potential to accurately predict the atmospheric boundary layer flow (ABL) and its interactions with wind turbines. An understanding of these interactions is important for optimizing turbine siting in wind farms and improving the power performance and lifetime of individual machines. In particular, Doppler wind Light Detection and Ranging (LiDAR) can be used to remotely measure the wind characteristics (speed, direction and turbulence intensity) approaching a rotor. This information can be utilised to improve turbine lifetime (advanced detection of incoming wind shear, wind veer and extreme wind conditions, such as gusts) and optimise power production (improved yaw, pitch and speed control). LiDAR can also make detailed measurements of the disturbed wind profile in the wake, which can damage surrounding turbines and reduce efficiency. These observational techniques can help engineers better understand and model wakes to optimize turbine spacing in large wind farms, improving efficiency and reducing the cost of energy. NEL is currently undertaking research to measure the disturbed wind profile in the wake of a 950 kW wind turbine using a ZephIR Dual Mode LiDAR at its Myres Hill wind turbine test site located near Glasgow, Scotland. Myres Hill is moderately complex terrain comprising deep peat, low lying grass and heathers, localised slopes and nearby forest, approximately 2 km away. Measurements have been obtained by vertically scanning at 10 recorded heights across and above the rotor plane to determine the wind speed, wind direction and turbulence intensity profiles. Measurement stations located at various rotor diameters downstream of the turbine were selected in an attempt to capture the development of the wake and its recovery towards free stream conditions. Results of the measurement campaign will also highlight how the wake behaves as a result of sudden gusts or rapid changes in wind direction. NEL has carried out simulations to model the wake of the turbine using Computational Fluid Dynamics (CFD) software provided by ANSYS Inc. The model incorporates a simple actuator disk concept to model the turbine and its wake, typical of that used in many commercial wind farm optimization tools. The surrounding terrain, including the forestry is modelled allowing an investigation of the wake-terrain interactions occurring across the site. The overall aim is to compare the LiDAR measurements with simulated data to assess the quality of the model and its sensitivity to variables such as mesh size and turbulence/forestry modelling techniques. Knowledge acquired from the study will help to define techniques for combining LiDAR measurements with CFD modelling to improve predictions of wake losses in large wind farms and hence, energy production. In addition, the impact of transient wind conditions on the results of predictions based on idealised, steady state models has been examined.