Numerical Analysis of Shear Thickening Fluids for Blast Mitigation Applications

DTIC Science & Technology

2011-12-01

integrate with other types of physics simulation technologies ( ANSYS , 2011). One well-known product offered by ANSYS is the ANSYS CFX . The ANSYS CFD...centered. The ANSYS CFX solver uses coupled algebraic multigrid to achieve its solutions and its engineered scalability ensures a linear increase in CPU...on the user-defined distribution and size. As the numerical analysis focused on the behavior of each individual particle, the ANSYS CFX Rigid Body

The numerical simulation based on CFD of hydraulic turbine pump

NASA Astrophysics Data System (ADS)

Duan, X. H.; Kong, F. Y.; Liu, Y. Y.; Zhao, R. J.; Hu, Q. L.

2016-05-01

As the functions of hydraulic turbine pump including self-adjusting and compensation with each other, it is far-reaching to analyze its internal flow by the numerical simulation based on CFD, mainly including the pressure field and the velocity field in hydraulic turbine and pump.The three-dimensional models of hydraulic turbine pump are made by Pro/Engineer software;the internal flow fields in hydraulic turbine and pump are simulated numerically by CFX ANSYS software. According to the results of the numerical simulation in design condition, the pressure field and the velocity field in hydraulic turbine and pump are analyzed respectively .The findings show that the static pressure decreases systematically and the pressure gradient is obvious in flow area of hydraulic turbine; the static pressure increases gradually in pump. The flow trace is regular in suction chamber and flume without spiral trace. However, there are irregular traces in the turbine runner channels which contrary to that in flow area of impeller. Most of traces in the flow area of draft tube are spiral.

CFD Modeling and Simulation of Aeorodynamic Cooling of Automotive Brake Rotor

NASA Astrophysics Data System (ADS)

Belhocien, Ali; Omar, Wan Zaidi Wan

Braking system is one of the important control systems of an automotive. For many years, the disc brakes have been used in automobiles for the safe retarding of the vehicles. During the braking enormous amount of heat will be generated and for effective braking sufficient heat dissipation is essential. The thermal performance of disc brake depends upon the characteristics of the airflow around the brake rotor and hence the aerodynamics is an important in the region of brake components. A CFD analysis is carried out on the braking system as a case study to make out the behavior of airflow distribution around the disc brake components using ANSYS CFX software. We are interested in the determination of the heat transfer coefficient (HTC) on each surface of a ventilated disc rotor varying with time in a transient state using CFD analysis, and then imported the surface film condition data into a corresponding FEM model for disc temperature analysis.

Analyse et design aerodynamique haute-fidelite de l'integration moteur sur un avion BWB

NASA Astrophysics Data System (ADS)

Mirzaei Amirabad, Mojtaba

BWB (Blended Wing Body) is an innovative type of aircraft based on the flying wing concept. In this configuration, the wing and the fuselage are blended together smoothly. BWB offers economical and environmental advantages by reducing fuel consumption through improving aerodynamic performance. In this project, the goal is to improve the aerodynamic performance by optimizing the main body of BWB that comes from conceptual design. The high fidelity methods applied in this project have been less frequently addressed in the literature. This research develops an automatic optimization procedure in order to reduce the drag force on the main body. The optimization is carried out in two main stages: before and after engine installation. Our objective is to minimize the drag by taking into account several constraints in high fidelity optimization. The commercial software, Isight is chosen as an optimizer in which MATLAB software is called to start the optimization process. Geometry is generated using ANSYS-DesignModeler, unstructured mesh is created by ANSYS-Mesh and CFD calculations are done with the help of ANSYS-Fluent. All of these software are coupled together in ANSYS-Workbench environment which is called by MATLAB. The high fidelity methods are used during optimization by solving Navier-Stokes equations. For verifying the results, a finer structured mesh is created by ICEM software to be used in each stage of optimization. The first stage includes a 3D optimization on the surface of the main body, before adding the engine. The optimized case is then used as an input for the second stage in which the nacelle is added. It could be concluded that this study leads us to obtain appropriate reduction in drag coefficient for BWB without nacelle. In the second stage (adding the nacelle) a drag minimization is also achieved by performing a local optimization. Furthermore, the flow separation, created in the main body-nacelle zone, is reduced.

Computational hemodynamics of an implanted coronary stent based on three-dimensional cine angiography reconstruction.

PubMed

Chen, Mounter C Y; Lu, Po-Chien; Chen, James S Y; Hwang, Ned H C

2005-01-01

Coronary stents are supportive wire meshes that keep narrow coronary arteries patent, reducing the risk of restenosis. Despite the common use of coronary stents, approximately 20-35% of them fail due to restenosis. Flow phenomena adjacent to the stent may contribute to restenosis. Three-dimensional computational fluid dynamics (CFD) and reconstruction based on biplane cine angiography were used to assess coronary geometry and volumetric blood flows. A patient-specific left anterior descending (LAD) artery was reconstructed from single-plane x-ray imaging. With corresponding electrocardiographic signals, images from the same time phase were selected from the angiograms for dynamic three-dimensional reconstruction. The resultant three-dimensional LAD artery at end-diastole was adopted for detailed analysis. Both the geometries and flow fields, based on a computational model from CAE software (ANSYS and CATIA) and full three-dimensional Navier-Stroke equations in the CFD-ACE+ software, respectively, changed dramatically after stent placement. Flow fields showed a complex three-dimensional spiral motion due to arterial tortuosity. The corresponding wall shear stresses, pressure gradient, and flow field all varied significantly after stent placement. Combined angiography and CFD techniques allow more detailed investigation of flow patterns in various segments. The implanted stent(s) may be quantitatively studied from the proposed hemodynamic modeling approach.

Dynamic Response of Composite Structures Underwater

DTIC Science & Technology

2013-09-01

then run and the desired data was viewed in CFD-post of the CFX tool. The ANSYS model illustrates the changing concavity of the beam along its...OF ABSTRACT Unclassified 20. LIMITATION OF ABSTRACT UU NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89) Prescribed by ANSI Std. 239-18...41 Figure 36. ANSYS Beam Displacement

Modeling and analysis of visual digital impact model for a Chinese human thorax.

PubMed

Zhu, Jin; Wang, Kai-Ming; Li, Shu; Liu, Hai-Yan; Jing, Xiao; Li, Xiao-Fang; Liu, Yi-He

2017-01-01

To establish a three-dimensional finite element model of the human chest for engineering research on individual protection. Computed tomography (CT) scanning data were used for three-dimensional reconstruction with the medical image reconstruction software Mimics. The finite element method (FEM) preprocessing software ANSYS ICEM CFD was used for cell mesh generation, and the relevant material behavior parameters of all of the model's parts were specified. The finite element model was constructed with the FEM software, and the model availability was verified based on previous cadaver experimental data. A finite element model approximating the anatomical structure of the human chest was established, and the model's simulation results conformed to the results of the cadaver experiment overall. Segment data of the human body and specialized software can be utilized for FEM model reconstruction to satisfy the need for numerical analysis of shocks to the human chest in engineering research on body mechanics.

Numerical study of the influence of flow blockage on the aerodynamic coefficients of models in low-speed wind tunnels

NASA Astrophysics Data System (ADS)

Bui, V. T.; Kalugin, V. T.; Lapygin, V. I.; Khlupnov, A. I.

2017-11-01

With the use of ANSYS Fluent software and ANSYS ICEM CFD calculation grid generator, the flows past a wing airfoil, an infinite cylinder, and 3D blunted bodies located in the open and closed test sections of low-speed wind tunnels were calculated. The mathematical model of the flows included the Reynolds equations and the SST model of turbulence. It was found that the ratios between the aerodynamic coefficients in the test section and in the free (unbounded) stream could be fairly well approximated with a piecewise-linear function of the blockage factor, whose value weakly depended on the angle of attack. The calculated data and data gained in the analysis of previously reported experimental studies proved to be in a good agreement. The impact of the extension of the closed test section on the airfoil lift force is analyzed.

Integration of Twenty-Bladed Cross-Flow Fan into Vertical Take-Off and Landing Aircraft

DTIC Science & Technology

2013-06-01

a new 20-bladed rotor was designed in SolidWorks and imported into ANSYS - CFX , which was used to analytically determine the thrust generated at speeds...implementation and experimentation. To accomplish this task, a new 20-bladed rotor was designed in SolidWorks and imported into ANSYS - CFX , which was...11 4. ANSYS - CFX CFD Analysis

Experimental investigation and CFD simulation of multi-pipe earth-to-air heat exchangers (EAHEs) flow performance

NASA Astrophysics Data System (ADS)

Amanowicz, Łukasz; Wojtkowiak, Janusz

2017-11-01

In this paper the experimentally obtained flow characteristics of multi-pipe earth-to-air heat exchangers (EAHEs) were used to validate the EAHE flow performance numerical model prepared by means of CFD software Ansys Fluent. The cut-cell meshing and the k-ɛ realizable turbulence model with default coefficients values and enhanced wall treatment was used. The total pressure losses and airflow in each pipe of multi-pipe exchangers was investigated both experimentally and numerically. The results show that airflow in each pipe of multi-pipe EAHE structures is not equal. The validated numerical model can be used for a proper designing of multi-pipe EAHEs from the flow characteristics point of view. The influence of EAHEs geometrical parameters on the total pressure losses and airflow division between the exchanger pipes can be also analysed. Usage of CFD for designing the EAHEs can be helpful for HVAC engineers (Heating Ventilation and Air Conditioning) for optimizing the geometrical structure of multi-pipe EAHEs in order to save the energy and decrease operational costs of low-energy buildings.

Numerical Performance Prediction of a Miniature Ramjet at Mach 4

DTIC Science & Technology

2012-09-01

with the computational fluids dynamic (CFD) code from ANSYS - CFX . The nozzle-throat area was varied to increase the backpressure and this pushed the...normal shock that was sitting within the inlet, out to the lip of the inlet cowl. Using the eddy dissipation combustion model in ANSYS - CFX , a...improved accuracy in turbulence modeling. 14. SUBJECT TERMS Mach 4, Ramjet, Drag, Turbulence Modeling, Simulation, ANSYS CFX 15. NUMBER

Transitional hemodynamics in intracranial aneurysms - Comparative velocity investigations with high resolution lattice Boltzmann simulations, normal resolution ANSYS simulations, and MR imaging.

PubMed

Jain, Kartik; Jiang, Jingfeng; Strother, Charles; Mardal, Kent-André

2016-11-01

Blood flow in intracranial aneurysms has, until recently, been considered to be disturbed but still laminar. Recent high resolution computational studies have demonstrated, in some situations, however, that the flow may exhibit high frequency fluctuations that resemble weakly turbulent or transitional flow. Due to numerous assumptions required for simplification in computational fluid dynamics (CFD) studies, the occurrence of these events, in vivo, remains unsettled. The detection of these fluctuations in aneurysmal blood flow, i.e., hemodynamics by CFD, poses additional challenges as such phenomena cannot be captured in clinical data acquisition with magnetic resonance (MR) due to inadequate temporal and spatial resolutions. The authors' purpose was to address this issue by comparing results from highly resolved simulations, conventional resolution laminar simulations, and MR measurements, identify the differences, and identify their causes. Two aneurysms in the basilar artery, one with disturbed yet laminar flow and the other with transitional flow, were chosen. One set of highly resolved direct numerical simulations using the lattice Boltzmann method (LBM) and another with adequate resolutions under laminar flow assumption were conducted using a commercially available ANSYS Fluent solver. The velocity fields obtained from simulation results were qualitatively and statistically compared against each other and with MR acquisition. Results from LBM, ANSYS Fluent, and MR agree well qualitatively and quantitatively for one of the aneurysms with laminar flow in which fluctuations were <80 Hz. The comparisons for the second aneurysm with high fluctuations of > ∼ 600 Hz showed vivid differences between LBM, ANSYS Fluent, and magnetic resonance imaging. After ensemble averaging and down-sampling to coarser space and time scales, these differences became minimal. A combination of MR derived data and CFD can be helpful in estimating the hemodynamic environment of intracranial aneurysms. Adequately resolved CFD would suffice gross assessment of hemodynamics, potentially in a clinical setting, and highly resolved CFD could be helpful in a detailed and retrospective understanding of the physiological mechanisms.

Buoyancy Driven Coolant Mixing Studies of Natural Circulation Flows at the ROCOM Test Facility Using ANSYS CFX

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

Hohne, Thomas; Kliem, Soren; Rohde, Ulrich

2006-07-01

Coolant mixing in the cold leg, downcomer and the lower plenum of pressurized water reactors is an important phenomenon mitigating the reactivity insertion into the core. Therefore, mixing of the de-borated slugs with the ambient coolant in the reactor pressure vessel was investigated at the four loop 1:5 scaled ROCOM mixing test facility. Thermal hydraulics analyses showed, that weakly borated condensate can accumulate in particular in the pump loop seal of those loops, which do not receive safety injection. After refilling of the primary circuit, natural circulation in the stagnant loops can re-establish simultaneously and the de-borated slugs are shiftedmore » towards the reactor pressure vessel (RPV). In the ROCOM experiments, the length of the flow ramp and the initial density difference between the slugs and the ambient coolant was varied. From the test matrix experiments with 0 resp. 2% density difference between the de-borated slugs and the ambient coolant were used to validate the CFD software ANSYS CFX. To model the effects of turbulence on the mean flow a higher order Reynolds stress turbulence model was employed and a mesh consisting of 6.4 million hybrid elements was utilized. Only the experiments and CFD calculations with modeled density differences show a stratification in the downcomer. Depending on the degree of density differences the less dense slugs flow around the core barrel at the top of the downcomer. At the opposite side the lower borated coolant is entrained by the colder safety injection water and transported to the core. The validation proves that ANSYS CFX is able to simulate appropriately the flow field and mixing effects of coolant with different densities. (authors)« less

Lactation in the Human Breast From a Fluid Dynamics Point of View.

PubMed

Negin Mortazavi, S; Geddes, Donna; Hassanipour, Fatemeh

2017-01-01

This study is a collaborative effort among lactation specialists and fluid dynamic engineers. The paper presents clinical results for suckling pressure pattern in lactating human breast as well as a 3D computational fluid dynamics (CFD) modeling of milk flow using these clinical inputs. The investigation starts with a careful, statistically representative measurement of suckling vacuum pressure, milk flow rate, and milk intake in a group of infants. The results from clinical data show that suckling action does not occur with constant suckling rate but changes in a rhythmic manner for infants. These pressure profiles are then used as the boundary condition for the CFD study using commercial ansys fluent software. For the geometric model of the ductal system of the human breast, this work takes advantage of a recent advance in the development of a validated phantom that has been produced as a ground truth for the imaging applications for the breast. The geometric model is introduced into CFD simulations with the aforementioned boundary conditions. The results for milk intake from the CFD simulation and clinical data were compared and cross validated. Also, the variation of milk intake versus suckling pressure are presented and analyzed. Both the clinical and CFD simulation show that the maximum milk flow rate is not related to the largest vacuum pressure or longest feeding duration indicating other factors influence the milk intake by infants.

Verification of a research prototype for hemodynamic analysis of cerebral aneurysms.

PubMed

Suzuki, Takashi; Ioan Nita, Cosmin; Rapaka, Saikiran; Takao, Hiroyuki; Mihalef, Viorel; Fujimura, Soichiro; Dahmani, Chihebeddine; Sharma, Puneet; Mamori, Hiroya; Ishibashi, Toshihiro; Redel, Thomas; Yamamoto, Makoto; Murayama, Yuichi

2016-08-01

Owing to its clinical importance, there has been a growing body of research on understanding the hemodynamics of cerebral aneurysms. Traditionally, this work has been performed using general-purpose, state-of-the-art commercial solvers. This has meant requiring engineering expertise for making appropriate choices on the geometric discretization, time-step selection, choice of boundary conditions etc. Recently, a CFD research prototype has been developed (Siemens Healthcare GmbH, Prototype - not for diagnostic use) for end-to-end analysis of aneurysm hemodynamics. This prototype enables anatomical model preparation, hemodynamic computations, advanced visualizations and quantitative analysis capabilities. In this study, we investigate the accuracy of the hemodynamic solver in the prototype against a commercially available CFD solver ANSYS CFX 16.0 (ANSYS Inc., Canonsburg, PA, www.ansys.com) retrospectively on a sample of twenty patient-derived aneurysm models, and show good agreement of hemodynamic parameters of interest.

Application of a single-fluid model for the steam condensing flow prediction

NASA Astrophysics Data System (ADS)

Smołka, K.; Dykas, S.; Majkut, M.; Strozik, M.

2016-10-01

One of the results of many years of research conducted in the Institute of Power Engineering and Turbomachinery of the Silesian University of Technology are computational algorithms for modelling steam flows with a non-equilibrium condensation process. In parallel with theoretical and numerical research, works were also started on experimental testing of the steam condensing flow. This paper presents a comparison of calculations of a flow field modelled by means of a single-fluid model using both an in-house CFD code and the commercial Ansys CFX v16.2 software package. The calculation results are compared to inhouse experimental testing.

Criteria for Analyzing the Quality Estimate shake using two different impellers, “Rushton Turbine” and “PBT 45”

NASA Astrophysics Data System (ADS)

Oliveira, E. C. M.; Silva, M. O. M.; Nunhez, J. R.; Ribeiro, e. L. C. L. J.

2016-08-01

The Computational Fluid Dynamics (CFD) is used to numerically simulate the behavior of fluid flow, and all the laws that rule the study of fluids, both the energy and mass transfer, chemical reactions, hydraulic behavior, and other applications. Among these innumerable applications, the local behavior of a mixing tank can be estimated using the CFD techniques. In order to follow-up studies in the literature giving them increased credibility, this project aimed to determine whether both the scheduling Potency/Volume and Torque/Volume maintain the necessary level of agitation in the mix tank to extrapolate the volume 10 times and 100 times, using an axial impeller blades inclined at 45 degrees type (PBT 45), and a radial impeller (Rushton turbine) with the use of the CFD. With the results, was analyzed if a criterion is superior to the other in terms of maintaining the level of agitation in scheduling. The case study made it possible to achieve the main objective, deepen studies in Computational Fluid Dynamics. Therefore, managed to the largest domain in tools offered by CFX-ANSYS 14.0 software, allowing future work to be conducted.

Pressure pulsation in Kaplan turbines: Prototype-CFD comparison

NASA Astrophysics Data System (ADS)

Rivetti, A.; Lucino1, C.; Liscia, S.; Muguerza, D.; Avellan, F.

2012-11-01

Pressure pulsation phenomena in a large Kaplan turbine are investigated by means of numerical simulations (CFD) and prototype measurements in order to study the dynamic behavior of flow due to the blade passage and its interaction with other components of the turbine. Numerical simulations are performed with the commercial software Ansys CFX code, solving the incompressible Unsteady Reynolds-Averaged-Navier Stokes equations under a finite volume scheme. The computational domain involves the entire machine at prototype scale. Special care is taken in the discretization of the wicket gate overhang and runner blade gap. Prototype measurements are performed using pressure transducers at different locations among the wicket gate outlet and the draft tube inlet. Then, CFD results are compared with temporary signals of prototype measurements at identical locations to validate the numerical model. A detailed analysis was focused on the tip gap flow and the pressure field at the discharge ring. From a rotating reference frame perspective, it is found that the mean pressure fluctuates accordingly the wicket gate passage. Moreover, in prototype measurements the pressure frequency that reveals the presence of modulated cavitation at the discharge ring is distinguished, as also verified from the shape of erosion patches in concordance with the number of wicket gates.

Aerodynamic Analysis of the M33 Projectile Using the CFX Code

DTIC Science & Technology

2011-12-01

is unlimited 12b. DISTRIBUTION CODE A 13. ABSTRACT (maximum 200 words) The M33 projectile has been analyzed using the ANSYS CFX code that is based...analyzed using the ANSYS CFX code that is based on the numerical solution of the full Navier-Stokes equations. Simulation data were obtained...using the CFX code. The ANSYS - CFX code is a commercial CFD program used to simulate fluid flow in a variety of applications such as gas turbine

CFD Simulation of a Wing-In-Ground-Effect UAV

NASA Astrophysics Data System (ADS)

Lao, C. T.; Wong, E. T. T.

2018-05-01

This paper reports a numerical analysis on a wing section used for a Wing-In-Ground-Effect (WIG) unmanned aerial vehicle (UAV). The wing geometry was created by SolidWorks and the incompressible Reynolds-averaged Navier-Stokes (RANS) equations were solved with the Spalart–Allmaras turbulence model using CFD software ANSYS FLUENT. In FLUENT, the Spalart-Allmaras model has been implemented to use wall functions when the mesh resolution is not sufficiently fine. This might make it the best choice for relatively crude simulations on coarse meshes where accurate turbulent flow computations are not critical. The results show that the lift coefficient and lift-drag ratio derived excellent performance enhancement by ground effect. However, the moment coefficient shows inconsistency when the wing is operating in very low altitude - this is owing to the difficulty on the stability control of WIG vehicle. A drag polar estimation based on the analysis also indicated that the Oswald (or span) efficiency of the wing was improved by ground effect.

Development of a radial ventricular assist device using numerical predictions and experimental haemolysis.

PubMed

Carswell, Dave; Hilton, Andy; Chan, Chris; McBride, Diane; Croft, Nick; Slone, Avril; Cross, Mark; Foster, Graham

2013-08-01

The objective of this study was to demonstrate the potential of Computational Fluid Dynamics (CFD) simulations in predicting the levels of haemolysis in ventricular assist devices (VADs). Three different prototypes of a radial flow VAD have been examined experimentally and computationally using CFD modelling to assess device haemolysis. Numerical computations of the flow field were computed using a CFD model developed with the use of the commercial software Ansys CFX 13 and a set of custom haemolysis analysis tools. Experimental values for the Normalised Index of Haemolysis (NIH) have been calculated as 0.020 g/100 L, 0.014 g/100 L and 0.0042 g/100 L for the three designs. Numerical analysis predicts an NIH of 0.021 g/100 L, 0.017 g/100 L and 0.0057 g/100 L, respectively. The actual differences between experimental and numerical results vary between 0.0012 and 0.003 g/100 L, with a variation of 5% for Pump 1 and slightly larger percentage differences for the other pumps. The work detailed herein demonstrates how CFD simulation and, more importantly, the numerical prediction of haemolysis may be used as an effective tool in order to help the designers of VADs manage the flow paths within pumps resulting in a less haemolytic device. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

Using ANSYS Fluent on the Peregrine System | High-Performance Computing |

Science.gov Websites

two ways to run ANSYS CFD interactively on NREL HPC systems. When graphics rendering is not a critical when used as above is quite low (e.g., windows take a long time to come up). For small tasks, it may be , go to Category/Connection/SSH, and check off the box "enable compression". When graphics

Load calculation on the nozzle in a flue gas desulphurization system

NASA Astrophysics Data System (ADS)

Róbert, Olšiak; Zoltán, Fuszko; Zoltán, Csuka

2017-09-01

The desulphurization system is used to remove sulfur oxides from exhaust, so-called flue gases through absorbing them via the sprayed suspension. The suspension delivered from the pump system to the atmospheric bi-directional double hollow cone nozzle has the prescribed working pressure. The unknown mechanical load on the solid body of the nozzle is present through the change of moment due to the flow of the suspension through the bi-directional outflow areas [1], [4]. The calculation of the acting forces and torques in the 3 directions was carried out with the methods of computational fluid dynamics (CFD) in the software ANSYS Fluent. The geometric model of the flow areas of the nozzle were created with the methods of reverse engineering. The computational mesh required by the CFD solver was created, and its quality verified with the standard criteria. The used boundary conditions were defined by the hydraulic parameters of the pump system, the properties of the suspension present in the hydraulic system were specified by sample analysis. The post-processed and analyzed results of the CFD calculation, the pressure-field and the velocity magnitudes in particular directions were further used as input parameters at the mechanical analysis of the load on the bi-directional nozzle.

Design of A Cyclone Separator Using Approximation Method

NASA Astrophysics Data System (ADS)

Sin, Bong-Su; Choi, Ji-Won; Lee, Kwon-Hee

2017-12-01

A Separator is a device installed in industrial applications to separate mixed objects. The separator of interest in this research is a cyclone type, which is used to separate a steam-brine mixture in a geothermal plant. The most important performance of the cyclone separator is the collection efficiency. The collection efficiency in this study is predicted by performing the CFD (Computational Fluid Dynamics) analysis. This research defines six shape design variables to maximize the collection efficiency. Thus, the collection efficiency is set up as the objective function in optimization process. Since the CFD analysis requires a lot of calculation time, it is impossible to obtain the optimal solution by linking the gradient-based optimization algorithm. Thus, two approximation methods are introduced to obtain an optimum design. In this process, an L18 orthogonal array is adopted as a DOE method, and kriging interpolation method is adopted to generate the metamodel for the collection efficiency. Based on the 18 analysis results, the relative importance of each variable to the collection efficiency is obtained through the ANOVA (analysis of variance). The final design is suggested considering the results obtained from two optimization methods. The fluid flow analysis of the cyclone separator is conducted by using the commercial CFD software, ANSYS-CFX.

Numerical simulations of LNG vapor dispersion in Brayton Fire Training Field tests with ANSYS CFX.

PubMed

Qi, Ruifeng; Ng, Dedy; Cormier, Benjamin R; Mannan, M Sam

2010-11-15

Federal safety regulations require the use of validated consequence models to determine the vapor cloud dispersion exclusion zones for accidental liquefied natural gas (LNG) releases. One tool that is being developed in industry for exclusion zone determination and LNG vapor dispersion modeling is computational fluid dynamics (CFD). This paper uses the ANSYS CFX CFD code to model LNG vapor dispersion in the atmosphere. Discussed are important parameters that are essential inputs to the ANSYS CFX simulations, including the atmospheric conditions, LNG evaporation rate and pool area, turbulence in the source term, ground surface temperature and roughness height, and effects of obstacles. A sensitivity analysis was conducted to illustrate uncertainties in the simulation results arising from the mesh size and source term turbulence intensity. In addition, a set of medium-scale LNG spill tests were performed at the Brayton Fire Training Field to collect data for validating the ANSYS CFX prediction results. A comparison of test data with simulation results demonstrated that CFX was able to describe the dense gas behavior of LNG vapor cloud, and its prediction results of downwind gas concentrations close to ground level were in approximate agreement with the test data. Copyright © 2010 Elsevier B.V. All rights reserved.

Numerical investigation of hub clearance flow in a Kaplan turbine

NASA Astrophysics Data System (ADS)

Wu, H.; Feng, J. J.; Wu, G. K.; Luo, X. Q.

2012-11-01

In this paper, the flow field considering the hub clearance flow in a Kaplan turbine has been investigated through using the commercial CFD code ANSYS CFX based on high-quality structured grids generated by ANSYS ICEM CFD. The turbulence is simulated by k-ω based shear stress transport (SST) turbulence model together with automatic near wall treatments. Four kinds of simulations have been conducted for the runner geometry without hub clearance, with only the hub front clearance, with only the rear hub clearance, and with both front and rear clearance. The analysis of the obtained results is focused on the flow structure of the hub clearance flow, the effect on the turbine performance including hydraulic efficiency and cavitation performance, which can improve the understanding on the flow field in a Kaplan turbine.

CFD comparison with centrifugal compressor measurements on a wide operating range

NASA Astrophysics Data System (ADS)

Le Sausse, P.; Fabrie, P.; Arnou, D.; Clunet, F.

2013-04-01

Centrifugal compressors are widely used in industrial applications thanks to their high efficiency. They are able to provide a wide operating range before reaching the flow barrier or surge limits. Performances and range are described by compressor maps obtained experimentally. After a description of performance test rig, this article compares measured centrifugal compressor performances with computational fluid dynamics results. These computations are performed at steady conditions with R134a refrigerant as fluid. Navier-Stokes equations, coupled with k-ɛ turbulence model, are solved by the commercial software ANSYS-CFX by means of volume finite method. Input conditions are varied in order to calculate several speed lines. Theoretical isentropic efficiency and theoretical surge line are finally compared to experimental data.

Computational Analysis of an effect of aerodynamic pressure on the side view mirror geometry

NASA Astrophysics Data System (ADS)

Murukesavan, P.; Mu'tasim, M. A. N.; Sahat, I. M.

2013-12-01

This paper describes the evaluation of aerodynamic flow effects on side mirror geometry for a passenger car using ANSYS Fluent CFD simulation software. Results from analysis of pressure coefficient on side view mirror designs is evaluated to analyse the unsteady forces that cause fluctuations to mirror surface and image blurring. The fluctuation also causes drag forces that increase the overall drag coefficient, with an assumption resulting in higher fuel consumption and emission. Three features of side view mirror design were investigated with two input velocity parameters of 17 m/s and 33 m/s. Results indicate that the half-sphere design shows the most effective design with less pressure coefficient fluctuation and drag coefficient.

CFD analysis of the plate heat exchanger - Mathematical modelling of mass and heat transfer in serial connection with tubular heat exchanger

NASA Astrophysics Data System (ADS)

Bojko, Marian; Kocich, Radim

2016-06-01

Application of numerical simulations based on the CFD calculation when the mass and heat transfer between the fluid flows is essential component of thermal calculation. In this article the mathematical model of the heat exchanger is defined, which is subsequently applied to the plate heat exchanger, which is connected in series with the other heat exchanger (tubular heat exchanger). The present contribution deals with the possibility to use the waste heat of the flue gas produced by small micro turbine. Inlet boundary conditions to the mathematical model of the plate heat exchanger are obtained from the results of numerical simulation of the tubular heat exchanger. Required parameters such for example inlet temperature was evaluated from temperature field, which was subsequently imported to the inlet boundary condition to the simulation of plate heat exchanger. From the results of 3D numerical simulations are evaluated basic flow variables including the evaluation of dimensionless parameters such as Colburn j-factor and friction ft factor. Numerical simulation is realized by software ANSYS Fluent15.0.

Verification of ANSYS Fluent and OpenFOAM CFD platforms for prediction of impact flow

NASA Astrophysics Data System (ADS)

Tisovská, Petra; Peukert, Pavel; Kolář, Jan

The main goal of the article is a verification of the heat transfer coefficient numerically predicted by two CDF platforms - ANSYS-Fluent and OpenFOAM on the problem of impact flows oncoming from 2D nozzle. Various mesh parameters and solver settings were tested under several boundary conditions and compared to known experimental results. The best solver setting, suitable for further optimization of more complex geometry is evaluated.

The conical stent in coronary artery improves hemodynamics compared with the traditional cylindrical stent.

PubMed

Yu, Yi; Zhou, Yujie; Ma, Qian; Jia, Shuo; Wu, Sijing; Sun, Yan; Liu, Xiaoli; Zhao, Yingxin; Liu, Yuyang; Shi, Dongmei

2017-01-15

This study sought to explore the efficacy of the conical stent implantation in the coronary artery by comparing the effects of cylindrical and conical stents on wall shear stress (WSS) and velocity of flow and fractional flow reserve (FFR). The traditional cylindrical stent currently used in the percutaneous coronary intervention (PCI) has a consistent diameter, which does not match the physiological change of the coronary artery. On the contrary, as a new patent, the conical stent with tapering lumen is consistent with the physiological change of vascular diameter. However, the effect of the conical stent implantation on the coronary hemodynamics remains unclear. The coronary artery, artery stenosis and two stent models were established by Solidworks software. All models were imported into the computational fluid dynamics (CFD) software ANSYS ICEM-CFD to establish the fluid model. After the boundary conditions were set, CFD analysis was proceeded to compare the effects of two stent implantation on the change of WSS, velocity of flow and FFR. Hemodynamic indexes including FFR, blood flow velocity distribution (BVD) and WSS were improved by either the cylindrical or the conical stent implantation. However, after the conical stent implantation, the change of FFR seemed to be slower and more homogenous; the blood flow velocity was more appropriate without any obvious blood stagnation and direction changes; the WSS after the conical stent implantation was uniform from the proximal to distal side of the stent. Compared with the cylindrical stent, the conical stent implantation in the coronary artery can make the changes of vascular hemodynamic more closer to the physiological condition, which can reduce the incidence of intra-stent restenosis and thrombosis, thus making it more suitable for PCI therapy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Computational Fluid Dynamics (CFD) study of the 4th generation prototype of a continuous flow Ventricular Assist Device (VAD).

PubMed

Song, Xinwei; Wood, Houston G; Olsen, Don

2004-04-01

The continuous flow ventricular assist device (VAD) is a miniature centrifugal pump, fully suspended by magnetic bearings, which is being developed for implantation in humans. The CF4 model is the first actual prototype of the final design product. The overall performances of blood flow in CF4 have been simulated using computational fluid dynamics (CFD) software: CFX, which is commercially available from ANSYS Inc. The flow regions modeled in CF4 include the inlet elbow, the five-blade impeller, the clearance gap below the impeller, and the exit volute. According to different needs from patients, a wide range of flow rates and revolutions per minute (RPM) have been studied. The flow rate-pressure curves are given. The streamlines in the flow field are drawn to detect stagnation points and vortices that could lead to thrombosis. The stress is calculated in the fluid field to estimate potential hemolysis. The stress is elevated to the decreased size of the blood flow paths through the smaller pump, but is still within the safe range. The thermal study on the pump, the blood and the surrounding tissue shows the temperature rise due to magnetoelectric heat sources and thermal dissipation is insignificant. CFD simulation proved valuable to demonstrate and to improve the performance of fluid flow in the design of a small size pump.

Computational fluid dynamics (CFD) simulation of a newly designed passive particle sampler.

PubMed

Sajjadi, H; Tavakoli, B; Ahmadi, G; Dhaniyala, S; Harner, T; Holsen, T M

2016-07-01

In this work a series of computational fluid dynamics (CFD) simulations were performed to predict the deposition of particles on a newly designed passive dry deposition (Pas-DD) sampler. The sampler uses a parallel plate design and a conventional polyurethane foam (PUF) disk as the deposition surface. The deposition of particles with sizes between 0.5 and 10 μm was investigated for two different geometries of the Pas-DD sampler for different wind speeds and various angles of attack. To evaluate the mean flow field, the k-ɛ turbulence model was used and turbulent fluctuating velocities were generated using the discrete random walk (DRW) model. The CFD software ANSYS-FLUENT was used for performing the numerical simulations. It was found that the deposition velocity increased with particle size or wind speed. The modeled deposition velocities were in general agreement with the experimental measurements and they increased when flow entered the sampler with a non-zero angle of attack. The particle-size dependent deposition velocity was also dependent on the geometry of the leading edge of the sampler; deposition velocities were more dependent on particle size and wind speeds for the sampler without the bend in the leading edge of the deposition plate, compared to a flat plate design. Foam roughness was also found to have a small impact on particle deposition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Technology for Transient Simulation of Vibration during Combustion Process in Rocket Thruster

NASA Astrophysics Data System (ADS)

Zubanov, V. M.; Stepanov, D. V.; Shabliy, L. S.

2018-01-01

The article describes the technology for simulation of transient combustion processes in the rocket thruster for determination of vibration frequency occurs during combustion. The engine operates on gaseous propellant: oxygen and hydrogen. Combustion simulation was performed using the ANSYS CFX software. Three reaction mechanisms for the stationary mode were considered and described in detail. The way for obtaining quick CFD-results with intermediate combustion components using an EDM model was found. The way to generate the Flamelet library with CFX-RIF was described. A technique for modeling transient combustion processes in the rocket thruster was proposed based on the Flamelet library. A cyclic irregularity of the temperature field like vortex core precession was detected in the chamber. Frequency of flame precession was obtained with the proposed simulation technique.

Performance simulation of a radial flow type impeller of centrifugal pumps using CFD

NASA Astrophysics Data System (ADS)

López, R.; Vaca, M.; Terres, H.; Lizardi, A.; Chávez, S.; García., M.

2017-01-01

The numerical simulation of a centrifugal impeller that had previously been designed and manufactured is presented in this paper. The following operating conditions were determined: 0.50 m3/min volumetric flow at a load of 25 m, velocity of rotation of 1750 rpm, and specific velocity of 0. 27. The ANSYS CFX 14.5 software with the k-ε turbulence model was used for simulation with appropriate boundary conditions. The distributions of velocities in the flow field in addition to the distribution of pressures on the entire impeller were obtained. The simulation showed no negative values for the pressure at the entrance of the impeller. The curve of hydrodynamic behaviour of the impeller, which contains the point of operation in which the pump will work was also developed.

Numerical simulation of air distribution in a room with a sidewall jet under benchmark test conditions

NASA Astrophysics Data System (ADS)

Zasimova, Marina; Ivanov, Nikolay

2018-05-01

The goal of the study is to validate Large Eddy Simulation (LES) data on mixing ventilation in an isothermal room at conditions of benchmark experiments by Hurnik et al. (2015). The focus is on the accuracy of the mean and rms velocity fields prediction in the quasi-free jet zone of the room with 3D jet supplied from a sidewall rectangular diffuser. Calculations were carried out using the ANSYS Fluent 16.2 software with an algebraic wall-modeled LES subgrid-scale model. CFD results on the mean velocity vector are compared with the Laser Doppler Anemometry data. The difference between the mean velocity vector and the mean air speed in the jet zone, both LES-computed, is presented and discussed.

CFD Prediction on the Pressure Distribution and Streamlines around an Isolated Single-Storey House Considering the Effect of Topographic Characteristics

NASA Astrophysics Data System (ADS)

Abdullah, J.; Zaini, S. S.; Aziz, M. S. A.; Majid, T. A.; Deraman, S. N. C.; Yahya, W. N. W.

2018-04-01

Single-storey houses are classified as low rise building and vulnerable to damages under windstorm event. This study was carried out with the aim to investigate the pressure distribution and streamlines around an isolated house by considering the effect of terrain characteristics. The topographic features such as flat, depression, ridge, and valley, are considered in this study. This simulation were analysed with Ansys FLUENT 14.0 software package. The result showed the topography characteristics influence the value of pressure coefficient and streamlines especially when the house was located at ridge terrain. The findings strongly suggested that wind analysis should include all topographic features in the analysis in order to establish the true wind force exerted on any structure.

Influence of Contact Angle Boundary Condition on CFD Simulation of T-Junction

NASA Astrophysics Data System (ADS)

Arias, S.; Montlaur, A.

2018-03-01

In this work, we study the influence of the contact angle boundary condition on 3D CFD simulations of the bubble generation process occurring in a capillary T-junction. Numerical simulations have been performed with the commercial Computational Fluid Dynamics solver ANSYS Fluent v15.0.7. Experimental results serve as a reference to validate numerical results for four independent parameters: the bubble generation frequency, volume, velocity and length. CFD simulations accurately reproduce experimental results both from qualitative and quantitative points of view. Numerical results are very sensitive to the gas-liquid-wall contact angle boundary conditions, confirming that this is a fundamental parameter to obtain accurate CFD results for simulations of this kind of problems.

Data resulting from the CFD analysis of ten window frames according to the UNI EN ISO 10077-2.

PubMed

Baglivo, Cristina; Malvoni, Maria; Congedo, Paolo Maria

2016-09-01

Data are related to the numerical simulation performed in the study entitled "CFD modeling to evaluate the thermal performances of window frames in accordance with the ISO 10077" (Malvoni et al., 2016) [1]. The paper focuses on the results from a two-dimensional numerical analysis for ten frame sections suggested by the ISO 10077-2 and performed using GAMBIT 2.2 and ANSYS FLUENT 14.5 CFD code. The dataset specifically includes information about the CFD setup and boundary conditions considered as the input values of the simulations. The trend of the isotherms points out the different impacts on the thermal behaviour of all sections with air solid material or ideal gas into the cavities.

Nonequilibrium Hypersonic Aerothermodynamics Using the Direct Simulation Monte Carlo And Navier-Stokes Models

DTIC Science & Technology

2008-01-17

15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18 . NUMBER OF PAGES 261 19a. NAME OF RESPONSIBLE PERSON a...REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39- 18 This material...Sciences Meeting and Exhibit. Several DSMC [13, 58] and CFD [ 18 , 28, 43] solutions were submitted. Later, others compared CFD and DSMC solutions to these

Comparison of modeled and experimental PV array temperature profiles for accurate interpretation of module performance and degradation

NASA Astrophysics Data System (ADS)

Elwood, Teri; Simmons-Potter, Kelly

2017-08-01

Quantification of the effect of temperature on photovoltaic (PV) module efficiency is vital to the correct interpretation of PV module performance under varied environmental conditions. However, previous work has demonstrated that PV module arrays in the field are subject to significant location-based temperature variations associated with, for example, local heating/cooling and array edge effects. Such thermal non-uniformity can potentially lead to under-prediction or over-prediction of PV array performance due to an incorrect interpretation of individual module temperature de-rating. In the current work, a simulated method for modeling the thermal profile of an extended PV array has been investigated through extensive computational modeling utilizing ANSYS, a high-performance computational fluid dynamics (CFD) software tool. Using the local wind speed as an input, simulations were run to determine the velocity at particular points along modular strings corresponding to the locations of temperature sensors along strings in the field. The point velocities were utilized along with laminar flow theories in order to calculate Nusselt's number for each point. These calculations produced a heat flux profile which, when combined with local thermal and solar radiation profiles, were used as inputs in an ANSYS Thermal Transient model that generated a solar string operating temperature profile. A comparison of the data collected during field testing, and the data fabricated by ANSYS simulations, will be discussed in order to authenticate the accuracy of the model.

Exploratory investigation of the HIPPO gas-jet target fluid dynamic properties

NASA Astrophysics Data System (ADS)

Meisel, Zach; Shi, Ke; Jemcov, Aleksandar; Couder, Manoel

2016-08-01

In order to optimize the performance of gas-jet targets for future nuclear reaction measurements, a detailed understanding of the dependence of the gas-jet properties on experiment design parameters is required. Common methods of gas-jet characterization rely on measuring the effective thickness using nuclear elastic scattering and energy loss techniques; however, these tests are time intensive and limit the range of design modifications which can be explored to improve the properties of the jet as a nuclear reaction target. Thus, a more rapid jet-characterization method is desired. We performed the first steps towards characterizing the gas-jet density distribution of the HIPPO gas-jet target at the University of Notre Dame's Nuclear Science Laboratory by reproducing results from 20Ne(α,α)20Ne elastic scattering measurements with computational fluid dynamics (CFD) simulations performed with the state-of-the-art CFD software ANSYS Fluent. We find a strong sensitivity to experimental design parameters of the gas-jet target, such as the jet nozzle geometry and ambient pressure of the target chamber. We argue that improved predictive power will require moving to three-dimensional simulations and additional benchmarking with experimental data.

Verification of transport equations in a general purpose commercial CFD code.

NASA Astrophysics Data System (ADS)

Melot, Matthieu; Nennemann, Bernd; Deschênes, Claire

2016-11-01

In this paper, the Verification and Validation methodology is presented. This method aims to increase the reliability and the trust that can be placed into complex CFD simulations. The first step of this methodology, the code verification is presented in greater details. The CFD transport equations in steady state, transient and Arbitrary Eulerian Lagrangian (ALE, used for transient moving mesh) formulations in Ansys CFX are verified. It is shown that the expected spatial and temporal order of convergence are achieved for the steady state and the transient formulations. Unfortunately this is not completely the case for the ALE formulation. As for a lot of other commercial and in-house CFD codes, the temporal convergence of the velocity is limited to a first order where a second order would have been expected.

Verification of Advective Bar Elements Implemented in the Aria Thermal Response Code.

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

Mills, Brantley

2016-01-01

A verification effort was undertaken to evaluate the implementation of the new advective bar capability in the Aria thermal response code. Several approaches to the verification process were taken : a mesh refinement study to demonstrate solution convergence in the fluid and the solid, visually examining the mapping of the advective bar element nodes to the surrounding surfaces, and a comparison of solutions produced using the advective bars for simple geometries with solutions from commercial CFD software . The mesh refinement study has shown solution convergence for simple pipe flow in both temperature and velocity . Guidelines were provided tomore » achieve appropriate meshes between the advective bar elements and the surrounding volume. Simulations of pipe flow using advective bars elements in Aria have been compared to simulations using the commercial CFD software ANSYS Fluent (r) and provided comparable solutions in temperature and velocity supporting proper implementation of the new capability. Verification of Advective Bar Elements iv Acknowledgements A special thanks goes to Dean Dobranich for his guidance and expertise through all stages of this effort . His advice and feedback was instrumental to its completion. Thanks also goes to Sam Subia and Tolu Okusanya for helping to plan many of the verification activities performed in this document. Thank you to Sam, Justin Lamb and Victor Brunini for their assistance in resolving issues encountered with running the advective bar element model. Finally, thanks goes to Dean, Sam, and Adam Hetzler for reviewing the document and providing very valuable comments.« less

RotCFD Software Validation - Computational and Experimental Data Comparison

NASA Technical Reports Server (NTRS)

Fernandez, Ovidio Montalvo

2014-01-01

RotCFD is a software intended to ease the design of NextGen rotorcraft. Since RotCFD is a new software still in the development process, the results need to be validated to determine the software's accuracy. The purpose of the present document is to explain one of the approaches to accomplish that goal.

Improved design of a cone-shaped rotating disk for shear force loading in a cell culture plate

NASA Astrophysics Data System (ADS)

Keawprachum, Boonrit; Limjeerajarus, Nuttapol; Nakalekha Limjeerajarus, Chalida; Srisungsitthisunti, Pornsak

2018-01-01

In our previous study, a cone-shaped rotating disk had been designed and proposed for generating shear force on the cell in a cell culture plate. This study aims to improve the design of the rotating disk that could provide a better uniformity of shear stress distribution. The top of the cone was designed to be trimmed off to obtain a flat head area. The effect of tilt angle (θ) was numerically studied using computational fluid dynamics (CFD) technique in ANSYS-Fluent software. The results revealed that for 500 rpm, the new designed rotating disk with a height of cone-shaped top to the plate bottom h = 1 mm and θ = 25° provided the best uniformity of 0.820 which was better than that of the previously designed.

Static analysis of the hull plate using the finite element method

NASA Astrophysics Data System (ADS)

Ion, A.

2015-11-01

This paper aims at presenting the static analysis for two levels of a container ship's construction as follows: the first level is at the girder / hull plate and the second level is conducted at the entire strength hull of the vessel. This article will describe the work for the static analysis of a hull plate. We shall use the software package ANSYS Mechanical 14.5. The program is run on a computer with four Intel Xeon X5260 CPU processors at 3.33 GHz, 32 GB memory installed. In terms of software, the shared memory parallel version of ANSYS refers to running ANSYS across multiple cores on a SMP system. The distributed memory parallel version of ANSYS (Distributed ANSYS) refers to running ANSYS across multiple processors on SMP systems or DMP systems.

Reduced combustion mechanism for C1-C4 hydrocarbons and its application in computational fluid dynamics flare modeling.

PubMed

Damodara, Vijaya; Chen, Daniel H; Lou, Helen H; Rasel, Kader M A; Richmond, Peyton; Wang, Anan; Li, Xianchang

2017-05-01

Emissions from flares constitute unburned hydrocarbons, carbon monoxide (CO), soot, and other partially burned and altered hydrocarbons along with carbon dioxide (CO 2 ) and water. Soot or visible smoke is of particular concern for flare operators/regulatory agencies. The goal of the study is to develop a computational fluid dynamics (CFD) model capable of predicting flare combustion efficiency (CE) and soot emission. Since detailed combustion mechanisms are too complicated for (CFD) application, a 50-species reduced mechanism, LU 3.0.1, was developed. LU 3.0.1 is capable of handling C 4 hydrocarbons and soot precursor species (C 2 H 2 , C 2 H 4 , C 6 H 6 ). The new reduced mechanism LU 3.0.1 was first validated against experimental performance indicators: laminar flame speed, adiabatic flame temperature, and ignition delay. Further, CFD simulations using LU 3.0.1 were run to predict soot emission and CE of air-assisted flare tests conducted in 2010 in Tulsa, Oklahoma, using ANSYS Fluent software. Results of non-premixed probability density function (PDF) model and eddy dissipation concept (EDC) model are discussed. It is also noteworthy that when used in conjunction with the EDC turbulence-chemistry model, LU 3.0.1 can reasonably predict volatile organic compound (VOC) emissions as well. A reduced combustion mechanism containing 50 C 1 -C 4 species and soot precursors has been developed and validated against experimental data. The combustion mechanism is then employed in the computational fluid dynamics (CFD) of modeling of soot emission and combustion efficiency (CE) of controlled flares for which experimental soot and CE data are available. The validated CFD modeling tools are useful for oil, gas, and chemical industries to comply with U.S. Environmental Protection Agency's (EPA) mandate to achieve smokeless flaring with a high CE.

CFD Analysis of Coolant Flow in VVER-440 Fuel Assemblies with the Code ANSYS CFX 10.0

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

Toth, Sandor; Legradi, Gabor; Aszodi, Attila

2006-07-01

From the aspect of planning the power upgrading of nuclear reactors - including the VVER-440 type reactor - it is essential to get to know the flow field in the fuel assembly. For this purpose we have developed models of the fuel assembly of the VVER-440 reactor using the ANSYS CFX 10.0 CFD code. At first a 240 mm long part of a 60 degrees segment of the fuel pin bundle was modelled. Implementing this model a sensitivity study on the appropriate meshing was performed. Based on the development of the above described model, further models were developed: a 960more » mm long part of a 60-degree-segment and a full length part (2420 mm) of the fuel pin bundle segment. The calculations were run using constant coolant properties and several turbulence models. The impacts of choosing different turbulence models were investigated. The results of the above-mentioned investigations are presented in this paper. (authors)« less

CFD Modeling of Water Flow through Sudden Contraction and Expansion in a Horizontal Pipe

ERIC Educational Resources Information Center

Kaushik, V. V. R.; Ghosh, S.; Das, G.; Das, P. K.

2011-01-01

This paper deals with the use of commercial CFD software in teaching graduate level computational fluid dynamics. FLUENT 6.3.26 was chosen as the CFD software to teach students the entire CFD process in a single course. The course objective is to help students to learn CFD, use it in some practical problems and analyze as well as validate the…

Software Framework for Advanced Power Plant Simulations

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

John Widmann; Sorin Munteanu; Aseem Jain

2010-08-01

This report summarizes the work accomplished during the Phase II development effort of the Advanced Process Engineering Co-Simulator (APECS). The objective of the project is to develop the tools to efficiently combine high-fidelity computational fluid dynamics (CFD) models with process modeling software. During the course of the project, a robust integration controller was developed that can be used in any CAPE-OPEN compliant process modeling environment. The controller mediates the exchange of information between the process modeling software and the CFD software. Several approaches to reducing the time disparity between CFD simulations and process modeling have been investigated and implemented. Thesemore » include enabling the CFD models to be run on a remote cluster and enabling multiple CFD models to be run simultaneously. Furthermore, computationally fast reduced-order models (ROMs) have been developed that can be 'trained' using the results from CFD simulations and then used directly within flowsheets. Unit operation models (both CFD and ROMs) can be uploaded to a model database and shared between multiple users.« less

Structural Performance’s Optimally Analysing and Implementing Based on ANSYS Technology

NASA Astrophysics Data System (ADS)

Han, Na; Wang, Xuquan; Yue, Haifang; Sun, Jiandong; Wu, Yongchun

2017-06-01

Computer-aided Engineering (CAE) is a hotspot both in academic field and in modern engineering practice. Analysis System(ANSYS) simulation software for its excellent performance become outstanding one in CAE family, it is committed to the innovation of engineering simulation to help users to shorten the design process, improve product innovation and performance. Aimed to explore a structural performance’s optimally analyzing model for engineering enterprises, this paper introduced CAE and its development, analyzed the necessity for structural optimal analysis as well as the framework of structural optimal analysis on ANSYS Technology, used ANSYS to implement a reinforced concrete slab structural performance’s optimal analysis, which was display the chart of displacement vector and the chart of stress intensity. Finally, this paper compared ANSYS software simulation results with the measured results,expounded that ANSYS is indispensable engineering calculation tools.

3D CFD Quantification of the Performance of a Multi-Megawatt Wind Turbine

NASA Astrophysics Data System (ADS)

Laursen, J.; Enevoldsen, P.; Hjort, S.

2007-07-01

This paper presents the results of 3D CFD rotor computations of a Siemens SWT-2.3-93 variable speed wind turbine with 45m blades. In the paper CFD is applied to a rotor at stationary wind conditions without wind shear, using the commercial multi-purpose CFD-solvers ANSYS CFX 10.0 and 11.0. When comparing modelled mechanical effects with findings from other models and measurements, good agreement is obtained. Similarly the computed force distributions compare very well, whereas some discrepancies are found when comparing with an in-house BEM model. By applying the reduced axial velocity method the local angle of attack has been derived from the CFD solutions, and from this knowledge and the computed force distributions, local airfoil profile coefficients have been computed and compared to BEM airfoil coefficients. Finally, the transition model of Langtry and Menter is tested on the rotor, and the results are compared with the results from the fully turbulent setup.

Preliminary design of mesoscale turbocompressor and rotordynamics tests of rotor bearing system

NASA Astrophysics Data System (ADS)

Hossain, Md Saddam

2011-12-01

A mesoscale turbocompressor spinning above 500,000 RPM is evolutionary technology for micro turbochargers, turbo blowers, turbo compressors, micro-gas turbines, auxiliary power units, etc for automotive, aerospace, and fuel cell industries. Objectives of this work are: (1) to evaluate different air foil bearings designed for the intended applications, and (2) to design & perform CFD analysis of a micro-compressor. CFD analysis of shrouded 3-D micro compressor was conducted using Ansys Bladegen as blade generation tool, ICEM CFD as mesh generation tool, and CFX as main solver for different design and off design cases and also for different number of blades. Comprehensive experimental facilities for testing the turbocompressor system have been also designed and proposed for future work.

Use of computational fluid dynamics in respiratory medicine.

PubMed

Fernández Tena, Ana; Casan Clarà, Pere

2015-06-01

Computational Fluid Dynamics (CFD) is a computer-based tool for simulating fluid movement. The main advantages of CFD over other fluid mechanics studies include: substantial savings in time and cost, the analysis of systems or conditions that are very difficult to simulate experimentally (as is the case of the airways), and a practically unlimited level of detail. We used the Ansys-Fluent CFD program to develop a conducting airway model to simulate different inspiratory flow rates and the deposition of inhaled particles of varying diameters, obtaining results consistent with those reported in the literature using other procedures. We hope this approach will enable clinicians to further individualize the treatment of different respiratory diseases. Copyright © 2014 SEPAR. Published by Elsevier Espana. All rights reserved.

Tribological characteristic enhancement effects by polymer thickened oil in lubricated sliding contacts

NASA Astrophysics Data System (ADS)

Pratomo, Ariawan Wahyu; Muchammad, Tauviqirrahman, Mohammad; Jamari, Bayuseno, Athanasius P.

2016-04-01

Polymer thickened oils are the most preferred materials for modern lubrication applications due to their high shear. The present paper explores a lubrication mechanism in sliding contact lubricated with polymer thickened oil considering cavitation. Investigations are carried out by using a numerical method based on commercial CFD (computational fluid dynamic) software ANSYS for fluid flow phenomenon (Fluent) to assess the tribological characteristic (i.e. hydrodynamic pressure distribution) of lubricated sliding contact. The Zwart-Gerber-Belamri model for cavitation is adopted in this simulation to predict the extent of the full film region. The polymer thickened oil is characterized as non-Newtonian power-law fluid. The simulation results show that the cavitation lead lower pressure profile compared to that without cavitation. In addition, it is concluded that the characteristic of the lubrication performance with polymer thickened oil is strongly dependent on the Power-law index of lubricant.

CFD analysis of hydrodynamic studies of a bubbling fluidized bed

NASA Astrophysics Data System (ADS)

Rao, B. J. M.; Rao, K. V. N. S.; Ranga Janardhana, G.

2018-03-01

Fluidization velocity is one of the most important parameter to characterize the hydrodynamic studies of fluidized bed asit determines different flow regimes. Computational Fluid Dynamics simulations are carriedfor a cylindrical bubbling fluidized bed with a static bed height 1m with 0.150m diameter of gasification chamber. The parameter investigated is fluidization velocity in range of 0.05m/s to 0.7m/s. Sand with density 2600kg/m3 and with a constant particle diameter of sand 385μm is employed for all the simulations. Simulations are conducted using the commercial Computational Fluid Dynamics software, ANSYS-FLUENT.The bubbling flow regime is appeared above the air inlet velocity of 0.2m/s. Bubbling character is increased with increase in inlet air velocities indicated by asymmetrical fluctuations of volume fractions in radial directions at different bed heights

The influence of fuel type to combustion characteristic in diffusion flame drying by computational fluid dynamics simulation

NASA Astrophysics Data System (ADS)

Septiani, Eka Lutfi; Widiyastuti, W.; Machmudah, Siti; Nurtono, Tantular; Winardi, Sugeng

2017-05-01

Diffusion flame spray drying has become promising method in nanoparticles synthesis giving several advantages and low operation cost. In order to scale up the process which needs high experimentation time and cost, Computational Fluid Dynamics (CFD) by Ansys Fluent 15.0 software has been used. Combustion characteristic in diffusion flame reactor may affects particle size distribution. This study aims to observe influence of fuel type to combustion characteristic in the reactor. Large Eddy Simulation (LES) and non-premixed combustion model are selected for the turbulence and combustion model respectively. Methane, propane, and LPG in 0.5 L/min were used as type of fuel. While the oxidizer is air with 200% excess of O2. Simulation result shown that the maximum temperature was obtained from propane-air combustion in 2268 K. However, the stable temperature contour was achieved by methane-air combustion.

Determination of the oil distribution in a hermetic compressor using numerical simulation

NASA Astrophysics Data System (ADS)

Posch, S.; Hopfgartner, J.; Berger, E.; Zuber, B.; Almbauer, R.; Schöllauf, P.

2017-08-01

In addition to the reduction of friction the oil in a hermetic compressor is very important for the transfer of heat from hot parts to the compressor shell. The simulation of the oil distribution in a hermetic reciprocating compressor for refrigeration application is shown in the present work. Using the commercial Computational Fluid Dynamics (CFD) software ANSYS Fluent, the oil flow inside the compressor shell from the oil pump outlet to the oil sump is calculated. A comprehensive overview of the used models and the boundary conditions is given. After reaching steady-state conditions the oil covered surfaces are analysed concerning heat transfer coefficients. The gained heat transfer coefficients are used as input parameters for a thermal model of a hermetic compressor. An increase in accuracy of the thermal model with the simulated heat transfer coefficients compared to values from literature is shown by model validation with experimental data.

NASA geometry data exchange specification for computational fluid dynamics (NASA IGES)

NASA Technical Reports Server (NTRS)

Blake, Matthew W.; Kerr, Patricia A.; Thorp, Scott A.; Jou, Jin J.

1994-01-01

This document specifies a subset of an existing product data exchange specification that is widely used in industry and government. The existing document is called the Initial Graphics Exchange Specification. This document, a subset of IGES, is intended for engineers analyzing product performance using tools such as computational fluid dynamics (CFD) software. This document specifies how to define mathematically and exchange the geometric model of an object. The geometry is represented utilizing nonuniform rational B-splines (NURBS) curves and surfaces. Only surface models are represented; no solid model representation is included. This specification does not include most of the other types of product information available in IGES (e.g., no material properties or surface finish properties) and does not provide all the specific file format details of IGES. The data exchange protocol specified in this document is fully conforming to the American National Standard (ANSI) IGES 5.2.

Numerical Study on the Particle Trajectory Tracking in a Micro-UV Bio-Fluorescence Sensor.

PubMed

Byeon, Sun-Seok; Cho, Moon-Young; Lee, Jong-Chul; Kim, Youn-Jea

2015-03-01

A micro-UV bio-fluorescence sensor was developed to detect primary biological aerosols including bacteria, bacterial spores, fungal spores, pollens, viruses, algae, etc. In order to effectively detect the bio-particles in a micro-UV bio-fluorescence sensor, numerical calculations were performed to adjust for appropriate flow conditions of the sensor by regulating the sample aerosols and sheath flow. In particular, a CFD-based model of hydrodynamic processes was developed by computing the trajectory of particles using commercially available ANSYS CFX-14 software and the Lagrangian tracking model. The established model was evaluated with regard to the variation of sheath flow rate and particle size. Results showed that the sheath flow was changed rapidly at the end of nozzle tip, but the sample particles moved near the center of aerosol jet for aerodynamic focusing with little deviation from the axis.

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

Pauzi, Anas Muhamad, E-mail: Anas@uniten.edu.my; Cioncolini, Andrea; Iacovides, Hector

The Molten Salt Reactor (MSR) is one of the most promising system proposed by Generation IV Forum (GIF) for future nuclear reactor systems. Advantages of the MSR are significantly larger compared to other reactor system, and is mainly achieved from its liquid nature of fuel and coolant. Further improvement to this system, which is a natural circulating molten fuel salt inside its tube in the reactor core is proposed, to achieve advantages of reducing and simplifying the MSR design proposed by GIF. Thermal hydraulic analysis on the proposed system was completed using a commercial computation fluid dynamics (CFD) software calledmore » FLUENT by ANSYS Inc. An understanding on theory behind this unique natural circulation flow inside the tube caused by fission heat generated in molten fuel salt and tube cooling was briefly introduced. Currently, no commercial CFD software could perfectly simulate natural circulation flow, hence, modeling this flow problem in FLUENT is introduced and analyzed to obtain best simulation results. Results obtained demonstrate the existence of periodical transient nature of flow problem, hence improvements in tube design is proposed based on the analysis on temperature and velocity profile. Results show that the proposed system could operate at up to 750MW core power, given that turbulence are enhanced throughout flow region, and precise molten fuel salt physical properties could be defined. At the request of the authors and the Proceedings Editor the name of the co-author Andrea Cioncolini was corrected from Andrea Coincolini. The same name correction was made in the Acknowledgement section on page 030004-10 and in reference number 4. The updated article was published on 11 May 2015.« less

Modeling of microalgal shear-induced flocculation and sedimentation using a coupled CFD-population balance approach.

PubMed

Golzarijalal, Mohammad; Zokaee Ashtiani, Farzin; Dabir, Bahram

2018-01-01

In this study, shear-induced flocculation modeling of Chlorella sp. microalgae was conducted by combination of population balance modeling and CFD. The inhomogeneous Multiple Size Group (MUSIG) and the Euler-Euler two fluid models were coupled via Ansys-CFX-15 software package to achieve both fluid and particle dynamics during the flocculation. For the first time, a detailed model was proposed to calculate the collision frequency and breakage rate during the microalgae flocculation by means of the response surface methodology as a tool for optimization. The particle size distribution resulted from the model was in good agreement with that of the jar test experiment. Furthermore, the subsequent sedimentation step was also examined by removing the shear rate in both simulations and experiments. Consequently, variation in the shear rate and its effects on the flocculation behavior, sedimentation rate and recovery efficiency were evaluated. Results indicate that flocculation of Chlorella sp. microalgae under shear rates of 37, 182, and 387 s -1 is a promising method of pre-concentration which guarantees the cost efficiency of the subsequent harvesting process by recovering more than 90% of the biomass. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:160-174, 2018. © 2017 American Institute of Chemical Engineers.

CFD analysis of turboprop engine oil cooler duct for best rate of climb condition

NASA Astrophysics Data System (ADS)

Kalia, Saurabh; CA, Vinay; Hegde, Suresh M.

2016-09-01

Turboprop engines are widely used in commuter category airplanes. Aircraft Design bureaus routinely conduct the flight tests to confirm the performance of the system. The lubrication system of the engine is designed to provide a constant supply of clean lubrication oil to the engine bearings, the reduction gears, the torque-meter, the propeller and the accessory gearbox. The oil lubricates, cools and also conducts foreign material to the oil filter where it is removed from further circulation. Thus a means of cooling the engine oil must be provided and a suitable oil cooler (OC) and ducting system was selected and designed for this purpose. In this context, it is relevant to study and analyse behaviour of the engine oil cooler system before commencing actual flight tests. In this paper, the performance of the oil cooler duct with twin flush NACA inlet housed inside the nacelle has been studied for aircraft best rate of climb (ROC) condition using RANS based SST K-omega model by commercial software ANSYS Fluent 13.0. From the CFD analysis results, it is found that the mass flow rate captured and pressure drop across the oil cooler for the best ROC condition is meeting the oil cooler manufacturer requirements thus, the engine oil temperature is maintained within prescribed limits.

Clinical questions and the role CFD can play

NASA Astrophysics Data System (ADS)

Basu, Phd, Saikat; Kimbell, Phd, Julia S.; Zanation, Md, Adam M.; Ebert, Md, Charles S.; Senior, Md, Brent A.

2016-11-01

Use of computational fluid dynamics has revolutionized our perspectives on flow problems in engineering. These tools are however still underused in exploring clinical questions. Here we present some representative CFD-based findings that can improve current clinical practice. Chronic rhinosinusitis (CRS) is a complex inflammatory disease affecting over 11 million Americans yearly. It obstructs sinus pathways, thus hindering ventilation and clearance. Prescribed topical medications are often ineffective even after surgeries, partially owing to scanty drug delivery to the affected areas. We focus on improving the use of the most frequently used topical nasal sprays. From computed tomography (CT) scans, we develop 3D sinonasal airway models on the medical imaging software MimicsTM, which are then meshed using ICEM-CFDTM followed by airflow and particle simulations on FluentTM (v.14.5, ANSYS, Inc.). The results quantify aerosol particle delivery to target cavities before and after surgical alleviation. Various combinations of breathing techniques and head-nozzle orientations can increase target-site particle deposition over depositions using prevalent physician recommendations, and our findings facilitate identification of such optimal conditions. Supported by the National Institutes of Health (NIH) Grant R01 HL122154. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

The numerical modelling of falling film thickness flow on horizontal tubes

NASA Astrophysics Data System (ADS)

Hassan, I. A.; Sadikin, A.; Isa, N. Mat

2017-04-01

This paper presents a computational modelling of water falling film flowing over horizontal tubes. The objective of this study is to use numerical predictions for comparing the film thickness along circumferential direction of tube on 2-D CFD models. The results are then validated with a theoretical result in previous literatures. A comprehensive design of 2-D models have been developed according to the real application and actual configuration of the falling film evaporator as well as previous experimental parameters. A computational modelling of the water falling film is presented with the aid of Ansys Fluent software. The Volume of Fluid (VOF) technique is adapted in this analysis since its capabilities of determining the film thickness on tubes surface is highly reliable. The numerical analysis is carried out under influence of ambient pressures at temperature of 27 °C. Three types of CFD numerical models were analyzed in this simulation with inter tube spacing of 30 mm, 20 mm and 10 mm respectively. The use of a numerical simulation tool on water falling film has resulted in a detailed investigation of film thickness. Based on the numerical simulated results, it is found that the average values of water film thickness for each model are 0.53 mm, 0.58 mm, and 0.63 mm.

Application of CFD in Indonesian Research: A review

NASA Astrophysics Data System (ADS)

Ambarita, H.; Siregar, M. R.; Kishinami, K.; Daimaruya, M.; Kawai, H.

2018-04-01

Computational Fluid Dynamics (CFD) is a numerical method that solves fluid flow and related governing equations using a computational tool. The studies on CFD, its methodology and its application as a research tool, are increasing. In this study, application of CFD by Indonesian researcher is briefly reviewed. The main objective is to explore the characteristics of CFD applications in Indonesian researchers. Considering the size and reputation, this study uses Scopus publications indexed data base. All of the documents in Scopus related to CFD which is affiliated by at least one of Indonesian researcher are collected to be reviewed. Research topics, CFD method, and simulation results are reviewed in brief. The results show that there are 260 documents found in literature indexed by Scopus. These documents divided into research articles 125 titles, conference paper 135 titles, book 1 title and review 1 title. In the research articles, only limited researchers focused on the development of CFD methodology. Almost all of the articles focus on using CFD in a particular application, as a research tool, such as aircraft application, wind power and heat exchanger. The topics of the 125 research articles can be divided into 12 specific applications and 1 miscellaneous application. The most popular application is Heating Ventilating and Air Conditioning and followed by Reactor, Transportation and Heat Exchanger applications. The most popular commercial CFD code used is ANSYS Fluent and only several researchers use CFX.

Development of a Cross-Flow Fan Rotor for Vertical Take-Off and Landing Aircraft

DTIC Science & Technology

2013-06-01

ANSYS CFX , along with the commercial computer-aided design software SolidWorks, was used to model and perform a parametric study on the number of rotor...the results found using ANSYS CFX . The experimental and analytical models were successfully compared at speeds ranging from 4,000 to 7,000 RPM...will make vertical take-off possible. The commercial computational fluid dynamics software ANSYS CFX , along with the commercial computer-aided design

Optimally analyzing and implementing of bolt fittings in steel structure based on ANSYS

NASA Astrophysics Data System (ADS)

Han, Na; Song, Shuangyang; Cui, Yan; Wu, Yongchun

2018-03-01

ANSYS simulation software for its excellent performance become outstanding one in Computer-aided Engineering (CAE) family, it is committed to the innovation of engineering simulation to help users to shorten the design process. First, a typical procedure to implement CAE was design. The framework of structural numerical analysis on ANSYS Technology was proposed. Then, A optimally analyzing and implementing of bolt fittings in beam-column join of steel structure was implemented by ANSYS, which was display the cloud chart of XY-shear stress, the cloud chart of YZ-shear stress and the cloud chart of Y component of stress. Finally, ANSYS software simulating results was compared with the measured results by the experiment. The result of ANSYS simulating and analyzing is reliable, efficient and optical. In above process, a structural performance's numerical simulating and analyzing model were explored for engineering enterprises' practice.

Numerical simulation of pressure fluctuation in 1000MW Francis turbine under small opening condition

NASA Astrophysics Data System (ADS)

Gong, R. Z.; Wang, H. G.; Yao, Y.; Shu, L. F.; Huang, Y. J.

2012-11-01

In order to study the cause of abnormal vibration in large Francis turbine under small opening condition, CFD method was adopted to analyze the flow filed and pressure fluctuation. Numerical simulation was performed on the commercial CFD code Ansys FLUENT 12, using DES method. After an effective validation of the computation result, the flow behaviour of internal flow field under small opening condition is analyzed. Pressure fluctuation in different working mode is obtained by unsteady CFD simulation, and results is compared to study its change. Radial force fluctuation is also analyzed. The result shows that the unstable flow under small opening condition leads to an increase of turbine instability in reverse pump mode, and is one possible reason of the abnormal oscillation.

Computer fluid dynamics (CFD) study of a micro annular gear pump

NASA Astrophysics Data System (ADS)

Stan, Liviu-Constantin; Cǎlimǎnescu, Ioan

2016-12-01

Micro technology makes it possible to design products simply, efficiently and sustainably and at the same time, opens up the creation of new functionalities. The field of application of the micro annular gear pumps lies in analytical instrumentation, mechanical and plant engineering, chemical and pharmaceutical process engineering as well as in new markets like fuel cells or biotechnology, organic electronics or aerospace. The purpose of this paper is to investigate by using the powerful ANSYS 16 CFX module the hydrodynamic behavior of an 8/9 teeth annular gear pump. The solving of solids evolving inside fluids was very cumbersome until the advent of the Ansys immersed solid technology. By deploying this technology for very special topics like the CFD analysis of Micro annular gear pumps, credible and reliable results may be pulled leading thus the way for more in depth studies like geometrical a functional optimization of the existing devices. This paper is a valuable guide for the professionals working in the design field of micro pumps handing them a new and powerful design tool.

Hemodynamics model of fluid–solid interaction in internal carotid artery aneurysms

PubMed Central

Fu-Yu, Wang; Lei, Liu; Xiao-Jun, Zhang; Hai-Yue, Ju

2010-01-01

The objective of this study is to present a relatively simple method to reconstruct cerebral aneurysms as 3D numerical grids. The method accurately duplicates the geometry to provide computer simulations of the blood flow. Initial images were obtained by using CT angiography and 3D digital subtraction angiography in DICOM format. The image was processed by using MIMICS software, and the 3D fluid model (blood flow) and 3D solid model (wall) were generated. The subsequent output was exported to the ANSYS workbench software to generate the volumetric mesh for further hemodynamic study. The fluid model was defined and simulated in CFX software while the solid model was calculated in ANSYS software. The force data calculated firstly in the CFX software were transferred to the ANSYS software, and after receiving the force data, total mesh displacement data were calculated in the ANSYS software. Then, the mesh displacement data were transferred back to the CFX software. The data exchange was processed in workbench software. The results of simulation could be visualized in CFX-post. Two examples of grid reconstruction and blood flow simulation for patients with internal carotid artery aneurysms were presented. The wall shear stress, wall total pressure, and von Mises stress could be visualized. This method seems to be relatively simple and suitable for direct use by neurosurgeons or neuroradiologists, and maybe a practical tool for planning treatment and follow-up of patients after neurosurgical or endovascular interventions with 3D angiography. PMID:20812022

Hemodynamics model of fluid-solid interaction in internal carotid artery aneurysms.

PubMed

Bai-Nan, Xu; Fu-Yu, Wang; Lei, Liu; Xiao-Jun, Zhang; Hai-Yue, Ju

2011-01-01

The objective of this study is to present a relatively simple method to reconstruct cerebral aneurysms as 3D numerical grids. The method accurately duplicates the geometry to provide computer simulations of the blood flow. Initial images were obtained by using CT angiography and 3D digital subtraction angiography in DICOM format. The image was processed by using MIMICS software, and the 3D fluid model (blood flow) and 3D solid model (wall) were generated. The subsequent output was exported to the ANSYS workbench software to generate the volumetric mesh for further hemodynamic study. The fluid model was defined and simulated in CFX software while the solid model was calculated in ANSYS software. The force data calculated firstly in the CFX software were transferred to the ANSYS software, and after receiving the force data, total mesh displacement data were calculated in the ANSYS software. Then, the mesh displacement data were transferred back to the CFX software. The data exchange was processed in workbench software. The results of simulation could be visualized in CFX-post. Two examples of grid reconstruction and blood flow simulation for patients with internal carotid artery aneurysms were presented. The wall shear stress, wall total pressure, and von Mises stress could be visualized. This method seems to be relatively simple and suitable for direct use by neurosurgeons or neuroradiologists, and maybe a practical tool for planning treatment and follow-up of patients after neurosurgical or endovascular interventions with 3D angiography.

ANSYS UIDL-Based CAE Development of Axial Support System for Optical Mirror

NASA Astrophysics Data System (ADS)

Yang, De-Hua; Shao, Liang

2008-09-01

The Whiffle-tree type axial support mechanism is widely adopted by most relatively large optical mirrors. Based on the secondary developing tools offered by the commonly used Finite Element Anylysis (FEA) software ANSYS, ANSYS Parametric Design Language (APDL) is used for creating the mirror FEA model driven by parameters, and ANSYS User Interface Design Language (UIDL) for generating custom menu of interactive manner, whereby, the relatively independent dedicated Computer Aided Engineering (CAE) module is embedded in ANSYS for calculation and optimization of axial Whiffle-tree support of optical mirrors. An example is also described to illustrate the intuitive and effective usage of the dedicated module by boosting work efficiency and releasing related engineering knowledge of user. The philosophy of secondary-developed special module with commonly used software also suggests itself for product development in other industries.

Pilot-in-the-Loop CFD Method Development

DTIC Science & Technology

2014-06-16

CFD analysis. Coupled simulations will be run at PSU on the COCOA -4 cluster, a high performance computing cluster. The CRUNCH CFD software has...been installed on the COCOA -4 servers and initial software tests are being conducted. Initial efforts will use the Generic Frigate Shape SFS-2 to

Pre- and Post-Processing Tools to Streamline the CFD Process

NASA Technical Reports Server (NTRS)

Dorney, Suzanne Miller

2002-01-01

This viewgraph presentation provides information on software development tools to facilitate the use of CFD (Computational Fluid Dynamics) codes. The specific CFD codes FDNS and CORSAIR are profiled, and uses for software development tools with these codes during pre-processing, interim-processing, and post-processing are explained.

[Finite Element Analysis of Intravascular Stent Based on ANSYS Software].

PubMed

Shi, Gengqiang; Song, Xiaobing

2015-10-01

This paper adopted UG8.0 to bulid the stent and blood vessel models. The models were then imported into the finite element analysis software ANSYS. The simulation results of ANSYS software showed that after endothelial stent implantation, the velocity of the blood was slow and the fluctuation of velocity was small, which meant the flow was relatively stable. When blood flowed through the endothelial stent, the pressure gradually became smaller, and the range of the pressure was not wide. The endothelial shear stress basically unchanged. In general, it can be concluded that the endothelial stents have little impact on the flow of blood and can fully realize its function.

Elasto-Plastic Behavior of Aluminum Foams Subjected to Compression Loading

NASA Astrophysics Data System (ADS)

Silva, H. M.; Carvalho, C. D.; Peixinho, N. R.

2017-05-01

The non-linear behavior of uniform-size cellular foams made of aluminum is investigated when subjected to compressive loads while comparing numerical results obtained in the Finite Element Method software (FEM) ANSYS workbench and ANSYS Mechanical APDL (ANSYS Parametric Design Language). The numerical model is built on AUTODESK INVENTOR, being imported into ANSYS and solved by the Newton-Raphson iterative method. The most similar conditions were used in ANSYS mechanical and ANSYS workbench, as possible. The obtained numerical results and the differences between the two programs are presented and discussed

A method for gear fatigue life prediction considering the internal flow field of the gear pump

NASA Astrophysics Data System (ADS)

Shen, Haidong; Li, Zhiqiang; Qi, Lele; Qiao, Liang

2018-01-01

Gear pump is the most widely used volume type hydraulic pump, and it is the main power source of the hydraulic system. Its performance is influenced by many factors, such as working environment, maintenance, fluid pressure and so on. It is different from the gear transmission system, the internal flow field of gear pump has a greater impact on the gear life, therefore it needs to consider the internal hydraulic system when predicting the gear fatigue life. In this paper, a certain aircraft gear pump as the research object, aim at the typical failure forms, gear contact fatigue, of gear pump, proposing the prediction method based on the virtual simulation. The method use CFD (Computational fluid dynamics) software to analyze pressure distribution of internal flow field of the gear pump, and constructed the unidirectional flow-solid coupling model of gear to acquire the contact stress of tooth surface on Ansys workbench software. Finally, employing nominal stress method and Miner cumulative damage theory to calculated the gear contact fatigue life based on modified material P-S-N curve. Engineering practice show that the method is feasible and efficient.

Parametric study of natural circulation flow in molten salt fuel in molten salt reactor

NASA Astrophysics Data System (ADS)

Pauzi, Anas Muhamad; Cioncolini, Andrea; Iacovides, Hector

2015-04-01

The Molten Salt Reactor (MSR) is one of the most promising system proposed by Generation IV Forum (GIF) for future nuclear reactor systems. Advantages of the MSR are significantly larger compared to other reactor system, and is mainly achieved from its liquid nature of fuel and coolant. Further improvement to this system, which is a natural circulating molten fuel salt inside its tube in the reactor core is proposed, to achieve advantages of reducing and simplifying the MSR design proposed by GIF. Thermal hydraulic analysis on the proposed system was completed using a commercial computation fluid dynamics (CFD) software called FLUENT by ANSYS Inc. An understanding on theory behind this unique natural circulation flow inside the tube caused by fission heat generated in molten fuel salt and tube cooling was briefly introduced. Currently, no commercial CFD software could perfectly simulate natural circulation flow, hence, modeling this flow problem in FLUENT is introduced and analyzed to obtain best simulation results. Results obtained demonstrate the existence of periodical transient nature of flow problem, hence improvements in tube design is proposed based on the analysis on temperature and velocity profile. Results show that the proposed system could operate at up to 750MW core power, given that turbulence are enhanced throughout flow region, and precise molten fuel salt physical properties could be defined. At the request of the authors and the Proceedings Editor the name of the co-author Andrea Cioncolini was corrected from Andrea Coincolini. The same name correction was made in the Acknowledgement section on page 030004-10 and in reference number 4. The updated article was published on 11 May 2015.

Computer simulation of refining process of a high consistency disc refiner based on CFD

NASA Astrophysics Data System (ADS)

Wang, Ping; Yang, Jianwei; Wang, Jiahui

2017-08-01

In order to reduce refining energy consumption, the ANSYS CFX was used to simulate the refining process of a high consistency disc refiner. In the first it was assumed to be uniform Newton fluid of turbulent state in disc refiner with the k-ɛ flow model; then meshed grids and set the boundary conditions in 3-D model of the disc refiner; and then was simulated and analyzed; finally, the viscosity of the pulp were measured. The results show that the CFD method can be used to analyze the pressure and torque on the disc plate, so as to calculate the refining power, and streamlines and velocity vectors can also be observed. CFD simulation can optimize parameters of the bar and groove, which is of great significance to reduce the experimental cost and cycle.

Method for CFD Simulation of Propellant Slosh in a Spherical Tank

NASA Technical Reports Server (NTRS)

Benson, David J.; Mason, Paul A.

2011-01-01

Propellant sloshing can impart unwanted disturbances to spacecraft, especially if the spacecraft controller is driving the system at the slosh frequency. This paper describes the work performed by the authors in simulating propellant slosh in a spherical tank using computational fluid dynamics (CFD). ANSYS-CFX is the CFD package used to perform the analysis. A 42 in spherical tank is studied with various fill fractions. Results are provided for the forces on the walls and the frequency of the slosh. Snapshots of slosh animation give a qualitative understanding of the propellant slosh. The results show that maximum slosh forces occur at a tank fill fraction of 0.4 and 0.6 due to the amount of mass participating in the slosh and the room available for sloshing to occur. The slosh frequency increases as the tank fill fraction increases.

VALIDATION OF ANSYS FINITE ELEMENT ANALYSIS SOFTWARE

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

HAMM, E.R.

2003-06-27

This document provides a record of the verification and Validation of the ANSYS Version 7.0 software that is installed on selected CH2M HILL computers. The issues addressed include: Software verification, installation, validation, configuration management and error reporting. The ANSYS{reg_sign} computer program is a large scale multi-purpose finite element program which may be used for solving several classes of engineering analysis. The analysis capabilities of ANSYS Full Mechanical Version 7.0 installed on selected CH2M Hill Hanford Group (CH2M HILL) Intel processor based computers include the ability to solve static and dynamic structural analyses, steady-state and transient heat transfer problems, mode-frequency andmore » buckling eigenvalue problems, static or time-varying magnetic analyses and various types of field and coupled-field applications. The program contains many special features which allow nonlinearities or secondary effects to be included in the solution, such as plasticity, large strain, hyperelasticity, creep, swelling, large deflections, contact, stress stiffening, temperature dependency, material anisotropy, and thermal radiation. The ANSYS program has been in commercial use since 1970, and has been used extensively in the aerospace, automotive, construction, electronic, energy services, manufacturing, nuclear, plastics, oil and steel industries.« less

Probabilistic Prediction of Lifetimes of Ceramic Parts

NASA Technical Reports Server (NTRS)

Nemeth, Noel N.; Gyekenyesi, John P.; Jadaan, Osama M.; Palfi, Tamas; Powers, Lynn; Reh, Stefan; Baker, Eric H.

2006-01-01

ANSYS/CARES/PDS is a software system that combines the ANSYS Probabilistic Design System (PDS) software with a modified version of the Ceramics Analysis and Reliability Evaluation of Structures Life (CARES/Life) Version 6.0 software. [A prior version of CARES/Life was reported in Program for Evaluation of Reliability of Ceramic Parts (LEW-16018), NASA Tech Briefs, Vol. 20, No. 3 (March 1996), page 28.] CARES/Life models effects of stochastic strength, slow crack growth, and stress distribution on the overall reliability of a ceramic component. The essence of the enhancement in CARES/Life 6.0 is the capability to predict the probability of failure using results from transient finite-element analysis. ANSYS PDS models the effects of uncertainty in material properties, dimensions, and loading on the stress distribution and deformation. ANSYS/CARES/PDS accounts for the effects of probabilistic strength, probabilistic loads, probabilistic material properties, and probabilistic tolerances on the lifetime and reliability of the component. Even failure probability becomes a stochastic quantity that can be tracked as a response variable. ANSYS/CARES/PDS enables tracking of all stochastic quantities in the design space, thereby enabling more precise probabilistic prediction of lifetimes of ceramic components.

Design and analysis of flow velocity distribution inside a raceway pond using computational fluid dynamics.

PubMed

Pandey, Ramakant; Premalatha, M

2017-03-01

Open raceway ponds are widely adopted for cultivating microalgae on a large scale. Working depth of the raceway pond is the major component to be analysed for increasing the volume to surface area ratio. The working depth is limited up to 5-15 cm in conventional ponds but in this analysis working depth of raceway pond is considered as 25 cm. In this work, positioning of the paddle wheel is analysed and corresponding Vertical Mixing Index are calculated using CFD. Flow pattern along the length of the raceway pond, at three different paddle wheel speeds are analysed for L/W ratio of 6, 8 and 10, respectively. Effect of clearance (C) between rotor blade tip and bottom surface is also analysed by taking four clearance conditions i.e. C = 2, 5, 10 and 15. Moving reference frame method of Fluent is used for the modeling of six blade paddle wheel and realizable k-ε model is used for capturing turbulence characteristics. Overall objective of this work is to analyse the required geometry for maintaining a minimum flow velocity to avoid settling of algae corresponding to 25 cm working depth. Geometry given in [13] is designed using ANSYS Design modular and CFD results are generated using ANSYS FLUENT for the purpose of validation. Good agreement of results is observed between CFD and experimental Particle image velocimetry results with the deviation of 7.23%.

Accounting for Uncertainties in Strengths of SiC MEMS Parts

NASA Technical Reports Server (NTRS)

Nemeth, Noel; Evans, Laura; Beheim, Glen; Trapp, Mark; Jadaan, Osama; Sharpe, William N., Jr.

2007-01-01

A methodology has been devised for accounting for uncertainties in the strengths of silicon carbide structural components of microelectromechanical systems (MEMS). The methodology enables prediction of the probabilistic strengths of complexly shaped MEMS parts using data from tests of simple specimens. This methodology is intended to serve as a part of a rational basis for designing SiC MEMS, supplementing methodologies that have been borrowed from the art of designing macroscopic brittle material structures. The need for this or a similar methodology arises as a consequence of the fundamental nature of MEMS and the brittle silicon-based materials of which they are typically fabricated. When tested to fracture, MEMS and structural components thereof show wide part-to-part scatter in strength. The methodology involves the use of the Ceramics Analysis and Reliability Evaluation of Structures Life (CARES/Life) software in conjunction with the ANSYS Probabilistic Design System (PDS) software to simulate or predict the strength responses of brittle material components while simultaneously accounting for the effects of variability of geometrical features on the strength responses. As such, the methodology involves the use of an extended version of the ANSYS/CARES/PDS software system described in Probabilistic Prediction of Lifetimes of Ceramic Parts (LEW-17682-1/4-1), Software Tech Briefs supplement to NASA Tech Briefs, Vol. 30, No. 9 (September 2006), page 10. The ANSYS PDS software enables the ANSYS finite-element-analysis program to account for uncertainty in the design-and analysis process. The ANSYS PDS software accounts for uncertainty in material properties, dimensions, and loading by assigning probabilistic distributions to user-specified model parameters and performing simulations using various sampling techniques.

A Solution Strategy to Include the Opening of the Opercular Slits in Moving-Mesh CFD Models of Suction Feeding.

PubMed

Van Wassenbergh, Sam

2015-07-01

The gill cover of fish and pre-metamorphic salamanders has a key role in suction feeding by acting as a one-way valve. It initially closes and avoids an inflow of water through the gill slits, after which it opens to allow outflow of the water that was sucked through the mouth into the expanded buccopharyngeal cavity. However, due to the inability of analytical models (relying on the continuity principle) to calculate the flow of fluid through a cavity with two openings and that was changing in shape and size, stringent boundary conditions had to be used in previously developed mathematical models after the moment of the valve's opening. By solving additionally for the conservation of momentum, computational fluid dynamics (CFD) has the capacity to dynamically simulate these flows, but this technique also faces complications in modeling a transition from closed to open valves. Here, I present a relatively simple solution strategy to incorporate the opening of the valves, exemplified in an axisymmetrical model of a suction-feeding sunfish in ANSYS Fluent software. By controlling viscosity of a separately defined fluid entity in the region of the opercular cavity, early inflow can be blocked (high viscosity assigned) and later outflow can be allowed (changing viscosity to that of water). Finally, by analyzing the CFD solution obtained for the sunfish model, a few new insights into the biomechanics of suction feeding are gained. © The Author 2015. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Mitigation of turbidity currents in reservoirs with passive retention systems: validation of CFD modeling

NASA Astrophysics Data System (ADS)

Ferreira, E.; Alves, E.; Ferreira, R. M. L.

2012-04-01

Sediment deposition by continuous turbidity currents may affect eco-environmental river dynamics in natural reservoirs and hinder the maneuverability of bottom discharge gates in dam reservoirs. In recent years, innovative techniques have been proposed to enforce the deposition of turbidity further upstream in the reservoir (and away from the dam), namely, the use of solid and permeable obstacles such as water jet screens , geotextile screens, etc.. The main objective of this study is to validate a computational fluid dynamics (CFD) code applied to the simulation of the interaction between a turbidity current and a passive retention system, designed to induce sediment deposition. To accomplish the proposed objective, laboratory tests were conducted where a simple obstacle configuration was subjected to the passage of currents with different initial sediment concentrations. The experimental data was used to build benchmark cases to validate the 3D CFD software ANSYS-CFX. Sensitivity tests of mesh design, turbulence models and discretization requirements were performed. The validation consisted in comparing experimental and numerical results, involving instantaneous and time-averaged sediment concentrations and velocities. In general, a good agreement between the numerical and the experimental values is achieved when: i) realistic outlet conditions are specified, ii) channel roughness is properly calibrated, iii) two equation k - ɛ models are employed iv) a fine mesh is employed near the bottom boundary. Acknowledgements This study was funded by the Portuguese Foundation for Science and Technology through the project PTDC/ECM/099485/2008. The first author thanks the assistance of Professor Moitinho de Almeida from ICIST and to all members of the project and of the Fluvial Hydraulics group of CEHIDRO.

AdapChem

NASA Technical Reports Server (NTRS)

Oluwole, Oluwayemisi O.; Wong, Hsi-Wu; Green, William

2012-01-01

AdapChem software enables high efficiency, low computational cost, and enhanced accuracy on computational fluid dynamics (CFD) numerical simulations used for combustion studies. The software dynamically allocates smaller, reduced chemical models instead of the larger, full chemistry models to evolve the calculation while ensuring the same accuracy to be obtained for steady-state CFD reacting flow simulations. The software enables detailed chemical kinetic modeling in combustion CFD simulations. AdapChem adapts the reaction mechanism used in the CFD to the local reaction conditions. Instead of a single, comprehensive reaction mechanism throughout the computation, a dynamic distribution of smaller, reduced models is used to capture accurately the chemical kinetics at a fraction of the cost of the traditional single-mechanism approach.

Estimating the mirror seeing for a large optical telescope with a numerical method

NASA Astrophysics Data System (ADS)

Zhang, En-Peng; Cui, Xiang-Qun; Li, Guo-Ping; Zhang, Yong; Shi, Jian-Rong; Zhao, Yong-Heng

2018-05-01

It is widely accepted that mirror seeing is caused by turbulent fluctuations in the index of air refraction in the vicinity of a telescope mirror. Computational Fluid Dynamics (CFD) is a useful tool to evaluate the effects of mirror seeing. In this paper, we present a numerical method to estimate the mirror seeing for a large optical telescope (∼ 4 m) in cases of natural convection with the ANSYS ICEPAK software. We get the FWHM of the image for different inclination angles (i) of the mirror and different temperature differences (ΔT) between the mirror and ambient air. Our results show that the mirror seeing depends very weakly on i, which agrees with observational data from the Canada-France-Hawaii Telescope. The numerical model can be used to estimate mirror seeing in the case of natural convection although with some limitations. We can determine ΔT for thermal control of the primary mirror according to the simulation, empirical data and site seeing.

Development of thermal model to analyze thermal flux distribution in thermally enhanced machining of high chrome white cast iron

NASA Astrophysics Data System (ADS)

Ravi, A. M.; Murigendrappa, S. M.

2018-04-01

In recent times, thermally enhanced machining (TEM) slowly gearing up to cut hard metals like high chrome white cast iron (HCWCI) which were impossible in conventional procedures. Also setting up of suitable cutting parameters and positioning of the heat source against the work appears to be critical in order to enhance the machinability characteristics of the work material. In this research work, the Oxy - LPG flame was used as the heat source and HCWCI as the workpiece. ANSYS-CFD-Flow software was used to develop the transient thermal model to analyze the thermal flux distribution on the work surface during TEM of HCWCI using Cubic boron nitride (CBN) tools. Non-contact type Infrared thermo sensor was used to measure the surface temperature continuously at different positions, and is validated with the thermal model results. The result confirms thermal model is a better predictive tool for thermal flux distribution analysis in TEM process.

Numerical investigation of solid mixing in a fluidized bed coating process

NASA Astrophysics Data System (ADS)

Kenche, Venkatakrishna; Feng, Yuqing; Ying, Danyang; Solnordal, Chris; Lim, Seng; Witt, Peter J.

2013-06-01

Fluidized beds are widely used in many process industries including the food and pharmaceutical sectors. Despite being an intensive research area, there are no design rules or correlations that can be used to quantitatively predict the solid mixing in a specific system for a given set of operating conditions. This paper presents a numerical study of the gas and solid dynamics in a laboratory scale fluidized bed coating process used for food and pharmaceutical industries. An Eulerian-Eulerian model (EEM) with kinetic theory of granular flow is selected as the modeling technique, with the commercial computational fluid dynamics (CFD) software package ANSYS/Fluent being the numerical platform. The flow structure is investigated in terms of the spatial distribution of gas and solid flow. The solid mixing has been evaluated under different operating conditions. It was found that the solid mixing rate in the horizontal direction is similar to that in the vertical direction under the current design and operating conditions. It takes about 5 s to achieve good mixing.

Computational System For Rapid CFD Analysis In Engineering

NASA Technical Reports Server (NTRS)

Barson, Steven L.; Ascoli, Edward P.; Decroix, Michelle E.; Sindir, Munir M.

1995-01-01

Computational system comprising modular hardware and software sub-systems developed to accelerate and facilitate use of techniques of computational fluid dynamics (CFD) in engineering environment. Addresses integration of all aspects of CFD analysis process, including definition of hardware surfaces, generation of computational grids, CFD flow solution, and postprocessing. Incorporates interfaces for integration of all hardware and software tools needed to perform complete CFD analysis. Includes tools for efficient definition of flow geometry, generation of computational grids, computation of flows on grids, and postprocessing of flow data. System accepts geometric input from any of three basic sources: computer-aided design (CAD), computer-aided engineering (CAE), or definition by user.

Studies of turbulence models in a computational fluid dynamics model of a blood pump.

PubMed

Song, Xinwei; Wood, Houston G; Day, Steven W; Olsen, Don B

2003-10-01

Computational fluid dynamics (CFD) is used widely in design of rotary blood pumps. The choice of turbulence model is not obvious and plays an important role on the accuracy of CFD predictions. TASCflow (ANSYS Inc., Canonsburg, PA, U.S.A.) has been used to perform CFD simulations of blood flow in a centrifugal left ventricular assist device; a k-epsilon model with near-wall functions was used in the initial numerical calculation. To improve the simulation, local grids with special distribution to ensure the k-omega model were used. Iterations have been performed to optimize the grid distribution and turbulence modeling and to predict flow performance more accurately comparing to experimental data. A comparison of k-omega model and experimental measurements of the flow field obtained by particle image velocimetry shows better agreement than k-epsilon model does, especially in the near-wall regions.

Controls/CFD Interdisciplinary Research Software Generates Low-Order Linear Models for Control Design From Steady-State CFD Results

NASA Technical Reports Server (NTRS)

Melcher, Kevin J.

1997-01-01

The NASA Lewis Research Center is developing analytical methods and software tools to create a bridge between the controls and computational fluid dynamics (CFD) disciplines. Traditionally, control design engineers have used coarse nonlinear simulations to generate information for the design of new propulsion system controls. However, such traditional methods are not adequate for modeling the propulsion systems of complex, high-speed vehicles like the High Speed Civil Transport. To properly model the relevant flow physics of high-speed propulsion systems, one must use simulations based on CFD methods. Such CFD simulations have become useful tools for engineers that are designing propulsion system components. The analysis techniques and software being developed as part of this effort are an attempt to evolve CFD into a useful tool for control design as well. One major aspect of this research is the generation of linear models from steady-state CFD results. CFD simulations, often used during the design of high-speed inlets, yield high resolution operating point data. Under a NASA grant, the University of Akron has developed analytical techniques and software tools that use these data to generate linear models for control design. The resulting linear models have the same number of states as the original CFD simulation, so they are still very large and computationally cumbersome. Model reduction techniques have been successfully applied to reduce these large linear models by several orders of magnitude without significantly changing the dynamic response. The result is an accurate, easy to use, low-order linear model that takes less time to generate than those generated by traditional means. The development of methods for generating low-order linear models from steady-state CFD is most complete at the one-dimensional level, where software is available to generate models with different kinds of input and output variables. One-dimensional methods have been extended somewhat so that linear models can also be generated from two- and three-dimensional steady-state results. Standard techniques are adequate for reducing the order of one-dimensional CFD-based linear models. However, reduction of linear models based on two- and three-dimensional CFD results is complicated by very sparse, ill-conditioned matrices. Some novel approaches are being investigated to solve this problem.

CFD Investigation of Pollutant Emission in Can-Type Combustor Firing Natural Gas, LNG and Syngas

NASA Astrophysics Data System (ADS)

Hasini, H.; Fadhil, SSA; Mat Zian, N.; Om, NI

2016-03-01

CFD investigation of flow, combustion process and pollutant emission using natural gas, liquefied natural gas and syngas of different composition is carried out. The combustor is a can-type combustor commonly used in thermal power plant gas turbine. The investigation emphasis on the comparison of pollutant emission such in particular CO2, and NOx between different fuels. The numerical calculation for basic flow and combustion process is done using the framework of ANSYS Fluent with appropriate model assumptions. Prediction of pollutant species concentration at combustor exit shows significant reduction of CO2 and NOx for syngas combustion compared to conventional natural gas and LNG combustion.

Pneumafil casing blower through moving reference frame (MRF) - A CFD simulation

NASA Astrophysics Data System (ADS)

Manivel, R.; Vijayanandh, R.; Babin, T.; Sriram, G.

2018-05-01

In this analysis work, the ring frame of Pneumafil casing blower of the textile mills with a power rating of 5 kW have been simulated using Computational Fluid Dynamics (CFD) code. The CFD analysis of the blower is carried out in Ansys Workbench 16.2 with Fluent using MRF solver settings. The simulation settings and boundary conditions are based on literature study and field data acquired. The main objective of this work is to reduce the energy consumption of the blower. The flow analysis indicated that the power consumption is influenced by the deflector plate orientation and deflector plate strip situated at the outlet casing of the blower. The energy losses occurred in the blower is due to the recirculation zones formed around the deflector plate strip. The deflector plate orientation is changed and optimized to reduce the energy consumption. The proposed optimized model is based on the simulation results which had relatively lesser power consumption than the existing and other cases. The energy losses in the Pneumafil casing blower are reduced through CFD analysis.

Steel refining possibilities in LF

NASA Astrophysics Data System (ADS)

Dumitru, M. G.; Ioana, A.; Constantin, N.; Ciobanu, F.; Pollifroni, M.

2018-01-01

This article presents the main possibilities for steel refining in Ladle Furnace (LF). These, are presented: steelmaking stages, steel refining through argon bottom stirring, online control of the bottom stirring, bottom stirring diagram during LF treatment of a heat, porous plug influence over the argon stirring, bottom stirring porous plug, analysis of porous plugs disposal on ladle bottom surface, bottom stirring simulation with ANSYS, bottom stirring simulation with Autodesk CFD.

Arbitrary Shape Deformation in CFD Design

NASA Technical Reports Server (NTRS)

Landon, Mark; Perry, Ernest

2014-01-01

Sculptor(R) is a commercially available software tool, based on an Arbitrary Shape Design (ASD), which allows the user to perform shape optimization for computational fluid dynamics (CFD) design. The developed software tool provides important advances in the state-of-the-art of automatic CFD shape deformations and optimization software. CFD is an analysis tool that is used by engineering designers to help gain a greater understanding of the fluid flow phenomena involved in the components being designed. The next step in the engineering design process is to then modify, the design to improve the components' performance. This step has traditionally been performed manually via trial and error. Two major problems that have, in the past, hindered the development of an automated CFD shape optimization are (1) inadequate shape parameterization algorithms, and (2) inadequate algorithms for CFD grid modification. The ASD that has been developed as part of the Sculptor(R) software tool is a major advancement in solving these two issues. First, the ASD allows the CFD designer to freely create his own shape parameters, thereby eliminating the restriction of only being able to use the CAD model parameters. Then, the software performs a smooth volumetric deformation, which eliminates the extremely costly process of having to remesh the grid for every shape change (which is how this process had previously been achieved). Sculptor(R) can be used to optimize shapes for aerodynamic and structural design of spacecraft, aircraft, watercraft, ducts, and other objects that affect and are affected by flows of fluids and heat. Sculptor(R) makes it possible to perform, in real time, a design change that would manually take hours or days if remeshing were needed.

CFD Simulations for the Effect of Unsteady Wakes on the Boundary Layer of a Highly Loaded Low-Pressure Turbine Airfoil (L1A)

NASA Technical Reports Server (NTRS)

Vinci, Samuel, J.

2012-01-01

This report is the third part of a three-part final report of research performed under an NRA cooperative Agreement contract. The first part was published as NASA/CR-2012-217415. The second part was published as NASA/CR-2012-217416. The study of the very high lift low-pressure turbine airfoil L1A in the presence of unsteady wakes was performed computationally and compared against experimental results. The experiments were conducted in a low speed wind tunnel under high (4.9%) and then low (0.6%) freestream turbulence intensity for Reynolds number equal to 25,000 and 50,000. The experimental and computational data have shown that in cases without wakes, the boundary layer separated without reattachment. The CFD was done with LES and URANS utilizing the finite-volume code ANSYS Fluent (ANSYS, Inc.) under the same freestream turbulence and Reynolds number conditions as the experiment but only at a rod to blade spacing of 1. With wakes, separation was largely suppressed, particularly if the wake passing frequency was sufficiently high. This was validated in the 3D CFD efforts by comparing the experimental results for the pressure coefficients and velocity profiles, which were reasonable for all cases examined. The 2D CFD efforts failed to capture the three dimensionality effects of the wake and thus were less consistent with the experimental data. The effect of the freestream turbulence intensity levels also showed a little more consistency with the experimental data at higher intensities when compared with the low intensity cases. Additional cases with higher wake passing frequencies which were not run experimentally were simulated. The results showed that an initial 25% increase from the experimental wake passing greatly reduced the size of the separation bubble, nearly completely suppressing it.

DEVELOPMENT AND APPLICATIONS OF CFD SIMULATIONS SUPPORTING URBAN AIR QUALITY AND HOMELAND SECURITY

EPA Science Inventory

Prior to September 11, 2001 developments of Computational Fluid Dynamics (CFD) were begun to support air quality applications. CFD models are emerging as a promising technology for such assessments, in part due to the advancing power of computational hardware and software. CFD si...

Integrating Multibody Simulation and CFD: toward Complex Multidisciplinary Design Optimization

NASA Astrophysics Data System (ADS)

Pieri, Stefano; Poloni, Carlo; Mühlmeier, Martin

This paper describes the use of integrated multidisciplinary analysis and optimization of a race car model on a predefined circuit. The objective is the definition of the most efficient geometric configuration that can guarantee the lowest lap time. In order to carry out this study it has been necessary to interface the design optimization software modeFRONTIER with the following softwares: CATIA v5, a three dimensional CAD software, used for the definition of the parametric geometry; A.D.A.M.S./Motorsport, a multi-body dynamic simulation software; IcemCFD, a mesh generator, for the automatic generation of the CFD grid; CFX, a Navier-Stokes code, for the fluid-dynamic forces prediction. The process integration gives the possibility to compute, for each geometrical configuration, a set of aerodynamic coefficients that are then used in the multiboby simulation for the computation of the lap time. Finally an automatic optimization procedure is started and the lap-time minimized. The whole process is executed on a Linux cluster running CFD simulations in parallel.

Real gas CFD simulations of hydrogen/oxygen supercritical combustion

NASA Astrophysics Data System (ADS)

Pohl, S.; Jarczyk, M.; Pfitzner, M.; Rogg, B.

2013-03-01

A comprehensive numerical framework has been established to simulate reacting flows under conditions typically encountered in rocket combustion chambers. The model implemented into the commercial CFD Code ANSYS CFX includes appropriate real gas relations based on the volume-corrected Peng-Robinson (PR) equation of state (EOS) for the flow field and a real gas extension of the laminar flamelet combustion model. The results indicate that the real gas relations have a considerably larger impact on the flow field than on the detailed flame structure. Generally, a realistic flame shape could be achieved for the real gas approach compared to experimental data from the Mascotte test rig V03 operated at ONERA when the differential diffusion processes were only considered within the flame zone.

Aerodynamic study of state transport bus using computational fluid dynamics

NASA Astrophysics Data System (ADS)

Kanekar, Siddhesh; Thakre, Prashant; Rajkumar, E.

2017-11-01

The main purpose of this study was to develop the aerodynamic study of a Maharashtra state road transport bus. The rising fuel price and strict government regulations makes the road transport uneconomical now days. With the objective of increasing fuel efficiency and reducing the emission of harmful exhaust gases. It has been proven experimentally that vehicle consumes almost 40% of the available useful engine power to overcome the drag resistance. This provides us a huge scope to study the influence of aerodynamic drag. The initial of the project was to identify the drag coefficient of the existing ordinary type model called “Parivartan” from ANSYS fluent. After preliminary analysis of the existing model corresponding changes are made in such a way that their implementation should be possible at workshop level. The simulation of the air flow over the bus was performed in two steps: design on SolidWorks CAD and ANSYS (FLUENT) is used as a virtual analysis tool to estimate the drag coefficient of the bus. We have used the turbulence models k-ε Realizable having a better approximation of the actual result. Around 28% improvement in the drag coefficient is achieved by CFD driven changes in the bus design. Coefficient of drag is improved by 28% and fuel efficiency increased by 20% by CFD driven changes.

77 FR 24541 - Virginia Electric and Power Company, North Anna Power Station Units 1 and 2, Independent Spent...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-24

... submitted TN Calculation No. 10494-174, which performed a bounding thermal analysis using ANSYS finite element software to evaluate the misloading events. The ANSYS analysis consists of a half-symmetric, three...

User Interface Developed for Controls/CFD Interdisciplinary Research

NASA Technical Reports Server (NTRS)

1996-01-01

The NASA Lewis Research Center, in conjunction with the University of Akron, is developing analytical methods and software tools to create a cross-discipline "bridge" between controls and computational fluid dynamics (CFD) technologies. Traditionally, the controls analyst has used simulations based on large lumping techniques to generate low-order linear models convenient for designing propulsion system controls. For complex, high-speed vehicles such as the High Speed Civil Transport (HSCT), simulations based on CFD methods are required to capture the relevant flow physics. The use of CFD should also help reduce the development time and costs associated with experimentally tuning the control system. The initial application for this research is the High Speed Civil Transport inlet control problem. A major aspect of this research is the development of a controls/CFD interface for non-CFD experts, to facilitate the interactive operation of CFD simulations and the extraction of reduced-order, time-accurate models from CFD results. A distributed computing approach for implementing the interface is being explored. Software being developed as part of the Integrated CFD and Experiments (ICE) project provides the basis for the operating environment, including run-time displays and information (data base) management. Message-passing software is used to communicate between the ICE system and the CFD simulation, which can reside on distributed, parallel computing systems. Initially, the one-dimensional Large-Perturbation Inlet (LAPIN) code is being used to simulate a High Speed Civil Transport type inlet. LAPIN can model real supersonic inlet features, including bleeds, bypasses, and variable geometry, such as translating or variable-ramp-angle centerbodies. Work is in progress to use parallel versions of the multidimensional NPARC code.

77 FR 50726 - Software Requirement Specifications for Digital Computer Software and Complex Electronics Used in...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-22

... Computer Software and Complex Electronics Used in Safety Systems of Nuclear Power Plants AGENCY: Nuclear...-1209, ``Software Requirement Specifications for Digital Computer Software and Complex Electronics used... Electronics Engineers (ANSI/IEEE) Standard 830-1998, ``IEEE Recommended Practice for Software Requirements...

CFD modeling using PDF approach for investigating the flame length in rotary kilns

NASA Astrophysics Data System (ADS)

Elattar, H. F.; Specht, E.; Fouda, A.; Bin-Mahfouz, Abdullah S.

2016-12-01

Numerical simulations using computational fluid dynamics (CFD) are performed to investigate the flame length characteristics in rotary kilns using probability density function (PDF) approach. A commercial CFD package (ANSYS-Fluent) is employed for this objective. A 2-D axisymmetric model is applied to study the effect of both operating and geometric parameters of rotary kiln on the characteristics of the flame length. Three types of gaseous fuel are used in the present work; methane (CH4), carbon monoxide (CO) and biogas (50 % CH4 + 50 % CO2). Preliminary comparison study of 2-D modeling outputs of free jet flames with available experimental data is carried out to choose and validate the proper turbulence model for the present numerical simulations. The results showed that the excess air number, diameter of kiln air entrance, radiation modeling consideration and fuel type have remarkable effects on the flame length characteristics. Numerical correlations for the rotary kiln flame length are presented in terms of the studied kiln operating and geometric parameters within acceptable error.

Virtual surgery for patients with nasal obstruction: Use of computational fluid dynamics (MeComLand®, Digbody® & Noseland®) to document objective flow parameters and optimise surgical results.

PubMed

Burgos, Manuel A; Sevilla García, Maria Agustina; Sanmiguel Rojas, Enrique; Del Pino, Carlos; Fernández Velez, Carlos; Piqueras, Francisco; Esteban Ortega, Francisco

Computational fluid dynamics (CFD) is a mathematical tool to analyse airflow. We present a novel CFD software package to improve results following nasal surgery for obstruction. A group of engineers in collaboration with otolaryngologists have developed a very intuitive CFD software package called MeComLand®, which uses the patient's cross-sectional (tomographic) images, thus showing in detail results originated by CFD such as airflow distributions, velocity profiles, pressure, or wall shear stress. NOSELAND® helps medical evaluation with dynamic reports by using a 3D endoscopic view. Using this CFD-based software a patient underwent virtual surgery (septoplasty, turbinoplasty, spreader grafts, lateral crural J-flap and combinations) to choose the best improvement in nasal flow. To present a novel software package to improve nasal surgery results. To apply the software on CT slices from a patient affected by septal deviation. To evaluate several surgical procedures (septoplasty, turbinectomy, spreader-grafts, J-flap and combination among them) to find the best alternative with less morbidity. The combination of all the procedures does not provide the best nasal flow improvement. Septoplasty plus turbinoplasty obtained the best results. Turbinoplasty alone rendered almost similar results to septoplasty in our simulation. CFD provides useful complementary information to cover diagnosis, prognosis, and follow-up of nasal pathologies based on quantitative magnitudes linked to fluid flow. MeComLand®, DigBody® and NoseLand® represent a non-invasive, low-cost alternative for the functional study of patients with nasal obstruction. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

CFD simulation of the combustion process of the low-emission vortex boiler

NASA Astrophysics Data System (ADS)

Chernov, A. A.; Maryandyshev, P. A.; Pankratov, E. V.; Lubov, V. K.

2017-11-01

Domestic heat and power engineering needs means and methods for optimizing the existing boiler plants in order to increase their technical, economic and environmental work. The development of modern computer technology, methods of numerical modeling and specialized software greatly facilitates the solution of many emerging problems. CFD simulation allows to obtaine precise results of thermochemical and aerodynamic processes taking place in the furnace of boilers in order to optimize their operation modes and develop directions for their modernization. The paper presents the results of simulation of the combustion process of a low-emission vortex coal boiler of the model E-220/100 using the software package Ansys Fluent. A hexahedral grid with a number of 2 million cells was constructed for the chosen boiler model. A stationary problem with a two-phase flow was solved. The gaseous components are air, combustion products and volatile substances. The solid phase is coal particles at different burnup stages. The Euler-Lagrange approach was taken as a basis. Calculation of the coal particles trajectories was carried out using the Discrete Phase Model which distribution of the size particle of coal dust was accounted for using the Rosin-Rammler equation. Partially Premixed combustion model was used as the combustion model which take into account elemental composition of the fuel and heat analysis. To take turbulence into account, a two-parameter k-ε model with a standard wall function was chosen. Heat transfer by radiation was calculated using the P1-approximation of the method of spherical harmonics. The system of spatial equations was numerically solved by the control volume method using the SIMPLE algorithm of Patankar and Spaulding. Comparison of data obtained during the industrial-operational tests of low-emission vortex boilers with the results of mathematical modeling showed acceptable convergence of the tasks of this level, which confirms the adequacy of the realized mathematical model.

Study on the leakage flow through a clearance gap between two stationary walls

NASA Astrophysics Data System (ADS)

Zhao, W.; Billdal, J. T.; Nielsen, T. K.; Brekke, H.

2012-11-01

In the present paper, the leakage flow in the clearance gap between stationary walls was studied experimentally, theoretically and numerically by the computational fluid dynamics (CFD) in order to find the relationship between leakage flow, pressure difference and clearance gap. The experimental set-up of the clearance gap between two stationary walls is the simplification of the gap between the guide vane faces and facing plates in Francis turbines. This model was built in the Waterpower laboratory at Norwegian University of Science and Technology (NTNU). The empirical formula for calculating the leakage flow rate between the two stationary walls was derived from the empirical study. The experimental model is simulated by computational fluid dynamics employing the ANSYS CFX commercial software in order to study the flow structure. Both numerical simulation results and empirical formula results are in good agreement with the experimental results. The correction of the empirical formula is verified by experimental data and has been proven to be very useful in terms of quickly predicting the leakage flow rate in the guide vanes for hydraulic turbines.

Effect of jet-mainstream velocity ratio on flow characteristics and heat transfer enhancement of jet on flat plate flow

NASA Astrophysics Data System (ADS)

Puzu, N.; Prasertsan, S.; Nuntadusit, C.

2017-09-01

The aim of this research was to study the effect of jet-mainstream velocity ratio on flow and heat transfer characteristics of jet on flat plate flow. The jet from pipe nozzle with inner diameter of D=14 mm was injected perpendicularly to mainstream on flat plate. The flat plate was blown by mainstream with uniform velocity profile at 10 m/s. The velocity ratio (jet to mainstream velociy) was varied at VR=0.25 and 3.5 by adjusting velocity of jet flow. For heat transfer measurement, a thin foil technique was used to evaluate the heat transfer coefficient by measuring temperature distributions on heat transfer surface with constant heat flux by using infrared camera. Flow characteristics were simulated by using a computational fluid dynamics (CFD) with commercial software ANSYS Fluent (Ver.15.0). The results showed that the enhancement of heat transfer along downstream direction for the case of VR=0.25 was from the effect of jet stream whereas for the case of VR=3.5 was from the effect of mainstream.

Numerical analysis on centrifugal compressor with membrane type dryer

NASA Astrophysics Data System (ADS)

Razali, M. A.; Zulkafli, M. F.; Mat Isa, N.; Subari, Z.

2017-09-01

Moisture content is a common phenomenon in industrial processes especially in oil and gas industries. This contaminant has a lot of disadvantages which can lead to mechanical failure DEC (Deposition, Erosion & Corrosion) problems. To overcome DEC problem, this study proposed to design a centrifugal compressor with a membrane type dryer to reduce moisture content of a gas. The effectiveness of such design has been analyzed in this study using Computational Fluid Dynamics (CFD) approach. Numerical scheme based on multiphase flow technique is used in ANSYS Fluent software to evaluate the moisture content of the gas. Through this technique, two kind of centrifugal compressor, with and without membrane type dryer has been tested. The results show that the effects of pressure on dew point temperature of the gas change the composition of its moisture content, where high value lead more condensation to occur. However, with the injection of cool dry gas through membrane type dryer in the centrifugal compressor, the pressure and temperature of moisture content as well as mass fraction of H2O in centrifugal compressor show significant reduction.

Numerical Simulation of Creep Characteristic for Composite Rock Mass with Weak Interlayer

NASA Astrophysics Data System (ADS)

Li, Jian-guang; Zhang, Zuo-liang; Zhang, Yu-biao; Shi, Xiu-wen; Wei, Jian

2017-06-01

The composite rock mass with weak interlayer is widely exist in engineering, and it’s essential to research the creep behavior which could cause stability problems of rock engineering and production accidents. However, due to it is difficult to take samples, the losses and damages in delivery and machining process, we always cannot get enough natural layered composite rock mass samples, so the indirect test method has been widely used. In this paper, we used ANSYS software (a General Finite Element software produced by American ANSYS, Inc) to carry out the numerical simulation based on the uniaxial compression creep experiments of artificial composite rock mass with weak interlayer, after experimental data fitted. The results show that the laws obtained by numerical simulations and experiments are consistent. Thus confirmed that carry out numerical simulation for the creep characteristics of rock mass with ANSYS software is feasible, and this method can also be extended to other underground engineering of simulate the weak intercalations.

Employing a Modified Diffuser Momentum Model to Simulate Ventilation of the Orion CEV

NASA Technical Reports Server (NTRS)

Straus, John; Lewis, John F.

2011-01-01

The Ansys CFX CFD modeling tool was used to support the design efforts of the ventilation system for the Orion CEV. CFD modeling was used to establish the flow field within the cabin for several supply configurations. A mesh and turbulence model sensitivity study was performed before the design studies. Results were post-processed for comparison with performance requirements. Most configurations employed straight vaned diffusers to direct and throw the flow. To manage the size of the models, the diffuser vanes were not resolved. Instead, a momentum model was employed to account for the effect of the diffusers. The momentum model was tested against a separate, vane-resolved side study. Results are presented for a single diffuser configuration for a low supply flow case.

SIDS-toADF File Mapping Manual

NASA Technical Reports Server (NTRS)

McCarthy, Douglas; Smith, Matthew; Poirier, Diane; Smith, Charles A. (Technical Monitor)

2002-01-01

The "CFD General Notation System" (CGNS) consists of a collection of conventions, and conforming software, for the storage and retrieval of Computational Fluid Dynamics (CFD) data. It facilitates the exchange of data between sites and applications, and helps stabilize the archiving of aerodynamic data. This effort was initiated in order to streamline the procedures in exchanging data and software between NASA and its customers, but the goal is to develop CGNS into a National Standard for the exchange of aerodynamic data. The CGNS development team is comprised of members from Boeing Commercial Airplane Group, NASA-Ames, NASA-Langley, NASA-Lewis, McDonnell-Douglas Corporation (now Boeing-St. Louis), Air Force-Wright Lab., and ICEM-CFD Engineering. The elements of CGNS address all activities associated with the storage of data on external media and its movement to and from application programs. These elements include: 1) The Advanced Data Format (ADF) Database manager, consisting of both a file format specification and its I/O software, which handles the actual reading and writing of data from and to external storage media; 2) The Standard Interface Data Structures (SIDS), which specify the intellectual content of CFD data and the conventions governing naming and terminology; 3) The SIDS-to-ADF File Mapping conventions, which specify the exact location where the CFD data defined by the SIDS is to be stored within the ADF file(s); and 4) The CGNS Mid-level Library, which provides CFD-knowledgeable routines suitable for direct installation into application codes. The SIDS-toADF File Mapping Manual specifies the exact manner in which, under CGNS conventions, CFD data structures (the SIDS) are to be stored in (i.e., mapped onto) the file structure provided by the database manager (ADF). The result is a conforming CGNS database. Adherence to the mapping conventions guarantees uniform meaning and location of CFD data within ADF files, and thereby allows the construction of universal software to read and write the data.

MiniWall Tool for Analyzing CFD and Wind Tunnel Large Data Sets

NASA Technical Reports Server (NTRS)

Schuh, Michael J.; Melton, John E.; Stremel, Paul M.

2017-01-01

It is challenging to review and assimilate large data sets created by Computational Fluid Dynamics (CFD) simulations and wind tunnel tests. Over the past 10 years, NASA Ames Research Center has developed and refined a software tool dubbed the MiniWall to increase productivity in reviewing and understanding large CFD-generated data sets. Under the recent NASA ERA project, the application of the tool expanded to enable rapid comparison of experimental and computational data. The MiniWall software is browser based so that it runs on any computer or device that can display a web page. It can also be used remotely and securely by using web server software such as the Apache HTTP server. The MiniWall software has recently been rewritten and enhanced to make it even easier for analysts to review large data sets and extract knowledge and understanding from these data sets. This paper describes the MiniWall software and demonstrates how the different features are used to review and assimilate large data sets.

MiniWall Tool for Analyzing CFD and Wind Tunnel Large Data Sets

NASA Technical Reports Server (NTRS)

Schuh, Michael J.; Melton, John E.; Stremel, Paul M.

2017-01-01

It is challenging to review and assimilate large data sets created by Computational Fluid Dynamics (CFD) simulations and wind tunnel tests. Over the past 10 years, NASA Ames Research Center has developed and refined a software tool dubbed the "MiniWall" to increase productivity in reviewing and understanding large CFD-generated data sets. Under the recent NASA ERA project, the application of the tool expanded to enable rapid comparison of experimental and computational data. The MiniWall software is browser based so that it runs on any computer or device that can display a web page. It can also be used remotely and securely by using web server software such as the Apache HTTP Server. The MiniWall software has recently been rewritten and enhanced to make it even easier for analysts to review large data sets and extract knowledge and understanding from these data sets. This paper describes the MiniWall software and demonstrates how the different features are used to review and assimilate large data sets.

Use of Computational Fluid Dynamics for improvement of Balloon Borne Frost Point Hygrometer

NASA Astrophysics Data System (ADS)

Jorge, Teresa; Brunamonti, Simone; Wienhold, Frank G.; Peter, Thomas

2017-04-01

In the StratoClim 2016 Balloon Campaign in Nainital (India) during the Asian Summer Monsoon, balloon born payloads containing the EN-SCI CFH - Cryogenic Frost point Hygrometer - were flown to observe water vapor and cloud formation processes in the Upper Troposphere and Lower Stratosphere. Some of the recorded atmospheric water vapor profiles showed unexpected values above the tropopause and were considered contaminated. To interpret these contaminated results and in the scope of the development of a new frost point hygrometer - the Peltier Cooled Frost point Hygrometer (PCFH) - computational fluid dynamic (CFD) simulations with ANSYS Fluent software have been carried out. These simulations incorporate the fluid and thermodynamic characteristics of stratospheric air to predict airflow in the inlet tube of the instrument. An ice wall boundary layer based on the Murphy and Koop 2005 ice-vapor parametrization was created as a cause of the unexpected water vapor. Sensitivity was tested in relation to the CFD mesh, ice wall surface, inlet flow, inlet tube dimension, sensor head location and variation of atmospheric conditions. The development of the PCFH uses the results of this study and other computational fluid dynamic studies concerning the whole instrument boundary layer and heat exchanger design to improve on previous realizations of frost point hygrometers. As a novelty in the field of frost point hygrometry, Optimal Control Theory will be used to optimize the cooling of the mirror by the Peltier element, which will be described in a physical "plant model", since the cooling capacity of a cryogenic liquid will no longer be available in the new instrument.

Translator for Optimizing Fluid-Handling Components

NASA Technical Reports Server (NTRS)

Landon, Mark; Perry, Ernest

2007-01-01

A software interface has been devised to facilitate optimization of the shapes of valves, elbows, fittings, and other components used to handle fluids under extreme conditions. This software interface translates data files generated by PLOT3D (a NASA grid-based plotting-and- data-display program) and by computational fluid dynamics (CFD) software into a format in which the files can be read by Sculptor, which is a shape-deformation- and-optimization program. Sculptor enables the user to interactively, smoothly, and arbitrarily deform the surfaces and volumes in two- and three-dimensional CFD models. Sculptor also includes design-optimization algorithms that can be used in conjunction with the arbitrary-shape-deformation components to perform automatic shape optimization. In the optimization process, the output of the CFD software is used as feedback while the optimizer strives to satisfy design criteria that could include, for example, improved values of pressure loss, velocity, flow quality, mass flow, etc.

Coupled modeling of a directly heated tubular solar receiver for supercritical carbon dioxide Brayton cycle: Optical and thermal-fluid evaluation

DOE PAGES

Ortega, Jesus; Khivsara, Sagar; Christian, Joshua; ...

2016-05-30

In single phase performance and appealing thermo-physical properties supercritical carbon dioxide (s-CO 2) make a good heat transfer fluid candidate for concentrating solar power (CSP) technologies. The development of a solar receiver capable of delivering s-CO 2 at outlet temperatures ~973 K is required in order to merge CSP and s-CO 2 Brayton cycle technologies. A coupled optical and thermal-fluid modeling effort for a tubular receiver is undertaken to evaluate the direct tubular s-CO 2 receiver’s thermal performance when exposed to a concentrated solar power input of ~0.3–0.5 MW. Ray tracing, using SolTrace, is performed to determine the heat fluxmore » profiles on the receiver and computational fluid dynamics (CFD) determines the thermal performance of the receiver under the specified heating conditions. Moreover, an in-house MATLAB code is developed to couple SolTrace and ANSYS Fluent. CFD modeling is performed using ANSYS Fluent to predict the thermal performance of the receiver by evaluating radiation and convection heat loss mechanisms. Understanding the effects of variation in heliostat aiming strategy and flow configurations on the thermal performance of the receiver was achieved through parametric analyses. Finally, a receiver thermal efficiency ~85% was predicted and the surface temperatures were observed to be within the allowable limit for the materials under consideration.« less

Coupled modeling of a directly heated tubular solar receiver for supercritical carbon dioxide Brayton cycle: Optical and thermal-fluid evaluation

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

Ortega, Jesus; Khivsara, Sagar; Christian, Joshua

In single phase performance and appealing thermo-physical properties supercritical carbon dioxide (s-CO 2) make a good heat transfer fluid candidate for concentrating solar power (CSP) technologies. The development of a solar receiver capable of delivering s-CO 2 at outlet temperatures ~973 K is required in order to merge CSP and s-CO 2 Brayton cycle technologies. A coupled optical and thermal-fluid modeling effort for a tubular receiver is undertaken to evaluate the direct tubular s-CO 2 receiver’s thermal performance when exposed to a concentrated solar power input of ~0.3–0.5 MW. Ray tracing, using SolTrace, is performed to determine the heat fluxmore » profiles on the receiver and computational fluid dynamics (CFD) determines the thermal performance of the receiver under the specified heating conditions. Moreover, an in-house MATLAB code is developed to couple SolTrace and ANSYS Fluent. CFD modeling is performed using ANSYS Fluent to predict the thermal performance of the receiver by evaluating radiation and convection heat loss mechanisms. Understanding the effects of variation in heliostat aiming strategy and flow configurations on the thermal performance of the receiver was achieved through parametric analyses. Finally, a receiver thermal efficiency ~85% was predicted and the surface temperatures were observed to be within the allowable limit for the materials under consideration.« less

Simulation of Dual Firing of Hydrogen and JP-8 in a Swirling Combustor

DTIC Science & Technology

2012-06-14

completed using the Ansys CFX computational fluid dynamics software. The total Lower Heating Value of the fuel mixture is maintained at a constant 6 kW...PERSON a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18

Noise optimization of a regenerative automotive fuel pump

NASA Astrophysics Data System (ADS)

Wang, J. F.; Feng, H. H.; Mou, X. L.; Huang, Y. X.

2017-03-01

The regenerative pump used in automotive is facing a noise problem. To understand the mechanism in detail, Computational Fluid Dynamics (CFD) and Computational Acoustic Analysis (CAA) together were used to understand the fluid and acoustic characteristics of the fuel pump using ANSYS-CFX 15.0 and LMS Virtual. Lab Rev12, respectively. The CFD model and acoustical model were validated by mass flow rate test and sound pressure test, respectively. Comparing the computational and experimental results shows that sound pressure levels at the observer position are consistent at high frequencies, especially at blade passing frequency. After validating the models, several numerical models were analyzed in the study for noise improvement. It is observed that for configuration having greater number of impeller blades, noise level was significantly improved at blade passing frequency, when compared to that of the original model.

Computational analysis of water entry of a circular section at constant velocity based on Reynold's averaged Navier-Stokes method

NASA Astrophysics Data System (ADS)

Uddin, M. Maruf; Fuad, Muzaddid-E.-Zaman; Rahaman, Md. Mashiur; Islam, M. Rabiul

2017-12-01

With the rapid decrease in the cost of computational infrastructure with more efficient algorithm for solving non-linear problems, Reynold's averaged Navier-Stokes (RaNS) based Computational Fluid Dynamics (CFD) has been used widely now-a-days. As a preliminary evaluation tool, CFD is used to calculate the hydrodynamic loads on offshore installations, ships, and other structures in the ocean at initial design stages. Traditionally, wedges have been studied more than circular cylinders because cylinder section has zero deadrise angle at the instant of water impact, which increases with increase of submergence. In Present study, RaNS based commercial code ANSYS Fluent is used to simulate the water entry of a circular section at constant velocity. It is seen that present computational results were compared with experiment and other numerical method.

Aerodynamic investigations of a disc-wing

NASA Astrophysics Data System (ADS)

Dumitrache, Alexandru; Frunzulica, Florin; Grigorescu, Sorin

2017-01-01

The purpose of this paper is to evaluate the aerodynamic characteristics of a wing-disc, for a civil application in the fire-fighting system. The aerodynamic analysis is performed using a CFD code, named ANSYS Fluent, in the flow speed range up to 25 m/s, at lower and higher angle of attack. The simulation is three-dimensional, using URANS completed by a SST turbulence model. The results are used to examine the flow around the disc with increasing angle of attack and the structure of the wake.

Numerical Analysis of the Cavity Flow subjected to Passive Controls Techniques

NASA Astrophysics Data System (ADS)

Melih Guleren, Kursad; Turk, Seyfettin; Mirza Demircan, Osman; Demir, Oguzhan

2018-03-01

Open-source flow solvers are getting more and more popular for the analysis of challenging flow problems in aeronautical and mechanical engineering applications. They are offered under the GNU General Public License and can be run, examined, shared and modified according to user’s requirements. SU2 and OpenFOAM are the two most popular open-source solvers in Computational Fluid Dynamics (CFD) community. In the present study, some passive control methods on the high-speed cavity flows are numerically simulated using these open-source flow solvers along with one commercial flow solver called ANSYS/Fluent. The results are compared with the available experimental data. The solver SU2 are seen to predict satisfactory the mean streamline velocity but not turbulent kinetic energy and overall averaged sound pressure level (OASPL). Whereas OpenFOAM predicts all these parameters nearly as the same levels of ANSYS/Fluent.

Application of CFD in aeronautics at NASA Ames Research Center

NASA Astrophysics Data System (ADS)

Maksymiuk, Catherine M.; Enomoto, Francis Y.; Vandalsem, William R.

1995-03-01

The role of Computational Fluid Dynamics (CFD) at Ames Research Center has expanded to address a broad range of aeronautical problems, including wind tunnel support, flight test support, design, and analysis. Balancing the requirements of each new problem against the available resources - software, hardware, time, and expertise - is critical to the effective use of CFD. Several case studies of recent applications highlight the depth of CFD capability at Ames, the tradeoffs involved in various approaches, and lessons learned in the use of CFD as an engineering tool.

Evaluation of Cooling Conditions for a High Heat Flux Testing Facility Based on Plasma-Arc Lamps

DOE PAGES

Charry, Carlos H.; Abdel-khalik, Said I.; Yoda, Minami; ...

2015-07-31

The new Irradiated Material Target Station (IMTS) facility for fusion materials at Oak Ridge National Laboratory (ORNL) uses an infrared plasma-arc lamp (PAL) to deliver incident heat fluxes as high as 27 MW/m 2. The facility is being used to test irradiated plasma-facing component materials as part of the joint US-Japan PHENIX program. The irradiated samples are to be mounted on molybdenum sample holders attached to a water-cooled copper rod. Depending on the size and geometry of samples, several sample holders and copper rod configurations have been fabricated and tested. As a part of the effort to design sample holdersmore » compatible with the high heat flux (HHF) testing to be conducted at the IMTS facility, numerical simulations have been performed for two different water-cooled sample holder designs using the ANSYS FLUENT 14.0 commercial computational fluid dynamics (CFD) software package. The primary objective of this work is to evaluate the cooling capability of different sample holder designs, i.e. to estimate their maximum allowable incident heat flux values. 2D axisymmetric numerical simulations are performed using the realizable k-ε turbulence model and the RPI nucleate boiling model within ANSYS FLUENT 14.0. The results of the numerical model were compared against the experimental data for two sample holder designs tested in the IMTS facility. The model has been used to parametrically evaluate the effect of various operational parameters on the predicted temperature distributions. The results were used to identify the limiting parameter for safe operation of the two sample holders and the associated peak heat flux limits. The results of this investigation will help guide the development of new sample holder designs.« less

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.

Benchmark tests for a Formula SAE Student car prototyping

NASA Astrophysics Data System (ADS)

Mariasiu, Florin

2011-12-01

Aerodynamic characteristics of a vehicle are important elements in its design and construction. A low drag coefficient brings significant fuel savings and increased engine power efficiency. In designing and developing vehicles trough computer simulation process to determine the vehicles aerodynamic characteristics are using dedicated CFD (Computer Fluid Dynamics) software packages. However, the results obtained by this faster and cheaper method, are validated by experiments in wind tunnels tests, which are expensive and were complex testing equipment are used in relatively high costs. Therefore, the emergence and development of new low-cost testing methods to validate CFD simulation results would bring great economic benefits for auto vehicles prototyping process. This paper presents the initial development process of a Formula SAE Student race-car prototype using CFD simulation and also present a measurement system based on low-cost sensors through which CFD simulation results were experimentally validated. CFD software package used for simulation was Solid Works with the FloXpress add-on and experimental measurement system was built using four piezoresistive force sensors FlexiForce type.

Concurrent extensions to the FORTRAN language for parallel programming of computational fluid dynamics algorithms

NASA Technical Reports Server (NTRS)

Weeks, Cindy Lou

1986-01-01

Experiments were conducted at NASA Ames Research Center to define multi-tasking software requirements for multiple-instruction, multiple-data stream (MIMD) computer architectures. The focus was on specifying solutions for algorithms in the field of computational fluid dynamics (CFD). The program objectives were to allow researchers to produce usable parallel application software as soon as possible after acquiring MIMD computer equipment, to provide researchers with an easy-to-learn and easy-to-use parallel software language which could be implemented on several different MIMD machines, and to enable researchers to list preferred design specifications for future MIMD computer architectures. Analysis of CFD algorithms indicated that extensions of an existing programming language, adaptable to new computer architectures, provided the best solution to meeting program objectives. The CoFORTRAN Language was written in response to these objectives and to provide researchers a means to experiment with parallel software solutions to CFD algorithms on machines with parallel architectures.

Multi-physics CFD simulations in engineering

NASA Astrophysics Data System (ADS)

Yamamoto, Makoto

2013-08-01

Nowadays Computational Fluid Dynamics (CFD) software is adopted as a design and analysis tool in a great number of engineering fields. We can say that single-physics CFD has been sufficiently matured in the practical point of view. The main target of existing CFD software is single-phase flows such as water and air. However, many multi-physics problems exist in engineering. Most of them consist of flow and other physics, and the interactions between different physics are very important. Obviously, multi-physics phenomena are critical in developing machines and processes. A multi-physics phenomenon seems to be very complex, and it is so difficult to be predicted by adding other physics to flow phenomenon. Therefore, multi-physics CFD techniques are still under research and development. This would be caused from the facts that processing speed of current computers is not fast enough for conducting a multi-physics simulation, and furthermore physical models except for flow physics have not been suitably established. Therefore, in near future, we have to develop various physical models and efficient CFD techniques, in order to success multi-physics simulations in engineering. In the present paper, I will describe the present states of multi-physics CFD simulations, and then show some numerical results such as ice accretion and electro-chemical machining process of a three-dimensional compressor blade which were obtained in my laboratory. Multi-physics CFD simulations would be a key technology in near future.

ICEG2D (v2.0) - An Integrated Software Package for Automated Prediction of Flow Fields for Single-Element Airfoils With Ice Accretion

NASA Technical Reports Server (NTRS)

Thompson David S.; Soni, Bharat K.

2001-01-01

An integrated geometry/grid/simulation software package, ICEG2D, is being developed to automate computational fluid dynamics (CFD) simulations for single- and multi-element airfoils with ice accretions. The current version, ICEG213 (v2.0), was designed to automatically perform four primary functions: (1) generate a grid-ready surface definition based on the geometrical characteristics of the iced airfoil surface, (2) generate high-quality structured and generalized grids starting from a defined surface definition, (3) generate the input and restart files needed to run the structured grid CFD solver NPARC or the generalized grid CFD solver HYBFL2D, and (4) using the flow solutions, generate solution-adaptive grids. ICEG2D (v2.0) can be operated in either a batch mode using a script file or in an interactive mode by entering directives from a command line within a Unix shell. This report summarizes activities completed in the first two years of a three-year research and development program to address automation issues related to CFD simulations for airfoils with ice accretions. As well as describing the technology employed in the software, this document serves as a users manual providing installation and operating instructions. An evaluation of the software is also presented.

Numerical modeling of continuous flow microwave heating: a critical comparison of COMSOL and ANSYS.

PubMed

Salvi, D; Boldor, Dorin; Ortego, J; Aita, G M; Sabliov, C M

2010-01-01

Numerical models were developed to simulate temperature profiles in Newtonian fluids during continuous flow microwave heating by one way coupling electromagnetism, fluid flow, and heat transport in ANSYS 8.0 and COMSOL Multiphysics v3.4. Comparison of the results from the COMSOL model with the results from a pre-developed and validated ANSYS model ensured accuracy of the COMSOL model. Prediction of power Loss by both models was in close agreement (5-13% variation) and the predicted temperature profiles were similar. COMSOL provided a flexible model setup whereas ANSYS required coupling incompatible elements to transfer load between electromagnetic, fluid flow, and heat transport modules. Overall, both software packages provided the ability to solve multiphysics phenomena accurately.

[The study of noninvasive ventilator impeller based on ANSYS].

PubMed

Hu, Zhaoyan; Lu, Pan; Xie, Haiming; Zhou, Yaxu

2011-06-01

An impeller plays a significant role in the non-invasive ventilator. This paper shows a model of impeller for noninvasive ventilator established with the software Solidworks. The model was studied for feasibility based on ANSYS. Then stress and strain of the impeller were discussed under the external loads. The results of the analysis provided verification for the reliable design of impellers.

77 FR 24539 - Virginia Electric and Power Company; Surry Power Station Units 1 and 2; Independent Spent Fuel...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-24

... bounding thermal analysis using ANSYS finite element software to evaluate the misloading events. The ANSYS analysis consists of a half-symmetric, three-dimensional model of a 32PTH DSC with a number of conservative... the maximum fuel cladding temperature presented in the UFSAR analysis dated October 2, 2009, with the...

Modeling of short fiber reinforced injection moulded composite

NASA Astrophysics Data System (ADS)

Kulkarni, A.; Aswini, N.; Dandekar, C. R.; Makhe, S.

2012-09-01

A micromechanics based finite element model (FEM) is developed to facilitate the design of a new production quality fiber reinforced plastic injection molded part. The composite part under study is composed of a polyetheretherketone (PEEK) matrix reinforced with 30% by volume fraction of short carbon fibers. The constitutive material models are obtained by using micromechanics based homogenization theories. The analysis is carried out by successfully coupling two commercial codes, Moldflow and ANSYS. Moldflow software is used to predict the fiber orientation by considering the flow kinetics and molding parameters. Material models are inputted into the commercial software ANSYS as per the predicted fiber orientation and the structural analysis is carried out. Thus in the present approach a coupling between two commercial codes namely Moldflow and ANSYS has been established to enable the analysis of the short fiber reinforced injection moulded composite parts. The load-deflection curve is obtained based on three constitutive material model namely an isotropy, transversely isotropy and orthotropy. Average values of the predicted quantities are compared to experimental results, obtaining a good correlation. In this manner, the coupled Moldflow-ANSYS model successfully predicts the load deflection curve of a composite injection molded part.

CFD Approach To Investigate The Flow Characteristics In Bi-Directional Ventilated Disc Brake

NASA Astrophysics Data System (ADS)

Munisamy, Kannan M.; Yusoff, Mohd. Zamri; Shuaib, Norshah Hafeez; Thangaraju, Savithry K.

2010-06-01

This paper presents experimental and Computational Fluids Dynamics (CFD) investigations of the flow in ventilated brake discs. Development of an experiment rig with basic measuring devices are detailed out and following a validation study, the possible improvement in the brake cooling can be further analyzed using CFD analysis. The mass flow rate is determined from basic flow measurement technique following that the conventional bi-directional passenger car is simulated using commercial CFD software FLUENT™. The CFD simulation is used to investigate the flow characteristics in between blade flow of the bi-directional ventilated disc brake.

Numerical and experimental investigation of enhancement of heat transfer in dimpled rib heat exchanger tube

NASA Astrophysics Data System (ADS)

Kumar, Anil; Maithani, Rajesh; Suri, Amar Raj Singh

2017-12-01

In this study, numerical and experimental investigation has been carried out for a range of system and operating parameters in order to analyse the effect of dimpled rib on heat and fluid flow behaviours in heat exchanger tube. Tube has, stream wise spacing ( x/ d d ) range of 15-35, span wise spacing ( y/ d d ) range of 15-35, ratio of dimpled depth to print diameter ( e/ d d ) of 1.0 and Reynolds number ( Re n ) ranges from 4000 to 28,000. Simulations were carried out to obtain heat and fluid flow behaviour of smooth and rough tube, using commercial CFD software, ANSYS 16.0 (Fluent). Renormalization k - ɛ model was employed to assess the influence of dimpled on turbulent flow and velocity field. Simulation results show that, the enhancement of 3.18 times in heat transfer and 2.87 times enhancement in thermal hydraulic performance as a function of stream wise direction ( x/ d d ) of 15 and span wise direction ( y/ d d ) of 15 respectively. Comparison between numerical and experimental simulation results showed that good agreement as the data fell within ±10% error band.

Design and analysis of drum lathe for manufacturing large-scale optical microstructured surface and load characteristics of aerostatic spindle

NASA Astrophysics Data System (ADS)

Wu, Dongxu; Qiao, Zheng; Wang, Bo; Wang, Huiming; Li, Guo

2014-08-01

In this paper, a four-axis ultra-precision lathe for machining large-scale drum mould with microstructured surface is presented. Firstly, because of the large dimension and weight of drum workpiece, as well as high requirement of machining accuracy, the design guidelines and component parts of this drum lathe is introduced in detail, including control system, moving and driving components, position feedback system and so on. Additionally, the weight of drum workpiece would result in the structural deformation of this lathe, therefore, this paper analyses the effect of structural deformation on machining accuracy by means of ANSYS. The position change is approximately 16.9nm in the X-direction(sensitive direction) which could be negligible. Finally, in order to study the impact of bearing parameters on the load characteristics of aerostatic journal bearing, one of the famous computational fluid dynamics(CFD) software, FLUENT, is adopted, and a series of simulations are carried out. The result shows that the aerostatic spindle has superior performance of carrying capacity and stiffness, it is possible for this lathe to bear the weight of drum workpiece up to 1000kg since there are two aerostatic spindles in the headstock and tailstock.

Software Performs Complex Design Analysis

NASA Technical Reports Server (NTRS)

2008-01-01

Designers use computational fluid dynamics (CFD) to gain greater understanding of the fluid flow phenomena involved in components being designed. They also use finite element analysis (FEA) as a tool to help gain greater understanding of the structural response of components to loads, stresses and strains, and the prediction of failure modes. Automated CFD and FEA engineering design has centered on shape optimization, which has been hindered by two major problems: 1) inadequate shape parameterization algorithms, and 2) inadequate algorithms for CFD and FEA grid modification. Working with software engineers at Stennis Space Center, a NASA commercial partner, Optimal Solutions Software LLC, was able to utilize its revolutionary, one-of-a-kind arbitrary shape deformation (ASD) capability-a major advancement in solving these two aforementioned problems-to optimize the shapes of complex pipe components that transport highly sensitive fluids. The ASD technology solves the problem of inadequate shape parameterization algorithms by allowing the CFD designers to freely create their own shape parameters, therefore eliminating the restriction of only being able to use the computer-aided design (CAD) parameters. The problem of inadequate algorithms for CFD grid modification is solved by the fact that the new software performs a smooth volumetric deformation. This eliminates the extremely costly process of having to remesh the grid for every shape change desired. The program can perform a design change in a markedly reduced amount of time, a process that would traditionally involve the designer returning to the CAD model to reshape and then remesh the shapes, something that has been known to take hours, days-even weeks or months-depending upon the size of the model.

Modelling of Underground Coal Gasification Process Using CFD Methods / Modelowanie Procesu Podziemnego Zgazowania Węgla Kamiennego Z Zastosowaniem Metod CFD

NASA Astrophysics Data System (ADS)

Wachowicz, Jan; Łączny, Jacek Marian; Iwaszenko, Sebastian; Janoszek, Tomasz; Cempa-Balewicz, Magdalena

2015-09-01

The results of model studies involving numerical simulation of underground coal gasification process are presented. For the purpose of the study, the software of computational fluid dynamics (CFD) was selected for simulation of underground coal gasification. Based on the review of the literature, it was decided that ANSYS-Fluent will be used as software for the performance of model studies. The ANSYS- -Fluent software was used for numerical calculations in order to identify the distribution of changes in the concentration of syngas components as a function of duration of coal gasification process. The nature of the calculations was predictive. A geometric model has been developed based on construction data of the georeactor used during the researches in Experimental Mine "Barbara" and Coal Mine "Wieczorek" and it was prepared by generating a numerical grid. Data concerning the georeactor power supply method and the parameters maintained during the process used to define the numerical model. Some part of data was supplemented based on the literature sources. The main assumption was to base the simulation of the georeactor operation on a mathematical models describing reactive fluid flow. Components of the process gas and the gasification agent move along the gasification channel and simulate physicochemical phenomena associated with the transfer of mass and energy as well as chemical reactions (together with the energy effect). Chemical reactions of the gasification process are based on a kinetic equation which determines the course of a particular type of equation of chemical coal gasification. The interaction of gas with the surrounding coal layer has also been described as a part of the model. The description concerned the transport of thermal energy. The coal seam and the mass rock are treated as a homogeneous body. Modelling studies assumed the coal gasification process is carried out with the participation of separately oxygen and air as a gasification agent, under the specific conditions of the georeactor operations within the time interval of 100 hours and 305 hours. The results of the numerical solution have been compared with the results of experimental results under in-situ conditions. Zaprezentowano wyniki badań modelowych polegających na numerycznej symulacji procesu podziemnego zgazowania węgla. Dla potrzeb realizowanej pracy dokonano wyboru oprogramowania wykorzystywanego do symulacji procesu podziemnego zgazowania węgla. Na podstawie przeglądu literatury zdecydowano, że oprogramowaniem, za pomocą, którego będą realizowane badania modelowe, będzie oprogramowanie informatyczne ANSYS-Fluent. Za jego pomocą przeprowadzano obliczenia numeryczne z zamiarem zidentyfikowania rozkładu zmian stężenia składników gazu procesowego w funkcji czasu trwania procesu zgazowania węgla. Przeprowadzone obliczenia miały charakter predykcji. W oparciu o dane konstrukcyjne georeaktora stosowanego podczas badań na KD Barbara oraz KWK Wieczorek, opracowano model geometryczny oraz wykonano jego dyskretyzację poprzez wygenerowanie odpowiedniej siatki numerycznej w oparciu, o którą wykonywane są obliczenia. Dane dotyczące sposobu zasilania georeaktora oraz parametrów utrzymywanych podczas procesu wykorzystano do definiowania modelu numerycznego. Część danych została uzupełniona w oparciu o źródła literaturowe. Głównym przyjętym założeniem było oparcie symulacji pracy georeaktora o modele opisujące reaktywny przepływ płynu. Składniki gazu procesowego oraz czynnik zgazowujący przemieszczają się wzdłuż kanału zgazowującego symulując zjawiska fizykochemiczne związane z transportem masy i energii oraz zachodzące reakcje chemiczne (wraz z efektem energetycznym). Chemizm procesu zgazowania oparto o równanie kinetyczne, które determinuje przebieg danego typu równania chemicznego zgazowania węgla. W ramach modelu opisano też interakcję gazu z otaczającą warstwą węgla. Opis ten dotyczył transportu energii cieplnej. Warstwę węgla oraz warstwy geologiczne otaczające georeaktor traktuje się jako ciało jednorodne. Badania modelowe zakładały prowadzenie procesu zgazowania calizny węglowej przy udziale, osobno tlenu i powietrza, jako czynnika zgazowującego, w warunkach ustalonych pracy georeaktora w przedziale czasu 100 godzin i 305 godzin. Uzyskane wyniki rozwiązania numerycznego zestawiono z wynikami badań eksperymentalnych w warunkach in-situ.

Interpreting CMMI High Maturity for Small Organizations

DTIC Science & Technology

2008-09-01

Stoddard September, 2008 Congreso Internacional en Ingeniería de Software y sus Aplicaciones (International Congress of Software Engineering d...Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Congreso Internacional en Ingeniería de Software y sus Aplicaciones (International Congress of...de Software y sus Aplicaciones (International Congress of Software Engineering and its Applications) Why This Workshop? CMMI Process Performance

Turbulent heat transfer and nanofluid flow in a protruded ribbed square passage

NASA Astrophysics Data System (ADS)

Kumar, Sunil; Kothiyal, Alok Darshan; Bisht, Mangal Singh; Kumar, Anil

In this article, turbulent heat transfer of nanofluid flow in square passage with protruded rib shape is numerically and experimentally studied over Reynolds number ranges of 4000-18000. Different nanoparticles (Al2O3, CuO, and ZnO), with different concentration (φ) range of 1-4% and different nanoparticle diameter (dnp) range of 30-45 nm are disperse in water (base fluid). Several parameters such as stream wise distance (Xs /dp) range of 1.4-2.6, span wise distance (Ys /dp) range of 1.4-2.6, ratio of protruded height to print diameter (ep /dp) range of 0.83-1.67 also studied to find the consequence on thermal and hydrodynamic characteristics. Simulations were carried out to obtain heat and fluid flow behaviour of smooth and ribbed square channel using commercial CFD software, ANSYS 15.0 (Fluent). Renormalization k - ε model was employed to assess the influence of protruded ribs on turbulent flow and velocity field. The outcome indicates that Al2O3 nanofluid has the highest value of average Nusselt number as compare to other nanofluids. The average Nusselt number increases as the concentration increases and it decreases as nanoparticle diameter increases. The thermal hydrodynamic performance parameter based on equal pumping power, average Nusselt number and average friction factor were found to be highest for Al2O3, φ = 0.04, dnp = 30 nm, Xs /dp = 1.8, Ys /dp = 1.8 and ep /dp = 1.0 . The numerical data are compared with the corresponding experimental data. Comparison between CFD and experimental analysis results showed that good agreement as the data fell within ±7.0% error band.

Comparison of turbulence models and CFD solution options for a plain pipe

NASA Astrophysics Data System (ADS)

Canli, Eyub; Ates, Ali; Bilir, Sefik

2018-06-01

Present paper is partly a declaration of state of a currently ongoing PhD work about turbulent flow in a thick walled pipe in order to analyze conjugate heat transfer. An ongoing effort on CFD investigation of this problem using cylindrical coordinates and dimensionless governing equations is identified alongside a literature review. The mentioned PhD work will be conducted using an in-house developed code. However it needs preliminary evaluation by means of commercial codes available in the field. Accordingly ANSYS CFD was utilized in order to evaluate mesh structure needs and asses the turbulence models and solution options in terms of computational power versus difference signification. Present work contains a literature survey, an arrangement of governing equations of the PhD work, CFD essentials of the preliminary analysis and findings about the mesh structure and solution options. Mesh element number was changed between 5,000 and 320,000. k-ɛ, k-ω, Spalart-Allmaras and Viscous-Laminar models were compared. Reynolds number was changed between 1,000 and 50,000. As it may be expected due to the literature, k-ɛ yields more favorable results near the pipe axis and k-ωyields more convenient results near the wall. However k-ɛ is found sufficient to give turbulent structures for a conjugate heat transfer problem in a thick walled plain pipe.

New CFD tools to evaluate nasal airflow.

PubMed

Burgos, M A; Sanmiguel-Rojas, E; Del Pino, C; Sevilla-García, M A; Esteban-Ortega, F

2017-08-01

Computational fluid dynamics (CFD) is a mathematical tool to analyse airflow. As currently CFD is not a usual tool for rhinologists, a group of engineers in collaboration with experts in Rhinology have developed a very intuitive CFD software. The program MECOMLAND ® only required snapshots from the patient's cross-sectional (tomographic) images, being the output those results originated by CFD, such as airflow distributions, velocity profiles, pressure, temperature, or wall shear stress. This is useful complementary information to cover diagnosis, prognosis, or follow-up of nasal pathologies based on quantitative magnitudes linked to airflow. In addition, the user-friendly environment NOSELAND ® helps the medical assessment significantly in the post-processing phase with dynamic reports using a 3D endoscopic view. Specialists in Rhinology have been asked for a more intuitive, simple, powerful CFD software to offer more quality and precision in their work to evaluate the nasal airflow. We present MECOMLAND ® and NOSELAND ® which have all the expected characteristics to fulfil this demand and offer a proper assessment with the maximum of quality plus safety for the patient. These programs represent a non-invasive, low-cost (as the CT scan is already performed in every patient) alternative for the functional study of the difficult rhinologic case. To validate the software, we studied two groups of patients from the Ear Nose Throat clinic, a first group with normal noses and a second group presenting septal deviations. Wall shear stresses are lower in the cases of normal noses in comparison with those for septal deviation. Besides, velocity field distributions, pressure drop between nasopharynx and the ambient, and flow rates in each nostril were different among the nasal cavities in the two groups. These software modules open up a promising future to simulate the nasal airflow behaviour in virtual surgery intervention scenarios under different pressure or temperature conditions to understand the effects on nasal airflow.

CGNS Mid-Level Software Library and Users Guide

NASA Technical Reports Server (NTRS)

Poirier, Diane; Smith, Charles A. (Technical Monitor)

1998-01-01

The "CFD General Notation System" (CGNS) consists of a collection of conventions, and conforming software, for the storage and retrieval of Computational Fluid Dynamics (CFD) data. It facilitates the exchange of data between sites and applications, and helps stabilize the archiving of aerodynamic data. This effort was initiated in order to streamline the procedures in exchanging data and software between NASA and its customers, but the goal is to develop CGNS into a National Standard for the exchange of aerodynamic data. The CGNS development team is comprised of members from Boeing Commercial Airplane Group, NASA-Ames, NASA-Langley, NASA-Lewis, McDonnell-Douglas Corporation (now Boeing-St. Louis), Air Force-Wright Lab., and ICEM-CFD Engineering. The elements of CGNS address all activities associated with the storage of data on external media and its movement to and from application programs. These elements include: - The Advanced Data Format (ADF) Database manager, consisting of both a file format specification and its I/O software, which handles the actual reading and writing of data from and to external storage media; - The Standard Interface Data Structures (SIDS), which specify the intellectual content of CFD data and the conventions governing naming and terminology; - The SIDS-to-ADF File Mapping conventions, which specify the exact location where the CFD data defined by the SIDS is to be stored within the ADF file(s); and - The CGNS Mid-level Library, which provides CFD-knowledgeable routines suitable for direct installation into application codes. The CGNS Mid-level Library was designed to ease the implementation of CGNS by providing developers with a collection of handy I/O functions. Since knowledge of the ADF core is not required to use this library, it will greatly facilitate the task of interfacing with CGNS. There are currently 48 user callable functions that comprise the Mid-level library and are described in the Users Guide. The library is written in C, but each function has a FORTRAN counterpart.

Numerical simulation on the cavitation of waterjet propulsion pump

NASA Astrophysics Data System (ADS)

Xia, C. Z.; Cheng, L.; Shang, Y. N.; Zhou, J. R.; Yang, F.; Jin, Y.

2016-05-01

Waterjet propulsion system is widely used in high speed vessels with advantages of simple transmission mechanism, low noise underwater and good manoeuvrability. Compared with the propeller, waterjet propulsion can be used flow stamping to increasing cavitation resistance at high speed. But under certain conditions, such as low ship speed or high ship speed, cavitation problem still exists. If water-jet propulsion pump is run in cavitation condition for a long time, then the cavitation will cause a great deal of noise CFD is applied to analysis and predict the process of production and development of cavitation in waterjet propulsion pump. Based on the cavitation model of Zwart-Gerber-Belamri and a mixture of homogeneous flow model, commercial CFD software CFX was taken for characteristics of cavitation under the three operating conditions. Commercial software ANSYS 14.0 is used to build entity model, mesh and numerical simulation. The grid independence analysis determine the grid number of mixed flow pump model is about 1.6 million and the grid number of water-jet pump system unit is about 2.7 million. The cavitation characteristics of waterjet pump under three operating conditions are studied. The results show that the cavitation development trend is similar design and small rate of flow condition .Under the design conditions Cavitation bubbles are mainly gathered in suction surface of blade near the inlet side of the hub under the primary stage, and gradually extended to the water side in the direction of the rim with the loss of the inlet total pressure. Cavitation appears in hub before the blade rim, but the maximum value of gas content in blade rim is bigger than that in hub. Under large flow conditions, bubble along the direction of wheel hub extends to the rim gradually. Cavitation is found in the pressure surface of blade near the hub region under the critical point of cavitation nearby. When NPSHa is lower than critical point, the area covering by bubbles is about 40% in the suction surface of blade. It means that the critical point of cavitation of pump system is not the accrue point of install cavitation but cavitation has been developed to a certain stage.

Analysis of wall shear stress around a competitive swimmer using 3D Navier-Stokes equations in CFD.

PubMed

Popa, C V; Zaidi, H; Arfaoui, A; Polidori, G; Taiar, R; Fohanno, S

2011-01-01

This paper deals with the flow dynamics around a competitive swimmer during underwater glide phases occurring at the start and at every turn. The influence of the head position, namely lifted up, aligned and lowered, on the wall shear stress and the static pressure distributions is analyzed. The problem is considered as 3D and in steady hydrodynamic state. Three velocities (1.4 m/s, 2.2 m/s and 3.1 m/s) that correspond to inter-regional, national and international swimming levels are studied. The flow around the swimmer is assumed turbulent. The Reynolds-averaged Navier-Stokes (RANS) equations are solved with the standard k-ω turbulent model by using the CFD (computational fluid dynamics) numerical method based on a volume control approach. Numerical simulations are carried out with the ANSYS FLUENT® CFD code. The results show that the wall shear stress increases with the velocity and consequently the drag force opposing the movement of the swimmer increases as well. Also, high wall shear stresses are observed in the areas where the body shape, globally rigid in form, presents complex surface geometries such as the head, shoulders, buttocks, heel and chest.

Computational studies of an intake manifold for restricted engine application

NASA Astrophysics Data System (ADS)

Prasetyo, Bagus Dwi; Ubaidillah, Maharani, Elliza Tri; Setyohandoko, Gabriel; Idris, Muhammad Idzdihar

2018-02-01

The Formula Society of Automotive Engineer (FSAE) student competition is an international contest for a vehicle that entirely designed and built by students from various universities. The engine design in the Formula SAE competition has to comply a tight regulation. Concerning the engine intake line, an air restrictor of circular cross-section less than 20 mm must be fitted between the throttle valve and the engine inlet. The throat is aimed to limit the engine air flow rate as it strongly influences the volumetric efficiency and then the maximum power. This article focuses on the design of the engine intake system of the Bengawan FSAE team vehicle to optimize the engine power output and its stability. The performance of engine intake system is studied through computational fluid dynamics (CFD). The objective of CFD is to know the pressure, velocity, and airflow of the air intake manifold for the best performance of the engine. The three-dimensional drawing of the intake manifold was made, and CFD simulation was conducted using ANSYS FLUENT. Two models were studied. The result shows that the different design produces a different value of the velocity of airflow and the kind of flow type.

Argonne Bubble Experiment Thermal Model Development III

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

Buechler, Cynthia Eileen

This report describes the continuation of the work reported in “Argonne Bubble Experiment Thermal Model Development” and “Argonne Bubble Experiment Thermal Model Development II”. The experiment was performed at Argonne National Laboratory (ANL) in 2014. A rastered 35 MeV electron beam deposited power in a solution of uranyl sulfate, generating heat and radiolytic gas bubbles. Irradiations were performed at beam power levels between 6 and 15 kW. Solution temperatures were measured by thermocouples, and gas bubble behavior was recorded. The previous report2 described the Monte-Carlo N-Particle (MCNP) calculations and Computational Fluid Dynamics (CFD) analysis performed on the as-built solution vesselmore » geometry. The CFD simulations in the current analysis were performed using Ansys Fluent, Ver. 17.2. The same power profiles determined from MCNP calculations in earlier work were used for the 12 and 15 kW simulations. The primary goal of the current work is to calculate the temperature profiles for the 12 and 15 kW cases using reasonable estimates for the gas generation rate, based on images of the bubbles recorded during the irradiations. Temperature profiles resulting from the CFD calculations are compared to experimental measurements.« less

Validation of numerical models for flow simulation in labyrinth seals

NASA Astrophysics Data System (ADS)

Frączek, D.; Wróblewski, W.

2016-10-01

CFD results were compared with the results of experiments for the flow through the labyrinth seal. RANS turbulence models (k-epsilon, k-omega, SST and SST-SAS) were selected for the study. Steady and transient results were analyzed. ANSYS CFX was used for numerical computation. The analysis included flow through sealing section with the honeycomb land. Leakage flows and velocity profiles in the seal were compared. In addition to the comparison of computational models, the divergence of modeling and experimental results has been determined. Tips for modeling these problems were formulated.

ICEG2D: An Integrated Software Package for Automated Prediction of Flow Fields for Single-Element Airfoils with Ice Accretion

NASA Technical Reports Server (NTRS)

Thompson, David S.; Soni, Bharat K.

2000-01-01

An integrated software package, ICEG2D, was developed to automate computational fluid dynamics (CFD) simulations for single-element airfoils with ice accretion. ICEG2D is designed to automatically perform three primary functions: (1) generating a grid-ready, surface definition based on the geometrical characteristics of the iced airfoil surface, (2) generating a high-quality grid using the generated surface point distribution, and (3) generating the input and restart files needed to run the general purpose CFD solver NPARC. ICEG2D can be executed in batch mode using a script file or in an interactive mode by entering directives from a command line. This report summarizes activities completed in the first year of a three-year research and development program to address issues related to CFD simulations for aircraft components with ice accretion. Specifically, this document describes the technology employed in the software, the installation procedure, and a description of the operation of the software package. Validation of the geometry and grid generation modules of ICEG2D is also discussed.

Nonlinear vibration of a hemispherical dome under external water pressure

NASA Astrophysics Data System (ADS)

Ross, C. T. F.; McLennan, A.; Little, A. P. F.

2011-07-01

The aim of this study was to analyse the behaviour of a hemi-spherical dome when vibrated under external water pressure, using the commercial computer package ANSYS 11.0. In order to achieve this aim, the dome was modelled and vibrated in air and then in water, before finally being vibrated under external water pressure. The results collected during each of the analyses were compared to the previous studies, and this demonstrated that ANSYS was a suitable program and produced accurate results for this type of analysis, together with excellent graphical displays. The analysis under external water pressure, clearly demonstrated that as external water pressure was increased, the resonant frequencies decreased and a type of dynamic buckling became likely; because the static buckling eigenmode was similar to the vibration eigenmode. ANSYS compared favourably with the in-house software, but had the advantage that it produced graphical displays. This also led to the identification of previously undetected meridional modes of vibration; which were not detected with the in-house software.

NASA software specification and evaluation system: Software verification/validation techniques

NASA Technical Reports Server (NTRS)

1977-01-01

NASA software requirement specifications were used in the development of a system for validating and verifying computer programs. The software specification and evaluation system (SSES) provides for the effective and efficient specification, implementation, and testing of computer software programs. The system as implemented will produce structured FORTRAN or ANSI FORTRAN programs, but the principles upon which SSES is designed allow it to be easily adapted to other high order languages.

ANSYS Fluent Modelling of an Underexpanded Supersonic Sootblower Jet Impinging into Recovery Boiler Tube Geometries

NASA Astrophysics Data System (ADS)

Doroudi, Shahed

Sootblowers generate high pressure supersonic steam jets to control fireside deposition on heat transfer tubes of a kraft recovery boiler. Sootblowing is energy expensive, using 3-12% of the mill's total steam production. This motivates research on the dynamics of sootblower jet interaction with tubes and deposits, to optimize their use. A CFD investigation was performed using ANSYS Fluent 15.0 to model three-dimensional steady-state impingement of a Mach 2.5 mildly underexpanded (PR 1.2) air jet onto arrays of cylindrical tubes with and without fins, at various nozzle-to-tube centerline offsets. A free jet and four impingement cases for each of the economizer and generating bank geometries are compared to experimental visualizations. Pressure distributions on impinging surfaces suggest that the fins in the economizer produce a reduced but uniform sootblowing force. Pressure contours along the tubes (in the vertical direction) show a sharp decline one tube diameter away from the jet mid-plane.

Comparison of fluid dynamic numerical models for a clinical ventricular assist device and experimental validation

PubMed Central

Zhang, Jiafeng; Zhang, Pei; Fraser, Katharine H.; Griffith, Bartley P.; Wu, Zhongjun J.

2012-01-01

With the recent advances in computer technology, computational fluid dynamics (CFD) has become an important tool to design and improve blood contacting artificial organs, and to study the device-induced blood damage. Commercial CFD software packages are readily available, and multiple CFD models are provided by CFD software developers. However, the best approach of using CFD effectively to characterize fluid flow and to predict blood damage in these medical devices remains debatable. This study aimed to compare these CFD models and provide useful information on the accuracy of each model in modeling blood flow in circulatory assist devices. The laminar and five turbulence models (Spalart-Allmaras, k-ε (k-epsilon), k-ω (k-omega), SST (Menter’s Shear Stress Transport), and Reynolds Stress) were implemented to predict blood flow in a clinically used circulatory assist device, CentriMag® centrifugal blood pump (Thoratec, MA). In parallel, a transparent replica of the CentriMag® pump was constructed and selected views of the flow fields were measured with digital particle image velocimetry (DPIV). CFD results were compared with the DPIV experimental results. Compared with the experiment, all the selected CFD models predicted the flow pattern fairly well except the area of the outlet. However, quantitatively, the laminar model results were the most deviated from the experimental data. On the other hand, k-ε RNG models and Reynolds Stress model are the most accurate. In conclusion, for the circulatory assist devices, turbulence models provide more accurate results than laminar model. Among the selected turbulence models, k-ε and Reynolds Stress Method models are recommended. PMID:23441681

Numerical Analysis of Coolant Flow and Heat Transfer in ITER Diagnostic First Wall

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

Khodak, A.; Loesser, G.; Zhai, Y.

2015-07-24

We performed numerical simulations of the ITER Diagnostic First Wall (DFW) using ANSYS workbench. During operation DFW will include solid main body as well as liquid coolant. Thus thermal and hydraulic analysis of the DFW was performed using conjugated heat transfer approach, in which heat transfer was resolved in both solid and liquid parts, and simultaneously fluid dynamics analysis was performed only in the liquid part. This approach includes interface between solid and liquid part of the systemAnalysis was performed using ANSYS CFX software. CFX software allows solution of heat transfer equations in solid and liquid part, and solution ofmore » the flow equations in the liquid part. Coolant flow in the DFW was assumed turbulent and was resolved using Reynolds averaged Navier-Stokes equations with Shear Stress Transport turbulence model. Meshing was performed using CFX method available within ANSYS. The data cloud for thermal loading consisting of volumetric heating and surface heating was imported into CFX Volumetric heating source was generated using Attila software. Surface heating was obtained using radiation heat transfer analysis. Our results allowed us to identify areas of excessive heating. Proposals for cooling channel relocation were made. Additional suggestions were made to improve hydraulic performance of the cooling system.« less

Advanced Methodology for Simulation of Complex Flows Using Structured Grid Systems

NASA Technical Reports Server (NTRS)

Steinthorsson, Erlendur; Modiano, David

1995-01-01

Detailed simulations of viscous flows in complicated geometries pose a significant challenge to current capabilities of Computational Fluid Dynamics (CFD). To enable routine application of CFD to this class of problems, advanced methodologies are required that employ (a) automated grid generation, (b) adaptivity, (c) accurate discretizations and efficient solvers, and (d) advanced software techniques. Each of these ingredients contributes to increased accuracy, efficiency (in terms of human effort and computer time), and/or reliability of CFD software. In the long run, methodologies employing structured grid systems will remain a viable choice for routine simulation of flows in complex geometries only if genuinely automatic grid generation techniques for structured grids can be developed and if adaptivity is employed more routinely. More research in both these areas is urgently needed.

CFD analysis of linear compressors considering load conditions

NASA Astrophysics Data System (ADS)

Bae, Sanghyun; Oh, Wonsik

2017-08-01

This paper is a study on computational fluid dynamics (CFD) analysis of linear compressor considering load conditions. In the conventional CFD analysis of the linear compressor, the load condition was not considered in the behaviour of the piston. In some papers, behaviour of piston is assumed as sinusoidal motion provided by user defined function (UDF). In the reciprocating type compressor, the stroke of the piston is restrained by the rod, while the stroke of the linear compressor is not restrained, and the stroke changes depending on the load condition. The greater the pressure difference between the discharge refrigerant and the suction refrigerant, the more the centre point of the stroke is pushed backward. And the behaviour of the piston is not a complete sine wave. For this reason, when the load condition changes in the CFD analysis of the linear compressor, it may happen that the ANSYS code is changed or unfortunately the modelling is changed. In addition, a separate analysis or calculation is required to find a stroke that meets the load condition, which may contain errors. In this study, the coupled mechanical equations and electrical equations are solved using the UDF, and the behaviour of the piston is solved considering the pressure difference across the piston. Using the above method, the stroke of the piston with respect to the motor specification of the analytical model can be calculated according to the input voltage, and the piston behaviour can be realized considering the thrust amount due to the pressure difference.

High temperature high velocity direct power extraction using an open-cycle oxy-combustion system

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

Love, Norman

The implementation of oxy-fuel technology in fossil-fuel power plants may contribute to increased system efficiencies and a reduction of pollutant emissions. One technology that has potential to utilize the temperature of undiluted oxy-combustion flames is open-cycle magnetohydrodynamic (MHD) power generators. These systems can be configured as a topping cycle and provide high enthalpy, electrically conductive flows for direct conversion of electricity. This report presents the design and modeling strategies of a MHD combustor operating at temperatures exceeding 3000 K. Throughout the study, computational fluid dynamics (CFD) models were extensively used as a design and optimization tool. A lab-scale 60 kWthmore » model was designed, manufactured and tested as part of this project. A fully-coupled numerical method was developed in ANSYS FLUENT to characterize the heat transfer in the system. This study revealed that nozzle heat transfer may be predicted through a 40% reduction of the semi-empirical Bartz correlation. Experimental results showed good agreement with the numerical evaluation, with the combustor exhibiting a favorable performance when tested during extended time periods. A transient numerical method was employed to analyze fuel injector geometries for the 60-kW combustor. The ANSYS FLUENT study revealed that counter-swirl inlets achieve a uniform pressure and velocity ratio when the ports of the injector length to diameter ratio (L/D) is 4. An angle of 115 degrees was found to increase distribution efficiency. The findings show that this oxy-combustion concept is capable of providing a high-enthalpy environment for seeding, in order to render the flow to be conductive. Based on previous findings, temperatures in the range of 2800-3000 K may enable magnetohydrodynamic power extraction. The heat loss fraction in this oxy-combustion system, based on CFD and analytical calculations, at optimal operating conditions, was estimated to be less than 10 percent. Furthermore, the heat transfer design removed approximately 7 MW/m2. The results observed in the lab-scale system were employed to develop a 1-MW scaled prototype. Scaling methods were based on critical design criteria found in similar systems, aimed at replicating combustion flow fields and reducing possible instabilities. A numerical simulation of the combustor wall was developed for a combined thermal steady model and static structural model. This combined model was developed predict combined stress parameters within the wall during testing conditions. Both models were developed within ANSYS FEA software package. The relative accuracy presented as well major performance parameters are discussed to assess the design's validity and ensure safety. The scaled prototype was manufactured through selective laser melting (SLM)-based additive manufacturing to reduce lead times and increase geometrical complexity. Additional CFD models were developed to optimize coolant manifold system parameters and perform a parametric study on channel geometry. An investigation on coolant manifold geometry demonstrated improvements in channel flow distribution when enlarging manifold lengths and increasing the number of tubes feeding into the flow. A three-dimensional model based on a single channel was developed to capture the effect of variable properties and thermal stratification. All cases in the simulation exhibited higher wall temperatures and lower convective coefficients than those determined through 1-D analytical equations. This implies that pressure and velocity safety factors must be implemented during system operation. Overall, the findings made in this investigation are thought to be of value to researchers and industrial practitioners when designing oxy-fuel direct power extraction systems operating at temperatures exceeding 3000 K. In addition to this, the implementation of the developed technology at pilot and commercial scales could result in a significant improvement in the efficiencies of heritage and next-generation power cycles.« less

Computational Fluid Dynamics (CFD) investigation onto passenger car disk brake design

NASA Astrophysics Data System (ADS)

Munisamy, Kannan M.; Kanasan Moorthy, Shangkari K.

2013-06-01

The aim of this study is to investigate the flow and heat transfer in ventilated disc brakes using Computational Fluid Dynamics (CFD). NACA Series blade is designed for ventilated disc brake and the cooling characteristic is compared to the baseline design. The ventilated disc brakes are simulated using commercial CFD software FLUENTTM using simulation configuration that was obtained from experiment data. The NACA Series blade design shows improvements in Nusselt number compared to baseline design.

Comparison of lenses' thermal expansion formulation in Zemax versus ANSYS with SigFit post processing

NASA Astrophysics Data System (ADS)

Faria, João.; Alves, J. L.; Nunes-Pereira, Eduardo J.

2017-08-01

The goal of this paper is to study in which extent the use of Zemax is suited for athermalization purposes. The research questions targeted in this paper are: what are the differences in the formulation of materials' thermal expansion between Zemax and Ansys; what is the impact on optical quality between both approaches; quantification of the differences between the two methodologies in terms of back focal length, spot radius and modulation transfer function (MTF). To quantify the differences between both approaches, it is used an objective working between -40°C and 110°C. Initially, only Zemax was used to evaluate the objective. Zemax considers a linear geometric expansion of every optical surface, which is here proved to not be the best approach to find a deformed geometry after a thermal load. The second approach is to create a 3D model and perform a finite element simulation in Ansys software. The input data is the thermal variation and the output is the deformed geometry of the lenses. Using SigFit software, it was possible to generate new mathematical equations of the deformed lenses and import this data into Zemax to start a new ray tracing. The new shape and location of lenses differs for both scenarios, and the difference in the focal plane shift is around 12%. The maximum spot radius difference is 27% and MTF relative error goes up to 16%. Zemax as a standalone software is valid if used as an initial guess for the optical designer. However, as a final stage for validation and detailed design, the approach containing Ansys and SigFit should be preferable.

Advanced Data Format (ADF) Software Library and Users Guide

NASA Technical Reports Server (NTRS)

Smith, Matthew; Smith, Charles A. (Technical Monitor)

1998-01-01

The "CFD General Notation System" (CGNS) consists of a collection of conventions, and conforming software, for the storage and retrieval of Computational Fluid Dynamics (CFD) data. It facilitates the exchange of data between sites and applications, and helps stabilize the archiving of aerodynamic data. This effort was initiated in order to streamline the procedures in exchanging data and software between NASA and its customers, but the goal is to develop CGNS into a National Standard for the exchange of aerodynamic data. The CGNS development team is comprised of members from Boeing Commercial. Airplane Group, NASA-Ames, NASA-Langley, NASA-Lewis, McDonnell-Douglas Corporation (now Boeing-St. Louis), Air Force-Wright Lab., and ICEM-CFD Engineering. The elements of CGNS address all activities associated with the storage of data on external media and its movement to and from application programs. These elements include: 1) The Advanced Data Format (ADF) Database manager, consisting of both a file format specification and its 1/0 software, which handles the actual reading and writing of data from and to external storage media; 2) The Standard Interface Data Structures (SIDS), which specify the intellectual content of CFD data and the conventions governing naming and terminology; 3) The SIDS-to-ADF File Mapping conventions, which specify the exact location where the CFD data defined by the SIDS is to be stored within the ADF file(s); and 4) The CGNS Mid-level Library, which provides CFD-knowledgeable routines suitable for direct installation into application codes. The ADF is a generic database manager with minimal intrinsic capability. It was written for the purpose of storing large numerical datasets in an efficient, platform independent manner. To be effective, it must be used in conjunction with external agreements on how the data will be organized within the ADF database such defined by the SIDS. There are currently 34 user callable functions that comprise the ADF Core library and are described in the Users Guide. The library is written in C, but each function has a FORTRAN counterpart.

CFD analysis of heat transfer performance of graphene based hybrid nanofluid in radiators

NASA Astrophysics Data System (ADS)

Bharadwaj, Bharath R.; Sanketh Mogeraya, K.; Manjunath, D. M.; Rao Ponangi, Babu; Rajendra Prasad, K. S.; Krishna, V.

2018-04-01

For Improved performance of an automobile engine, Cooling systems are one of the critical systems that need attention. With increased capacity to carry away large amounts of wasted heat, performance of an engine is increased. Current research on Nano-fluids suggests that they offer higher heat transfer rate compared to that of conventional coolants. Hence this project seeks to investigate the use of hybrid-nanofluids in radiators so as to increase its heat transfer performance. Carboxyl Graphene and Graphene Oxide based nanoparticles were selected due to the very high thermal conductivity of Graphene. System Analysis of the radiator was performed by considering a small part of the whole automobile radiator modelled using SEIMENS NX. CFD analysis was conducted using ANSYS FLUENT® for the nanofluid defined and the increase in effectiveness was compared to that of conventional coolants. Usage of such nanofluids for a fixed cooling requirement in the future can lead to significant downsizing of the radiator.

CFD simulation of fatty acid methyl ester production in bubble column reactor

NASA Astrophysics Data System (ADS)

Salleh, N. S. Mohd; Nasir, N. F.

2017-09-01

Non-catalytic transesterification is one of the method that was used to produce the fatty acid methyl ester (FAME) by blowing superheated methanol bubbles continuously into the vegetable oil without using any catalyst. This research aimed to simulate the production of FAME from palm oil in a bubble column reactor. Computational Fluid Dynamic (CFD) simulation was used to predict the distribution of fatty acid methyl ester and other product in the reactor. The fluid flow and component of concentration along the reaction time was investigated and the effects of reaction temperature (523 K and 563 K) on the non-catalytic transesterification process has been examined. The study was carried out using ANSYS CFX 17.1. The finding from the study shows that increasing the temperature leads to higher amount of fatty acid methyl ester can be produced in shorter time. On the other hand, concentration of the component such as triglyceride (TG), glycerol (GL) and fatty acid methyl ester (FAME) can be known when reaching the optimum condition.

Numerical investigation of heat transfer in annulus laminar flow of multi tubes-in-tube helical coil

NASA Astrophysics Data System (ADS)

Nada, S. A.; Elattar, H. F.; Fouda, A.; Refaey, H. A.

2018-03-01

In the present study, a CFD analysis using ANSYS-FLUENT 14.5 CFD package is used to investigate the characteristics of heat transfer of laminar flow in annulus formed by multi tubes in tube helically coiled heat exchanger. The numerical results are validated by comparison with previous experimental data and fair agreements were existed. The influences of the design and operation parameters such as heat flux, Reynolds numbers and annulus geometry on the heat transfer characteristics are investigated. Different annulus of different numbers of inner tubes, specifically 1, 2, 3, 4 and 5 tubes, are tested. The Results showed that for all the studied annulus, the heat flux has no effect on the Nusselt number and compactness parameter. The annulus formed by using five inner tubes showed the best heat transfer performance and compactness parameter. Correlation of predicting Nusselt number in terms of Reynolds number and number of inner tubes are presented.

Taguchi Based Regression Analysis of End-Wall Film Cooling in a Gas Turbine Cascade with Single Row of Holes

NASA Astrophysics Data System (ADS)

Ravi, D.; Parammasivam, K. M.

2016-09-01

Numerical investigations were conducted on a turbine cascade, with end-wall cooling by a single row of cylindrical holes, inclined at 30°. The mainstream fluid was hot air and the coolant was CO2 gas. Based on the Reynolds number, the flow was turbulent at the inlet. The film hole row position, its pitch and blowing ratio was varied with five different values. Taguchi approach was used in designing a L25 orthogonal array (OA) for these parameters. The end-wall averaged film cooling effectiveness (bar η) was chosen as the quality characteristic. CFD analyses were carried out using Ansys Fluent on computational domains designed with inputs from OA. Experiments were conducted for one chosen OA configuration and the computational results were found to correlate well with experimental measurements. The responses from the CFD analyses were fed to the statistical tool to develop a correlation for bar η using regression analysis.

Predicting the flow & noise of a rotor in a turbulent boundary layer using an actuator disk -- RANS approach

NASA Astrophysics Data System (ADS)

Buono, Armand C.

The numerical method presented in this study attempts to predict the mean, non-uniform flow field upstream of a propeller partially immersed in a thick turbulent boundary layer with an actuator disk using CFD based on RANS in ANSYS FLUENT. Three different configurations, involving an infinitely thin actuator disk in the freestream (Configuration 1), an actuator disk near a wall with a turbulent boundary layer (Configuration 2), and an actuator disk with a hub near a wall with a turbulent boundary layer (Configuration 3), were analyzed for a variety of advance ratios ranging from J = 0.48 to J =1.44. CFD results are shown to be in agreement with previous works and validated with experimental data of reverse flow occurring within the boundary layer above the flat plate upstream of a rotor in the Virginia Tech's Stability Wind Tunnel facility. Results from Configuration 3 will be used in future aero-acoustic computations.

Performance analysis of a counter-rotating tubular type micro-turbine by experiment and CFD

NASA Astrophysics Data System (ADS)

Lee, N. J.; Choi, J. W.; Hwang, Y. H.; Kim, Y. T.; Lee, Y. H.

2012-11-01

Micro hydraulic turbines have a growing interest because of its small and simple structure, as well as a high possibility of using in micro and small hydropower applications. The differential pressure existing in city water pipelines can be used efficiently to generate electricity in a way similar to that of energy being generated through gravitational potential energy in dams. The pressure energy in the city pipelines is often wasted by using pressure reducing valves at the inlet of water cleaning centers. Instead of using the pressure reducing valves, a micro counter-rotating hydraulic turbine can be used to make use of the pressure energy. In the present paper, a counter-rotating tubular type micro-turbine is studied, with the front runner connected to the generator stator and the rear runner connected to the generator rotor. The performance of the turbine is investigated experimentally and numerically. A commercial ANSYS CFD code was used for numerical analysis.

CFD Analysis of Turbo Expander for Cryogenic Refrigeration and Liquefaction Cycles

NASA Astrophysics Data System (ADS)

Verma, Rahul; Sam, Ashish Alex; Ghosh, Parthasarathi

Computational Fluid Dynamics analysis has emerged as a necessary tool for designing of turbomachinery. It helps to understand the various sources of inefficiency through investigation of flow physics of the turbine. In this paper, 3D turbulent flow analysis of a cryogenic turboexpander for small scale air separation was performed using Ansys CFX®. The turboexpander has been designed following assumptions based on meanlineblade generation procedure provided in open literature and good engineering judgement. Through analysis of flow field, modifications and further analysis required to evolve a more robust design procedure, have been suggested.

Recent Updates to the CFD General Notation System (CGNS)

NASA Technical Reports Server (NTRS)

Rumsey, Christopher L.; Wedan, Bruce; Hauser, Thomas; Poinot, Marc

2012-01-01

The CFD General Notation System (CGNS) - a general, portable, and extensible standard for the storage and retrieval of computational fluid dynamics (CFD) analysis data has been in existence for more than a decade (Version 1.0 was released in May 1998). Both structured and unstructured CFD data are covered by the standard, and CGNS can be easily extended to cover any sort of data imaginable, while retaining backward compatibility with existing CGNS data files and software. Although originally designed for CFD, it is readily extendable to any field of computational analysis. In early 2011, CGNS Version 3.1 was released, which added significant capabilities. This paper describes these recent enhancements and highlights the continued usefulness of the CGNS methodology.

Coupling scales for modelling heavy metal vaporization from municipal solid waste incineration in a fluid bed by CFD

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

Soria, José, E-mail: jose.soria@probien.gob.ar; Gauthier, Daniel; Flamant, Gilles

2015-09-15

Highlights: • A CFD two-scale model is formulated to simulate heavy metal vaporization from waste incineration in fluidized beds. • MSW particle is modelled with the macroscopic particle model. • Influence of bed dynamics on HM vaporization is included. • CFD predicted results agree well with experimental data reported in literature. • This approach may be helpful for fluidized bed reactor modelling purposes. - Abstract: Municipal Solid Waste Incineration (MSWI) in fluidized bed is a very interesting technology mainly due to high combustion efficiency, great flexibility for treating several types of waste fuels and reduction in pollutants emitted with themore » flue gas. However, there is a great concern with respect to the fate of heavy metals (HM) contained in MSW and their environmental impact. In this study, a coupled two-scale CFD model was developed for MSWI in a bubbling fluidized bed. It presents an original scheme that combines a single particle model and a global fluidized bed model in order to represent the HM vaporization during MSW combustion. Two of the most representative HM (Cd and Pb) with bed temperatures ranging between 923 and 1073 K have been considered. This new approach uses ANSYS FLUENT 14.0 as the modelling platform for the simulations along with a complete set of self-developed user-defined functions (UDFs). The simulation results are compared to the experimental data obtained previously by the research group in a lab-scale fluid bed incinerator. The comparison indicates that the proposed CFD model predicts well the evolution of the HM release for the bed temperatures analyzed. It shows that both bed temperature and bed dynamics have influence on the HM vaporization rate. It can be concluded that CFD is a rigorous tool that provides valuable information about HM vaporization and that the original two-scale simulation scheme adopted allows to better represent the actual particle behavior in a fluid bed incinerator.« less

TU-H-CAMPUS-IeP2-03: Development of 3D Printed Coronary Phantoms for In-Vitro CT-FFR Validation Using Data from 320- Detector Row Coronary CT Angiography

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

Ionita, C; Rudin, S; Bednarek, D

Purpose: To validate Computed Tomography Fractional Flow Reserve (CT-FFR) measurements with accurate 3D printed coronary phantoms. Methods: DICOM data from four phases in two patients imaged with a standard 320 × 0.5mm coronary CT acquisition (70–80% cardiac cycle) underwent semi-automated segmentation using a research workstation. Both patients had a >50% stenosis from the clinical image interpretation. Each volume was saved as a Stereo Lithographic (STL) file with 250 micron resolution. The 3D geometries were qualitatively assessed; the best of the four phases was 3D printed using a Stratasys Eden260V printer in Tango+, a rubber-like material that roughly emulates mechanical propertiesmore » of human vasculature. We connected the model to a programmable pump and measured the pressure drop using pressure sensors embedded proximal and distal to the arterial stenosis. Next, the STL files used for the 3D printed models were uploaded in the ANSYS meshing tool (ICEM CFD 16.1). A standard meshing process was applied and the meshed geometry was directly imported in the ANSYS Fluent for Computational Flow Dynamics simulations. The CFD simulations were used to calculate the CT-FFR and compared to the bench top FFR measured in the 3D printed phantoms. Results: FFR-CT measurements and phantoms were completed in within an hour after the segmentation. Patient 1 had a 60% stenosis that resulted in a CT-FFR of 0.68. The second case had a 50% stenosis and a CT-FFR of 0.75. The average bench top FFR measurements were 0.72 and 0.80, respectively. Conclusion: This pilot investigation demonstrated the use of a bench-top coronary model for CT-FFR validation. The measurements and the CFD simulations agreed within 6%. Project supported by Support: Toshiba America Medical Systems Corp.and NIH grant R01-EB002873. Project supported by Toshiba America Medical Systems Corp.and partial support from NIH grant R01-EB002873.« less

Development of a %22solar patch%22 calculator to evaluate heliostat-field irradiance as a boundary condition in CFD models.

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

Khalsa, Siri Sahib; Ho, Clifford Kuofei

2010-04-01

A rigorous computational fluid dynamics (CFD) approach to calculating temperature distributions, radiative and convective losses, and flow fields in a cavity receiver irradiated by a heliostat field is typically limited to the receiver domain alone for computational reasons. A CFD simulation cannot realistically yield a precise solution that includes the details within the vast domain of an entire heliostat field in addition to the detailed processes and features within a cavity receiver. Instead, the incoming field irradiance can be represented as a boundary condition on the receiver domain. This paper describes a program, the Solar Patch Calculator, written in Microsoftmore » Excel VBA to characterize multiple beams emanating from a 'solar patch' located at the aperture of a cavity receiver, in order to represent the incoming irradiance from any field of heliostats as a boundary condition on the receiver domain. This program accounts for cosine losses; receiver location; heliostat reflectivity, areas and locations; field location; time of day and day of year. This paper also describes the implementation of the boundary conditions calculated by this program into a Discrete Ordinates radiation model using Ansys{reg_sign} FLUENT (www.fluent.com), and compares the results to experimental data and to results generated by the code DELSOL.« less

Development of a %22Solar Patch%22 calculator to evaluate heliostat-field irradiance as a boundary condition in CFD models.

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

Khalsa, Siri Sahib S.; Ho, Clifford Kuofei

2010-05-01

A rigorous computational fluid dynamics (CFD) approach to calculating temperature distributions, radiative and convective losses, and flow fields in a cavity receiver irradiated by a heliostat field is typically limited to the receiver domain alone for computational reasons. A CFD simulation cannot realistically yield a precise solution that includes the details within the vast domain of an entire heliostat field in addition to the detailed processes and features within a cavity receiver. Instead, the incoming field irradiance can be represented as a boundary condition on the receiver domain. This paper describes a program, the Solar Patch Calculator, written in Microsoftmore » Excel VBA to characterize multiple beams emanating from a 'solar patch' located at the aperture of a cavity receiver, in order to represent the incoming irradiance from any field of heliostats as a boundary condition on the receiver domain. This program accounts for cosine losses; receiver location; heliostat reflectivity, areas and locations; field location; time of day and day of year. This paper also describes the implementation of the boundary conditions calculated by this program into a Discrete Ordinates radiation model using Ansys{reg_sign} FLUENT (www.fluent.com), and compares the results to experimental data and to results generated by the code DELSOL.« less

Experimental and Numerical Study on Supersonic Ejectors Working with R-1234ze(E)

NASA Astrophysics Data System (ADS)

Kracik, Jan; Dvorak, Vaclav; Nguyen Van, Vu; Smierciew, Kamil

2018-06-01

These days, much effort is being put into lowering the consumption of electric energy and involving renewable energy sources. Many engineers and designers are trying to develop environment-friendly technologies worldwide. It is related to incorporating appropriate devices into such technologies. The object of this paper is to investigate these devices in connection with refrigeration systems. Ejectors can be considered such as these devices. The primary interest of this paper is to investigate the suitability of a numerical model for an ejector, which is incorporated into a refrigeration system. In the present paper, there have been investigated seven different test runs of working of the ejector with a working fluid R-1234ze(E). Some of the investigated cases seem to have a good agreement and there are no significant discrepancies between them, however, there are also cases that do not correspond to the experimental data at all. The ejector has been investigated in both on-design and off-design working modes. A comparison between the experimental and numerical data (CFD) performed by Ansys Fluent software is presented and discussed for both an ideal and a real gas model. In addition, an enhanced analytical model has been introduced for all runs of the ejector.

The technique for Simulation of Transient Combustion Processes in the Rocket Engine Operating with Gaseous Fuel “Hydrogen and Oxygen”

NASA Astrophysics Data System (ADS)

Zubanov, V. M.; Stepanov, D. V.; Shabliy, L. S.

2017-01-01

The article describes the method for simulation of transient combustion processes in the rocket engine. The engine operates on gaseous propellant: oxygen and hydrogen. Combustion simulation was performed using the ANSYS CFX software. Three reaction mechanisms for the stationary mode were considered and described in detail. Reactions mechanisms have been taken from several sources and verified. The method for converting ozone properties from the Shomate equation to the NASA-polynomial format was described in detail. The way for obtaining quick CFD-results with intermediate combustion components using an EDM model was found. Modeling difficulties with combustion model Finite Rate Chemistry, associated with a large scatter of reference data were identified and described. The way to generate the Flamelet library with CFX-RIF is described. Formulated adequate reaction mechanisms verified at a steady state have also been tested for transient simulation. The Flamelet combustion model was recognized as adequate for the transient mode. Integral parameters variation relates to the values obtained during stationary simulation. A cyclic irregularity of the temperature field, caused by precession of the vortex core, was detected in the chamber with the proposed simulation technique. Investigations of unsteady processes of rocket engines including the processes of ignition were proposed as the area for application of the described simulation technique.

The study of the influence of the diameter ratio and blade number to the performance of the cross flow wind turbine by using 2D computational fluid dynamics modeling

NASA Astrophysics Data System (ADS)

Tjahjana, Dominicus Danardono Dwi Prija; Purbaningrum, Pradityasari; Hadi, Syamsul; Wicaksono, Yoga Arob; Adiputra, Dimas

2018-02-01

Cross flow turbine can be one of the alternative energies for regions with low wind speed. Collision between wind and the blades which happened two times caused the cross flow turbine to have high power coefficient. Some factors that influence the turbine power coefficient are diameter ratio and blade number. The objective of the research was to study the effect of the diameter ratio and the blade number to the cross flow wind turbine performance. The study was done in two dimensional (2D) computational fluid dynamics (CFD) simulation method using the ANSYS-Fluent software. The turbine diameter ratio were 0.58, 0.63, 0.68 and 0.73. The diameter ratio resulting in the highest power coefficient value was then simulated by varying the number of blades, namely 16, 20 and 24. Each variation was tested on the wind speed of 2 m/s and at the tip speed ratio (TSR) of 0.1 to 0.4 with the interval of 0.1. The wind turbine with the ratio diameter of 0.68 and the number of blades of 20 generated the highest power coefficient of 0.5 at the TSR of 0.3.

Effects of Turbulence Model and Numerical Time Steps on Von Karman Flow Behavior and Drag Accuracy of Circular Cylinder

NASA Astrophysics Data System (ADS)

Amalia, E.; Moelyadi, M. A.; Ihsan, M.

2018-04-01

The flow of air passing around a circular cylinder on the Reynolds number of 250,000 is to show Von Karman Vortex Street Phenomenon. This phenomenon was captured well by using a right turbulence model. In this study, some turbulence models available in software ANSYS Fluent 16.0 was tested to simulate Von Karman vortex street phenomenon, namely k- epsilon, SST k-omega and Reynolds Stress, Detached Eddy Simulation (DES), and Large Eddy Simulation (LES). In addition, it was examined the effect of time step size on the accuracy of CFD simulation. The simulations are carried out by using two-dimensional and three- dimensional models and then compared with experimental data. For two-dimensional model, Von Karman Vortex Street phenomenon was captured successfully by using the SST k-omega turbulence model. As for the three-dimensional model, Von Karman Vortex Street phenomenon was captured by using Reynolds Stress Turbulence Model. The time step size value affects the smoothness quality of curves of drag coefficient over time, as well as affecting the running time of the simulation. The smaller time step size, the better inherent drag coefficient curves produced. Smaller time step size also gives faster computation time.

Analysis of Wind Forces on Roof-Top Solar Panel

NASA Astrophysics Data System (ADS)

Panta, Yogendra; Kudav, Ganesh

2011-03-01

Structural loads on solar panels include forces due to high wind, gravity, thermal expansion, and earthquakes. International Building Code (IBC) and the American Society of Civil Engineers are two commonly used approaches in solar industries to address wind loads. Minimum Design Loads for Buildings and Other Structures (ASCE 7-02) can be used to calculate wind uplift loads on roof-mounted solar panels. The present study is primarily focused on 2D and 3D modeling with steady, and turbulent flow over an inclined solar panel on the flat based roof to predict the wind forces for designing wind management system. For the numerical simulation, 3-D incompressible flow with the standard k- ɛ was adopted and commercial CFD software ANSYS FLUENT was used. Results were then validated with wind tunnel experiments with a good agreement. Solar panels with various aspect ratios for various high wind speeds and angle of attacks were modeled and simulated in order to predict the wind loads in various scenarios. The present study concluded to reduce the strong wind uplift by designing a guide plate or a deflector before the panel. Acknowledgments to Northern States Metal Inc., OH (GK & YP) and School of Graduate Studies of YSU for RP & URC 2009-2010 (YP).

CFD analysis on effect of front windshield angle on aerodynamic drag

NASA Astrophysics Data System (ADS)

Abdellah, Essaghouri; Wang, Bo

2017-09-01

The external aerodynamics plays an important role in the design process of any automotive. The whole performance of the vehicle can be improved with the help of external aerodynamics. The aerodynamic analysis nowadays is implemented in the recent research in the automotive industry to achieve better cars in terms of design and efficiency. The major objective of the present work is to find out the effect of changing the angle between the engine hood and the front windshield on reducing the car air resistance. A full scale three dimensional (BMW 3 series) sedan car model was carried out using the ALIAS AUTOSTUDIO 2016 a NURBS modeling tool with high quality surfaces, only the external shape of the car was modeled while the interior was not modeled. The ANSYS 17.0 WORKBENCH software package was used to analyse the airflow around the external shape of the car - the solutions of Reynolds Average Navier Stokes (RANS) equations has been carried out using realizable k-epsilon turbulence model (which is perfectly suitable for the automated calculation process) for the given car domain. In this work, the boundary layer, mesh quality, and turbulent value simulation has been compared and discussed in the result section. Finally the optimal model was selected and the redesigned car was analysed to verify the results.

Visualization of unsteady computational fluid dynamics

NASA Astrophysics Data System (ADS)

Haimes, Robert

1994-11-01

A brief summary of the computer environment used for calculating three dimensional unsteady Computational Fluid Dynamic (CFD) results is presented. This environment requires a super computer as well as massively parallel processors (MPP's) and clusters of workstations acting as a single MPP (by concurrently working on the same task) provide the required computational bandwidth for CFD calculations of transient problems. The cluster of reduced instruction set computers (RISC) is a recent advent based on the low cost and high performance that workstation vendors provide. The cluster, with the proper software can act as a multiple instruction/multiple data (MIMD) machine. A new set of software tools is being designed specifically to address visualizing 3D unsteady CFD results in these environments. Three user's manuals for the parallel version of Visual3, pV3, revision 1.00 make up the bulk of this report.

Visualization of unsteady computational fluid dynamics

NASA Technical Reports Server (NTRS)

Haimes, Robert

1994-01-01

A brief summary of the computer environment used for calculating three dimensional unsteady Computational Fluid Dynamic (CFD) results is presented. This environment requires a super computer as well as massively parallel processors (MPP's) and clusters of workstations acting as a single MPP (by concurrently working on the same task) provide the required computational bandwidth for CFD calculations of transient problems. The cluster of reduced instruction set computers (RISC) is a recent advent based on the low cost and high performance that workstation vendors provide. The cluster, with the proper software can act as a multiple instruction/multiple data (MIMD) machine. A new set of software tools is being designed specifically to address visualizing 3D unsteady CFD results in these environments. Three user's manuals for the parallel version of Visual3, pV3, revision 1.00 make up the bulk of this report.

Numerical modeling of immiscible two-phase flow in micro-models using a commercial CFD code

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

Crandall, Dustin; Ahmadia, Goodarz; Smith, Duane H.

2009-01-01

Off-the-shelf CFD software is being used to analyze everything from flow over airplanes to lab-on-a-chip designs. So, how accurately can two-phase immiscible flow be modeled flowing through some small-scale models of porous media? We evaluate the capability of the CFD code FLUENT{trademark} to model immiscible flow in micro-scale, bench-top stereolithography models. By comparing the flow results to experimental models we show that accurate 3D modeling is possible.

The role of CFD in the design process

NASA Astrophysics Data System (ADS)

Jennions, Ian K.

1994-05-01

Over the last decade the role played by CFD codes in turbomachinery design has changed remarkably. While convergence/stability or even the existence of unique solutions was discussed fervently ten years ago, CFD codes now form a valuable part of an overall integrated design system and have caused us to re-think much of what we do. The geometric and physical complexities addressed have also evolved, as have the number of software houses competing with in-house developers to provide solutions to daily design problems. This paper reviews how GE Aircraft Engines (GEAE) uses CFD in the turbomachinery design process and examines many of the issues faced in successful code implementation.

CFD modeling of space-time evolution of fast pyrolysis products in a bench-scale fluidized-bed reactor

USDA-ARS?s Scientific Manuscript database

A model for the evolution of pyrolysis products in a fluidized bed has been developed. In this study the unsteady constitutive transport equations for inert gas flow and decomposition kinetics were modeled using the commercial computational fluid dynamics (CFD) software FLUENT-12. The model system d...

Numerical simulation of an elastic structure behavior under transient fluid flow excitation

NASA Astrophysics Data System (ADS)

Afanasyeva, Irina N.; Lantsova, Irina Yu.

2017-01-01

This paper deals with the verification of a numerical technique of modeling fluid-structure interaction (FSI) problems. The configuration consists of incompressible viscous fluid around an elastic structure in the channel. External flow is laminar. Multivariate calculations are performed using special software ANSYS CFX and ANSYS Mechanical. Different types of parameters of mesh deformation and solver controls (time step, under relaxation factor, number of iterations at coupling step) were tested. The results are presented in tables and plots in comparison with reference data.

Modeling of an argon cascaded arc plasma by ANSYS FLUENT

NASA Astrophysics Data System (ADS)

Wei, Guodong; Qi, Xin; Yang, Lei

2014-04-01

In this work, an argon cascaded arc plasma is simulated by the business software ANSYS FLUENT. In fact, thus plasma is a high temperature arc (plasma window) with an average temperature of 12000 °C, which can be used as a medium between high pressure and vacuum mainly due to its characteristics of high temperature. According to the simulating results, the temperature can reach as high as 11500 °C which is in great agreement with that of other reports about plasma window.

ANSYS simulation of the capacitance coupling of quartz tuning fork gyroscope

NASA Astrophysics Data System (ADS)

Zhang, Qing; Feng, Lihui; Zhao, Ke; Cui, Fang; Sun, Yu-nan

2013-12-01

Coupling error is one of the main error sources of the quartz tuning fork gyroscope. The mechanism of capacitance coupling error is analyzed in this article. Finite Element Method (FEM) is used to simulate the structure of the quartz tuning fork by ANSYS software. The voltage output induced by the capacitance coupling is simulated with the harmonic analysis and characteristics of electrical and mechanical parameters influenced by the capacitance coupling between drive electrodes and sense electrodes are discussed with the transient analysis.

Thermal analysis of electron gun for travelling wave tubes

NASA Astrophysics Data System (ADS)

Bhat, K. S.; Sreedevi, K.; Ravi, M.

2006-11-01

Thermal analysis of a pierce type electron gun using the FEM software ANSYS and its experimental validation are presented in this paper. Thermal analysis of the electron gun structure has been carried out to find out the effect of heater power on steady state temperature and warm-up time. The thermal drain of the supporting structure has also been analyzed for different materials. These results were experimentally verified in an electron gun. The experimental results closely match the ANSYS results.

Best Practices for Reduction of Uncertainty in CFD Results

NASA Technical Reports Server (NTRS)

Mendenhall, Michael R.; Childs, Robert E.; Morrison, Joseph H.

2003-01-01

This paper describes a proposed best-practices system that will present expert knowledge in the use of CFD. The best-practices system will include specific guidelines to assist the user in problem definition, input preparation, grid generation, code selection, parameter specification, and results interpretation. The goal of the system is to assist all CFD users in obtaining high quality CFD solutions with reduced uncertainty and at lower cost for a wide range of flow problems. The best-practices system will be implemented as a software product which includes an expert system made up of knowledge databases of expert information with specific guidelines for individual codes and algorithms. The process of acquiring expert knowledge is discussed, and help from the CFD community is solicited. Benefits and challenges associated with this project are examined.

Design of a Hydro-Turbine Blade for Acoustic and Performance Validation Studies

NASA Astrophysics Data System (ADS)

Johnson, E.; Barone, M.

2011-12-01

To meet the growing, global energy demands governments and industry have recently begun to focus on marine hydrokinetic (MHK) devices as an additional form of power generation. Water turbines have become a popular design choice since they are able to leverage experience from the decades-old wind industry in the hope of decreasing time-to-market. However, the difference in environments poses challenges that need to be addressed. In particular, little research has addressed the acoustic effects of common aerofoils in a marine setting. This has both a potential impact on marine life and may cause early fatigue by exciting new structural modes. An initial blade design is presented, which has been used to begin characterization of any structural and acoustic issues that may arise from a direct one-to-one swap of wind technologies into MHK devices. The blade was optimized for performance using blade-element momentum theory while requiring that it not exceed the allowable stress under a specified extreme operating design condition. This limited the maximum power generated, while ensuring a realizable blade. A stress analysis within ANSYS was performed to validate the structural integrity of the design. Additionally, predictions of the radiated noise from the MHK rotor will be made using boundary element modeling based on flow results from ANSYS CFX, a computational fluid dynamics (CFD) code. The FEA and CFD results demonstrate good comparison to the expected design. Determining a range for the anticipated noise produced from a MHK turbine provides a look at the environmental impact these devices will have. Future efforts will focus on the design constraints noise generation places on MHK devices.

A Recommended Framework for the Network-Centric Acquisition Process

DTIC Science & Technology

2009-09-01

ISO /IEC 12207 , Systems and Software Engineering-Software Life-Cycle Processes  ANSI/EIA 632, Processes for Engineering a System. There are...engineering [46]. Some of the process models presented in the DAG are:  ISO /IEC 15288, Systems and Software Engineering-System Life-Cycle Processes...e.g., ISO , IA, Security, etc.). Vetting developers helps ensure that they are using industry best industry practices and maximize the IA compliance

Simulating flow around scaled model of a hypersonic vehicle in wind tunnel

NASA Astrophysics Data System (ADS)

Markova, T. V.; Aksenov, A. A.; Zhluktov, S. V.; Savitsky, D. V.; Gavrilov, A. D.; Son, E. E.; Prokhorov, A. N.

2016-11-01

A prospective hypersonic HEXAFLY aircraft is considered in the given paper. In order to obtain the aerodynamic characteristics of a new construction design of the aircraft, experiments with a scaled model have been carried out in a wind tunnel under different conditions. The runs have been performed at different angles of attack with and without hydrogen combustion in the scaled propulsion engine. However, the measured physical quantities do not provide all the information about the flowfield. Numerical simulation can complete the experimental data as well as to reduce the number of wind tunnel experiments. Besides that, reliable CFD software can be used for calculations of the aerodynamic characteristics for any possible design of the full-scale aircraft under different operation conditions. The reliability of the numerical predictions must be confirmed in verification study of the software. The given work is aimed at numerical investigation of the flowfield around and inside the scaled model of the HEXAFLY-CIAM module under wind tunnel conditions. A cold run (without combustion) was selected for this study. The calculations are performed in the FlowVision CFD software. The flow characteristics are compared against the available experimental data. The carried out verification study confirms the capability of the FlowVision CFD software to calculate the flows discussed.

Coupling scales for modelling heavy metal vaporization from municipal solid waste incineration in a fluid bed by CFD.

PubMed

Soria, José; Gauthier, Daniel; Flamant, Gilles; Rodriguez, Rosa; Mazza, Germán

2015-09-01

Municipal Solid Waste Incineration (MSWI) in fluidized bed is a very interesting technology mainly due to high combustion efficiency, great flexibility for treating several types of waste fuels and reduction in pollutants emitted with the flue gas. However, there is a great concern with respect to the fate of heavy metals (HM) contained in MSW and their environmental impact. In this study, a coupled two-scale CFD model was developed for MSWI in a bubbling fluidized bed. It presents an original scheme that combines a single particle model and a global fluidized bed model in order to represent the HM vaporization during MSW combustion. Two of the most representative HM (Cd and Pb) with bed temperatures ranging between 923 and 1073K have been considered. This new approach uses ANSYS FLUENT 14.0 as the modelling platform for the simulations along with a complete set of self-developed user-defined functions (UDFs). The simulation results are compared to the experimental data obtained previously by the research group in a lab-scale fluid bed incinerator. The comparison indicates that the proposed CFD model predicts well the evolution of the HM release for the bed temperatures analyzed. It shows that both bed temperature and bed dynamics have influence on the HM vaporization rate. It can be concluded that CFD is a rigorous tool that provides valuable information about HM vaporization and that the original two-scale simulation scheme adopted allows to better represent the actual particle behavior in a fluid bed incinerator. Copyright © 2015 Elsevier Ltd. All rights reserved.

Convective Heating of the LIFE Engine Target During Injection

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

Holdener, D S; Tillack, M S; Wang, X R

2011-10-24

Target survival in the hostile, high temperature xenon environment of the proposed Laser Inertial Fusion Energy (LIFE) engine is critical. This work focuses on the flow properties and convective heat load imposed upon the surface of the indirect drive target while traveling through the xenon gas. While this rarefied flow is traditionally characterized as being within the continuum regime, it is approaching transition where conventional CFD codes reach their bounds of operation. Thus ANSYS, specifically the Navier-Stokes module CFX, will be used in parallel with direct simulation Monte Carlo code DS2V and analytically and empirically derived expressions for heat transfermore » to the hohlraum for validation. Comparison of the viscous and thermal boundary layers of ANSYS and DS2V were shown to be nearly identical, with the surface heat flux varying less than 8% on average. From the results herein, external baffles have been shown to reduce this heat transfer to the sensitive laser entrance hole (LEH) windows and optimize target survival independent of other reactor parameters.« less

Effects of fluid structure interaction in a three dimensional model of the spinal subarachnoid space.

PubMed

Cheng, Shaokoon; Fletcher, David; Hemley, Sarah; Stoodley, Marcus; Bilston, Lynne

2014-08-22

It is unknown whether spinal cord motion has a significant effect on cerebrospinal fluid (CSF) pressure and therefore the importance of including fluid structure interaction (FSI) in computational fluid dynamics models (CFD) of the spinal subarachnoid space (SAS) is unclear. This study aims to determine the effects of FSI on CSF pressure and spinal cord motion in a normal and in a stenosis model of the SAS. A three-dimensional patient specific model of the SAS and spinal cord were constructed from MR anatomical images and CSF flow rate measurements obtained from a healthy human being. The area of SAS at spinal level T4 was constricted by 20% to represent the stenosis model. FSI simulations in both models were performed by running ANSYS CFX and ANSYS Mechanical in tandem. Results from this study show that the effect of FSI on CSF pressure is only about 1% in both the normal and stenosis models and therefore show that FSI has a negligible effect on CSF pressure. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Evaluation of cavity size, kind, and filling technique of composite shrinkage by finite element.

PubMed

Jafari, Toloo; Alaghehmad, Homayoon; Moodi, Ehsan

2018-01-01

Cavity preparation reduces the rigidity of tooth and its resistance to deformation. The purpose of this study was to evaluate the dimensional changes of the repaired teeth using two types of light cure composite and two methods of incremental and bulk filling by the use of finite element method. In this computerized in vitro experimental study, an intact maxillary premolar was scanned using cone beam computed tomography instrument (SCANORA, Switzerland), then each section of tooth image was transmitted to Ansys software using AUTOCAD. Then, eight sizes of cavity preparations and two methods of restoration (bulk and incremental) using two different types of composite resin materials (Heliomolar, Brilliant) were proposed on software and analysis was completed with Ansys software. Dimensional change increased by widening and deepening of the cavities. It was also increased using Brilliant composite resin and incremental filling technique. Increase in depth and type of filling technique has the greatest role of dimensional change after curing, but the type of composite resin does not have a significant role.

Finite element analysis of container ship's cargo hold using ANSYS and POSEIDON software

NASA Astrophysics Data System (ADS)

Tanny, Tania Tamiz; Akter, Naznin; Amin, Osman Md.

2017-12-01

Nowadays ship structural analysis has become an integral part of the preliminary ship design providing further support for the development and detail design of ship structures. Structural analyses of container ship's cargo holds are carried out for the balancing of their safety and capacity, as those ships are exposed to the high risk of structural damage during voyage. Two different design methodologies have been considered for the structural analysis of a container ship's cargo hold. One is rule-based methodology and the other is a more conventional software based analyses. The rule based analysis is done by DNV-GL's software POSEIDON and the conventional package based analysis is done by ANSYS structural module. Both methods have been applied to analyze some of the mechanical properties of the model such as total deformation, stress-strain distribution, Von Mises stress, Fatigue etc., following different design bases and approaches, to indicate some guidance's for further improvements in ship structural design.

Assessment of CFD capability for prediction of hypersonic shock interactions

NASA Astrophysics Data System (ADS)

Knight, Doyle; Longo, José; Drikakis, Dimitris; Gaitonde, Datta; Lani, Andrea; Nompelis, Ioannis; Reimann, Bodo; Walpot, Louis

2012-01-01

The aerothermodynamic loadings associated with shock wave boundary layer interactions (shock interactions) must be carefully considered in the design of hypersonic air vehicles. The capability of Computational Fluid Dynamics (CFD) software to accurately predict hypersonic shock wave laminar boundary layer interactions is examined. A series of independent computations performed by researchers in the US and Europe are presented for two generic configurations (double cone and cylinder) and compared with experimental data. The results illustrate the current capabilities and limitations of modern CFD methods for these flows.

Computational fluid dynamics simulation of airflow in the trachea and main bronchi for the subjects with left pulmonary artery sling

PubMed Central

2014-01-01

Background Left pulmonary artery sling (LPAS) is a rare but severe congenital anomaly, in which the stenoses are formed in the trachea and/or main bronchi. Multi-detector computed tomography (MDCT) provides useful anatomical images, but does not offer functional information. The objective of the present study is to quantitatively analyze the airflow in the trachea and main bronchi of LPAS subjects through computational fluid dynamics (CFD) simulation. Methods Five subjects (four LPAS patients, one normal control) aging 6-19 months are analyzed. The geometric model of the trachea and the two main bronchi is extracted from the MDCT images. The inlet velocity is determined based on the body weight and the inlet area. Both the geometric model and personalized inflow conditions are imported into CFD software, ANSYS. The pressure drop, mass flow ratio through two bronchi, wall pressure, flow velocity and wall shear stress (WSS) are obtained, and compared to the normal control. Results Due to the tracheal and/or bronchial stenosis, the pressure drop for the LPAS patients ranges 78.9 - 914.5 Pa, much higher than for the normal control (0.7 Pa). The mass flow ratio through the two bronchi does not correlate with the sectional area ratio if the anomalous left pulmonary artery compresses the trachea or bronchi. It is suggested that the C-shaped trachea plays an important role on facilitating the air flow into the left bronchus with the inertia force. For LPAS subjects, the distributions of velocities, wall pressure and WSS are less regular than for the normal control. At the stenotic site, high velocity, low wall pressure and high WSS are observed. Conclusions Using geometric models extracted from CT images and the patient-specified inlet boundary conditions, CFD simulation can provide vital quantitative flow information for LPAS. Due to the stenosis, high pressure drops, inconsistent distributions of velocities, wall pressure and WSS are observed. The C-shaped trachea may facilitate a larger flow of air into the left bronchus under the inertial force, and decrease the ventilation of the right lung. Quantitative and personalized information may help understand the mechanism of LPAS and the correlations between stenosis and dyspnea, and facilitate the structural and functional assessment of LPAS. PMID:24957947

Application of Benchmark Examples to Assess the Single and Mixed-Mode Static Delamination Propagation Capabilities in ANSYS

NASA Technical Reports Server (NTRS)

Krueger, Ronald

2012-01-01

The application of benchmark examples for the assessment of quasi-static delamination propagation capabilities is demonstrated for ANSYS. The examples are independent of the analysis software used and allow the assessment of the automated delamination propagation in commercial finite element codes based on the virtual crack closure technique (VCCT). The examples selected are based on two-dimensional finite element models of Double Cantilever Beam (DCB), End-Notched Flexure (ENF), Mixed-Mode Bending (MMB) and Single Leg Bending (SLB) specimens. First, the quasi-static benchmark examples were recreated for each specimen using the current implementation of VCCT in ANSYS . Second, the delamination was allowed to propagate under quasi-static loading from its initial location using the automated procedure implemented in the finite element software. Third, the load-displacement relationship from a propagation analysis and the benchmark results were compared, and good agreement could be achieved by selecting the appropriate input parameters. The benchmarking procedure proved valuable by highlighting the issues associated with choosing the input parameters of the particular implementation. Overall the results are encouraging, but further assessment for three-dimensional solid models is required.

Fluid-dynamics modelling of the human left ventricle with dynamic mesh for normal and myocardial infarction: preliminary study.

PubMed

Khalafvand, S S; Ng, E Y K; Zhong, L; Hung, T K

2012-08-01

Pulsating blood flow patterns in the left ventricular (LV) were computed for three normal subjects and three patients after myocardial infarction (MI). Cardiac magnetic resonance (MR) images were obtained, segmented and transformed into 25 frames of LV for a computational fluid dynamics (CFD) study. Multi-block structure meshes were generated for 25 frames and 75 intermediate grids. The complete LV cycle was modelled by using ANSYS-CFX 12. The flow patterns and pressure drops in the LV chamber of this study provided some useful information on intra-LV flow patterns with heart diseases. Copyright © 2012 Elsevier Ltd. All rights reserved.

Numerical and experimental modelling of the radial compressor stage

NASA Astrophysics Data System (ADS)

Syka, Tomáš; Matas, Richard; LuÅáček, Ondřej

2016-06-01

This article deals with the description of the numerical and experimental model of the new compressor stage designed for process centrifugal compressors. It's the first member of the new stages family developed to achieve the state of the art thermodynamic parameters. This stage (named RTK01) is designed for high flow coefficient with 3D shaped impeller blades. Some interesting findings were gained during its development. The article is focused mainly on some interesting aspects of the development methodology and numerical simulations improvement, not on the specific stage properties. Conditions and experimental equipment, measured results and their comparison with ANSYS CFX and NUMECA FINE/Turbo CFD simulations are described.

Integrated thermal disturbance analysis of optical system of astronomical telescope

NASA Astrophysics Data System (ADS)

Yang, Dehua; Jiang, Zibo; Li, Xinnan

2008-07-01

During operation, astronomical telescope will undergo thermal disturbance, especially more serious in solar telescope, which may cause degradation of image quality. As drives careful thermal load investigation and measure applied to assess its effect on final image quality during design phase. Integrated modeling analysis is boosting the process to find comprehensive optimum design scheme by software simulation. In this paper, we focus on the Finite Element Analysis (FEA) software-ANSYS-for thermal disturbance analysis and the optical design software-ZEMAX-for optical system design. The integrated model based on ANSYS and ZEMAX is briefed in the first from an overview of point. Afterwards, we discuss the establishment of thermal model. Complete power series polynomial with spatial coordinates is introduced to present temperature field analytically. We also borrow linear interpolation technique derived from shape function in finite element theory to interface the thermal model and structural model and further to apply the temperatures onto structural model nodes. Thereby, the thermal loads are transferred with as high fidelity as possible. Data interface and communication between the two softwares are discussed mainly on mirror surfaces and hence on the optical figure representation and transformation. We compare and comment the two different methods, Zernike polynomials and power series expansion, for representing and transforming deformed optical surface to ZEMAX. Additionally, these methods applied to surface with non-circular aperture are discussed. At the end, an optical telescope with parabolic primary mirror of 900 mm in diameter is analyzed to illustrate the above discussion. Finite Element Model with most interested parts of the telescope is generated in ANSYS with necessary structural simplification and equivalence. Thermal analysis is performed and the resulted positions and figures of the optics are to be retrieved and transferred to ZEMAX, and thus final image quality is evaluated with thermal disturbance.

Virtual Diagnostics Interface: Real Time Comparison of Experimental Data and CFD Predictions for a NASA Ares I-Like Vehicle

NASA Technical Reports Server (NTRS)

Schwartz, Richard J.; Fleming, Gary A.

2007-01-01

Virtual Diagnostics Interface technology, or ViDI, is a suite of techniques utilizing image processing, data handling and three-dimensional computer graphics. These techniques aid in the design, implementation, and analysis of complex aerospace experiments. LiveView3D is a software application component of ViDI used to display experimental wind tunnel data in real-time within an interactive, three-dimensional virtual environment. The LiveView3D software application was under development at NASA Langley Research Center (LaRC) for nearly three years. LiveView3D recently was upgraded to perform real-time (as well as post-test) comparisons of experimental data with pre-computed Computational Fluid Dynamics (CFD) predictions. This capability was utilized to compare experimental measurements with CFD predictions of the surface pressure distribution of the NASA Ares I Crew Launch Vehicle (CLV) - like vehicle when tested in the NASA LaRC Unitary Plan Wind Tunnel (UPWT) in December 2006 - January 2007 timeframe. The wind tunnel tests were conducted to develop a database of experimentally-measured aerodynamic performance of the CLV-like configuration for validation of CFD predictive codes.

CFD research and systems in Kawasaki Heavy Industries and its future prospects

NASA Astrophysics Data System (ADS)

Hiraoka, Koichi

1990-09-01

KHI Computational Fluid Dynamics (CFD) system is composed of VP100 computer and 2-D and 3-D Euler and/or Navier-Stokes (NS) analysis softwares. For KHI, this system has become a very powerful aerodynamic tool together with the Kawasaki 1 m Transonic Wind Tunnel. The 2-D Euler/NS software, developed in-house, is fully automated, requires no special skill, and was successfully applied to the design of YXX high lift devices and SST supersonic inlet, etc. The 3-D Euler/NS software, developed under joint research with NAL, has an interactively operated Multi-Block type grid generator and can effectively generate grids around complex airplane shapes. Due to the main memory size limitation, 3-D analysis of relatively simple shape, such as SST wing-body, was computed in-house on VP100, otherwise, such as detailed 3-D analyses of ASUKA and HOPE, were computed on NAL VP400, which is 10 times more powerful than VP100, under KHI-NAL joint research. These analysis results have very good correlation with experimental results. However, the present CFD system is less productive than wind tunnel and has applicability limitations.

FEM and Multiphysics Applications at NASA/GSFC

NASA Technical Reports Server (NTRS)

Loughlin, James

2004-01-01

FEM software available to the Mechanical Systems Analysis and Simulation Branch at Goddard Space Flight Center (GSFC) include: 1) MSC/Nastran; 2) Abaqus; 3) Ansys/Multiphysics; 4) COSMOS/M; 5) 'Home-grown' programs; 6) Pre/post processors such as Patran and FEMAP. This viewgraph presentation provides additional information on MSC/Nastran and Ansys/Multiphysics, and includes screen shots of analyzed equipment, including the Wilkinson Microwave Anistropy Probe, a micro-mirror, a MEMS tunable filter, and a micro-shutter array. The presentation also includes information on the verification of results.

Simulation of blast action on civil structures using ANSYS Autodyn

NASA Astrophysics Data System (ADS)

Fedorova, N. N.; Valger, S. A.; Fedorov, A. V.

2016-10-01

The paper presents the results of 3D numerical simulations of shock wave spreading in cityscape area. ANSYS Autodyne software is used for the computations. Different test cases are investigated numerically. On the basis of the computations, the complex transient flowfield structure formed in the vicinity of prismatic bodies was obtained and analyzed. The simulation results have been compared to the experimental data. The ability of two numerical schemes is studied to correctly predict the pressure history in several gauges placed on walls of the obstacles.

Development and testing of a numerical simulation method for thermally nonequilibrium dissociating flows in ANSYS Fluent

NASA Astrophysics Data System (ADS)

Shoev, G. V.; Bondar, Ye. A.; Oblapenko, G. P.; Kustova, E. V.

2016-03-01

Various issues of numerical simulation of supersonic gas flows with allowance for thermochemical nonequilibrium on the basis of fluid dynamic equations in the two-temperature approximation are discussed. The computational tool for modeling flows with thermochemical nonequilibrium is the commercial software package ANSYS Fluent with an additional userdefined open-code module. A comparative analysis of results obtained by various models of vibration-dissociation coupling in binary gas mixtures of nitrogen and oxygen is performed. Results of numerical simulations are compared with available experimental data.

Comparison of Numerical Analyses with a Static Load Test of a Continuous Flight Auger Pile

NASA Astrophysics Data System (ADS)

Hoľko, Michal; Stacho, Jakub

2014-12-01

The article deals with numerical analyses of a Continuous Flight Auger (CFA) pile. The analyses include a comparison of calculated and measured load-settlement curves as well as a comparison of the load distribution over a pile's length. The numerical analyses were executed using two types of software, i.e., Ansys and Plaxis, which are based on FEM calculations. Both types of software are different from each other in the way they create numerical models, model the interface between the pile and soil, and use constitutive material models. The analyses have been prepared in the form of a parametric study, where the method of modelling the interface and the material models of the soil are compared and analysed. Our analyses show that both types of software permit the modelling of pile foundations. The Plaxis software uses advanced material models as well as the modelling of the impact of groundwater or overconsolidation. The load-settlement curve calculated using Plaxis is equal to the results of a static load test with a more than 95 % degree of accuracy. In comparison, the load-settlement curve calculated using Ansys allows for the obtaining of only an approximate estimate, but the software allows for the common modelling of large structure systems together with a foundation system.

Effect of Spray Cone Angle on Flame Stability in an Annular Gas Turbine Combustor

NASA Astrophysics Data System (ADS)

Mishra, R. K.; Kumar, S. Kishore; Chandel, Sunil

2016-04-01

Effect of fuel spray cone angle in an aerogas turbine combustor has been studied using computational fluid dynamics (CFD) and full-scale combustor testing. For CFD analysis, a 22.5° sector of an annular combustor is modeled and the governing equations are solved using the eddy dissipation combustion model in ANSYS CFX computational package. The analysis has been carried out at 125 kPa and 303 K inlet conditions for spray cone angles from 60° to 140°. The lean blowout limits are established by studying the behavior of combustion zone during transient engine operation from an initial steady-state condition. The computational study has been followed by testing the practical full-scale annular combustor in an aerothermal test facility. The experimental result is in a good agreement with the computational predictions. The lean blowout fuel-air ratio increases as the spray cone angle is decreased at constant operating pressure and temperature. At higher spray cone angle, the flame and high-temperature zone moves upstream close to atomizer face and a uniform flame is sustained over a wide region causing better flame stability.

Aerodynamic analysis of Audi A4 Sedan using CFD

NASA Astrophysics Data System (ADS)

Birwa, S. K.; Rathi, N.; Gupta, R.

2013-04-01

This paper presents the aerodynamic influence of velocity and ground clearance for Audi A4 Sedan. The topology of the test vehicle was modeled using CATIA P3 V5 R17. ANSYS FLUENT 12 was the CFD solver employed in this study. The distribution of pressure and velocity was obtained. The velocities were 30, 40, 50 and 60 m/s and ground clearances were 76.2 mm,101.6 mm,127 mm and 152.4 mm. The simulation results were compared with the available resources. It was found that the drag coefficient decreases with the velocity increasing from 30 to 60 m/s and increases with the ground clearance from 101.6 mm to 152.4 mm. Further decrease in ground clearance showed no effect on the value of coefficient of drag. The lift coefficient was found to decrease firstly with ground clearance from 152.4 mm to 101.6 mm, and then increase from 101.6 mm to 76.2 mm. Both the lift coefficient and drag coefficient was found to be minimum for the ground clearance of 101.6 mm as designed by the company.

Application of CAD/CAE class systems to aerodynamic analysis of electric race cars

NASA Astrophysics Data System (ADS)

Grabowski, L.; Baier, A.; Buchacz, A.; Majzner, M.; Sobek, M.

2015-11-01

Aerodynamics is one of the most important factors which influence on every aspect of a design of a car and car driving parameters. The biggest influence aerodynamics has on design of a shape of a race car body, especially when the main objective of the race is the longest distance driven in period of time, which can not be achieved without low energy consumption and low drag of a car. Designing shape of the vehicle body that must generate the lowest possible drag force, without compromising the other parameters of the drive. In the article entitled „Application of CAD/CAE class systems to aerodynamic analysis of electric race cars” are being presented problems solved by computer analysis of cars aerodynamics and free form modelling. Analysis have been subjected to existing race car of a Silesian Greenpower Race Team. On a basis of results of analysis of existence of Kammback aerodynamic effect innovative car body were modeled. Afterwards aerodynamic analysis were performed to verify existence of aerodynamic effect for innovative shape and to recognize aerodynamics parameters of the shape. Analysis results in the values of coefficients and aerodynamic drag forces. The resulting drag forces Fx, drag coefficients Cx(Cd) and aerodynamic factors Cx*A allowed to compare all of the shapes to each other. Pressure distribution, air velocities and streams courses were useful in determining aerodynamic features of analyzed shape. For aerodynamic tests was used Ansys Fluent CFD software. In a paper the ways of surface modeling with usage of Realize Shape module and classic surface modeling were presented. For shapes modeling Siemens NX 9.0 software was used. Obtained results were used to estimation of existing shapes and to make appropriate conclusions.

Numerical Analysis of 2-D and 3-D MHD Flows Relevant to Fusion Applications

DOE PAGES

Khodak, Andrei

2017-08-21

Here, the analysis of many fusion applications such as liquid-metal blankets requires application of computational fluid dynamics (CFD) methods for electrically conductive liquids in geometrically complex regions and in the presence of a strong magnetic field. A current state of the art general purpose CFD code allows modeling of the flow in complex geometric regions, with simultaneous conjugated heat transfer analysis in liquid and surrounding solid parts. Together with a magnetohydrodynamics (MHD) capability, the general purpose CFD code will be a valuable tool for the design and optimization of fusion devices. This paper describes an introduction of MHD capability intomore » the general purpose CFD code CFX, part of the ANSYS Workbench. The code was adapted for MHD problems using a magnetic induction approach. CFX allows introduction of user-defined variables using transport or Poisson equations. For MHD adaptation of the code three additional transport equations were introduced for the components of the magnetic field, in addition to the Poisson equation for electric potential. The Lorentz force is included in the momentum transport equation as a source term. Fusion applications usually involve very strong magnetic fields, with values of the Hartmann number of up to tens of thousands. In this situation a system of MHD equations become very rigid with very large source terms and very strong variable gradients. To increase system robustness, special measures were introduced during the iterative convergence process, such as linearization using source coefficient for momentum equations. The MHD implementation in general purpose CFD code was tested against benchmarks, specifically selected for liquid-metal blanket applications. Results of numerical simulations using present implementation closely match analytical solutions for a Hartmann number of up to 1500 for a 2-D laminar flow in the duct of square cross section, with conducting and nonconducting walls. Results for a 3-D test case are also included.« less

Numerical Analysis of 2-D and 3-D MHD Flows Relevant to Fusion Applications

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

Khodak, Andrei

Here, the analysis of many fusion applications such as liquid-metal blankets requires application of computational fluid dynamics (CFD) methods for electrically conductive liquids in geometrically complex regions and in the presence of a strong magnetic field. A current state of the art general purpose CFD code allows modeling of the flow in complex geometric regions, with simultaneous conjugated heat transfer analysis in liquid and surrounding solid parts. Together with a magnetohydrodynamics (MHD) capability, the general purpose CFD code will be a valuable tool for the design and optimization of fusion devices. This paper describes an introduction of MHD capability intomore » the general purpose CFD code CFX, part of the ANSYS Workbench. The code was adapted for MHD problems using a magnetic induction approach. CFX allows introduction of user-defined variables using transport or Poisson equations. For MHD adaptation of the code three additional transport equations were introduced for the components of the magnetic field, in addition to the Poisson equation for electric potential. The Lorentz force is included in the momentum transport equation as a source term. Fusion applications usually involve very strong magnetic fields, with values of the Hartmann number of up to tens of thousands. In this situation a system of MHD equations become very rigid with very large source terms and very strong variable gradients. To increase system robustness, special measures were introduced during the iterative convergence process, such as linearization using source coefficient for momentum equations. The MHD implementation in general purpose CFD code was tested against benchmarks, specifically selected for liquid-metal blanket applications. Results of numerical simulations using present implementation closely match analytical solutions for a Hartmann number of up to 1500 for a 2-D laminar flow in the duct of square cross section, with conducting and nonconducting walls. Results for a 3-D test case are also included.« less

Methodology for Computational Fluid Dynamic Validation for Medical Use: Application to Intracranial Aneurysm.

PubMed

Paliwal, Nikhil; Damiano, Robert J; Varble, Nicole A; Tutino, Vincent M; Dou, Zhongwang; Siddiqui, Adnan H; Meng, Hui

2017-12-01

Computational fluid dynamics (CFD) is a promising tool to aid in clinical diagnoses of cardiovascular diseases. However, it uses assumptions that simplify the complexities of the real cardiovascular flow. Due to high-stakes in the clinical setting, it is critical to calculate the effect of these assumptions in the CFD simulation results. However, existing CFD validation approaches do not quantify error in the simulation results due to the CFD solver's modeling assumptions. Instead, they directly compare CFD simulation results against validation data. Thus, to quantify the accuracy of a CFD solver, we developed a validation methodology that calculates the CFD model error (arising from modeling assumptions). Our methodology identifies independent error sources in CFD and validation experiments, and calculates the model error by parsing out other sources of error inherent in simulation and experiments. To demonstrate the method, we simulated the flow field of a patient-specific intracranial aneurysm (IA) in the commercial CFD software star-ccm+. Particle image velocimetry (PIV) provided validation datasets for the flow field on two orthogonal planes. The average model error in the star-ccm+ solver was 5.63 ± 5.49% along the intersecting validation line of the orthogonal planes. Furthermore, we demonstrated that our validation method is superior to existing validation approaches by applying three representative existing validation techniques to our CFD and experimental dataset, and comparing the validation results. Our validation methodology offers a streamlined workflow to extract the "true" accuracy of a CFD solver.

Guide to NavyFOAM V1.0

DTIC Science & Technology

2011-04-01

NavyFOAM has been developed using an open-source CFD software tool-kit ( OpenFOAM ) that draws heavily upon object-oriented programming. The...numerical methods and the physical models in the original version of OpenFOAM have been upgraded in an effort to improve accuracy and robustness of...computational fluid dynamics OpenFOAM , Object Oriented Programming (OOP) (CFD), NavyFOAM, 16. SECURITY CLASSIFICATION OF: a. REPORT UNCLASSIFIED b

Modeling hemodynamics in intracranial aneurysms: Comparing accuracy of CFD solvers based on finite element and finite volume schemes.

PubMed

Botti, Lorenzo; Paliwal, Nikhil; Conti, Pierangelo; Antiga, Luca; Meng, Hui

2018-06-01

Image-based computational fluid dynamics (CFD) has shown potential to aid in the clinical management of intracranial aneurysms (IAs) but its adoption in the clinical practice has been missing, partially due to lack of accuracy assessment and sensitivity analysis. To numerically solve the flow-governing equations CFD solvers generally rely on two spatial discretization schemes: Finite Volume (FV) and Finite Element (FE). Since increasingly accurate numerical solutions are obtained by different means, accuracies and computational costs of FV and FE formulations cannot be compared directly. To this end, in this study we benchmark two representative CFD solvers in simulating flow in a patient-specific IA model: (1) ANSYS Fluent, a commercial FV-based solver and (2) VMTKLab multidGetto, a discontinuous Galerkin (dG) FE-based solver. The FV solver's accuracy is improved by increasing the spatial mesh resolution (134k, 1.1m, 8.6m and 68.5m tetrahedral element meshes). The dGFE solver accuracy is increased by increasing the degree of polynomials (first, second, third and fourth degree) on the base 134k tetrahedral element mesh. Solutions from best FV and dGFE approximations are used as baseline for error quantification. On average, velocity errors for second-best approximations are approximately 1cm/s for a [0,125]cm/s velocity magnitude field. Results show that high-order dGFE provide better accuracy per degree of freedom but worse accuracy per Jacobian non-zero entry as compared to FV. Cross-comparison of velocity errors demonstrates asymptotic convergence of both solvers to the same numerical solution. Nevertheless, the discrepancy between under-resolved velocity fields suggests that mesh independence is reached following different paths. This article is protected by copyright. All rights reserved.

Rapid Airplane Parametric Input Design (RAPID)

NASA Technical Reports Server (NTRS)

Smith, Robert E.

1995-01-01

RAPID is a methodology and software system to define a class of airplane configurations and directly evaluate surface grids, volume grids, and grid sensitivity on and about the configurations. A distinguishing characteristic which separates RAPID from other airplane surface modellers is that the output grids and grid sensitivity are directly applicable in CFD analysis. A small set of design parameters and grid control parameters govern the process which is incorporated into interactive software for 'real time' visual analysis and into batch software for the application of optimization technology. The computed surface grids and volume grids are suitable for a wide range of Computational Fluid Dynamics (CFD) simulation. The general airplane configuration has wing, fuselage, horizontal tail, and vertical tail components. The double-delta wing and tail components are manifested by solving a fourth order partial differential equation (PDE) subject to Dirichlet and Neumann boundary conditions. The design parameters are incorporated into the boundary conditions and therefore govern the shapes of the surfaces. The PDE solution yields a smooth transition between boundaries. Surface grids suitable for CFD calculation are created by establishing an H-type topology about the configuration and incorporating grid spacing functions in the PDE equation for the lifting components and the fuselage definition equations. User specified grid parameters govern the location and degree of grid concentration. A two-block volume grid about a configuration is calculated using the Control Point Form (CPF) technique. The interactive software, which runs on Silicon Graphics IRIS workstations, allows design parameters to be continuously varied and the resulting surface grid to be observed in real time. The batch software computes both the surface and volume grids and also computes the sensitivity of the output grid with respect to the input design parameters by applying the precompiler tool ADIFOR to the grid generation program. The output of ADIFOR is a new source code containing the old code plus expressions for derivatives of specified dependent variables (grid coordinates) with respect to specified independent variables (design parameters). The RAPID methodology and software provide a means of rapidly defining numerical prototypes, grids, and grid sensitivity of a class of airplane configurations. This technology and software is highly useful for CFD research for preliminary design and optimization processes.

Numerical study of the effects of lamp configuration and reactor wall roughness in an open channel water disinfection UV reactor.

PubMed

Sultan, Tipu

2016-07-01

This article describes the assessment of a numerical procedure used to determine the UV lamp configuration and surface roughness effects on an open channel water disinfection UV reactor. The performance of the open channel water disinfection UV reactor was numerically analyzed on the basis of the performance indictor reduction equivalent dose (RED). The RED values were calculated as a function of the Reynolds number to monitor the performance. The flow through the open channel UV reactor was modelled using a k-ε model with scalable wall function, a discrete ordinate (DO) model for fluence rate calculation, a volume of fluid (VOF) model to locate the unknown free surface, a discrete phase model (DPM) to track the pathogen transport, and a modified law of the wall to incorporate the reactor wall roughness effects. The performance analysis was carried out using commercial CFD software (ANSYS Fluent 15.0). Four case studies were analyzed based on open channel UV reactor type (horizontal and vertical) and lamp configuration (parallel and staggered). The results show that lamp configuration can play an important role in the performance of an open channel water disinfection UV reactor. The effects of the reactor wall roughness were Reynolds number dependent. The proposed methodology is useful for performance optimization of an open channel water disinfection UV reactor. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of a highly maneuverable unmanned underwater vehicle on the basis of quad-copter dynamics

NASA Astrophysics Data System (ADS)

Amin, Osman Md; Karim, Md. Arshadul; Saad, Abdullah His

2017-12-01

At present, research on unmanned underwater vehicle (UUV) has become a significant & familiar topic for researchers from various engineering fields. UUV is of mainly two types - AUV (Autonomous Underwater vehicle) & ROV (Remotely Operated Vehicle). There exist a significant number of published research papers on UUV, where very few researchers emphasize on the ease of maneuvering and control of UUV. Maneuvering is important for underwater vehicle in avoiding obstacles, installing underwater piping system, searching undersea resources, underwater mine disposal operations, oceanographic surveys etc. A team from Dept. of Naval Architecture & Marine Engineering of MIST has taken a project to design a highly maneuverable unmanned underwater vehicle on the basis of quad-copter dynamics. The main objective of the research is to develop a control system for UUV which would be able to maneuver the vehicle in six DOF (Degrees of Freedom) with great ease. For this purpose we are not only focusing on controllability but also designing an efficient hull with minimal drag force & optimized propeller using CFD technique. Motors were selected on the basis of the simulated thrust generated by propellers in ANSYS Fluent software module. Settings for control parameters to carry out different types of maneuvering such as hovering, spiral, one point rotation about its centroid, gliding, rolling, drifting and zigzag motions were explained in short at the end.

Evaluation of cavity size, kind, and filling technique of composite shrinkage by finite element

PubMed Central

Jafari, Toloo; Alaghehmad, Homayoon; Moodi, Ehsan

2018-01-01

Background: Cavity preparation reduces the rigidity of tooth and its resistance to deformation. The purpose of this study was to evaluate the dimensional changes of the repaired teeth using two types of light cure composite and two methods of incremental and bulk filling by the use of finite element method. Materials and Methods: In this computerized in vitro experimental study, an intact maxillary premolar was scanned using cone beam computed tomography instrument (SCANORA, Switzerland), then each section of tooth image was transmitted to Ansys software using AUTOCAD. Then, eight sizes of cavity preparations and two methods of restoration (bulk and incremental) using two different types of composite resin materials (Heliomolar, Brilliant) were proposed on software and analysis was completed with Ansys software. Results: Dimensional change increased by widening and deepening of the cavities. It was also increased using Brilliant composite resin and incremental filling technique. Conclusion: Increase in depth and type of filling technique has the greatest role of dimensional change after curing, but the type of composite resin does not have a significant role. PMID:29497445

Combined Uncertainty and A-Posteriori Error Bound Estimates for General CFD Calculations: Theory and Software Implementation

NASA Technical Reports Server (NTRS)

Barth, Timothy J.

2014-01-01

This workshop presentation discusses the design and implementation of numerical methods for the quantification of statistical uncertainty, including a-posteriori error bounds, for output quantities computed using CFD methods. Hydrodynamic realizations often contain numerical error arising from finite-dimensional approximation (e.g. numerical methods using grids, basis functions, particles) and statistical uncertainty arising from incomplete information and/or statistical characterization of model parameters and random fields. The first task at hand is to derive formal error bounds for statistics given realizations containing finite-dimensional numerical error [1]. The error in computed output statistics contains contributions from both realization error and the error resulting from the calculation of statistics integrals using a numerical method. A second task is to devise computable a-posteriori error bounds by numerically approximating all terms arising in the error bound estimates. For the same reason that CFD calculations including error bounds but omitting uncertainty modeling are only of limited value, CFD calculations including uncertainty modeling but omitting error bounds are only of limited value. To gain maximum value from CFD calculations, a general software package for uncertainty quantification with quantified error bounds has been developed at NASA. The package provides implementations for a suite of numerical methods used in uncertainty quantification: Dense tensorization basis methods [3] and a subscale recovery variant [1] for non-smooth data, Sparse tensorization methods[2] utilizing node-nested hierarchies, Sampling methods[4] for high-dimensional random variable spaces.

Experimental and simulation flow rate analysis of the 3/2 directional pneumatic valve

NASA Astrophysics Data System (ADS)

Blasiak, Slawomir; Takosoglu, Jakub E.; Laski, Pawel A.; Pietrala, Dawid S.; Zwierzchowski, Jaroslaw; Bracha, Gabriel; Nowakowski, Lukasz; Blasiak, Malgorzata

The work includes a study on the comparative analysis of two test methods. The first method - numerical method, consists in determining the flow characteristics with the use of ANSYS CFX. A modeled poppet directional valve 3/2 3D CAD software - SolidWorks was used for this purpose. Based on the solid model that was developed, simulation studies of the air flow through the way valve in the software for computational fluid dynamics Ansys CFX were conducted. The second method - experimental, entailed conducting tests on a specially constructed test stand. The comparison of the test results obtained on the basis of both methods made it possible to determine the cross-correlation. High compatibility of the results confirms the usefulness of the numerical procedures. Thus, they might serve to determine the flow characteristics of directional valves as an alternative to a costly and time-consuming test stand.

Comparative Investigation on Modal analysis of LM25 Aluminium alloy with other Aluminim alloys using Finite element analysis software

NASA Astrophysics Data System (ADS)

Arunkumar, S.; Baskaralal, V. P. M.; Muthuraman, V.

2017-03-01

The rudimentary steps of the modal analysis and simulation are carried out. The modal analysis is carried out on the different Aluminum Alloys cantilever beam. The cantilever beam is designed in the graphical environment of the ANSYS. The cantilever beam was fine-tuned on one end with all degree of liberation on this end were taken, beam cannot move and rotate. Mode shapes and natural frequencies are premeditated in platforms ANSYS with arithmetical formulation of the direct solver including the block Lanczos method. Aluminum alloys are widely utilized in much application due to their estimable weight to vigor property. Many examination works have been distributed out to make developments the mechanical properties of aluminum alloys. The composition of alloying elements plays a consequential role in deciding the properties of an alloy. In this study a numerical analysis implement i.e., finite element analysis (FEA) is utilized. The work obtainable in this paper is aimed at the study of effect of modal analysis of different aluminum alloys. The modeling and analysis is carried out utilizing ANSYS FEA software. A modal analysis is carried out to understand the modes of frequency demeanor of the material considered. The modal analysis play a vital role in the design of components subjected to high vibration.

Computational Methods for HSCT-Inlet Controls/CFD Interdisciplinary Research

NASA Technical Reports Server (NTRS)

Cole, Gary L.; Melcher, Kevin J.; Chicatelli, Amy K.; Hartley, Tom T.; Chung, Joongkee

1994-01-01

A program aimed at facilitating the use of computational fluid dynamics (CFD) simulations by the controls discipline is presented. The objective is to reduce the development time and cost for propulsion system controls by using CFD simulations to obtain high-fidelity system models for control design and as numerical test beds for control system testing and validation. An interdisciplinary team has been formed to develop analytical and computational tools in three discipline areas: controls, CFD, and computational technology. The controls effort has focused on specifying requirements for an interface between the controls specialist and CFD simulations and a new method for extracting linear, reduced-order control models from CFD simulations. Existing CFD codes are being modified to permit time accurate execution and provide realistic boundary conditions for controls studies. Parallel processing and distributed computing techniques, along with existing system integration software, are being used to reduce CFD execution times and to support the development of an integrated analysis/design system. This paper describes: the initial application for the technology being developed, the high speed civil transport (HSCT) inlet control problem; activities being pursued in each discipline area; and a prototype analysis/design system in place for interactive operation and visualization of a time-accurate HSCT-inlet simulation.

Analysis of turbulent synthetic jet by dynamic mode decomposition

NASA Astrophysics Data System (ADS)

Hyhlík, Tomáš; Netřebská, Hana; Devera, Jakub; Kalinay, Radomír

The article deals with the analysis of CFD results of the turbulent synthetic jet. The numerical simulation of Large Eddy Simulation (LES) using commercial solver ANSYS CFX has been performed. The unsteady flow field is studied from the point of view of identification of the moving vortex ring, which has been identified both on the snapshots of flow field using swirling-strength criterion and using the Dynamic Mode Decomposition (DMD) of five periods. It is shown that travelling vortex ring vanishes due to interaction with vortex structures in the synthesised turbulent jet. DMD modes with multiple of the basic frequency of synthetic jet, which are connected with travelling vortex structure, have largest DMD amplitudes.

Applications of CFD and visualization techniques

NASA Technical Reports Server (NTRS)

Saunders, James H.; Brown, Susan T.; Crisafulli, Jeffrey J.; Southern, Leslie A.

1992-01-01

In this paper, three applications are presented to illustrate current techniques for flow calculation and visualization. The first two applications use a commercial computational fluid dynamics (CFD) code, FLUENT, performed on a Cray Y-MP. The results are animated with the aid of data visualization software, apE. The third application simulates a particulate deposition pattern using techniques inspired by developments in nonlinear dynamical systems. These computations were performed on personal computers.

Modeling startup and shutdown transient of the microlinear piezo drive via ANSYS

NASA Astrophysics Data System (ADS)

Azin, A. V.; Bogdanov, E. P.; Rikkonen, S. V.; Ponomarev, S. V.; Khramtsov, A. M.

2017-02-01

The article describes the construction-design of the micro linear piezo drive intended for a peripheral cord tensioner in the reflecting surface shape regulator system for large-sized transformable spacecraft antenna reflectors. The research target -the development method of modeling startup and shutdown transient of the micro linear piezo drive. This method is based on application software package ANSYS. The method embraces a detailed description of the calculation stages to determine the operating characteristics of the designed piezo drive. Based on the numerical solutions, the time characteristics of the designed piezo drive are determined.

Methods of the working processes modelling of an internal combustion engine by an ANSYS IC Engine module

NASA Astrophysics Data System (ADS)

Kurchatkin, I. V.; Gorshkalev, A. A.; Blagin, E. V.

2017-01-01

This article deals with developed methods of the working processes modelling in the combustion chamber of an internal combustion engine (ICE). Methods includes description of the preparation of a combustion chamber 3-d model, setting of the finite-element mesh, boundary condition setting and solution customization. Aircraft radial engine M-14 was selected for modelling. The cycle of cold blowdown in the ANSYS IC Engine software was carried out. The obtained data were compared to results of known calculation methods. A method of engine’s induction port improvement was suggested.

Global simulation of the Czochralski silicon crystal growth in ANSYS FLUENT

NASA Astrophysics Data System (ADS)

Kirpo, Maksims

2013-05-01

Silicon crystals for high efficiency solar cells are produced mainly by the Czochralski (CZ) crystal growth method. Computer simulations of the CZ process established themselves as a basic tool for optimization of the growth process which allows to reduce production costs keeping high quality of the crystalline material. The author shows the application of the general Computational Fluid Dynamics (CFD) code ANSYS FLUENT to solution of the static two-dimensional (2D) axisymmetric global model of the small industrial furnace for growing of silicon crystals with a diameter of 100 mm. The presented numerical model is self-sufficient and incorporates the most important physical phenomena of the CZ growth process including latent heat generation during crystallization, crystal-melt interface deflection, turbulent heat and mass transport, oxygen transport, etc. The demonstrated approach allows to find the heater power for the specified pulling rate of the crystal but the obtained power values are smaller than those found in the literature for the studied furnace. However, the described approach is successfully verified with the respect to the heater power by its application for the numerical simulations of the real CZ pullers by "Bosch Solar Energy AG".

Simulation studies on the standing and traveling wave thermoacoustic prime movers

NASA Astrophysics Data System (ADS)

Skaria, Mathew; Rasheed, K. K. Abdul; Shafi, K. A.; Kasthurirengan, S.; Behera, Upendra

2014-01-01

Thermoacoustic systems have been a focus of recent research due to its structural simplicity, high reliability due to absence of moving parts, and can be driven by low grade energy such as fuel, gas, solar energy, waste heat etc. There has been extensive research on both standing wave and traveling wave systems. Towards the development of such systems, simulations can be carried out by several methods such as (a) solving the energy equation, (b) enthalpy flow model, (c) DeltaEC, a free software available from LANL, USA (d) Computational Fluid Dynamics (CFD) etc. We present here the simulation studies of standing wave and traveling wave thermoacoustic prime movers using CFD and DeltaEC. The CFD analysis is carried out using Fluent 6.3.26, incorporating the necessary boundary conditions with different working fluids at different operating pressures. The results obtained by CFD are compared with those obtained using DeltaEC. Also, the CFD simulation of the thermoacoustically driven refrigerator is presented.

Simulation studies on the standing and traveling wave thermoacoustic prime movers

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

Skaria, Mathew; Rasheed, K. K. Abdul; Shafi, K. A.

Thermoacoustic systems have been a focus of recent research due to its structural simplicity, high reliability due to absence of moving parts, and can be driven by low grade energy such as fuel, gas, solar energy, waste heat etc. There has been extensive research on both standing wave and traveling wave systems. Towards the development of such systems, simulations can be carried out by several methods such as (a) solving the energy equation, (b) enthalpy flow model, (c) DeltaEC, a free software available from LANL, USA (d) Computational Fluid Dynamics (CFD) etc. We present here the simulation studies of standingmore » wave and traveling wave thermoacoustic prime movers using CFD and DeltaEC. The CFD analysis is carried out using Fluent 6.3.26, incorporating the necessary boundary conditions with different working fluids at different operating pressures. The results obtained by CFD are compared with those obtained using DeltaEC. Also, the CFD simulation of the thermoacoustically driven refrigerator is presented.« less

Finite element modeling of concrete structures strengthened with FRP laminates

DOT National Transportation Integrated Search

2001-05-01

Linear and non-linear method models were developed for a reinforced concrete bridge that had been strengthened with fiber reinforced polymer (FRP) composites. ANSYS and SAP2000 modeling software were used; however, most of the development effort used...

Analysis of a hydraulic a scaled asymmetric labyrinth weir with Ansys-Fluent

NASA Astrophysics Data System (ADS)

Otálora Carmona, Andrés Humberto; Santos Granados, Germán Ricardo

2017-04-01

This document presents the three dimensional computational modeling of a labyrinth weir, using the version 17.0 of the Computational Fluid Dynamics (CFD) software ANSYS - FLUENT. The computational characteristics of the model such as the geometry consideration, the mesh sensitivity, the numerical scheme, and the turbulence modeling parameters. The volume fraction of the water mixture - air, the velocity profile, the jet trajectory, the discharge coefficient and the velocity field are analyzed. With the purpose of evaluating the hydraulic behavior of the labyrinth weir of the Naveta's hydroelectric, in Apulo - Cundinamarca, was development a 1:21 scale model of the original structure, which was tested in the laboratory of the hydraulic studies in the Escuela Colombiana de Ingeniería Julio Garavito. The scale model of the structure was initially developed to determine the variability of the discharge coefficient with respect to the flow rate and their influence on the water level. It was elaborate because the original weir (labyrinth weir with not symmetrical rectangular section), did not have the capacity to work with the design flow of 31 m3/s, because over 15 m3/s, there were overflows in the adduction channel. This variation of efficiency was due to the thickening of the lateral walls by structural requirements. During the physical modeling doing by Rodríguez, H. and Matamoros H. (2015) in the test channel, it was found that, with the increase in the width of the side walls, the discharge coefficient is reduced an average by 34%, generating an increase of the water level by 0.26 m above the structure. This document aims to develop a splicing methodology between the physical models of a labyrinth weir and numerical modeling, using concepts of computational fluid dynamics and finite volume theories. For this, was carried out a detailed analysis of the variations in the different directions of the main hydraulic variables involved in the behavior, such as, the components of the velocity and the distribution of pressures, For the numerical development, we worked with ANSYS - FLUENT software modeling version 17.0. Initially, a digital model of a conventional triangular weir with a vertical angle of 102° was developed in order to find the most appropriate numerical scheme and conditions. The numerical results were compared with conventional theories, evaluating the path and discharge coefficient. Subsequently, one of the five cycles that compose the labyrinth weir was simulated, evaluating the behavior of the discharge coefficient, the water level, the streamline and the velocity field, with the purpose of understanding the hydraulic variables that are related in these geometries. According to the previous results, the numerical modeling of labyrinth weir was performed, comparing the obtained results with the data of the physical scale model, analyzing the variation of the discharge coefficient, the streamline, velocity field, pressure distribution and shear stress. Finally, based on the lessons learned from physical and numerical modeling, a methodological guide was created for any user with a computational and hydraulic fluid mechanics knowledge to develop a good practice of a computational and physical modeling.

FAST - A multiprocessed environment for visualization of computational fluid dynamics

NASA Technical Reports Server (NTRS)

Bancroft, Gordon V.; Merritt, Fergus J.; Plessel, Todd C.; Kelaita, Paul G.; Mccabe, R. Kevin

1991-01-01

The paper presents the Flow Analysis Software Toolset (FAST) to be used for fluid-mechanics analysis. The design criteria for FAST including the minimization of the data path in the computational fluid-dynamics (CFD) process, consistent user interface, extensible software architecture, modularization, and the isolation of three-dimensional tasks from the application programmer are outlined. Each separate process communicates through the FAST Hub, while other modules such as FAST Central, NAS file input, CFD calculator, surface extractor and renderer, titler, tracer, and isolev might work together to generate the scene. An interprocess communication package making it possible for FAST to operate as a modular environment where resources could be shared among different machines as well as a single host is discussed.

Automated CFD Parameter Studies on Distributed Parallel Computers

NASA Technical Reports Server (NTRS)

Rogers, Stuart E.; Aftosmis, Michael; Pandya, Shishir; Tejnil, Edward; Ahmad, Jasim; Kwak, Dochan (Technical Monitor)

2002-01-01

The objective of the current work is to build a prototype software system which will automated the process of running CFD jobs on Information Power Grid (IPG) resources. This system should remove the need for user monitoring and intervention of every single CFD job. It should enable the use of many different computers to populate a massive run matrix in the shortest time possible. Such a software system has been developed, and is known as the AeroDB script system. The approach taken for the development of AeroDB was to build several discrete modules. These include a database, a job-launcher module, a run-manager module to monitor each individual job, and a web-based user portal for monitoring of the progress of the parameter study. The details of the design of AeroDB are presented in the following section. The following section provides the results of a parameter study which was performed using AeroDB for the analysis of a reusable launch vehicle (RLV). The paper concludes with a section on the lessons learned in this effort, and ideas for future work in this area.

Finite element modeling of reinforced concrete structures strengthened with FRP laminates : final report.

DOT National Transportation Integrated Search

2001-05-01

Linear and non-linear finite element method models were developed for a reinforced concrete bridge that had been strengthened with fiber reinforced polymer composites. ANSYS and SAP2000 modeling software were used; however, most of the development ef...

Computational fluid dynamics (CFD) study on the fetal aortic coarctation

NASA Astrophysics Data System (ADS)

Zhou, Yue; Zhang, Yutao; Wang, Jingying

2018-03-01

Blood flows in normal and coarctate fetal aortas are simulated by the CFD technique using T-rex grids. The three-dimensional (3-D) digital model of the fetal arota is reconstructed by the computer-aided design (CAD) software based on two-dimensional (2-D) ultrasono tomographic images. Simulation results displays the development and enhancement of the secondary flow structure in the coarctate fetal arota. As the diameter narrow ratio rises greater than 45%, the pressure and wall shear stress (WSS) of the aorta arch increase exponentially, which is consistent with the conventional clinical concept. The present study also demonstrates that CFD is a very promising assistant technique to investigate human cardiovascular diseases.

SIMOGEN - An Object-Oriented Language for Simulation

DTIC Science & Technology

1989-03-01

program generator must also be written in the same prcgramming languaje . In this case, the C language was chosen, for the following main reasons...3), March 88. 4. PRESTO: A System for Object-Oriented Parallel Programing B N Bershad, E D Lazowska & H M Levy Software Practice and Experience, Vol...U.S. Depare nt of Defence ANSI/ML-STD 1815A. 7. Object-oriented Development Grady Booch Transactions on Software Engineering , February 86. 8. A

Numerical modeling on carbon fiber composite material in Gaussian beam laser based on ANSYS

NASA Astrophysics Data System (ADS)

Luo, Ji-jun; Hou, Su-xia; Xu, Jun; Yang, Wei-jun; Zhao, Yun-fang

2014-02-01

Based on the heat transfer theory and finite element method, the macroscopic ablation model of Gaussian beam laser irradiated surface is built and the value of temperature field and thermal ablation development is calculated and analyzed rationally by using finite element software of ANSYS. Calculation results show that the ablating form of the materials in different irritation is of diversity. The laser irradiated surface is a camber surface rather than a flat surface, which is on the lowest point and owns the highest power density. Research shows that the higher laser power density absorbed by material surface, the faster the irritation surface regressed.

Research on electromechanical resonance of two-axis tracking system

NASA Astrophysics Data System (ADS)

Zhao, Zhi-ming; Xue, Ying-jie; Zeng, Shu-qin; Li, Zhi-guo

2017-02-01

The multi-axes synchronous system about the spatial two-axis turntable is the key equipment for semi-physical simulation and test in aerospace. In this paper, the whole structure design of the turntable is created by using Solidworks, then putting the three-dimensional solid model into ANSYS to build the finite element model. The software ANSYS is used to do the simulation about the static and dynamic analysis of two-axis turntable. Based on the modal analysis, we can forecast the inherent frequencies and the mode of vibration during the launch conditions which is very important to the design and safety of the structure.

Ship Air Wake Detection Using a Small Fixed Wing Unmanned Aerial Vehicle

NASA Astrophysics Data System (ADS)

Phelps, David M.

A ship's air wake is dynamically detected using an airborne inertial measurement unit (IMU) and global positioning system (GPS) attached to a fixed wing unmanned aerial system. A fixed wing unmanned aerial system (UAS) was flown through the air wake created by an underway 108 ft (32.9m) long research vessel in pre designated flight paths. The instrumented aircraft was used to validate computational fluid dynamic (CFD) simulations of naval ship air wakes. Computer models of the research ship and the fixed wing UAS were generated and gridded using NASA's TetrUSS software. Simulations were run using Kestrel, a Department of Defense CFD software to validate the physical experimental data collection method. Air wake simulations were run at various relative wind angles and speeds. The fixed wing UAS was subjected to extensive wind tunnel testing to generate a table of aerodynamic coefficients as a function of control surface deflections, angle of attack and sideslip. The wind tunnel experimental data was compared against similarly structured CFD experiments to validate the grid and model of fixed wing UAS. Finally, a CFD simulation of the fixed wing UAV flying through the generated wake was completed. Forces on the instrumented aircraft were calculated from the data collected by the IMU. Comparison of experimental and simulation data showed that the fixed wing UAS could detect interactions with the ship air wake.

Design and Optimization Method of a Two-Disk Rotor System

NASA Astrophysics Data System (ADS)

Huang, Jingjing; Zheng, Longxi; Mei, Qing

2016-04-01

An integrated analytical method based on multidisciplinary optimization software Isight and general finite element software ANSYS was proposed in this paper. Firstly, a two-disk rotor system was established and the mode, humorous response and transient response at acceleration condition were analyzed with ANSYS. The dynamic characteristics of the two-disk rotor system were achieved. On this basis, the two-disk rotor model was integrated to the multidisciplinary design optimization software Isight. According to the design of experiment (DOE) and the dynamic characteristics, the optimization variables, optimization objectives and constraints were confirmed. After that, the multi-objective design optimization of the transient process was carried out with three different global optimization algorithms including Evolutionary Optimization Algorithm, Multi-Island Genetic Algorithm and Pointer Automatic Optimizer. The optimum position of the two-disk rotor system was obtained at the specified constraints. Meanwhile, the accuracy and calculation numbers of different optimization algorithms were compared. The optimization results indicated that the rotor vibration reached the minimum value and the design efficiency and quality were improved by the multidisciplinary design optimization in the case of meeting the design requirements, which provided the reference to improve the design efficiency and reliability of the aero-engine rotor.

Technical Review of the CENWP Computational Fluid Dynamics Model of the John Day Dam Forebay

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

Rakowski, Cynthia L.; Serkowski, John A.; Richmond, Marshall C.

The US Army Corps of Engineers Portland District (CENWP) has developed a computational fluid dynamics (CFD) model of the John Day forebay on the Columbia River to aid in the development and design of alternatives to improve juvenile salmon passage at the John Day Project. At the request of CENWP, Pacific Northwest National Laboratory (PNNL) Hydrology Group has conducted a technical review of CENWP's CFD model run in CFD solver software, STAR-CD. PNNL has extensive experience developing and applying 3D CFD models run in STAR-CD for Columbia River hydroelectric projects. The John Day forebay model developed by CENWP is adequatelymore » configured and validated. The model is ready for use simulating forebay hydraulics for structural and operational alternatives. The approach and method are sound, however CENWP has identified some improvements that need to be made for future models and for modifications to this existing model.« less

OpenFOAM: Open source CFD in research and industry

NASA Astrophysics Data System (ADS)

Jasak, Hrvoje

2009-12-01

The current focus of development in industrial Computational Fluid Dynamics (CFD) is integration of CFD into Computer-Aided product development, geometrical optimisation, robust design and similar. On the other hand, in CFD research aims to extend the boundaries ofpractical engineering use in "non-traditional " areas. Requirements of computational flexibility and code integration are contradictory: a change of coding paradigm, with object orientation, library components, equation mimicking is proposed as a way forward. This paper describes OpenFOAM, a C++ object oriented library for Computational Continuum Mechanics (CCM) developed by the author. Efficient and flexible implementation of complex physical models is achieved by mimicking the form ofpartial differential equation in software, with code functionality provided in library form. Open Source deployment and development model allows the user to achieve desired versatility in physical modeling without the sacrifice of complex geometry support and execution efficiency.

Numerical simulation of flow in a high head Francis turbine with prediction of efficiency, rotor stator interaction and vortex structures in the draft tube

NASA Astrophysics Data System (ADS)

Jošt, D.; Škerlavaj, A.; Morgut, M.; Mežnar, P.; Nobile, E.

2015-01-01

The paper presents numerical simulations of flow in a model of a high head Francis turbine and comparison of results to the measurements. Numerical simulations were done by two CFD (Computational Fluid Dynamics) codes, Ansys CFX and OpenFOAM. Steady-state simulations were performed by k-epsilon and SST model, while for transient simulations the SAS SST ZLES model was used. With proper grid refinement in distributor and runner and with taking into account losses in labyrinth seals very accurate prediction of torque on the shaft, head and efficiency was obtained. Calculated axial and circumferential velocity components on two planes in the draft tube matched well with experimental results.

An attempt to make a reliable assessment of the wet steam flow field in the de Laval nozzle

NASA Astrophysics Data System (ADS)

Dykas, Sławomir; Majkut, Mirosław; Smołka, Krystian; Strozik, Michał

2018-02-01

This paper presents the results of research on the wet steam flow with spontaneous condensation in the de Laval nozzle. A comparison is made between the results of numerical modelling performed for two cases of boundary conditions obtained using an in-house CFD code and the Ansys CFX commercial package. The numerical modelling results are compared to the results of experimental testing carried out on an in-house laboratory steam tunnel. The differences between the numerical results produced by the two codes in terms of place and intensity of condensations of steam to water point to the difficulty in correct modelling of this type of flows and emphasize the need for further studies in this field.

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).

Influence of the gap size on the wind loading on heliostats

NASA Astrophysics Data System (ADS)

Poulain, Pierre E.; Craig, Ken J.; Meyer, Josua P.

2016-05-01

Generally built in desert areas, heliostat fields undergo various wind loading conditions. An ANSYS Fluent CFD model of an isolated heliostat in worst-case orientation for the drag force is realized via numerical simulations using the realizable k-ɛ turbulence model. This paper focuses on the gap width between the panels and its influence on the wind loading that heliostats are subjected to. An atmospheric boundary layer profile is generated based on a wind tunnel experiment. For a heliostat in upright and tilted orientations with the wind angle being zero degrees, the gap width is varied and the force and moment coefficients are calculated. In the range tested, all the coefficients globally increase with the widening of the gaps.

Optimization of Heat Transfer on Thermal Barrier Coated Gas Turbine Blade

NASA Astrophysics Data System (ADS)

Aabid, Abdul; Khan, S. A.

2018-05-01

In the field of Aerospace Propulsion technology, material required to resist the maximum temperature. In this paper, using thermal barrier coatings (TBCs) method in gas turbine blade is used to protect hot section component from high-temperature effect to extend the service life and reduce the maintenance costs. The TBCs which include three layers of coating corresponding initial coat is super alloy-INCONEL 718 with 1 mm thickness, bond coat is Nano-structured ceramic-metallic composite-NiCoCrAIY with 0.15 mm thickness and top coat is ceramic composite-La2Ce2O7 with 0.09 mm thickness on the nickel alloy turbine blade which in turn increases the strength, efficiency and life span of the blades. Modeling a gas turbine blade using CATIA software and determining the amount of heat transfer on thermal barrier coated blade using ANSYS software has been performed. Thermal stresses and effects of different TBCs blade base alloys are considered using CATIA and ANSYS.

[Numerical finite element modeling of custom car seat using computer aided design].

PubMed

Huang, Xuqi; Singare, Sekou

2014-02-01

A good cushion can not only provide the sitter with a high comfort, but also control the distribution of the hip pressure to reduce the incidence of diseases. The purpose of this study is to introduce a computer-aided design (CAD) modeling method of the buttocks-cushion using numerical finite element (FE) simulation to predict the pressure distribution on the buttocks-cushion interface. The buttock and the cushion model geometrics were acquired from a laser scanner, and the CAD software was used to create the solid model. The FE model of a true seated individual was developed using ANSYS software (ANSYS Inc, Canonsburg, PA). The model is divided into two parts, i.e. the cushion model made of foam and the buttock model represented by the pelvis covered with a soft tissue layer. Loading simulations consisted of imposing a vertical force of 520N on the pelvis, corresponding to the weight of the user upper extremity, and then solving iteratively the system.

Integrated Computational System for Aerodynamic Steering and Visualization

NASA Technical Reports Server (NTRS)

Hesselink, Lambertus

1999-01-01

In February of 1994, an effort from the Fluid Dynamics and Information Sciences Divisions at NASA Ames Research Center with McDonnel Douglas Aerospace Company and Stanford University was initiated to develop, demonstrate, validate and disseminate automated software for numerical aerodynamic simulation. The goal of the initiative was to develop a tri-discipline approach encompassing CFD, Intelligent Systems, and Automated Flow Feature Recognition to improve the utility of CFD in the design cycle. This approach would then be represented through an intelligent computational system which could accept an engineer's definition of a problem and construct an optimal and reliable CFD solution. Stanford University's role focused on developing technologies that advance visualization capabilities for analysis of CFD data, extract specific flow features useful for the design process, and compare CFD data with experimental data. During the years 1995-1997, Stanford University focused on developing techniques in the area of tensor visualization and flow feature extraction. Software libraries were created enabling feature extraction and exploration of tensor fields. As a proof of concept, a prototype system called the Integrated Computational System (ICS) was developed to demonstrate CFD design cycle. The current research effort focuses on finding a quantitative comparison of general vector fields based on topological features. Since the method relies on topological information, grid matching and vector alignment is not needed in the comparison. This is often a problem with many data comparison techniques. In addition, since only topology based information is stored and compared for each field, there is a significant compression of information that enables large databases to be quickly searched. This report will (1) briefly review the technologies developed during 1995-1997 (2) describe current technologies in the area of comparison techniques, (4) describe the theory of our new method researched during the grant year (5) summarize a few of the results and finally (6) discuss work within the last 6 months that are direct extensions from the grant.

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

Khan, Yasin; Khare, Vaibhav Rai; Mathur, Jyotirmay

The paper describes a parametric study developed to estimate the energy savings potential of a radiant cooling system installed in a commercial building in India. The study is based on numerical modeling of a radiant cooling system installed in an Information Technology (IT) office building sited in the composite climate of Hyderabad. To evaluate thermal performance and energy consumption, simulations were carried out using the ANSYS FLUENT and EnergyPlus softwares, respectively. The building model was calibrated using the measured data for the installed radiant system. Then this calibrated model was used to simulate the energy consumption of a building usingmore » a conventional all-air system to determine the proportional energy savings. For proper handling of the latent load, a dedicated outside air system (DOAS) was used as an alternative to Fan Coil Unit (FCU). A comparison of energy consumption calculated that the radiant system was 17.5 % more efficient than a conventional all-air system and that a 30% savings was achieved by using a DOAS system compared with a conventional system. Computational Fluid Dynamics (CFD) simulation was performed to evaluate indoor air quality and thermal comfort. It was found that a radiant system offers more uniform temperatures, as well as a better mean air temperature range, than a conventional system. To further enhance the energy savings in the radiant system, different operational strategies were analyzed based on thermal analysis using EnergyPlus. Lastly, the energy savings achieved in this parametric run were more than 10% compared with a conventional all-air system.« less

AirShow 1.0 CFD Software Users' Guide

NASA Technical Reports Server (NTRS)

Mohler, Stanley R., Jr.

2005-01-01

AirShow is visualization post-processing software for Computational Fluid Dynamics (CFD). Upon reading binary PLOT3D grid and solution files into AirShow, the engineer can quickly see how hundreds of complex 3-D structured blocks are arranged and numbered. Additionally, chosen grid planes can be displayed and colored according to various aerodynamic flow quantities such as Mach number and pressure. The user may interactively rotate and translate the graphical objects using the mouse. The software source code was written in cross-platform Java, C++, and OpenGL, and runs on Unix, Linux, and Windows. The graphical user interface (GUI) was written using Java Swing. Java also provides multiple synchronized threads. The Java Native Interface (JNI) provides a bridge between the Java code and the C++ code where the PLOT3D files are read, the OpenGL graphics are rendered, and numerical calculations are performed. AirShow is easy to learn and simple to use. The source code is available for free from the NASA Technology Transfer and Partnership Office.

CFD Vision 2030 Study: A Path to Revolutionary Computational Aerosciences

NASA Technical Reports Server (NTRS)

Slotnick, Jeffrey; Khodadoust, Abdollah; Alonso, Juan; Darmofal, David; Gropp, William; Lurie, Elizabeth; Mavriplis, Dimitri

2014-01-01

This report documents the results of a study to address the long range, strategic planning required by NASA's Revolutionary Computational Aerosciences (RCA) program in the area of computational fluid dynamics (CFD), including future software and hardware requirements for High Performance Computing (HPC). Specifically, the "Vision 2030" CFD study is to provide a knowledge-based forecast of the future computational capabilities required for turbulent, transitional, and reacting flow simulations across a broad Mach number regime, and to lay the foundation for the development of a future framework and/or environment where physics-based, accurate predictions of complex turbulent flows, including flow separation, can be accomplished routinely and efficiently in cooperation with other physics-based simulations to enable multi-physics analysis and design. Specific technical requirements from the aerospace industrial and scientific communities were obtained to determine critical capability gaps, anticipated technical challenges, and impediments to achieving the target CFD capability in 2030. A preliminary development plan and roadmap were created to help focus investments in technology development to help achieve the CFD vision in 2030.

BESTEST-EX | Buildings | NREL

Science.gov Websites

method for testing home energy audit software and associated calibration methods. BESTEST-EX is one of Energy Analysis Model Calibration Methods. When completed, the ANSI/RESNET SMOT will specify test procedures for evaluating calibration methods used in conjunction with predicting building energy use and

CFD simulation of a dry scroll vacuum pump with clearances, solid heating and thermal deformation

NASA Astrophysics Data System (ADS)

Spille-Kohoff, A.; Hesse, J.; Andres, R.; Hetze, F.

2017-08-01

Although dry scroll vacuum pumps (DSPV) are essential devices in many different industrial processes, the CFD simulation of such pumps is not widely used and often restricted to simplified cases due to its complexity: The working principle with a fixed and an orbiting scroll leads to working chambers that are changing in time and are connected through moving small radial and axial clearances in the range of 10 to 100 μm. Due to the low densities and low mass flow rates in vacuum pumps, it is important to include heat transfer towards and inside the solid components. Solid heating is very slow compared to the scroll revolution speed and the gas behaviour, thus a special workflow is necessary to reach the working conditions in reasonable simulation times. The resulting solid temperature is then used to compute the thermal deformation, which usually results in gap size changes that influence leakage flows. In this paper, setup steps and results for the simulation of a DSVP are shown and compared to theoretical and experimental results. The time-varying working chambers are meshed with TwinMesh, a hexahedral meshing programme for positive displacement machines. The CFD simulation with ANSYS CFX accounts for gas flow with compressibility and turbulence effects, conjugate heat transfer between gas and solids, and leakage flows through the clearances. Time-resolved results for torques, chamber pressure, mass flow, and heat flow between gas and solids are shown, as well as time- and space-resolved results for pressure, velocity, and temperature for different operating conditions of the DSVP.

Reduced order model based on principal component analysis for process simulation and optimization

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

Lang, Y.; Malacina, A.; Biegler, L.

2009-01-01

It is well-known that distributed parameter computational fluid dynamics (CFD) models provide more accurate results than conventional, lumped-parameter unit operation models used in process simulation. Consequently, the use of CFD models in process/equipment co-simulation offers the potential to optimize overall plant performance with respect to complex thermal and fluid flow phenomena. Because solving CFD models is time-consuming compared to the overall process simulation, we consider the development of fast reduced order models (ROMs) based on CFD results to closely approximate the high-fidelity equipment models in the co-simulation. By considering process equipment items with complicated geometries and detailed thermodynamic property models,more » this study proposes a strategy to develop ROMs based on principal component analysis (PCA). Taking advantage of commercial process simulation and CFD software (for example, Aspen Plus and FLUENT), we are able to develop systematic CFD-based ROMs for equipment models in an efficient manner. In particular, we show that the validity of the ROM is more robust within well-sampled input domain and the CPU time is significantly reduced. Typically, it takes at most several CPU seconds to evaluate the ROM compared to several CPU hours or more to solve the CFD model. Two case studies, involving two power plant equipment examples, are described and demonstrate the benefits of using our proposed ROM methodology for process simulation and optimization.« less

Experimental Study and CFD Simulation of a 2D Circulating Fluidized Bed

NASA Astrophysics Data System (ADS)

Kallio, S.; Guldén, M.; Hermanson, A.

Computational fluid dynamics (CFD) gains popularity in fluidized bed modeling. For model validation, there is a need of detailed measurements under well-defined conditions. In the present study, experiments were carried out in a 40 em wide and 3 m high 2D circulating fluidized bed. Two experiments were simulated by means of the Eulerian multiphase models of the Fluent CFD software. The vertical pressure and solids volume fraction profiles and the solids circulation rate obtained from the simulation were compared to the experimental results. In addition, lateral volume fraction profiles could be compared. The simulated CFB flow patterns and the profiles obtained from simulations were in general in a good agreement with the experimental results.

Surface Modeling, Grid Generation, and Related Issues in Computational Fluid Dynamic (CFD) Solutions

NASA Technical Reports Server (NTRS)

Choo, Yung K. (Compiler)

1995-01-01

The NASA Steering Committee for Surface Modeling and Grid Generation (SMAGG) sponsored a workshop on surface modeling, grid generation, and related issues in Computational Fluid Dynamics (CFD) solutions at Lewis Research Center, Cleveland, Ohio, May 9-11, 1995. The workshop provided a forum to identify industry needs, strengths, and weaknesses of the five grid technologies (patched structured, overset structured, Cartesian, unstructured, and hybrid), and to exchange thoughts about where each technology will be in 2 to 5 years. The workshop also provided opportunities for engineers and scientists to present new methods, approaches, and applications in SMAGG for CFD. This Conference Publication (CP) consists of papers on industry overview, NASA overview, five grid technologies, new methods/ approaches/applications, and software systems.

Genetic Algorithm (GA)-Based Inclinometer Layout Optimization.

PubMed

Liang, Weijie; Zhang, Ping; Chen, Xianping; Cai, Miao; Yang, Daoguo

2015-04-17

This paper presents numerical simulation results of an airflow inclinometer with sensitivity studies and thermal optimization of the printed circuit board (PCB) layout for an airflow inclinometer based on a genetic algorithm (GA). Due to the working principle of the gas sensor, the changes of the ambient temperature may cause dramatic voltage drifts of sensors. Therefore, eliminating the influence of the external environment for the airflow is essential for the performance and reliability of an airflow inclinometer. In this paper, the mechanism of an airflow inclinometer and the influence of different ambient temperatures on the sensitivity of the inclinometer will be examined by the ANSYS-FLOTRAN CFD program. The results show that with changes of the ambient temperature on the sensing element, the sensitivity of the airflow inclinometer is inversely proportional to the ambient temperature and decreases when the ambient temperature increases. GA is used to optimize the PCB thermal layout of the inclinometer. The finite-element simulation method (ANSYS) is introduced to simulate and verify the results of our optimal thermal layout, and the results indicate that the optimal PCB layout greatly improves (by more than 50%) the sensitivity of the inclinometer. The study may be useful in the design of PCB layouts that are related to sensitivity improvement of gas sensors.

Genetic Algorithm (GA)-Based Inclinometer Layout Optimization

PubMed Central

Liang, Weijie; Zhang, Ping; Chen, Xianping; Cai, Miao; Yang, Daoguo

2015-01-01

This paper presents numerical simulation results of an airflow inclinometer with sensitivity studies and thermal optimization of the printed circuit board (PCB) layout for an airflow inclinometer based on a genetic algorithm (GA). Due to the working principle of the gas sensor, the changes of the ambient temperature may cause dramatic voltage drifts of sensors. Therefore, eliminating the influence of the external environment for the airflow is essential for the performance and reliability of an airflow inclinometer. In this paper, the mechanism of an airflow inclinometer and the influence of different ambient temperatures on the sensitivity of the inclinometer will be examined by the ANSYS-FLOTRAN CFD program. The results show that with changes of the ambient temperature on the sensing element, the sensitivity of the airflow inclinometer is inversely proportional to the ambient temperature and decreases when the ambient temperature increases. GA is used to optimize the PCB thermal layout of the inclinometer. The finite-element simulation method (ANSYS) is introduced to simulate and verify the results of our optimal thermal layout, and the results indicate that the optimal PCB layout greatly improves (by more than 50%) the sensitivity of the inclinometer. The study may be useful in the design of PCB layouts that are related to sensitivity improvement of gas sensors. PMID:25897500

[Design of Complex Cavity Structure in Air Route System of Automated Peritoneal Dialysis Machine].

PubMed

Quan, Xiaoliang

2017-07-30

This paper introduced problems about Automated Peritoneal Dialysis machine(APD) that the lack of technical issues such as the structural design of the complex cavities. To study the flow characteristics of this special structure, the application of ANSYS CFX software is used with k-ε turbulence model as the theoretical basis of fluid mechanics. The numerical simulation of flow field simulation result in the internal model can be gotten after the complex structure model is imported into ANSYS CFX module. Then, it will present the distribution of complex cavities inside the flow field and the flow characteristics parameter, which will provide an important reference design for APD design.

Design and numerical simulation of novel giant magnetostrictive ultrasonic transducer

NASA Astrophysics Data System (ADS)

Li, Pengyang; Liu, Qiang; Li, Shujuan; Wang, Quandai; Zhang, Dongya; Li, Yan

This paper provides a design method of a novel giant magnetostrictive ultrasonic transducer utilized in incremental sheet metal forming. The frequency equations of the ultrasonic vibrator were deduced and the corresponding correctness verified by the modal and harmonic response characteristic through the finite element method (FEM) and ANSYS software. In addition, the magnetic field of the vibrator system was designed and verified by the ANSYS. Finally, the frequency tests based on the impedance response analysis and the amplitude measurements based on the laser displacement sensor were performed on the prototype. The results confirmed the appropriate design of this transducer, setting the foundation for a low mechanical quality factor and satisfying amplitude.

System Engineering Approach to Assessing Integrated Survivability

DTIC Science & Technology

2009-08-01

based response for the above engagements using LS- Dyna for blast modelling, MADYMO for safety and human response, CFD software (Fluent) is used to...Simulation JFAS Joint Force Analysis Simulation JANUS Joint Army Navy Uniform Simulation LS- DYNA Livermore Software-Dynamics MADYMO...management technologies. The “don’t be killed” layer of survivability protection accounts for many of the mitigation technologies (i.e. blast

Planar Inlet Design and Analysis Process (PINDAP)

NASA Technical Reports Server (NTRS)

Slater, John W.; Gruber, Christopher R.

2005-01-01

The Planar Inlet Design and Analysis Process (PINDAP) is a collection of software tools that allow the efficient aerodynamic design and analysis of planar (two-dimensional and axisymmetric) inlets. The aerodynamic analysis is performed using the Wind-US computational fluid dynamics (CFD) program. A major element in PINDAP is a Fortran 90 code named PINDAP that can establish the parametric design of the inlet and efficiently model the geometry and generate the grid for CFD analysis with design changes to those parameters. The use of PINDAP is demonstrated for subsonic, supersonic, and hypersonic inlets.

Grid generation methodology and CFD simulations in sliding vane compressors and expanders

NASA Astrophysics Data System (ADS)

Bianchi, Giuseppe; Rane, Sham; Kovacevic, Ahmed; Cipollone, Roberto; Murgia, Stefano; Contaldi, Giulio

2017-08-01

The limiting factor for the employment of advanced 3D CFD tools in the analysis and design of rotary vane machines is the unavailability of methods for generation of computational grids suitable for fast and reliable numerical analysis. The paper addresses this challenge presenting the development of an analytical grid generation for vane machines that is based on the user defined nodal displacement. In particular, mesh boundaries are defined as parametric curves generated using trigonometrical modelling of the axial cross section of the machine while the distribution of computational nodes is performed using algebraic algorithms with transfinite interpolation, post orthogonalisation and smoothing. Algebraic control functions are introduced for distribution of nodes on the rotor and casing boundaries in order to achieve good grid quality in terms of cell size and expansion. In this way, the moving and deforming fluid domain of the sliding vane machine is discretized and the conservation of intrinsic quantities in ensured by maintaining the cell connectivity and structure. For validation of generated grids, a mid-size air compressor and a small-scale expander for Organic Rankine Cycle applications have been investigated in this paper. Remarks on implementation of the mesh motion algorithm, stability and robustness experienced with the ANSYS CFX solver as well as the obtained flow results are presented.

Modeling and simulation of dense cloud dispersion in urban areas by means of computational fluid dynamics.

PubMed

Scargiali, F; Grisafi, F; Busciglio, A; Brucato, A

2011-12-15

The formation of toxic heavy clouds as a result of sudden accidental releases from mobile containers, such as road tankers or railway tank cars, may occur inside urban areas so the problem arises of their consequences evaluation. Due to the semi-confined nature of the dispersion site simplified models may often be inappropriate. As an alternative, computational fluid dynamics (CFD) has the potential to provide realistic simulations even for geometrically complex scenarios since the heavy gas dispersion process is described by basic conservation equations with a reduced number of approximations. In the present work a commercial general purpose CFD code (CFX 4.4 by Ansys(®)) is employed for the simulation of dense cloud dispersion in urban areas. The simulation strategy proposed involves a stationary pre-release flow field simulation followed by a dynamic after-release flow and concentration field simulations. In order to try a generalization of results, the computational domain is modeled as a simple network of straight roads with regularly distributed blocks mimicking the buildings. Results show that the presence of buildings lower concentration maxima and enlarge the side spread of the cloud. Dispersion dynamics is also found to be strongly affected by the quantity of heavy-gas released. Copyright © 2011 Elsevier B.V. All rights reserved.

Effect of trailing edge thickness on the performance of a helium turboexpander used in cryogenic refrigeration and liquefaction cycles

NASA Astrophysics Data System (ADS)

Sam, Ashish Alex; Ghosh, Parthasarathi

2017-02-01

Turboexpanders in cryogenic refrigeration and liquefaction cycles, which is of radial inflow configuration, constitute stationary and rotating components like nozzle, a rotating wheel and a diffuser. The relative motion between the stationary and rotating components and the interactions of secondary flows and vortices at different stages make the turboexpander flow unsteady. Computational Fluid Dynamics (CFD) analysis of this flow is essential to identify the scope for improvement in efficiency. The trailing edge vortex formed due to the mixing of the pressure and suction side streams is an important phenomenon to analyse, as this leads to efficiency degradation of the machine. Additionally, there are mechanical vibrations and dynamic loading associated with. This flow non-uniformity at the exit should be suppressed as this may affect the pressure recovery process in the diffuser and thereby the turboexpander’s performance. The strength of this vortex depends upon the geometrical parameters like trailing edge shape, thickness etc. In this paper, transient CFD analyses of a cryogenic turboexpander designed for helium refrigeration and liquefaction cycles using Ansys CFX® were performed to investigate the effect of trailing edge thickness on the turboexpander performance and the performance characteristics and the flow patterns were compared to understand the flow characteristics in each case.

Simulating Freak Waves in the Ocean with CFD Modeling

NASA Astrophysics Data System (ADS)

Manolidis, M.; Orzech, M.; Simeonov, J.

2017-12-01

Rogue, or freak, waves constitute an active topic of research within the world scientific community, as various maritime authorities around the globe seek to better understand and more accurately assess the risks that the occurrence of such phenomena entail. Several experimental studies have shed some light on the mechanics of rogue wave formation. In our work we numerically simulate the formation of such waves in oceanic conditions by means of Computational Fluid Dynamics (CFD) software. For this purpose we implement the NHWAVE and OpenFOAM software packages. Both are non-hydrostatic, turbulent flow solvers, but NHWAVE implements a shock-capturing scheme at the free surface-interface, while OpenFOAM utilizes the Volume Of Fluid (VOF) method. NHWAVE has been shown to accurately reproduce highly nonlinear surface wave phenomena, such as soliton propagation and wave shoaling. We conducted a range of tests simulating rogue wave formation and horizontally varying currents to evaluate and compare the capabilities of the two software packages. Then we used each model to investigate the effect of ocean currents and current gradients on the formation of rogue waves. We present preliminary results.

Temperature Field Simulation of Powder Sintering Process with ANSYS

NASA Astrophysics Data System (ADS)

He, Hongxiu; Wang, Jun; Li, Shuting; Chen, Zhilong; Sun, Jinfeng; You, Ying

2018-03-01

Aiming at the “spheroidization phenomenon” in the laser sintering of metal powder and other quality problems of the forming parts due to the thermal effect, the finite element model of the three-dimensional transient metal powder was established by using the atomized iron powder as the research object. The simulation of the mobile heat source was realized by means of parametric design. The distribution of the temperature field during the sintering process under different laser power and different spot sizes was simulated by ANSYS software under the condition of fully considering the influence of heat conduction, thermal convection, thermal radiation and thermophysical parameters. The influence of these factors on the actual sintering process was also analyzed, which provides an effective way for forming quality control.

Dynamic modelling of an adsorption storage tank using a hybrid approach combining computational fluid dynamics and process simulation

USGS Publications Warehouse

Mota, J.P.B.; Esteves, I.A.A.C.; Rostam-Abadi, M.

2004-01-01

A computational fluid dynamics (CFD) software package has been coupled with the dynamic process simulator of an adsorption storage tank for methane fuelled vehicles. The two solvers run as independent processes and handle non-overlapping portions of the computational domain. The codes exchange data on the boundary interface of the two domains to ensure continuity of the solution and of its gradient. A software interface was developed to dynamically suspend and activate each process as necessary, and be responsible for data exchange and process synchronization. This hybrid computational tool has been successfully employed to accurately simulate the discharge of a new tank design and evaluate its performance. The case study presented here shows that CFD and process simulation are highly complementary computational tools, and that there are clear benefits to be gained from a close integration of the two. ?? 2004 Elsevier Ltd. All rights reserved.

Assessment of the Unstructured Grid Software TetrUSS for Drag Prediction of the DLR-F4 Configuration

NASA Technical Reports Server (NTRS)

Pirzadeh, Shahyar Z.; Frink, Neal T.

2002-01-01

An application of the NASA unstructured grid software system TetrUSS is presented for the prediction of aerodynamic drag on a transport configuration. The paper briefly describes the underlying methodology and summarizes the results obtained on the DLR-F4 transport configuration recently presented in the first AIAA computational fluid dynamics (CFD) Drag Prediction Workshop. TetrUSS is a suite of loosely coupled unstructured grid CFD codes developed at the NASA Langley Research Center. The meshing approach is based on the advancing-front and the advancing-layers procedures. The flow solver employs a cell-centered, finite volume scheme for solving the Reynolds Averaged Navier-Stokes equations on tetrahedral grids. For the present computations, flow in the viscous sublayer has been modeled with an analytical wall function. The emphasis of the paper is placed on the practicality of the methodology for accurately predicting aerodynamic drag data.

CFD simulation and experimental validation of a GM type double inlet pulse tube refrigerator

NASA Astrophysics Data System (ADS)

Banjare, Y. P.; Sahoo, R. K.; Sarangi, S. K.

2010-04-01

Pulse tube refrigerator has the advantages of long life and low vibration over the conventional cryocoolers, such as GM and stirling coolers because of the absence of moving parts in low temperature. This paper performs a three-dimensional computational fluid dynamic (CFD) simulation of a GM type double inlet pulse tube refrigerator (DIPTR) vertically aligned, operating under a variety of thermal boundary conditions. A commercial computational fluid dynamics (CFD) software package, Fluent 6.1 is used to model the oscillating flow inside a pulse tube refrigerator. The simulation represents fully coupled systems operating in steady-periodic mode. The externally imposed boundary conditions are sinusoidal pressure inlet by user defined function at one end of the tube and constant temperature or heat flux boundaries at the external walls of the cold-end heat exchangers. The experimental method to evaluate the optimum parameters of DIPTR is difficult. On the other hand, developing a computer code for CFD analysis is equally complex. The objectives of the present investigations are to ascertain the suitability of CFD based commercial package, Fluent for study of energy and fluid flow in DIPTR and to validate the CFD simulation results with available experimental data. The general results, such as the cool down behaviours of the system, phase relation between mass flow rate and pressure at cold end, the temperature profile along the wall of the cooler and refrigeration load are presented for different boundary conditions of the system. The results confirm that CFD based Fluent simulations are capable of elucidating complex periodic processes in DIPTR. The results also show that there is an excellent agreement between CFD simulation results and experimental results.

Minimization of Blast furnace Fuel Rate by Optimizing Burden and Gas Distribution

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

Dr. Chenn Zhou

2012-08-15

The goal of the research is to improve the competitive edge of steel mills by using the advanced CFD technology to optimize the gas and burden distributions inside a blast furnace for achieving the best gas utilization. A state-of-the-art 3-D CFD model has been developed for simulating the gas distribution inside a blast furnace at given burden conditions, burden distribution and blast parameters. The comprehensive 3-D CFD model has been validated by plant measurement data from an actual blast furnace. Validation of the sub-models is also achieved. The user friendly software package named Blast Furnace Shaft Simulator (BFSS) has beenmore » developed to simulate the blast furnace shaft process. The research has significant benefits to the steel industry with high productivity, low energy consumption, and improved environment.« less

Effect of external turbulence on the efficiency of film cooling with coolant injection into a transverse trench

NASA Astrophysics Data System (ADS)

Khalatov, A. A.; Panchenko, N. A.; Severin, S. D.

2017-09-01

Film cooling is among the basic methods used for thermal protection of blades in modern high-temperature gas turbines. Results of computer simulation of film cooling with coolant injection via a row of conventional inclined holes or a row of holes in a trench are presented in this paper. The ANSYS CFX 14 commercial software package was used for CFD-modeling. The effect is studied of the mainstream turbulence on the film cooling efficiency for the blowing ratio range between 0.6 and 2.3 and three different turbulence intensities of 1, 5, and 10%. The mainstream velocity was 150 and 400 m/s, while the temperatures of the mainstream and the injected coolant were 1100 and 500°C, respectively. It is demonstrated that, for the coolant injection via one row of trenched holes, an increase in the mainstream turbulence intensity reduces the film cooling efficiency in the entire investigated range of blowing ratios. It was revealed that freestream turbulence had varied effects on the film cooling efficiency depending on the blowing ratio and mainstream velocity in a blade channel. Thus, an increase in the mainstream turbulence intensity from 1 to 10% decreases the surface-averaged film cooling efficiency by 3-10% at a high mainstream velocity (400 m/s) in the blade channel and by 12-23% at a moderate velocity (of 150 m/s). Here, lower film cooling efficiencies correspond to higher blowing ratios. The effect of mainstream turbulence intensity on the film cooling efficiency decreases with increasing the mainstream velocity in the modeled channel for both investigated configurations.

Large Eddy Simulation of turbulence induced secondary flows in stationary and rotating straight square ducts

NASA Astrophysics Data System (ADS)

Sudjai, W.; Juntasaro, V.; Juttijudata, V.

2018-01-01

The accuracy of predicting turbulence induced secondary flows is crucially important in many industrial applications such as turbine blade internal cooling passages in a gas turbine and fuel rod bundles in a nuclear reactor. A straight square duct is popularly used to reveal the characteristic of turbulence induced secondary flows which consists of two counter rotating vortices distributed in each corner of the duct. For a rotating duct, the flow can be divided into the pressure side and the suction side. The turbulence induced secondary flows are converted to the Coriolis force driven two large circulations with a pair of additional vortices on the pressure wall due to the rotational effect. In this paper, the Large Eddy Simulation (LES) of turbulence induced secondary flows in a straight square duct is performed using the ANSYS FLUENT CFD software. A dynamic kinetic energy subgrid-scale model is used to describe the three-dimensional incompressible turbulent flows in the stationary and the rotating straight square ducts. The Reynolds number based on the friction velocity and the hydraulic diameter is 300 with the various rotation numbers for the rotating cases. The flow is assumed fully developed by imposing the constant pressure gradient in the streamwise direction. For the rotating cases, the rotational axis is placed perpendicular to the streamwise direction. The simulation results on the secondary flows and the turbulent statistics are found to be in good agreement with the available Direct Numerical Simulation (DNS) data. Finally, the details of the Coriolis effects are discussed.

Heat transfer analysis of underground U-type heat exchanger of ground source heat pump system.

PubMed

Pei, Guihong; Zhang, Liyin

2016-01-01

Ground source heat pumps is a building energy conservation technique. The underground buried pipe heat exchanging system of a ground source heat pump (GSHP) is the basis for the normal operation of an entire heat pump system. Computational-fluid-dynamics (CFD) numerical simulation software, ANSYS-FLUENT17.0 have been performed the calculations under the working conditions of a continuous and intermittent operation over 7 days on a GSHP with a single-well, single-U and double-U heat exchanger and the impact of single-U and double-U buried heat pipes on the surrounding rock-soil temperature field and the impact of intermittent operation and continuous operation on the outlet water temperature. The influence on the rock-soil temperature is approximately 13 % higher for the double-U heat exchanger than that of the single-U heat exchanger. The extracted energy of the intermittent operation is 36.44 kw·h higher than that of the continuous mode, although the running time is lower than that of continuous mode, over the course of 7 days. The thermal interference loss and quantity of heat exchanged for unit well depths at steady-state condition of 2.5 De, 3 De, 4 De, 4.5 De, 5 De, 5.5 De and 6 De of sidetube spacing are detailed in this work. The simulation results of seven working conditions are compared. It is recommended that the side-tube spacing of double-U underground pipes shall be greater than or equal to five times of outer diameter (borehole diameter: 180 mm).

Performance evaluation of radiant cooling system integrated with air system under different operational strategies

DOE PAGES

Khan, Yasin; Khare, Vaibhav Rai; Mathur, Jyotirmay; ...

2015-03-26

The paper describes a parametric study developed to estimate the energy savings potential of a radiant cooling system installed in a commercial building in India. The study is based on numerical modeling of a radiant cooling system installed in an Information Technology (IT) office building sited in the composite climate of Hyderabad. To evaluate thermal performance and energy consumption, simulations were carried out using the ANSYS FLUENT and EnergyPlus softwares, respectively. The building model was calibrated using the measured data for the installed radiant system. Then this calibrated model was used to simulate the energy consumption of a building usingmore » a conventional all-air system to determine the proportional energy savings. For proper handling of the latent load, a dedicated outside air system (DOAS) was used as an alternative to Fan Coil Unit (FCU). A comparison of energy consumption calculated that the radiant system was 17.5 % more efficient than a conventional all-air system and that a 30% savings was achieved by using a DOAS system compared with a conventional system. Computational Fluid Dynamics (CFD) simulation was performed to evaluate indoor air quality and thermal comfort. It was found that a radiant system offers more uniform temperatures, as well as a better mean air temperature range, than a conventional system. To further enhance the energy savings in the radiant system, different operational strategies were analyzed based on thermal analysis using EnergyPlus. Lastly, the energy savings achieved in this parametric run were more than 10% compared with a conventional all-air system.« less

Evaluation of rotor axial vibrations in a turbo pump unit equipped with an automatic unloading machine

NASA Astrophysics Data System (ADS)

Martsynkovskyy, V. A.; Deineka, A.; Kovalenko, V.

2017-08-01

The article presents forced axial vibrations of the rotor with an automatic unloading machine in an oxidizer pump. A feature of the design is the use in the autoloading system of slotted throttles with mutually inverse throttling. Their conductivity is determined by a numerical experiment in the ANSYS CFX software package.

Visual Environments for CFD Research

NASA Technical Reports Server (NTRS)

Watson, Val; George, Michael W. (Technical Monitor)

1994-01-01

This viewgraph presentation gives an overview of the visual environments for computational fluid dynamics (CFD) research. It includes details on critical needs from the future computer environment, features needed to attain this environment, prospects for changes in and the impact of the visualization revolution on the human-computer interface, human processing capabilities, limits of personal environment and the extension of that environment with computers. Information is given on the need for more 'visual' thinking (including instances of visual thinking), an evaluation of the alternate approaches for and levels of interactive computer graphics, a visual analysis of computational fluid dynamics, and an analysis of visualization software.

Three-dimensional finite element modeling of a maxillary premolar tooth based on the micro-CT scanning: a detailed description.

PubMed

Huang, Zheng; Chen, Zhi

2013-10-01

This study describes the details of how to construct a three-dimensional (3D) finite element model of a maxillary first premolar tooth based on micro-CT data acquisition technique, MIMICS software and ANSYS software. The tooth was scanned by micro-CT, in which 1295 slices were obtained and then 648 slices were selected for modeling. The 3D surface mesh models of enamel and dentin were created by MIMICS (STL file). The solid mesh model was constructed by ANSYS. After the material properties and boundary conditions were set, a loading analysis was performed to demonstrate the applicableness of the resulting model. The first and third principal stresses were then evaluated. The results showed that the number of nodes and elements of the finite element model were 56 618 and 311801, respectively. The geometric form of the model was highly consistent with that of the true tooth, and the deviation between them was -0.28%. The loading analysis revealed the typical stress patterns in the contour map. The maximum compressive stress existed in the contact points and the maximum tensile stress existed in the deep fissure between the two cusps. It is concluded that by using the micro-CT and highly integrated software, construction of the 3D finite element model with high quality will not be difficult for clinical researchers.

CFD simulation research on residential indoor air quality.

PubMed

Yang, Li; Ye, Miao; He, Bao-Jie

2014-02-15

Nowadays people are excessively depending on air conditioning to create a comfortable indoor environment, but it could cause some health problems in a long run. In this paper, wind velocity field, temperature field and air age field in a bedroom with wall-hanging air conditioning running in summer are analyzed by CFD numerical simulation technology. The results show that wall-hanging air conditioning system can undertake indoor heat load and conduct good indoor thermal comfort. In terms of wind velocity, air speed in activity area where people sit and stand is moderate, most of which cannot feel wind flow and meet the summer indoor wind comfort requirement. However, for air quality, there are local areas without ventilation and toxic gases not discharged in time. Therefore it is necessary to take effective measures to improve air quality. Compared with the traditional measurement method, CFD software has many advantages in simulating indoor environment, so it is hopeful for humans to create a more comfortable, healthy living environment by CFD in the future. Copyright © 2013 Elsevier B.V. All rights reserved.

Development and acceleration of unstructured mesh-based cfd solver

NASA Astrophysics Data System (ADS)

Emelyanov, V.; Karpenko, A.; Volkov, K.

2017-06-01

The study was undertaken as part of a larger effort to establish a common computational fluid dynamics (CFD) code for simulation of internal and external flows and involves some basic validation studies. The governing equations are solved with ¦nite volume code on unstructured meshes. The computational procedure involves reconstruction of the solution in each control volume and extrapolation of the unknowns to find the flow variables on the faces of control volume, solution of Riemann problem for each face of the control volume, and evolution of the time step. The nonlinear CFD solver works in an explicit time-marching fashion, based on a three-step Runge-Kutta stepping procedure. Convergence to a steady state is accelerated by the use of geometric technique and by the application of Jacobi preconditioning for high-speed flows, with a separate low Mach number preconditioning method for use with low-speed flows. The CFD code is implemented on graphics processing units (GPUs). Speedup of solution on GPUs with respect to solution on central processing units (CPU) is compared with the use of different meshes and different methods of distribution of input data into blocks. The results obtained provide promising perspective for designing a GPU-based software framework for applications in CFD.

SCORE user`s manual

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

Brown, S.A.

SABrE is a set of tools to facilitate the development of portable scientific software and to visualize scientific data. As with most constructs, SABRE has a foundation. In this case that foundation is SCORE. SCORE (SABRE CORE) has two main functions. The first and perhaps most important is to smooth over the differences between different C implementations and define the parameters which drive most of the conditional compilations in the rest of SABRE. Secondly, it contains several groups of functionality that are used extensively throughout SABRE. Although C is highly standardized now, that has not always been the case. Roughlymore » speaking C compilers fall into three categories: ANSI standard; derivative of the Portable C Compiler (Kernighan and Ritchie); and the rest. SABRE has been successfully ported to many ANSI and PCC systems. It has never been successfully ported to a system in the last category. The reason is mainly that the ``standard`` C library supplied with such implementations is so far from true ANSI or PCC standard that SABRE would have to include its own version of the standard C library in order to work at all. Even with standardized compilers life is not dead simple. The ANSI standard leaves several crucial points ambiguous as ``implementation defined.`` Under these conditions one can find significant differences in going from one ANSI standard compiler to another. SCORE`s job is to include the requisite standard headers and ensure that certain key standard library functions exist and function correctly (there are bugs in the standard library functions supplied with some compilers) so that, to applications which include the SCORE header(s) and load with SCORE, all C implementations look the same.« less

SCORE user's manual

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

Brown, S.A.

SABrE is a set of tools to facilitate the development of portable scientific software and to visualize scientific data. As with most constructs, SABRE has a foundation. In this case that foundation is SCORE. SCORE (SABRE CORE) has two main functions. The first and perhaps most important is to smooth over the differences between different C implementations and define the parameters which drive most of the conditional compilations in the rest of SABRE. Secondly, it contains several groups of functionality that are used extensively throughout SABRE. Although C is highly standardized now, that has not always been the case. Roughlymore » speaking C compilers fall into three categories: ANSI standard; derivative of the Portable C Compiler (Kernighan and Ritchie); and the rest. SABRE has been successfully ported to many ANSI and PCC systems. It has never been successfully ported to a system in the last category. The reason is mainly that the standard'' C library supplied with such implementations is so far from true ANSI or PCC standard that SABRE would have to include its own version of the standard C library in order to work at all. Even with standardized compilers life is not dead simple. The ANSI standard leaves several crucial points ambiguous as implementation defined.'' Under these conditions one can find significant differences in going from one ANSI standard compiler to another. SCORE's job is to include the requisite standard headers and ensure that certain key standard library functions exist and function correctly (there are bugs in the standard library functions supplied with some compilers) so that, to applications which include the SCORE header(s) and load with SCORE, all C implementations look the same.« less

Analysis and Characterization of the Mechanical Structure for the I-Tracker of the Mu2e Experiment

NASA Astrophysics Data System (ADS)

De Lorenzis, L.; Grancagnolo, F.; L'Erario, A.; Maffezzoli, A.; Miccoli, A.; Rella, S.; Spedicato, M.; Zavarise, G.

2014-03-01

The design of a tracking detector for electrons in a magnetic field consisting of a drift chamber is discussed. The chosen materials for its construction must be light to minimize the effects of the subatomic particles interactions with the chamber walls. Low-density materials and very thin wall thicknesses are therefore needed. From a mechanical engineering point of view, it is important to analyse the drift chamber structure and define the conditions to which it is subject in terms of both mechanical loads and geometric constraints. The analysis of the structural response of the drift chamber has been performed through the Finite Element Method (FEM) as implemented in the commercial software ANSYS and its interface for the analysis for composite structures ACP (Ansys Composite Pre/Post).

Nonlinear analysis of concrete beams strengthened by date palm fibers

NASA Astrophysics Data System (ADS)

Bouzouaid, Samia; Kriker, Abdelouahed

2017-02-01

The behaviour of concrete beams strengthened with date palm fibers was studied by Nonlinear Finite Element Analysis using ANSYS software. Five beams that were experimentally tested in a previous research were considered. The results obtained from the ANSYS finite element analysis are compared with the experimental data for the five beams with different amounts of fibres, ranging from 0.2% to 0.5% by a step equal to 0.1% and with a fibre length of 0.04 m. The results obtained by FEA showed good agreement with those obtained by the experimental program. This research demonstrates the ability of FEA in predicting the behaviour of beams strengthened with Date Palm fibers. It will help researchers in studying beams with different configurations without the need to go through the lengthy experimental testing programs.

Modelling and structural analysis of skull/cranial implant: beyond mid-line deformities.

PubMed

Bogu, V Phanindra; Kumar, Y Ravi; Kumar Khanara, Asit

2017-01-01

This computational study explores modelling and finite element study of the implant under Intracranial pressure (ICP) conditions with normal ICP range (7 mm Hg to 15 mm Hg) or increased ICP (>I5 mm Hg). The implant fixation points allow implant behaviour with respect to intracranial pressure conditions. However, increased fixation points lead to variation in deformation and equivalent stress. Finite element analysis is providing a valuable insight to know the deformation and equivalent stress. The patient CT data (Computed Tomography) is processed in Mimics software to get the mesh model. The implant is modelled by using modified reverse engineering technique with the help of Rhinoceros software. This modelling method is applicable for all types of defects including those beyond the middle line and multiple ones. It is designed with eight fixation points and ten fixation points to fix an implant. Consequently, the mechanical deformation and equivalent stress (von Mises) are calculated in ANSYS 15 software with distinctive material properties such as Titanium alloy (Ti6Al4V), Polymethyl methacrylate (PMMA) and polyether-ether-ketone (PEEK). The deformation and equivalent stress results are obtained through ANSYS 15 software. It is observed that Ti6Al4V material shows low deformation and PEEK material shows less equivalent stress. Among all materials PEEK shows noticeably good result. Hence, a concept was established and more clinically relevant results can be expected with implementation of realistic 3D printed model in the future. This will allow physicians to gain knowledge and decrease surgery time with proper planning.

AFOSR BRI: Co-Design of Hardware/Software for Predicting MAV Aerodynamics

DTIC Science & Technology

2016-09-27

DOCUMENTATION PAGE Form ApprovedOMB No. 0704-0188 1. REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER 6. AUTHOR(S) 7...703-588-8494 AFOSR BRI While Moore’s Law theoretically doubles processor performance every 24 months, much of the realizable performance remains...past efforts to develop such CFD codes on accelerated processors showed limited success, our hardware/software co-design approach created malleable

Combining ray tracing and CFD in the thermal analysis of a parabolic dish tubular cavity receiver

NASA Astrophysics Data System (ADS)

Craig, Ken J.; Marsberg, Justin; Meyer, Josua P.

2016-05-01

This paper describes the numerical evaluation of a tubular receiver used in a dish Brayton cycle. In previous work considering the use of Computational Fluid Dynamics (CFD) to perform the calculation of the absorbed radiation from the parabolic dish into the cavity as well as the resulting conjugate heat transfer, it was shown that an axi-symmetric model of the dish and receiver absorbing surfaces was useful in reducing the computational cost required for a full 3-D discrete ordinates solution, but concerns remained about its accuracy. To increase the accuracy, the Monte Carlo ray tracer SolTrace is used to perform the calculation of the absorbed radiation profile to be used in the conjugate heat transfer CFD simulation. The paper describes an approach for incorporating a complex geometry like a tubular receiver generated using CFD software into SolTrace. The results illustrate the variation of CFD mesh density that translates into the number of elements in SolTrace as well as the number of rays used in the Monte Carlo approach and their effect on obtaining a resolution-independent solution. The conjugate heat transfer CFD simulation illustrates the effect of applying the SolTrace surface heat flux profile solution as a volumetric heat source to heat up the air inside the tube. Heat losses due to convection and thermal re-radiation are also determined as a function of different tube absorptivities.

Experimental and Numerical Investigation of Pressure Drop in Silicon Carbide Fuel Rod for Application in Pressurized Water Reactors

NASA Astrophysics Data System (ADS)

Abir, Ahmed Musafi

Spacer grids are used in Pressurized Water Reactors (PWRs) fuel assemblies which enhances heat transfer from fuel rods. However, there remain regions of low turbulence in between the spacer grids. To enhance turbulence in these regions surface roughness is applied on the fuel rod walls. Meyer [1] used empirical correlations to predict heat transfer and friction factor for artificially roughened fuel rod bundles at High Performance Light Water Reactors (LWRs). Their applicability was tested by Carrilho at University of South Carolina's (USC) Single Heated Element Loop Tester (SHELT). He attained a heat transfer and friction factor enhancement of 50% and 45% respectively, using Inconel nuclear fuel rods with square transverse ribbed surface. Following him Najeeb conducted a similar study due to three dimensional diamond shaped blocks in turbulent flow. He recorded a maximum heat transfer enhancement of 83%. At present, several types of materials are being used for fuel rod cladding including Zircaloy, Uranium oxide, etc. But researchers are actively searching for new material that can be a more practical alternative. Silicon Carbide (SiC) has been identified as a material of interest for application as fuel rod cladding [2]. The current study deals with the experimental investigation to find out the friction factor increase of a SiC fuel rod with 3D surface roughness. The SiC rod was tested at USC's SHELT loop. The experiment was conducted in turbulent flowing Deionized (DI) water at steady state conditions. Measurements of Flow rate and pressure drop were made. The experimental results were also validated by Computational Fluid Dynamics (CFD) analysis in ANSYS Fluent. To simplify the CFD analysis and to save computational resources the 3D roughness was approximated as a 2D one. The friction factor results of the CFD investigation was found to lie within +/-8% of the experimental results. A CFD model was also run with the energy equation turned on, and a heat generation of 8 kW applied to the rod. A maximum heat transfer enhancement of 18.4% was achieved at the highest flow rate investigated (i.e. Re=109204).

Simulation of SiO2 etching in an inductively coupled CF4 plasma

NASA Astrophysics Data System (ADS)

Xu, Qing; Li, Yu-Xing; Li, Xiao-Ning; Wang, Jia-Bin; Yang, Fan; Yang, Yi; Ren, Tian-Ling

2017-02-01

Plasma etching technology is an indispensable processing method in the manufacturing process of semiconductor devices. Because of the high fluorine/carbon ratio of CF4, the CF4 gas is often used for etching SiO2. A commercial software ESI-CFD is used to simulate the process of plasma etching with an inductively coupled plasma model. For the simulation part, CFD-ACE is used to simulate the chamber, and CFD-TOPO is used to simulate the surface of the sample. The effects of chamber pressure, bias voltage and ICP power on the reactant particles were investigated, and the etching profiles of SiO2 were obtained. Simulation can be used to predict the effects of reaction conditions on the density, energy and angular distributions of reactant particles, which can play a good role in guiding the etching process.

FUN3D Grid Refinement and Adaptation Studies for the Ares Launch Vehicle

NASA Technical Reports Server (NTRS)

Bartels, Robert E.; Vasta, Veer; Carlson, Jan-Renee; Park, Mike; Mineck, Raymond E.

2010-01-01

This paper presents grid refinement and adaptation studies performed in conjunction with computational aeroelastic analyses of the Ares crew launch vehicle (CLV). The unstructured grids used in this analysis were created with GridTool and VGRID while the adaptation was performed using the Computational Fluid Dynamic (CFD) code FUN3D with a feature based adaptation software tool. GridTool was developed by ViGYAN, Inc. while the last three software suites were developed by NASA Langley Research Center. The feature based adaptation software used here operates by aligning control volumes with shock and Mach line structures and by refining/de-refining where necessary. It does not redistribute node points on the surface. This paper assesses the sensitivity of the complex flow field about a launch vehicle to grid refinement. It also assesses the potential of feature based grid adaptation to improve the accuracy of CFD analysis for a complex launch vehicle configuration. The feature based adaptation shows the potential to improve the resolution of shocks and shear layers. Further development of the capability to adapt the boundary layer and surface grids of a tetrahedral grid is required for significant improvements in modeling the flow field.

Flow analysis of new type propulsion system for UV’s

NASA Astrophysics Data System (ADS)

Eimanis, M.; Auzins, J.

2017-10-01

This paper presents an original design of an autonomous underwater vehicle where thrust force is created by the helicoidal shape of the hull rather than screw propellers. Propulsion force is created by counter-rotating bow and stern parts. The middle part of the vehicle has the function of a cargo compartment containing all control mechanisms and communications. It’s made of elastic material, containing a Cardan-joint mechanism, which allows changing the direction of vehicle, actuated by bending drives. A bending drive velocity control algorithm for the automatic control of vehicle movement direction is proposed. The dynamics of AUV are simulated using multibody simulation software MSC Adams. For the simulation of water resistance forces and torques the surrogate polynomial metamodels are created on the basis of computer experiments with CFD software. For flow interaction with model geometry the simplified vehicle model is submerged in fluid medium using special CFD software, with the same idea used in wind tunnel experiments. The simulation results are compared with measurements of the AUV prototype, created at Institute of Mechanics of Riga Technical University. Experiments with the prototype showed good agreement with simulation results and confirmed the effectiveness and the future potential of the proposed principle.

Bending of I-beam with the transvers shear effect included - FEM calculated

NASA Astrophysics Data System (ADS)

Grygorowicz, Magdalena; Lewiński, Jerzy

2016-06-01

The paper is devoted to three-point bending of an I-beam with include of transvers shear effect. Numerical calculations were conducted independently with the use of the SolidWorks system and the multi-purpose software package ANSYS The results of FEM study conducted with the use of two systems were compared and presented in tables and figures.

Bending of I-beam with the transvers shear effect included – FEM calculated

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

Grygorowicz, Magdalena; Lewiński, Jerzy

2016-06-08

The paper is devoted to three-point bending of an I-beam with include of transvers shear effect. Numerical calculations were conducted independently with the use of the SolidWorks system and the multi-purpose software package ANSYS The results of FEM study conducted with the use of two systems were compared and presented in tables and figures.

Spring 2006. Industry Study. Information Technology Industry

DTIC Science & Technology

2006-01-01

unclassified c . THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 i Information Technology 2006 ABSTRACT...integration of processors, coprocessors, memory, storage, etc. into a user-programmable final product. C . Software (Apple, Oracle): These firms...able to support the U.S. national security interests. C . Manufacturing: The personal computer manufacturing industry has also changed considerably

Parameter optimization for the visco-hyperelastic constitutive model of tendon using FEM.

PubMed

Tang, C Y; Ng, G Y F; Wang, Z W; Tsui, C P; Zhang, G

2011-01-01

Numerous constitutive models describing the mechanical properties of tendons have been proposed during the past few decades. However, few were widely used owing to the lack of implementation in the general finite element (FE) software, and very few systematic studies have been done on selecting the most appropriate parameters for these constitutive laws. In this work, the visco-hyperelastic constitutive model of the tendon implemented through the use of three-parameter Mooney-Rivlin form and sixty-four-parameter Prony series were firstly analyzed using ANSYS FE software. Afterwards, an integrated optimization scheme was developed by coupling two optimization toolboxes (OPTs) of ANSYS and MATLAB for estimating these unknown constitutive parameters of the tendon. Finally, a group of Sprague-Dawley rat tendons was used to execute experimental and numerical simulation investigation. The simulated results showed good agreement with the experimental data. An important finding revealed that too many Maxwell elements was not necessary for assuring accuracy of the model, which is often neglected in most open literatures. Thus, all these proved that the constitutive parameter optimization scheme was reliable and highly efficient. Furthermore, the approach can be extended to study other tendons or ligaments, as well as any visco-hyperelastic solid materials.

Simulation of the Velocity and Temperature Distribution of Inhalation Thermal Injury in a Human Upper Airway Model by Application of Computational Fluid Dynamics.

PubMed

Chang, Yang; Zhao, Xiao-zhuo; Wang, Cheng; Ning, Fang-gang; Zhang, Guo-an

2015-01-01

Inhalation injury is an important cause of death after thermal burns. This study was designed to simulate the velocity and temperature distribution of inhalation thermal injury in the upper airway in humans using computational fluid dynamics. Cervical computed tomography images of three Chinese adults were imported to Mimics software to produce three-dimensional models. After grids were established and boundary conditions were defined, the simulation time was set at 1 minute and the gas temperature was set to 80 to 320°C using ANSYS software (ANSYS, Canonsburg, PA) to simulate the velocity and temperature distribution of inhalation thermal injury. Cross-sections were cut at 2-mm intervals, and maximum airway temperature and velocity were recorded for each cross-section. The maximum velocity peaked in the lower part of the nasal cavity and then decreased with air flow. The velocities in the epiglottis and glottis were higher than those in the surrounding areas. Further, the maximum airway temperature decreased from the nasal cavity to the trachea. Computational fluid dynamics technology can be used to simulate the velocity and temperature distribution of inhaled heated air.

ANSI/ASHRAE/IES Standard 90.1-2010 Performance Rating Method Reference Manual

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

Goel, Supriya; Rosenberg, Michael I.

This document is intended to be a reference manual for the Appendix G Performance Rating Method (PRM) of ANSI/ASHRAE/IES Standard 90.1- 2010 (Standard 90.1-2010).The PRM is used for rating the energy efficiency of commercial and high-rise residential buildings with designs that exceed the requirements of Standard 90.1. The procedures and processes described in this manual are designed to provide consistency and accuracy by filling in gaps and providing additional details needed by users of the PRM. It should be noted that this document is created independently from ASHRAE and SSPC 90.1 and is not sanctioned nor approved by either ofmore » those entities . Potential users of this manual include energy modelers, software developers and implementers of “beyond code” energy programs. Energy modelers using ASHRAE Standard 90.1-2010 for beyond code programs can use this document as a reference manual for interpreting requirements of the Performance Rating method. Software developers, developing tools for automated creation of the baseline model can use this reference manual as a guideline for developing the rules for the baseline model.« less

CFD simulations of transient load change on a high head Francis turbine

NASA Astrophysics Data System (ADS)

Jakobsen, Ken-Robert G.; Aasved Holst, Martin

2017-01-01

Motivated by the importance of better understanding the structural integrity of high-head hydraulic turbines operating at intermittent conditions, complete 360º steady-state and transient simulations of a Francis turbine are presented in this paper. The main target of the work has been to investigate different numerical approaches such as mesh deformation for different operating conditions. Steady-state simulations were performed at the best efficiency point (BEP) and used as initial conditions for the transient simulations considering load rejection from BEP to part load (BEP2PL) and during load acceptance from BEP to high load (BEP2HL). Simulation results were compared with experimental data available for the Francis-99 project where close agreement was found for the mesh independent solution. The transient load analyses showed general trends in accordance with the measurement reports, especially for the pressure in vaneless space that is of high importance regarding RSI effects. Some deviations were identified for the net head at load rejection for which further investigations will be conducted. All CFD simulations were performed at model scale with ANSYS CFX v. 17 at either 96 or 120 cores (2.60 GHz). The immersed boundary technique was tested during the initial stages of the project, but had to be abandoned due to severe memory requirements. Pressure amplitudes and other instantaneous results were not considered.

Microcirculation in the murine liver: a computational fluid dynamic model based on 3D reconstruction from in vivo microscopy.

PubMed

Piergiovanni, Monica; Bianchi, Elena; Capitani, Giada; Li Piani, Irene; Ganzer, Lucia; Guidotti, Luca G; Iannacone, Matteo; Dubini, Gabriele

2017-10-03

The liver is organized in hexagonal functional units - termed lobules - characterized by a rather peculiar blood microcirculation, due to the presence of a tangled network of capillaries - termed sinusoids. A better understanding of the hemodynamics that governs liver microcirculation is relevant to clinical and biological studies aimed at improving our management of liver diseases and transplantation. Herein, we built a CFD model of a 3D sinusoidal network, based on in vivo images of a physiological mouse liver obtained with a 2-photon microscope. The CFD model was developed with Fluent 16.0 (ANSYS Inc., Canonsburg, PA), particular care was taken in imposing the correct boundary conditions representing a physiological state. To account for the remaining branches of the sinusoids, a lumped parameter model was used to prescribe the correct pressure at each outlet. The effect of an adhered cell on local hemodynamics is also investigated for different occlusion degrees. The model here proposed accurately reproduces the fluid dynamics in a portion of the sinusoidal network in mouse liver. Mean velocities and mass flow rates are in agreement with literature values from in vivo measurements. Our approach provides details on local phenomena, hardly described by other computational studies, either focused on the macroscopic hepatic vasculature or based on homogeneous porous medium model. Copyright © 2017 Elsevier Ltd. All rights reserved.

Image-Based Computational Fluid Dynamics in Blood Vessel Models: Toward Developing a Prognostic Tool to Assess Cardiovascular Function Changes in Prolonged Space Flights

NASA Technical Reports Server (NTRS)

Chatzimavroudis, George P.; Spirka, Thomas A.; Setser, Randolph M.; Myers, Jerry G.

2004-01-01

One of NASA's objectives is to be able to perform a complete, pre-flight, evaluation of cardiovascular changes in astronauts scheduled for prolonged space missions. Computational fluid dynamics (CFD) has shown promise as a method for estimating cardiovascular function during reduced gravity conditions. For this purpose, MRI can provide geometrical information, to reconstruct vessel geometries, and measure all spatial velocity components, providing location specific boundary conditions. The objective of this study was to investigate the reliability of MRI-based model reconstruction and measured boundary conditions for CFD simulations. An aortic arch model and a carotid bifurcation model were scanned in a 1.5T Siemens MRI scanner. Axial MRI acquisitions provided images for geometry reconstruction (slice thickness 3 and 5 mm; pixel size 1x1 and 0.5x0.5 square millimeters). Velocity acquisitions provided measured inlet boundary conditions and localized three-directional steady-flow velocity data (0.7-3.0 L/min). The vessel walls were isolated using NIH provided software (ImageJ) and lofted to form the geometric surface. Constructed and idealized geometries were imported into a commercial CFD code for meshing and simulation. Contour and vector plots of the velocity showed identical features between the MRI velocity data, the MRI-based CFD data, and the idealized-geometry CFD data, with less than 10% differences in the local velocity values. CFD results on models reconstructed from different MRI resolution settings showed insignificant differences (less than 5%). This study illustrated, quantitatively, that reliable CFD simulations can be performed with MRI reconstructed models and gives evidence that a future, subject-specific, computational evaluation of the cardiovascular system alteration during space travel is feasible.

Image-based computational fluid dynamics in blood vessel models: toward developing a prognostic tool to assess cardiovascular function changes in prolonged space flights

NASA Astrophysics Data System (ADS)

Chatzimavroudis, George P.; Spirka, Thomas A.; Setser, Randolph M.; Myers, Jerry G.

2005-04-01

One of NASA"s objectives is to be able to perform a complete pre-flight evaluation of possible cardiovascular changes in astronauts scheduled for prolonged space missions. Blood flow is an important component of cardiovascular function. Lately, attention has focused on using computational fluid dynamics (CFD) to analyze flow with realistic vessel geometries. MRI can provide detailed geometrical information and is the only clinical technique to measure all three spatial velocity components. The objective of this study was to investigate the reliability of MRI-based model reconstruction for CFD simulations. An aortic arch model and a carotid bifurcation model were scanned in a 1.5T MRI scanner. Axial MRI acquisitions provided images for geometry reconstruction using different resolution settings. The vessel walls were identified and the geometry was reconstructed using existing software. The geometry was then imported into a commercial CFD package for meshing and numerical solution. MRI velocity acquisitions provided true inlet boundary conditions for steady flow, as well as three-directional velocity data at several locations. In addition, an idealized version of each geometry was created from the model drawings. Contour and vector plots of the velocity showed identical features between the MRI velocity data, the MRI-based CFD data, and the idealized-geometry CFD data, with mean differences <10%. CFD results from different MRI resolution settings did not show significant differences (<5%). This study showed quantitatively that reliable CFD simulations can be performed in models reconstructed from MRI acquisitions and gives evidence that a future, subject-specific, computational evaluation of the cardiovascular system is possible.

FUEL-FLEXIBLE GASIFICATION-COMBUSTION TECHNOLOGY FOR PRODUCTION OF H2 AND SEQUESTRATION-READY CO2

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

George Rizeq; Janice West; Arnaldo Frydman

Further development of a combustion Large Eddy Simulation (LES) code for the design of advanced gaseous combustion systems is described in this sixth quarterly report. CFD Research Corporation (CFDRC) is developing the LES module within the parallel, unstructured solver included in the commercial CFD-ACE+ software. In this quarter, in-situ adaptive tabulation (ISAT) for efficient chemical rate storage and retrieval was implemented and tested within the Linear Eddy Model (LEM). ISAT type 3 is being tested so that extrapolation can be performed and further improve the retrieval rate. Further testing of the LEM for subgrid chemistry was performed for parallel applicationsmore » and for multi-step chemistry. Validation of the software on backstep and bluff-body reacting cases were performed. Initial calculations of the SimVal experiment at Georgia Tech using their LES code were performed. Georgia Tech continues the effort to parameterize the LEM over composition space so that a neural net can be used efficiently in the combustion LES code. A new and improved Artificial Neural Network (ANN), with log-transformed output, for the 1-step chemistry was implemented in CFDRC's LES code and gave reasonable results. This quarter, the 2nd consortium meeting was held at CFDRC. Next quarter, LES software development and testing will continue. Alpha testing of the code will continue to be performed on cases of interest to the industrial consortium. Optimization of subgrid models will be pursued, particularly with the ISAT approach. Also next quarter, the demonstration of the neural net approach, for multi-step chemical kinetics speed-up in CFD-ACE+, will be accomplished.« less

Technical Support Document for Version 3.6.1 of the COMcheck Software

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

Bartlett, Rosemarie; Connell, Linda M.; Gowri, Krishnan

2009-09-29

This technical support document (TSD) is designed to explain the technical basis for the COMcheck software as originally developed based on the ANSI/ASHRAE/IES Standard 90.1-1989 (Standard 90.1-1989). Documentation for other national model codes and standards and specific state energy codes supported in COMcheck has been added to this report as appendices. These appendices are intended to provide technical documentation for features specific to the supported codes and for any changes made for state-specific codes that differ from the standard features that support compliance with the national model codes and standards.

An approach to design a 90Sr radioisotope thermoelectric generator using analytical and Monte Carlo methods with ANSYS, COMSOL, and MCNP.

PubMed

Khajepour, Abolhasan; Rahmani, Faezeh

2017-01-01

In this study, a 90 Sr radioisotope thermoelectric generator (RTG) with power of milliWatt was designed to operate in the determined temperature (300-312K). For this purpose, the combination of analytical and Monte Carlo methods with ANSYS and COMSOL software as well as the MCNP code was used. This designed RTG contains 90 Sr as a radioisotope heat source (RHS) and 127 coupled thermoelectric modules (TEMs) based on bismuth telluride. Kapton (2.45mm in thickness) and Cryotherm sheets (0.78mm in thickness) were selected as the thermal insulators of the RHS, as well as a stainless steel container was used as a generator chamber. The initial design of the RHS geometry was performed according to the amount of radioactive material (strontium titanate) as well as the heat transfer calculations and mechanical strength considerations. According to the Monte Carlo simulation performed by the MCNP code, approximately 0.35 kCi of 90 Sr is sufficient to generate heat power in the RHS. To determine the optimal design of the RTG, the distribution of temperature as well as the dissipated heat and input power to the module were calculated in different parts of the generator using the ANSYS software. Output voltage according to temperature distribution on TEM was calculated using COMSOL. Optimization of the dimension of the RHS and heat insulator was performed to adapt the average temperature of the hot plate of TEM to the determined hot temperature value. This designed RTG generates 8mW in power with an efficiency of 1%. This proposed approach of combination method can be used for the precise design of various types of RTGs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Computation of Sensitivity Derivatives of Navier-Stokes Equations using Complex Variables

NASA Technical Reports Server (NTRS)

Vatsa, Veer N.

2004-01-01

Accurate computation of sensitivity derivatives is becoming an important item in Computational Fluid Dynamics (CFD) because of recent emphasis on using nonlinear CFD methods in aerodynamic design, optimization, stability and control related problems. Several techniques are available to compute gradients or sensitivity derivatives of desired flow quantities or cost functions with respect to selected independent (design) variables. Perhaps the most common and oldest method is to use straightforward finite-differences for the evaluation of sensitivity derivatives. Although very simple, this method is prone to errors associated with choice of step sizes and can be cumbersome for geometric variables. The cost per design variable for computing sensitivity derivatives with central differencing is at least equal to the cost of three full analyses, but is usually much larger in practice due to difficulty in choosing step sizes. Another approach gaining popularity is the use of Automatic Differentiation software (such as ADIFOR) to process the source code, which in turn can be used to evaluate the sensitivity derivatives of preselected functions with respect to chosen design variables. In principle, this approach is also very straightforward and quite promising. The main drawback is the large memory requirement because memory use increases linearly with the number of design variables. ADIFOR software can also be cumber-some for large CFD codes and has not yet reached a full maturity level for production codes, especially in parallel computing environments.

Pilot-in-the-Loop CFD Method Development

DTIC Science & Technology

2017-02-01

Penn State University. All software supporting piloted simulations must run at real time speeds or faster. This requirement drives the number of...dynamics of interacting blade tip vortices with a ground plane,” American Helicopter Society 64 th Annual Forum Proceedings, 2008. [2] Johnson, W

GPU-accelerated Lattice Boltzmann method for anatomical extraction in patient-specific computational hemodynamics

NASA Astrophysics Data System (ADS)

Yu, H.; Wang, Z.; Zhang, C.; Chen, N.; Zhao, Y.; Sawchuk, A. P.; Dalsing, M. C.; Teague, S. D.; Cheng, Y.

2014-11-01

Existing research of patient-specific computational hemodynamics (PSCH) heavily relies on software for anatomical extraction of blood arteries. Data reconstruction and mesh generation have to be done using existing commercial software due to the gap between medical image processing and CFD, which increases computation burden and introduces inaccuracy during data transformation thus limits the medical applications of PSCH. We use lattice Boltzmann method (LBM) to solve the level-set equation over an Eulerian distance field and implicitly and dynamically segment the artery surfaces from radiological CT/MRI imaging data. The segments seamlessly feed to the LBM based CFD computation of PSCH thus explicit mesh construction and extra data management are avoided. The LBM is ideally suited for GPU (graphic processing unit)-based parallel computing. The parallel acceleration over GPU achieves excellent performance in PSCH computation. An application study will be presented which segments an aortic artery from a chest CT dataset and models PSCH of the segmented artery.

An Interface for Specifying Rigid-Body Motions for CFD Applications

NASA Technical Reports Server (NTRS)

Murman, Scott M.; Chan, William; Aftosmis, Michael; Meakin, Robert L.; Kwak, Dochan (Technical Monitor)

2003-01-01

An interface for specifying rigid-body motions for CFD applications is presented. This interface provides a means of describing a component hierarchy in a geometric configuration, as well as the motion (prescribed or six-degree-of-freedom) associated with any component. The interface consists of a general set of datatypes, along with rules for their interaction, and is designed to be flexible in order to evolve as future needs dictate. The specification is currently implemented with an XML file format which is portable across platforms and applications. The motion specification is capable of describing general rigid body motions, and eliminates the need to write and compile new code within the application software for each dynamic configuration, allowing client software to automate dynamic simulations. The interface is integrated with a GUI tool which allows rigid body motions to be prescribed and verified interactively, promoting access to non-expert users. Illustrative examples, as well as the raw XML source of the file specifications, are included.

CFD Study of the Performance of an Operational Wind Farm and its Impact on the Local Climate: CFD sensitivity to forestry modelling

NASA Astrophysics Data System (ADS)

Wylie, Scott; Watson, Simon

2013-04-01

Any past, current or projected future wind farm developments are highly dependent on localised climatic conditions. For example the mean wind speed, one of the main factors in assessing the economic feasibility of a wind farm, can vary significantly over length scales no greater than the size of a typical wind farm. Any additional heterogeneity at a potential site, such as forestry, can affect the wind resource further not accounting for the additional difficulty of installation. If a wind farm is sited in an environmentally sensitive area then the ability to predict the wind farm performance and possible impacts on the important localised climatic conditions are of increased importance. Siting of wind farms in environmentally sensitive areas is not uncommon, such as areas of peat-land as in this example. Areas of peat-land are important sinks for carbon in the atmosphere but their ability to sequester carbon is highly dependent on the local climatic conditions. An operational wind farm's impact on such an area was investigated using CFD. Validation of the model outputs were carried out using field measurements from three automatic weather stations (AWS) located throughout the site. The study focuses on validation of both wind speed and turbulence measurement, whilst also assessing the models ability to predict wind farm performance. The use of CFD to model the variation in wind speed over heterogeneous terrain, including wind turbines effects, is increasing in popularity. Encouraging results have increased confidence in the ability of CFD performance in complex terrain with features such as steep slopes and forests, which are not well modelled by the widely used linear models such as WAsP and MS-Micro. Using concurrent measurements from three stationary AWS across the wind farm will allow detailed validation of the model predicted flow characteristics, whilst aggregated power output information will allow an assessment of how accurate the model setup can predict wind farm performance. Given the dependence of the local climatic conditions influence on the peat-land's ability to sequester carbon, accurate predictions of the local wind and turbulence features will allow us to quantify any possible wind farm influences. This work was carried out using the commercially available Reynolds Averaged Navier-Stokes (RANS) CFD package ANSYS CFX. Utilising the Windmodeller add-on in CFX, a series of simulations were carried out to assess wind flow interactions through and around the wind farm, incorporating features such as terrain, forestry and rotor wake interactions. Particular attention was paid to forestry effects, as the AWS are located close to the vicinity of forestry. Different Leaf Area Densities (LAD) were tested to assess how sensitive the models output was to this change.

A comparison of FE beam and continuum elements for typical nitinol stent geometries

NASA Astrophysics Data System (ADS)

Ballew, Wesley; Seelecke, Stefan

2009-03-01

With interest in improved efficiency and a more complete description of the SMA material, this paper compares finite element (FE) simulations of typical stent geometries using two different constitutive models and two different element types. Typically, continuum elements are used for the simulation of stents, for example the commercial FE software ANSYS offers a continuum element based on Auricchio's SMA model. Almost every stent geometry, however, is made up of long and slender components and can be modeled more efficiently, in the computational sense, with beam elements. Using the ANSYS user programmable material feature, we implement the free energy based SMA model developed by Mueller and Seelecke into the ANSYS beam element 188. Convergence behavior for both, beam and continuum formulations, is studied in terms of element and layer number, respectively. This is systematically illustrated first for the case of a straight cantilever beam under end loading, and subsequently for a section of a z-bend wire, a typical stent sub-geometry. It is shown that the computation times for the beam element are reduced to only one third of those of the continuum element, while both formulations display a comparable force/displacement response.

Modeling Tools Predict Flow in Fluid Dynamics

NASA Technical Reports Server (NTRS)

2010-01-01

"Because rocket engines operate under extreme temperature and pressure, they present a unique challenge to designers who must test and simulate the technology. To this end, CRAFT Tech Inc., of Pipersville, Pennsylvania, won Small Business Innovation Research (SBIR) contracts from Marshall Space Flight Center to develop software to simulate cryogenic fluid flows and related phenomena. CRAFT Tech enhanced its CRUNCH CFD (computational fluid dynamics) software to simulate phenomena in various liquid propulsion components and systems. Today, both government and industry clients in the aerospace, utilities, and petrochemical industries use the software for analyzing existing systems as well as designing new ones."

Structural analysis of a ship on global aspect using ANSYS

NASA Astrophysics Data System (ADS)

Rahman, M. Muzibur; Kamol, Rajia Sultana; Islam, Reyana

2017-12-01

Ship is a complex geometry which undergoes a combination of loadings such as hydrostatic, hydrodynamic, wind, wave etc. at sea and thus adequate strength in a ship has always been one of the most challenging tasks for the ship designers. International Maritime Organization (IMO) and classification societies are providing the standards to ensure the adequacy of strength for the ship against all demands throughout its service life. Thus, structural analysis is needed to assess the overall strength of hull, and the means in this regard are based on finite element method which may be applied either local or global aspect of the ship. This paper is an attempt to carry out the structural analysis of a ship in global aspect using ANSYS software to locate the most stress concentration and deformed area, which will have ultimate effect on fatigue fracture.

The Role of Computational Fluid Dynamics in the Management of Unruptured Intracranial Aneurysms: A Clinicians' View

PubMed Central

Singh, Pankaj K.; Marzo, Alberto; Coley, Stuart C.; Berti, Guntram; Bijlenga, Philippe; Lawford, Patricia V.; Villa-Uriol, Mari-Cruz; Rufenacht, Daniel A.; McCormack, Keith M.; Frangi, Alejandro; Patel, Umang J.; Hose, D. Rodney

2009-01-01

Objective. The importance of hemodynamics in the etiopathogenesis of intracranial aneurysms (IAs) is widely accepted. Computational fluid dynamics (CFD) is being used increasingly for hemodynamic predictions. However, alogn with the continuing development and validation of these tools, it is imperative to collect the opinion of the clinicians. Methods. A workshop on CFD was conducted during the European Society of Minimally Invasive Neurological Therapy (ESMINT) Teaching Course, Lisbon, Portugal. 36 delegates, mostly clinicians, performed supervised CFD analysis for an IA, using the @neuFuse software developed within the European project @neurIST. Feedback on the workshop was collected and analyzed. The performance was assessed on a scale of 1 to 4 and, compared with experts' performance. Results. Current dilemmas in the management of unruptured IAs remained the most important motivating factor to attend the workshop and majority of participants showed interest in participating in a multicentric trial. The participants achieved an average score of 2.52 (range 0–4) which was 63% (range 0–100%) of an expert user. Conclusions. Although participants showed a manifest interest in CFD, there was a clear lack of awareness concerning the role of hemodynamics in the etiopathogenesis of IAs and the use of CFD in this context. More efforts therefore are required to enhance understanding of the clinicians in the subject. PMID:19696903

Evaluation of a CFD Method for Aerodynamic Database Development using the Hyper-X Stack Configuration

NASA Technical Reports Server (NTRS)

Parikh, Paresh; Engelund, Walter; Armand, Sasan; Bittner, Robert

2004-01-01

A computational fluid dynamic (CFD) study is performed on the Hyper-X (X-43A) Launch Vehicle stack configuration in support of the aerodynamic database generation in the transonic to hypersonic flow regime. The main aim of the study is the evaluation of a CFD method that can be used to support aerodynamic database development for similar future configurations. The CFD method uses the NASA Langley Research Center developed TetrUSS software, which is based on tetrahedral, unstructured grids. The Navier-Stokes computational method is first evaluated against a set of wind tunnel test data to gain confidence in the code s application to hypersonic Mach number flows. The evaluation includes comparison of the longitudinal stability derivatives on the complete stack configuration (which includes the X-43A/Hyper-X Research Vehicle, the launch vehicle and an adapter connecting the two), detailed surface pressure distributions at selected locations on the stack body and component (rudder, elevons) forces and moments. The CFD method is further used to predict the stack aerodynamic performance at flow conditions where no experimental data is available as well as for component loads for mechanical design and aero-elastic analyses. An excellent match between the computed and the test data over a range of flow conditions provides a computational tool that may be used for future similar hypersonic configurations with confidence.

Three dimensional, numerical analysis of an elasto hydrodynamic lubrication using fluid structure interaction (FSI) approach

NASA Astrophysics Data System (ADS)

Hanoca, P.; Ramakrishna, H. V.

2018-03-01

This work is related to develop a methodology to model and simulate the TEHD using the sequential application of CFD and CSD. The FSI analyses are carried out using ANSYS Workbench. In this analysis steady state, 3D Navier-Stoke equations along with energy equation are solved. Liquid properties are introduced where the viscosity and density are the function of pressure and temperature. The cavitation phenomenon is adopted in the analysis. Numerical analysis has been carried at different speeds and surfaces temperatures. During the analysis, it was found that as speed increases, hydrodynamic pressures will also increases. The pressure profile obtained from the Roelands equation is more sensitive to the temperature as compared to the Barus equation. The stress distributions specify the significant positions in the bearing structure. The developed method is capable of giving latest approaching into the physics of elasto hydrodynamic lubrication.

Finite Element Modeling and Analysis of Powder Stream in Low Pressure Cold Spray Process

NASA Astrophysics Data System (ADS)

Goyal, Tarun; Walia, Ravinderjit Singh; Sharma, Prince; Sidhu, Tejinder Singh

2016-07-01

Low pressure cold gas dynamic spray (LPCGDS) is a coating process that utilize low pressure gas (5-10 bars instead of 25-30 bars) and the radial injection of powder instead of axial injection with the particle range (1-50 μm). In the LPCGDS process, pressurized compressed gas is accelerated to the critical velocity, which depends on length of the divergent section of nozzle, the propellant gas and particle characteristics, and the diameters ratio of the inlet and outer diameters. This paper presents finite element modeling (FEM) of powder stream in supersonic nozzle wherein adiabatic gas flow and expansion of gas occurs in uniform manner and the same is used to evaluate the resultant temperature and velocity contours during coating process. FEM analyses were performed using commercial finite volume package, ANSYS CFD FLUENT. The results are helpful to predict the characteristics of powder stream at the exit of the supersonic nozzle.

Multiphysics Simulation of Welding-Arc and Nozzle-Arc System: Mathematical-Model, Solution-Methodology and Validation

NASA Astrophysics Data System (ADS)

Pawar, Sumedh; Sharma, Atul

2018-01-01

This work presents mathematical model and solution methodology for a multiphysics engineering problem on arc formation during welding and inside a nozzle. A general-purpose commercial CFD solver ANSYS FLUENT 13.0.0 is used in this work. Arc formation involves strongly coupled gas dynamics and electro-dynamics, simulated by solution of coupled Navier-Stoke equations, Maxwell's equations and radiation heat-transfer equation. Validation of the present numerical methodology is demonstrated with an excellent agreement with the published results. The developed mathematical model and the user defined functions (UDFs) are independent of the geometry and are applicable to any system that involves arc-formation, in 2D axisymmetric coordinates system. The high-pressure flow of SF6 gas in the nozzle-arc system resembles arc chamber of SF6 gas circuit breaker; thus, this methodology can be extended to simulate arcing phenomenon during current interruption.

Annotated Bibliography on Human Factors in Software Development

DTIC Science & Technology

1979-06-01

Information Sciences, 1976, 5, 123-143. Shneiderman. B., Mayer, R., McKay, D., & Heller, P. Experimental investi- gations of the utility of flowcharts ...REPRESENTATIONS OF PROGRAMS, PRODUCTION SCHEDULIWG, AUTOMATIC FLOWCHARTING , -MAPFSR,- AND CERTIFICATION TECHNIQUES. EXAMPLES OF HOW THSSE AIOS AND METHODS CAN...PROCiSS ARE PRESENTED, AND THE ANALYSIS Of THREE SPECIFIC MODELS IS REVIEWED. (0)SP, 5R. . 65 FLOWCHARTING CHAPIN, N. FLOWCHARTING WITH THE ANSI

Analysis of Dust Devils on Mars using CFD

NASA Astrophysics Data System (ADS)

Lange, C. F.; Chen, K.; Davis, J. A.; Gheynani, B. T.

2009-05-01

Recent Mars missions have reported evidence of the existence of dust devils. A detailed study of vortex dynamics will provide a better understanding of this swirling flow of the Martian atmosphere. Further, it is believed that there is a relationship between dust devils and water transport. Recently, the Phoenix Mars mission, designed to investigate ice water and natural events on Mars, has successfully finished. The Phoenix Surface Stereo Imager (SSI) camera captured images of the passage of dust devils over or close to the lander. Additionally, dustless devils, which have similar vortex characteristics but insufficient strength to raise dust from the surface, have been detected in the lander's pressure measurements. It was found that dust devils occur mainly in the early afternoon. Because of this, numerical models of a vortex generator are used to study the physics of this complex swirling flow and the effect of dust devils on the transport of water vapour from the regolith. Characteristic parameters such as core radius and swirl ratio are being explored for scaling factors. Scaling factors will be studied and tested, comparing the small and large scales of numerically generated vortices and laboratory generated vortices. Small scale of numerical models of atmospheric vortices are studied using a commercial software package, ANSYS/CFX11.0 with finite volume method (FVM). Large eddy simulations (LES) of planetary boundary layers are based on NCAR LES code to simulate convective vertical vortices that naturally form in quiescent convective boundary layers (CBL) over homogeneous flat surfaces. This will help to find the approximate location and physical characteristics of the vortices on the surface. The numerical models of atmospheric vortices and the experimental vortex generator validations will help to define the water vapour cycle on Mars.

CFD modelling of a membrane reactor for hydrogen production from ammonia

NASA Astrophysics Data System (ADS)

Shwe Hla, San; Dolan, Michael D.

2018-01-01

Despite the growing use of hydrogen (H2) as a transport fuel, one of the major barriers still remaining is efficient and inexpensive fuel distribution and storage. Current approaches, such as compression, liquefaction or metal hydride formation, incur a significant energy penalty. Ammonia (NH3) has long been considered a prospective H2 medium, exhibiting a higher volumetric H2 density than liquid H2, through liquid-phase storage at mild pressure. Decomposition of NH3 into H2 and N2 can be achieved via use of catalytic reactors and fuel-cell-grade H2 can be produced using metal membranes at H2 distribution sites.In this study, a 3-Dimensional (3D) Computational Fluid Dynamics (CFD) model has been developed to understand the performance of the H2 separation process in gas mixtures derived from an NH3-cracking reaction. The reactor consists of 19 tubular membrane tubes, each 470 mm long, inside a tubular shell with an inner diameter of 130 mm. Standard transport and energy equations governing a 3D, pressure-based, steady-state model were derived from the laws of conservation of mass, momentum and energy. The governing equations were solved using commercial CFD software ANSYS Fluent 18.0. Gas flow and mixing were modelled by the two-equation standard k-epsilon model for closure. Coupled solver was used for pressure-velocity coupling, enabling a pseudo-transient option with pseudo time steps of 0.01 s. To estimate H2 permeation through the metal membrane, a constant H2 permeability of 3.0E-07 mol.m-1 s-1 Pa-0.5 derived from series of experiments tested under a range of industrial conditions, was used. Model simulations were conducted for an adiabatic temperature of 300 °C, a feed-side pressure of 7.8 bara and a permeate side pressure of 0.1 bara. A parametric analysis was carried out to explore the effects of variation in total feed-gas flow and effects of changes in NH3-cracking efficiency on H2 production rates and H2 yields. The model estimated that 4.6-11.6 kg H2/day can be produced from a 30-70 L min-1 NH3 inlet flow with 80-90% NH3-cracking efficiency. At lower NH3 inlet flow rates, higher H2 yields can be obtained within a shorter distance of the membrane tubes due to relatively slower velocities and longer residence times. At high inlet flow rates, H2 yields were significantly lower due to their faster velocities and shorter resident times, but high yields (>95%) were still observed at the membrane reactor outlet. A sensitivity analysis of the model showed that even if metal membranes functioned at only 50% of the maximum permeability, a high H2 yield similar to that estimated using 100% permeability can still be achieved at the H2 outlets.

Simulation on friction taper plug welding of AA6063-20Gr metal matrix composite

NASA Astrophysics Data System (ADS)

Hynes, N. Rajesh Jesudoss; Nithin, Abeyram M.

2016-05-01

Friction taper plug welding a variant of friction welding is useful in welding of similar and dissimilar materials. It could be used for joining of composites to metals in sophisticated aerospace applications. In the present work numerical simulation of friction taper plug welding process is carried out using finite element based software. Graphite reinforced AA6063 is modelled using the software ANSYS 15.0 and temperature distribution is predicted. Effect of friction time on temperature distribution is numerically investigated. When the friction time is increased to 30 seconds, the tapered part of plug gets detached and fills the hole in the AA6063 plate perfectly.

PEGASUS 5: An Automated Pre-Processor for Overset-Grid CFD

NASA Technical Reports Server (NTRS)

Rogers, Stuart E.; Suhs, Norman; Dietz, William; Rogers, Stuart; Nash, Steve; Chan, William; Tramel, Robert; Onufer, Jeff

2006-01-01

This viewgraph presentation reviews the use and requirements of Pegasus 5. PEGASUS 5 is a code which performs a pre-processing step for the Overset CFD method. The code prepares the overset volume grids for the flow solver by computing the domain connectivity database, and blanking out grid points which are contained inside a solid body. PEGASUS 5 successfully automates most of the overset process. It leads to dramatic reduction in user input over previous generations of overset software. It also can lead to an order of magnitude reduction in both turn-around time and user expertise requirements. It is also however not a "black-box" procedure; care must be taken to examine the resulting grid system.

Conversion of Component-Based Point Definition to VSP Model and Higher Order Meshing

NASA Technical Reports Server (NTRS)

Ordaz, Irian

2011-01-01

Vehicle Sketch Pad (VSP) has become a powerful conceptual and parametric geometry tool with numerous export capabilities for third-party analysis codes as well as robust surface meshing capabilities for computational fluid dynamics (CFD) analysis. However, a capability gap currently exists for reconstructing a fully parametric VSP model of a geometry generated by third-party software. A computer code called GEO2VSP has been developed to close this gap and to allow the integration of VSP into a closed-loop geometry design process with other third-party design tools. Furthermore, the automated CFD surface meshing capability of VSP are demonstrated for component-based point definition geometries in a conceptual analysis and design framework.

Consistent multiphysics simulation of a central tower CSP plant as applied to ISTORE

NASA Astrophysics Data System (ADS)

Votyakov, Evgeny V.; Papanicolas, Costas N.

2017-06-01

We present a unified consistent multiphysics approach to model a central tower CSP plant. The framework for the model includes Monte Carlo ray tracing (RT) and computational fluid dynamics (CFD) components utilizing the OpenFOAM C++ software library. The RT part works effectively with complex surfaces of engineering design given in CAD formats. The CFD simulation, which is based on 3D Navier-Stokes equations, takes into account all possible heat transfer mechanisms: radiation, conduction, and convection. Utilizing this package, the solar field of the experimental Platform for Research, Observation, and TEchnological Applications in Solar Energy (PROTEAS) and the Integrated STOrage and Receiver (ISTORE), developed at the Cyprus Institute, are being examined.

Wind-US Flow Calculations for the M2129 S-Duct Using Structured and Unstructured Grids

NASA Technical Reports Server (NTRS)

Mohler, Stanley R., Jr.

2003-01-01

Computational Fluid Dynamics (CFD) flow solutions for the M2129 diffusing S-duct with and without vane effectors were computed by the Wind-US flow solver. Both structured and unstructured 3-D grids were used. Without vane effectors, the duct exhibited massive flow separation in both experiment and CFD. With vane effectors installed, the flow remained attached and aerodynamic losses were reduced. Total pressure recovery and distortion near the duct outlet were computed from the solutions and compared favorably to experimental values. These calculations are part of a validation effort for the Wind-US code. They also provide an example case to aid engineers in learning to use the Wind-US software.

Understanding the Impact of Reservoir Operations on Temperature Hydrodynamics at Shasta Lake through 2D and 3D Modeling

NASA Astrophysics Data System (ADS)

Hallnan, R.; Busby, D.; Saito, L.; Daniels, M.; Danner, E.; Tyler, S.

2016-12-01

Stress on California's salmon fisheries as a result of recent drought highlights a need for effective temperature management in the Sacramento River. Cool temperatures are required for Chinook salmon spawning and rearing. At Shasta Dam in northern California, managers use selective reservoir withdrawals to meet downstream temperature thresholds set for Chinook salmon populations. Shasta Dam is equipped with a temperature control device (TCD) that allows for water withdrawals at different reservoir depths. A two-dimensional CE-QUAL-W2 (W2) model of Shasta Reservoir has been used to understand the impacts of TCD operations on reservoir and discharge dynamics at Shasta. W2 models the entire reservoir based on hydrologic and meteorological inputs, and therefore can be used to simulate various hydroclimatic conditions, reservoir operations, and resulting reservoir conditions. A limitation of the W2 model is that it only captures reservoir conditions in two dimensions (length and depth), which may not represent local hydrodynamic effects of TCD operations that could affect simulation of discharge temperatures. Thus, a three-dimensional (3D) model of the TCD and the immediately adjacent upstream reservoir has been constructed using computational fluid dynamics (CFD) in ANSYS Fluent. This 3D model provides additional insight into the mixing effects of different TCD operations, and resulting reservoir outflow temperatures. The drought conditions of 2015 provide a valuable dataset for assessing the efficacy of modeling the temperature profile of Shasta Reservoir under very low inflow volumes, so the W2 and CFD models are compared for model performance in late 2015. To assist with this assessment, data from a distributed temperature sensing (DTS) deployment at Shasta Lake since August 2015 are used. This presentation describes model results from both W2 as well as the CFD model runs during late 2015, and discuss their efficacy for modeling drought conditions.

Three-dimensional simulation of beam propagation and heat transfer in static gas Cs DPALs using wave optics and fluid dynamics models

NASA Astrophysics Data System (ADS)

Waichman, Karol; Barmashenko, Boris D.; Rosenwaks, Salman

2017-10-01

Analysis of beam propagation, kinetic and fluid dynamic processes in Cs diode pumped alkali lasers (DPALs), using wave optics model and gasdynamic code, is reported. The analysis is based on a three-dimensional, time-dependent computational fluid dynamics (3D CFD) model. The Navier-Stokes equations for momentum, heat and mass transfer are solved by a commercial Ansys FLUENT solver based on the finite volume discretization technique. The CFD code which solves the gas conservation equations includes effects of natural convection and temperature diffusion of the species in the DPAL mixture. The DPAL kinetic processes in the Cs/He/C2H6 gas mixture dealt with in this paper involve the three lowest energy levels of Cs, (1) 62S1/2, (2) 62P1/2 and (3) 62P3/2. The kinetic processes include absorption due to the 1->3 D2 transition followed by relaxation the 3 to 2 fine structure levels and stimulated emission due to the 2->1 D1 transition. Collisional quenching of levels 2 and 3 and spontaneous emission from these levels are also considered. The gas flow conservation equations are coupled to fast-Fourier-transform algorithm for transverse mode propagation to obtain a solution of the scalar paraxial propagation equation for the laser beam. The wave propagation equation is solved by the split-step beam propagation method where the gain and refractive index in the DPAL medium affect the wave amplitude and phase. Using the CFD and beam propagation models, the gas flow pattern and spatial distributions of the pump and laser intensities in the resonator were calculated for end-pumped Cs DPAL. The laser power, DPAL medium temperature and the laser beam quality were calculated as a function of pump power. The results of the theoretical model for laser power were compared to experimental results of Cs DPAL.

Biomechanical analysis of titanium fixation plates and screws in sagittal split ramus osteotomies.

PubMed

Atik, F; Atac, M S; Özkan, A; Kılınc, Y; Arslan, M

2016-01-01

The aim of the study was to evaluate the mechanical behavior of three different fixation methods used in the bilateral sagittal split ramus osteotomy. Three different three-dimensional finite element models were created, each corresponding to three different fixation methods. The mandibles were fixed with double straight 4-hole, square 4-hole, and 5-hole Y plates. 150 N incisal occlusal loads were simulated on the distal segments. ANSYS software ((v 10; ANSYS Inc., Canonsburg, PA) was used to calculate the Von Mises stresses on fixative appliances. The highest Von Mises stress values were found in Y plate. The lowest values were isolated in double straight plate group. It was concluded that the use of double 4-hole straight plates provided the sufficient stability on the osteotomy site when compared with the other rigid fixation methods used in this study.

Method to simulate and analyse induced stresses for laser crystal packaging technologies.

PubMed

Ribes-Pleguezuelo, Pol; Zhang, Site; Beckert, Erik; Eberhardt, Ramona; Wyrowski, Frank; Tünnermann, Andreas

2017-03-20

A method to simulate induced stresses for a laser crystal packaging technique and the consequent study of birefringent effects inside the laser cavities has been developed. The method has been implemented by thermo-mechanical simulations implemented with ANSYS 17.0. ANSYS results were later imported in VirtualLab Fusion software where input/output beams in terms of wavelengths and polarization were analysed. The study has been built in the context of a low-stress soldering technique implemented for glass or crystal optics packaging's called the solderjet bumping technique. The outcome of the analysis showed almost no difference between the input and output laser beams for the laser cavity constructed with an yttrium aluminum garnet active laser crystal, a second harmonic generator beta-barium borate, and the output laser mirror made of fused silica assembled by the low-stress solderjet bumping technique.

Research on Impact Stress and Fatigue Simulation of a New Down-to-the-Hole Impactor Based on ANSYS

NASA Astrophysics Data System (ADS)

Wu, Tao; Wang, Wei; Yao, Aiguo; Li, Yongbo; He, Wangyong; Fei, Dongdong

2018-06-01

In the present work, a down-to-the-hole electric hammer driven by linear motor is reported for drilling engineering. It differs from the common hydraulic or pneumatic hammers in that it can be applied to some special occasions without circulating medium due to its independence of the drilling fluid. The impact stress caused by the reciprocating motion between stator and rotor and the fatigue damage in key components of linear motor are analyzed by the ANSYS Workbench software and 3D model. Based on simulation results, the hammer's structure is optimized by using special sliding bearing, increasing the wall thickness of key and multilayer buffer gasket. Fatigue life and coefficient issues of the new structure are dramatically improved. However buffer gasket reduces the impactor's energy, different bumper structure effect on life improving and energy loss have also been elaborated.

Multiaxial Creep-Fatigue and Creep-Ratcheting Failures of Grade 91 and Haynes 230 Alloys Toward Addressing Design Issues of Gen IV Nuclear Power Plants

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

Hassan, Tasnim; Lissenden, Cliff; Carroll, Laura

The proposed research will develop systematic sets of uniaxial and multiaxial experimental data at a very high temperature (850-950°C) for Alloy 617. The loading histories to be prescribed in the experiments will induce creep-fatigue and creep-ratcheting failure mechanisms. These experimental responses will be scrutinized in order to quantify the influences of temperature and creep on fatigue and ratcheting failures. A unified constitutive model (UCM) will be developed and validated against these experimental responses. The improved UCM will be incorporated into the widely used finite element commercial software packages ANSYS. The modified ANSYS will be validated so that it can bemore » used for evaluating the very high temperature ASME-NH design-by-analysis methodology for Alloy 617 and thereby addressing the ASME-NH design code issues.« less

DigBody®: A new 3D modeling tool for nasal virtual surgery.

PubMed

Burgos, M A; Sanmiguel-Rojas, E; Singh, Narinder; Esteban-Ortega, F

2018-07-01

Recent studies have demonstrated that a significant number of surgical procedures for nasal airway obstruction (NAO) have a high rate of surgical failure. In part, this problem is due to the lack of reliable objective clinical parameters to aid surgeons during preoperative planning. Modeling tools that allow virtual surgery to be performed do exist, but all require direct manipulation of computed tomography (CT) or magnetic resonance imaging (MRI) data. Specialists in Rhinology have criticized these tools for their complex user interface, and have requested more intuitive, user-friendly and powerful software to make virtual surgery more accessible and realistic. In this paper we present a new virtual surgery software tool, DigBody ® . This new surgery module is integrated into the computational fluid dynamics (CFD) program MeComLand ® , which was developed exclusively to analyze nasal airflow. DigBody ® works directly with a 3D nasal model that mimics real surgery. Furthermore, this surgery module permits direct assessment of the operated cavity following virtual surgery by CFD simulation. The effectiveness of DigBody ® has been demonstrated by real surgery on two patients based on prior virtual operation results. Both subjects experienced excellent surgical outcomes with no residual nasal obstruction. This tool has great potential to aid surgeons in modeling potential surgical maneuvers, minimizing complications, and being confident that patients will receive optimal postoperative outcomes, validated by personalized CFD testing. Copyright © 2018 Elsevier Ltd. All rights reserved.

A Bibliography of Software Engineering Terms.

DTIC Science & Technology

1979-10-01

WHAT HAPPENS TO DATA, HOW DATA IS TRANSFORMED, AND HOW ONE CAN PARTITION THE PROCESS INTO SUBPROCESSES WITH A MINIMAL NEED OF DATA TRANSFERS. (DAN 323...ANSI-X3HI) 75 p 1 PARANORMAL TERMINATION UNSTRUCTURED ESCAPES (IN CONTROL) FROM A MODULE IN RESPONSE TO NORMAL EVENTS OR CONDITIONS. MODULES HAVING... PARANORMAL TERMINATIONS MAY YET EXHIBIT A FORM OF STRUCTURED CONTROL FLOW, IF PROPERLY CONFIGURED INTO " PARANORMAL EXTENSIONS" OF STRUCTURED PROGRAMMING

Cost, Schedule, And Performance Elements For Comparison of Hydrodynamic Models of Near-Surface Unmanned Underwater Vehicle Operations

DTIC Science & Technology

2017-12-01

2-89) Prescribed by ANSI Std. 239-18 ii THIS PAGE INTENTIONALLY LEFT BLANK iii Approved for public release. Distribution is unlimited. COST ...from the scope of this demonstration due to time constraints. Further study of this software would benefit similar cost , schedule, and performance...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA SYSTEMS ENGINEERING CAPSTONE PROJECT REPORT Approved for public release. Distribution

Design and Test of a Transonic Axial Splittered Rotor

DTIC Science & Technology

2015-06-15

AXIAL SPLITTERED ROTOR A new design procedure was developed that uses commercial-off-the-shelf software (MATLAB, SolidWorks, and ANSYS-CFX) for the...geometric rendering and analysis of a transonic axial compressor rotor with splitter blades. Predictive numerical simulations were conducted and...Compressor, Splittered Rotor REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 10. SPONSOR/MONITOR’S ACRONYM(S) ARO 8. PERFORMING

Finite Element Method Applied to Fuse Protection Design

NASA Astrophysics Data System (ADS)

Li, Sen; Song, Zhiquan; Zhang, Ming; Xu, Liuwei; Li, Jinchao; Fu, Peng; Wang, Min; Dong, Lin

2014-03-01

In a poloidal field (PF) converter module, fuse protection is of great importance to ensure the safety of the thyristors. The fuse is pre-selected in a traditional way and then verified by finite element analysis. A 3D physical model is built by ANSYS software to solve the thermal-electric coupled problem of transient process in case of external fault. The result shows that this method is feasible.

Numerical simulation of a flow past a triangular sail-type blade of a wind generator using the ANSYS FLUENT software package

NASA Astrophysics Data System (ADS)

Kusaiynov, K.; Tanasheva, N. K.; Min'kov, L. L.; Nusupbekov, B. R.; Stepanova, Yu. O.; Rozhkova, A. V.

2016-02-01

An air flow past a single triangular sail-type blade of a wind turbine is analyzed by numerical simulation for low velocities of the incoming flow. The results of numerical simulation indicate a monotonic increase in the drag force and the lift force as functions of the incoming flow; empirical dependences of these quantities are obtained.

[Three-dimensional finite element analysis of the upper cervical-defected incisor with labial access or lingual access].

PubMed

Su, Fan; Zhao, Ying; Su, Qin

2013-08-01

To evaluate the stress distribution of the cervical-defected incisor with labial or lingual endodontic access with finite element analysis (FEA), and to explore the advantage of resistance in labial endodontic access. 3-D finite element models of upper cervical-defected incisor were established using cone-beam CT (CBCT), Mimics Catia, and Ansys software. The subjects were categorized according to the two endodontic accesses and three restorative ways, which were composite resin, glass fiber-reinforced composite resin and glass fiber-reinforced post-crown. All the models were loaded.The von Mises stress values and distribution were recorded and analyzed with Ansys 10.0 software. In this study, direct composite resin restoration showed no significant difference between the labial and lingual access. In glass fiber-reinforced composite resin, labial access could transfer the stress concentration area. It could reduce the incidence of fracture of the cervical lesion but increase the incidence of root fracture. Post-crown restoration could obviously reduce the incidence of fracture of the cervical lesion. When the cervical-defected incisor is restored with composite resin, labial and lingual accesses can be considered. Labial access with glass fiber-reinforced composite resin or post-crown restoration is a good choice.

Application of CFX-10 to the Investigation of RPV Coolant Mixing in VVER Reactors

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

Moretti, Fabio; Melideo, Daniele; Terzuoli, Fulvio

2006-07-01

Coolant mixing phenomena occurring in the pressure vessel of a nuclear reactor constitute one of the main objectives of investigation by researchers concerned with nuclear reactor safety. For instance, mixing plays a relevant role in reactivity-induced accidents initiated by de-boration or boron dilution events, followed by transport of a de-borated slug into the vessel of a pressurized water reactor. Another example is constituted by temperature mixing, which may sensitively affect the consequences of a pressurized thermal shock scenario. Predictive analysis of mixing phenomena is strongly improved by the availability of computational tools able to cope with the inherent three-dimensionality ofmore » such problem, like system codes with three-dimensional capabilities, and Computational Fluid Dynamics (CFD) codes. The present paper deals with numerical analyses of coolant mixing in the reactor pressure vessel of a VVER-1000 reactor, performed by the ANSYS CFX-10 CFD code. In particular, the 'swirl' effect that has been observed to take place in the downcomer of such kind of reactor has been addressed, with the aim of assessing the capability of the codes to predict that effect, and to understand the reasons for its occurrence. Results have been compared against experimental data from V1000CT-2 Benchmark. Moreover, a boron mixing problem has been investigated, in the hypothesis that a de-borated slug, transported by natural circulation, enters the vessel. Sensitivity analyses have been conducted on some geometrical features, model parameters and boundary conditions. (authors)« less

CFD study of mixing miscible liquid with high viscosity difference in a stirred tank

NASA Astrophysics Data System (ADS)

Madhania, S.; Cahyani, A. B.; Nurtono, T.; Muharam, Y.; Winardi, S.; Purwanto, W. W.

2018-03-01

The mixing process of miscible liquids with high viscosity difference is crucial role even though the solution mutually dissolved. This paper describes the mixing behaviour of the water-molasses system in a conical-bottomed cylindrical stirred tank (D = 0.28 m and H = 0.395 m) equipped with a side-entry Marine propeller (d = 0.036 m) under the turbulence regime using a three-dimensional and transient CFD-simulation. The objective of this work is to compare the solution strategies was applied in the computational analysis to capture the detail phenomena of mixing two miscible liquid with high viscosity difference. Four solution strategies that have been used are the RANS Standards k-ε (SKE) model as the turbulence model coupled with the Multiple Reference Frame (MRF) method for impeller motion, the RANS Realizable k-ε (RKE) combine with the MRF, the Large Eddy Simulation (LES) coupled with the Sliding Mesh (SM) method and the LES-MRF combination. The transient calculations were conducted with Ansys Fluent 17.1 version. The mixing behaviour and the propeller characteristic are to be compared and discussed in this work. The simulation results show the differences of flow pattern and the molasses distribution profile for every solution strategy. The variation of the flow pattern which happened in each solution strategy showing an instability of the mixing process in stirred tank. The LES-SM strategy shows the realistic direction of flow than another solution strategies.

Examination of a Thermally Viable Structure for an Unconventional Uni-Leg Mg2Si Thermoelectric Power Generator

NASA Astrophysics Data System (ADS)

Sakamoto, Tatsuya; Iida, Tsutomu; Taguchi, Yutaka; Kurosaki, Shota; Hayatsu, Yusuke; Nishio, Keishi; Kogo, Yasuo; Takanashi, Yoshifumi

2012-06-01

We have fabricated an unconventional uni-leg structure thermoelectric generator (TEG) element using quad thermoelectric (TE) chips of Sb-doped n-Mg2Si, which were prepared by a plasma-activated sintering process. The power curve characteristics, the effect of aging up to 500 h, and the thermal gradients at several points on the module were investigated. The observed maximum output power with the heat source at 975 K and the heat sink at 345 K was 341 mW, from which the Δ T for the TE chip was calculated to be about 333 K. In aging testing in air ambient, a remarkable feature of the results was that there was no notable change from the initial resistance of the TEG module for as long as 500 h. The thermal distribution for the fabricated uni-leg TEG element was analyzed by finite-element modeling using ANSYS software. To tune the calculation parameters of ANSYS, such as the thermal conductance properties of the corresponding coupled materials in the module, precise measurements of the temperature at various probe points on the module were made. Then, meticulous verification between the measured temperature values and the results calculated by ANSYS was carried out to optimize the parameters.

Optimizing Performance of Scientific Visualization Software to Support Frontier-Class Computations

DTIC Science & Technology

2015-08-01

Hypersonic Sciences Branch) for providing sample datasets and permission to use an image of Q_Criterion isosurface for this report; Dr Anders Grimsrud...10.1. EnSight CSM and CFD Post processing; c2014 [accessed 2015 July 6] http:// www.ceisoftware.com. Main Page. XDMF; 2014 Nov 7 [2015 July 6] http

Designing and Implementing an OVERFLOW Reader for ParaView and Comparing Performance Between Central Processing Units and Graphical Processing Units

NASA Technical Reports Server (NTRS)

Chawner, David M.; Gomez, Ray J.

2010-01-01

In the Applied Aerosciences and CFD branch at Johnson Space Center, computational simulations are run that face many challenges. Two of which are the ability to customize software for specialized needs and the need to run simulations as fast as possible. There are many different tools that are used for running these simulations and each one has its own pros and cons. Once these simulations are run, there needs to be software capable of visualizing the results in an appealing manner. Some of this software is called open source, meaning that anyone can edit the source code to make modifications and distribute it to all other users in a future release. This is very useful, especially in this branch where many different tools are being used. File readers can be written to load any file format into a program, to ease the bridging from one tool to another. Programming such a reader requires knowledge of the file format that is being read as well as the equations necessary to obtain the derived values after loading. When running these CFD simulations, extremely large files are being loaded and having values being calculated. These simulations usually take a few hours to complete, even on the fastest machines. Graphics processing units (GPUs) are usually used to load the graphics for computers; however, in recent years, GPUs are being used for more generic applications because of the speed of these processors. Applications run on GPUs have been known to run up to forty times faster than they would on normal central processing units (CPUs). If these CFD programs are extended to run on GPUs, the amount of time they would require to complete would be much less. This would allow more simulations to be run in the same amount of time and possibly perform more complex computations.

Software engineering and automatic continuous verification of scientific software

NASA Astrophysics Data System (ADS)

Piggott, M. D.; Hill, J.; Farrell, P. E.; Kramer, S. C.; Wilson, C. R.; Ham, D.; Gorman, G. J.; Bond, T.

2011-12-01

Software engineering of scientific code is challenging for a number of reasons including pressure to publish and a lack of awareness of the pitfalls of software engineering by scientists. The Applied Modelling and Computation Group at Imperial College is a diverse group of researchers that employ best practice software engineering methods whilst developing open source scientific software. Our main code is Fluidity - a multi-purpose computational fluid dynamics (CFD) code that can be used for a wide range of scientific applications from earth-scale mantle convection, through basin-scale ocean dynamics, to laboratory-scale classic CFD problems, and is coupled to a number of other codes including nuclear radiation and solid modelling. Our software development infrastructure consists of a number of free tools that could be employed by any group that develops scientific code and has been developed over a number of years with many lessons learnt. A single code base is developed by over 30 people for which we use bazaar for revision control, making good use of the strong branching and merging capabilities. Using features of Canonical's Launchpad platform, such as code review, blueprints for designing features and bug reporting gives the group, partners and other Fluidity uers an easy-to-use platform to collaborate and allows the induction of new members of the group into an environment where software development forms a central part of their work. The code repositoriy are coupled to an automated test and verification system which performs over 20,000 tests, including unit tests, short regression tests, code verification and large parallel tests. Included in these tests are build tests on HPC systems, including local and UK National HPC services. The testing of code in this manner leads to a continuous verification process; not a discrete event performed once development has ceased. Much of the code verification is done via the "gold standard" of comparisons to analytical solutions via the method of manufactured solutions. By developing and verifying code in tandem we avoid a number of pitfalls in scientific software development and advocate similar procedures for other scientific code applications.

An Analysis of SE and MBSE Concepts to Support Defence Capability Acquisition

DTIC Science & Technology

2014-09-01

Government Department of Finance and Deregulation, Canberra, ACT, August 2011. [online] URL: http://agimo.gov.au/files/2012/04/AGA_RM_v3_0.pdf ANSI...First Time, White Paper, Aberdeen Group Group, August 2011. [online] URL: http://www.aberdeen.com/Aberdeen- Library/7121/RA-system-design...Edge e-zine, IBM Software Group, August 2003. Cantor 2003b Cantor, Murray, Rational Unified Process for Systems Engineering Part I1: System

Analysis of seismic stability of large-sized tank VST-20000 with software package ANSYS

NASA Astrophysics Data System (ADS)

Tarasenko, A. A.; Chepur, P. V.; Gruchenkova, A. A.

2018-05-01

The work is devoted to the study of seismic stability of vertical steel tank VST-20000 with due consideration of the system response “foundation-tank-liquid”, conducted on the basis of the finite element method, modal analysis and linear spectral theory. The calculations are performed for the tank model with a high degree of detailing of metallic structures: shells, a fixed roof, a bottom, a reinforcing ring.

Simulating Effects of High Angle of Attack on Turbofan Engine Performance

NASA Technical Reports Server (NTRS)

Liu, Yuan; Claus, Russell W.; Litt, Jonathan S.; Guo, Ten-Huei

2013-01-01

A method of investigating the effects of high angle of attack (AOA) flight on turbofan engine performance is presented. The methodology involves combining a suite of diverse simulation tools. Three-dimensional, steady-state computational fluid dynamics (CFD) software is used to model the change in performance of a commercial aircraft-type inlet and fan geometry due to various levels of AOA. Parallel compressor theory is then applied to assimilate the CFD data with a zero-dimensional, nonlinear, dynamic turbofan engine model. The combined model shows that high AOA operation degrades fan performance and, thus, negatively impacts compressor stability margins and engine thrust. In addition, the engine response to high AOA conditions is shown to be highly dependent upon the type of control system employed.

Two-dimensional CFD modeling of the heat and mass transfer process during sewage sludge drying in a solar dryer

NASA Astrophysics Data System (ADS)

Krawczyk, Piotr; Badyda, Krzysztof

2011-12-01

The paper presents key assumptions of the mathematical model which describes heat and mass transfer phenomena in a solar sewage drying process, as well as techniques used for solving this model with the Fluent computational fluid dynamics (CFD) software. Special attention was paid to implementation of boundary conditions on the sludge surface, which is a physical boundary between the gaseous phase - air, and solid phase - dried matter. Those conditions allow to model heat and mass transfer between the media during first and second drying stages. Selection of the computational geometry is also discussed - it is a fragment of the entire drying facility. Selected modelling results are presented in the final part of the paper.

Enforcing elemental mass and energy balances for reduced order models

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

Ma, J.; Agarwal, K.; Sharma, P.

2012-01-01

Development of economically feasible gasification and carbon capture, utilization and storage (CCUS) technologies requires a variety of software tools to optimize the designs of not only the key devices involved (e., g., gasifier, CO{sub 2} adsorber) but also the entire power generation system. High-fidelity models such as Computational Fluid Dynamics (CFD) models are capable of accurately simulating the detailed flow dynamics, heat transfer, and chemistry inside the key devices. However, the integration of CFD models within steady-state process simulators, and subsequent optimization of the integrated system, still presents significant challenges due to the scale differences in both time and length,more » as well the high computational cost. A reduced order model (ROM) generated from a high-fidelity model can serve as a bridge between the models of different scales. While high-fidelity models are built upon the principles of mass, momentum, and energy conservations, ROMs are usually developed based on regression-type equations and hence their predictions may violate the mass and energy conservation laws. A high-fidelity model may also have the mass and energy balance problem if it is not tightly converged. Conservations of mass and energy are important when a ROM is integrated to a flowsheet for the process simulation of the entire chemical or power generation system, especially when recycle streams are connected to the modeled device. As a part of the Carbon Capture Simulation Initiative (CCSI) project supported by the U.S. Department of Energy, we developed a software framework for generating ROMs from CFD simulations and integrating them with Process Modeling Environments (PMEs) for system-wide optimization. This paper presents a method to correct the results of a high-fidelity model or a ROM such that the elemental mass and energy are conserved perfectly. Correction factors for the flow rates of individual species in the product streams are solved using a minimization algorithm based on Lagrangian multiplier method. Enthalpies of product streams are also modified to enforce the energy balance. The approach is illustrated for two ROMs, one based on a CFD model of an entrained-flow gasifier and the other based on the CFD model of a multiphase CO{sub 2} adsorber.« less

Automation of the CFD Process on Distributed Computing Systems

NASA Technical Reports Server (NTRS)

Tejnil, Ed; Gee, Ken; Rizk, Yehia M.

2000-01-01

A script system was developed to automate and streamline portions of the CFD process. The system was designed to facilitate the use of CFD flow solvers on supercomputer and workstation platforms within a parametric design event. Integrating solver pre- and postprocessing phases, the fully automated ADTT script system marshalled the required input data, submitted the jobs to available computational resources, and processed the resulting output data. A number of codes were incorporated into the script system, which itself was part of a larger integrated design environment software package. The IDE and scripts were used in a design event involving a wind tunnel test. This experience highlighted the need for efficient data and resource management in all parts of the CFD process. To facilitate the use of CFD methods to perform parametric design studies, the script system was developed using UNIX shell and Perl languages. The goal of the work was to minimize the user interaction required to generate the data necessary to fill a parametric design space. The scripts wrote out the required input files for the user-specified flow solver, transferred all necessary input files to the computational resource, submitted and tracked the jobs using the resource queuing structure, and retrieved and post-processed the resulting dataset. For computational resources that did not run queueing software, the script system established its own simple first-in-first-out queueing structure to manage the workload. A variety of flow solvers were incorporated in the script system, including INS2D, PMARC, TIGER and GASP. Adapting the script system to a new flow solver was made easier through the use of object-oriented programming methods. The script system was incorporated into an ADTT integrated design environment and evaluated as part of a wind tunnel experiment. The system successfully generated the data required to fill the desired parametric design space. This stressed the computational resources required to compute and store the information. The scripts were continually modified to improve the utilization of the computational resources and reduce the likelihood of data loss due to failures. An ad-hoc file server was created to manage the large amount of data being generated as part of the design event. Files were stored and retrieved as needed to create new jobs and analyze the results. Additional information is contained in the original.

Design Tool

NASA Technical Reports Server (NTRS)

1993-01-01

Developed under a Small Business Innovation Research (SBIR) contract, RAMPANT is a CFD software package for computing flow around complex shapes. The package is flexible, fast and easy to use. It has found a great number of applications, including computation of air flow around a Nordic ski jumper, prediction of flow over an airfoil and computation of the external aerodynamics of motor vehicles.

CASL VMA Milestone Report FY16 (L3:VMA.VUQ.P13.08): Westinghouse Mixing with STAR-CCM+

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

Gilkey, Lindsay Noelle

2016-09-30

STAR-CCM+ (STAR) is a high-resolution computational fluid dynamics (CFD) code developed by CD-adapco. STAR includes validated physics models and a full suite of turbulence models including ones from the k-ε and k-ω families. STAR is currently being developed to be able to do two phase flows, but the current focus of the software is single phase flow. STAR can use imported meshes or use the built in meshing software to create computation domains for CFD. Since the solvers generally require a fine mesh for good computational results, the meshes used with STAR tend to number in the millions of cells,more » with that number growing with simulation and geometry complexity. The time required to model the flow of a full 5x5 Mixing Vane Grid Assembly (5x5MVG) in the current STAR configuration is on the order of hours, and can be very computationally expensive. COBRA-TF (CTF) is a low-resolution subchannel code that can be trained using high fidelity data from STAR. CTF does not have turbulence models and instead uses a turbulent mixing coefficient β. With a properly calibrated β, CTF can be used a low-computational cost alternative to expensive full CFD calculations performed with STAR. During the Hi2Lo work with CTF and STAR, STAR-CCM+ will be used to calibrate β and to provide high-resolution results that can be used in the place of and in addition to experimental results to reduce the uncertainty in the CTF results.« less

Evolutionary algorithm based optimization of hydraulic machines utilizing a state-of-the-art block coupled CFD solver and parametric geometry and mesh generation tools

NASA Astrophysics Data System (ADS)

S, Kyriacou; E, Kontoleontos; S, Weissenberger; L, Mangani; E, Casartelli; I, Skouteropoulou; M, Gattringer; A, Gehrer; M, Buchmayr

2014-03-01

An efficient hydraulic optimization procedure, suitable for industrial use, requires an advanced optimization tool (EASY software), a fast solver (block coupled CFD) and a flexible geometry generation tool. EASY optimization software is a PCA-driven metamodel-assisted Evolutionary Algorithm (MAEA (PCA)) that can be used in both single- (SOO) and multiobjective optimization (MOO) problems. In MAEAs, low cost surrogate evaluation models are used to screen out non-promising individuals during the evolution and exclude them from the expensive, problem specific evaluation, here the solution of Navier-Stokes equations. For additional reduction of the optimization CPU cost, the PCA technique is used to identify dependences among the design variables and to exploit them in order to efficiently drive the application of the evolution operators. To further enhance the hydraulic optimization procedure, a very robust and fast Navier-Stokes solver has been developed. This incompressible CFD solver employs a pressure-based block-coupled approach, solving the governing equations simultaneously. This method, apart from being robust and fast, also provides a big gain in terms of computational cost. In order to optimize the geometry of hydraulic machines, an automatic geometry and mesh generation tool is necessary. The geometry generation tool used in this work is entirely based on b-spline curves and surfaces. In what follows, the components of the tool chain are outlined in some detail and the optimization results of hydraulic machine components are shown in order to demonstrate the performance of the presented optimization procedure.

CFD simulation of gas and non-Newtonian fluid two-phase flow in anaerobic digesters.

PubMed

Wu, Binxin

2010-07-01

This paper presents an Eulerian multiphase flow model that characterizes gas mixing in anaerobic digesters. In the model development, liquid manure is assumed to be water or a non-Newtonian fluid that is dependent on total solids (TS) concentration. To establish the appropriate models for different TS levels, twelve turbulence models are evaluated by comparing the frictional pressure drops of gas and non-Newtonian fluid two-phase flow in a horizontal pipe obtained from computational fluid dynamics (CFD) with those from a correlation analysis. The commercial CFD software, Fluent12.0, is employed to simulate the multiphase flow in the digesters. The simulation results in a small-sized digester are validated against the experimental data from literature. Comparison of two gas mixing designs in a medium-sized digester demonstrates that mixing intensity is insensitive to the TS in confined gas mixing, whereas there are significant decreases with increases of TS in unconfined gas mixing. Moreover, comparison of three mixing methods indicates that gas mixing is more efficient than mixing by pumped circulation while it is less efficient than mechanical mixing.

Numerical study of Tallinn storm-water system flooding conditions using CFD simulations of multi-phase flow in a large-scale inverted siphon

NASA Astrophysics Data System (ADS)

Kaur, K.; Laanearu, J.; Annus, I.

2017-10-01

The numerical experiments are carried out for qualitative and quantitative interpretation of a multi-phase flow processes associated with malfunctioning of the Tallinn storm-water system during rain storms. The investigations are focused on the single-line inverted siphon, which is used as under-road connection of pipes of the storm-water system under interest. A multi-phase flow solver of Computational Fluid Dynamics software OpenFOAM is used for simulating the three-phase flow dynamics in the hydraulic system. The CFD simulations are performed with different inflow rates under same initial conditions. The computational results are compared essentially in two cases 1) design flow rate and 2) larger flow rate, for emptying the initially filled inverted siphon from a slurry-fluid. The larger flow-rate situations are under particular interest to detected possible flooding. In this regard, it is anticipated that the CFD solutions provide an important insight to functioning of inverted siphon under a restricted water-flow conditions at simultaneous presence of air and slurry-fluid.

Simulation of Rotary-Wing Near-Wake Vortex Structures Using Navier-Stokes CFD Methods

NASA Technical Reports Server (NTRS)

Kenwright, David; Strawn, Roger; Ahmad, Jasim; Duque, Earl; Warmbrodt, William (Technical Monitor)

1997-01-01

This paper will use high-resolution Navier-Stokes computational fluid dynamics (CFD) simulations to model the near-wake vortex roll-up behind rotor blades. The locations and strengths of the trailing vortices will be determined from newly-developed visualization and analysis software tools applied to the CFD solutions. Computational results for rotor nearwake vortices will be used to study the near-wake vortex roll up for highly-twisted tiltrotor blades. These rotor blades typically have combinations of positive and negative spanwise loading and complex vortex wake interactions. Results of the computational studies will be compared to vortex-lattice wake models that are frequently used in rotorcraft comprehensive codes. Information from these comparisons will be used to improve the rotor wake models in the Tilt-Rotor Acoustic Code (TRAC) portion of NASA's Short Haul Civil Transport program (SHCT). Accurate modeling of the rotor wake is an important part of this program and crucial to the successful design of future civil tiltrotor aircraft. The rotor wake system plays an important role in blade-vortex interaction noise, a major problem for all rotorcraft including tiltrotors.

Cryogenic Pressure Control Modeling for Ellipsoidal Space Tanks in Reduced Gravity

NASA Technical Reports Server (NTRS)

Hedayat, Ali; Lopez, Alfredo; Grayson, Gary D.; Chandler, Frank O.; Hastings, Leon J.

2008-01-01

A computational fluid dynamics (CFD) model is developed to simulate pressure control of an ellipsoidal-shaped liquid hydrogen tank under external heating in low gravity. Pressure control is provided by an axial jet thermodynamic vent system (TVS) centered within the vessel that injects cooler liquid into the tank, mixing the contents and reducing tank pressure. The two-phase cryogenic tank model considers liquid hydrogen in its own vapor with liquid density varying with temperature only and a fully compressible ullage. The axisymmetric model is developed using a custom version of the commercially available FLOW-3D software and simulates low gravity extrapolations of engineering checkout tests performed at Marshall Space Flight Center in 1999 in support of the Solar Thermal Upper Stage Technology Demonstrator (STUSTD) program. Model results illustrate that stable low gravity liquid-gas interfaces are maintained during all phases of the pressure control cycle. Steady and relatively smooth ullage pressurization rates are predicted. This work advances current low gravity CFD modeling capabilities for cryogenic pressure control and aids the development of a low cost CFD-based design process for space hardware.

Free-Flowing Solutions for CFD

NASA Technical Reports Server (NTRS)

2003-01-01

Licensed to over 1,500 customers worldwide, an advanced computational fluid dynamics (CFD) post-processor with a quick learning curve is consistently providing engineering solutions, with just the right balance of visual insight and hard data. FIELDVIEW is the premier product of JMSI, Inc., d.b.a. Intelligent Light, a woman-owned, small business founded in 1994 and located in Lyndhurst, New Jersey. In the early 1990s, Intelligent Light entered into a joint development contract with a research based company to commercialize the post-processing FIELDVIEW code. As Intelligent Light established itself, it purchased the exclusive rights to the code, and structured its business solely around the software technology. As a result, it is enjoying profits and growing at a rate of 25 to 30 percent per year. Advancements made from the earliest commercial launch of FIELDVIEW, all the way up to the recently released versions 8 and 8.2 of the program, have been backed by research collaboration with NASA's Langley Research Center, where some of the world's most progressive work in transient (also known as time-varying) CFD takes place.

Improvement of film cooling effectiveness with a small downstream block body

NASA Astrophysics Data System (ADS)

Khorsi, A.; Guelailia, A.; Hamidou, M. K.

2016-07-01

The aim of this study is to predict the improvement in film cooling performance over a flat plate through a single row of cylindrical holes with different streamwise angles by using the Ansys CFX software package. In order to improve the film cooling effectiveness, a short crescent-shaped block is placed downstream of a cylindrical cooling hole. The numerical results of the cylindrical hole without the downstream short crescent-shaped block are compared with experimental data.

Status of the Body of Knowledge and Curriculum to Advance Systems Engineering (BKCASE (trademark)) Project

DTIC Science & Technology

2011-10-01

Systems engineer- ing knowledge has also been documented through the standards bodies, most notably : • ISO /IEC/IEEE 15288, Systems Engineer- ing...System Life Cycle Processes, 2008 (see [10]). • ANSI/EIA 632, Processes for Engineering a System, (1998) • IEEE 1220, ISO /IEC 26702 Application...tion • United States Defense Acquisition Guidebook, Chapter 4, June 27, 2011 • IEEE/EIA 12207 , Software Life Cycle Processes, 2008 • United

Updated Fatigue-Crack-Growth And Fracture-Mechanics Software

NASA Technical Reports Server (NTRS)

Forman, Royce G.; Shivakumar, Venkataraman; Newman, James C., Jr.

1995-01-01

NASA/FLAGRO 2.0 developed as analytical aid in predicting growth and stability of preexisting flaws and cracks in structural components of aerospace systems. Used for fracture-control analysis of space hardware. Organized into three modules to maximize efficiency in operation. Useful in: (1) crack-instability/crack-growth analysis, (2) processing raw crack-growth data from laboratory tests, and (3) boundary-element analysis to determine stresses and stress-intensity factors. Written in FORTRAN 77 and ANSI C.

Biomechanical Modeling and Measurement of Blast Injury and Hearing Protection Mechanisms

DTIC Science & Technology

2015-10-01

12 software into Workbench V. 15 in CFX/ANSYS; 2) building the geometry of the ear model with ossicular chain and cochlear load in CFX; 3...the ear canal to middle ear. The model consists of the ear canal, TM, middle ear ossicles and suspensory ligaments, middle ear cavity, and cochlear ...the TM, ossicles, and ligaments/muscle tendons with the cochlear load applied on the stapes footplate. 17 Fig. 21. Time-history plots of

Focus on Resiliency: A Process-Oriented Approach to Security

DTIC Science & Technology

2005-11-01

by ANSI Std Z39-18 © 2005 Carnegie Mellon University CSI v1.0 2 Agenda About the SEI Characterizing the problem Security, resiliency, and risk A...2005 Carnegie Mellon University CSI v1.0 5 SEI Technical Programs Product Line Systems Dynamic Systems Software Engineering Process Management...University CSI v1.0 7 What is the problem? Is your organization’s security capability sufficient to identify and manage risks that result from failed

Fluid-solid interaction: benchmarking of an external coupling of ANSYS with CFX for cardiovascular applications.

PubMed

Hose, D R; Lawford, P V; Narracott, A J; Penrose, J M T; Jones, I P

2003-01-01

Fluid-solid interaction is a primary feature of cardiovascular flows. There is increasing interest in the numerical solution of these systems as the extensive computational resource required for such studies becomes available. One form of coupling is an external weak coupling of separate solid and fluid mechanics codes. Information about the stress tensor and displacement vector at the wetted boundary is passed between the codes, and an iterative scheme is employed to move towards convergence of these parameters at each time step. This approach has the attraction that separate codes with the most extensive functionality for each of the separate phases can be selected, which might be important in the context of the complex rheology and contact mechanics that often feature in cardiovascular systems. Penrose and Staples describe a weak coupling of CFX for computational fluid mechanics to ANSYS for solid mechanics, based on a simple Jacobi iteration scheme. It is important to validate the coupled numerical solutions. An extensive analytical study of flow in elastic-walled tubes was carried out by Womersley in the late 1950s. This paper describes the performance of the coupling software for the straight elastic-walled tube, and compares the results with Womersley's analytical solutions. It also presents preliminary results demonstrating the application of the coupled software in the context of a stented vessel.

Stress distribution of endodontically treated teeth with titanium alloy post and carbon fiber post with different alveolar bone height: A three-dimensional finite element analysis.

PubMed

Singh, S Vijay; Bhat, Manohar; Gupta, Saurabh; Sharma, Deepak; Satija, Harsha; Sharma, Sumeet

2015-01-01

A three-dimensional (3D) finite element analysis (FEA) on the stress distribution of endodontically treated teeth with titanium alloy post and carbon fiber post with different alveolar bone height. The 3D model was fabricated using software to represent an endodontically treated mandibular second premolar with post and restored with a full ceramic crown restoration, which was then analyzed using FEA using FEA ANSYS Workbench V13.0 (ANSYS Inc., Canonsburg, Pennsylvania, U.S.A) software. The FEA showed the maximum stresses of 137.43 Mpa in dentin with alveolar bone height of 4 mm when the titanium post was used, 138.48 Mpa when carbon fiber post was used as compared to 105.91 Mpa in the model with alveolar bone height of 2 mm from the cement enamel junction (CEJ) when the titanium post was used and 107.37 Mpa when the carbon fiber post was used. Stress was observed more in alveolar bone height level of 4 mm from CEJ than 2 mm from CEJ. Stresses in the dentin were almost similar when the carbon fiber post was compared to titanium post. However, stresses in the post and the cement were much higher when titanium post was used as compared to carbon fiber post.

Fatigue life calculation of desuperheater for solving pipe cracking issue using finite element method (FEM) software

NASA Astrophysics Data System (ADS)

Kumar, Aravinda; Singh, Jeetendra Kumar; Mohan, K.

2012-06-01

Desuperheater assembly experiences thermal cycling in operation by design. During power plant's start up, load change and shut down, thermal gradient is highest. Desuperheater should be able to handle rapid ramp up or ramp down of temperature in these operations. With "hump style" two nozzle desuperheater, cracks were appearing in the pipe after only few cycles of operation. From the field data, it was clear that desuperheater is not able to handle disproportionate thermal expansion happening in the assembly during temperature ramp up and ramp down in operation and leading to cracks appearing in the piping. Growth of thermal fatigue crack is influenced by several factors including geometry, severity of thermal stress and applied mechanical load. This paper seeks to determine cause of failure of two nozzle "hump style" desuperheater using Finite Element Method (FEM) simulation technique. Thermal stress simulation and fatigue life calculation were performed using commercial FEA software "ANSYS" [from Ansys Inc, USA]. Simulation result showed that very high thermal stress is developing in the region where cracks are seen in the field. From simulation results, it is also clear that variable thermal expansion of two nozzle studs is creating high stress at the water manifold junction. A simple and viable solution is suggested by increasing the length of the manifold which solved the cracking issues in the pipe.

Design and Development of Turbodrill Blade Used in Crystallized Section

PubMed Central

Yu, Wang; Jianyi, Yao; Zhijun, Li

2014-01-01

Turbodrill is a type of hydraulic axial turbomachinery which has a multistage blade consisting of stators and rotors. In this paper, a turbodrill blade that can be applied in crystallized section under high temperature and pressure conditions is developed. On the basis of Euler equations, the law of energy transfer is analyzed and the output characteristics of turbodrill blade are proposed. Moreover, considering the properties of the layer and the bole-hole conditions, the radical size, the geometrical dimension, and the blade profile are optimized. A computational model of a single-stage blade is built on the ANSYS CFD into which the three-dimensional model of turbodrill is input. In light of the distribution law of the pressure and flow field, the functions of the turbodrill blade are improved and optimized. The turbodrill blade optimization model was verified based on laboratory experiments. The results show that the design meets the deep hard rock mineral exploration application and provides good references for further study. PMID:25276857

RANS Simulation (Virtual Blade Model [VBM]) of Single Full Scale DOE RM1 MHK Turbine

DOE Data Explorer

Javaherchi, Teymour; Aliseda, Alberto

2013-04-10

Attached are the .cas and .dat files along with the required User Defined Functions (UDFs) and look-up table of lift and drag coefficients for Reynolds Averaged Navier-Stokes (RANS) simulation of a single full scale DOE RM1 turbine implemented in ANSYS FLUENT CFD-package. In this case study the flow field around and in the wake of the full scale DOE RM1 turbine is simulated using Blade Element Model (a.k.a Virtual Blade Model) by solving RANS equations coupled with k-\\omega 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 Blade Element Theory. This simulation provides an accurate estimate for the performance of device and structure of it's turbulent far wake. Due to the simplifications implemented for modeling the rotating blades in this model, VBM is limited to capture details of the flow field in near wake region of the device.

Multi-point optimization of recirculation flow type casing treatment in centrifugal compressors

NASA Astrophysics Data System (ADS)

Tun, Min Thaw; Sakaguchi, Daisaku

2016-06-01

High-pressure ratio and wide operating range are highly required for a turbocharger in diesel engines. A recirculation flow type casing treatment is effective for flow range enhancement of centrifugal compressors. Two ring grooves on a suction pipe and a shroud casing wall are connected by means of an annular passage and stable recirculation flow is formed at small flow rates from the downstream groove toward the upstream groove through the annular bypass. The shape of baseline recirculation flow type casing is modified and optimized by using a multi-point optimization code with a metamodel assisted evolutionary algorithm embedding a commercial CFD code CFX from ANSYS. The numerical optimization results give the optimized design of casing with improving adiabatic efficiency in wide operating flow rate range. Sensitivity analysis of design parameters as a function of efficiency has been performed. It is found that the optimized casing design provides optimized recirculation flow rate, in which an increment of entropy rise is minimized at grooves and passages of the rotating impeller.

CFD modelling wall heat transfer inside a combustion chamber using ANSYS forte

NASA Astrophysics Data System (ADS)

Plengsa-ard, C.; Kaewbumrung, M.

2018-01-01

A computational model has been performed to analyze a wall heat transfer in a single cylinder, direct injection and four-stroke diesel engine. A direct integration using detailed chemistry CHEMKIN is employed in a combustion model and the Reynolds Averaged Navier Stokes (RANS) turbulence model is used to simulate the flow in the cylinder. To obtain heat flux results, a modified classical variable-density wall heat transfer model is also performed. The model is validated using experimental data from a CUMMINs engine operated with a conventional diesel combustion. One operating engine condition is simulated. Comparisons of simulated in-cylinder pressure and heat release rates with experimental data shows that the model predicts the cylinder pressure and heat release rates reasonably well. The contour plot of instantaneous temperature are presented. Also, the contours of predicted heat flux results are shown. The magnitude of peak heat fluxes as predicted by the wall heat transfer model is in the range of the typical measure values in diesel combustion.

High-temperature thermocline TES combining sensible and latent heat - CFD modeling and experimental validation

NASA Astrophysics Data System (ADS)

Zavattoni, Simone A.; Geissbühler, Lukas; Barbato, Maurizio C.; Zanganeh, Giw; Haselbacher, Andreas; Steinfeld, Aldo

2017-06-01

The concept of combined sensible/latent heat thermal energy storage (TES) has been exploited to mitigate an intrinsic thermocline TES systems drawback of heat transfer fluid outflow temperature reduction during discharging. In this study, the combined sensible/latent TES prototype under investigation is constituted by a packed bed of rocks and a small amount of encapsulated phase change material (AlSi12) as sensible heat and latent heat sections respectively. The thermo-fluid dynamics behavior of the combined TES prototype was analyzed by means of a computational fluid dynamics approach. Due to the small value of the characteristic vessel-to-particles diameter ratio, the effect of radial void-fraction variation, also known as channeling, was accounted for. Both the sensible and the latent heat sections of the storage were modeled as porous media under the assumption of local thermal non-equilibrium (LTNE). The commercial code ANSYS Fluent 15.0 was used to solve the model's constitutive conservation and transport equations obtaining a fairly good agreement with reference experimental measurements.

Multi-canister overpack project -- verification and validation, MCNP 4A

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

Goldmann, L.H.

This supporting document contains the software verification and validation (V and V) package used for Phase 2 design of the Spent Nuclear Fuel Multi-Canister Overpack. V and V packages for both ANSYS and MCNP are included. Description of Verification Run(s): This software requires that it be compiled specifically for the machine it is to be used on. Therefore to facilitate ease in the verification process the software automatically runs 25 sample problems to ensure proper installation and compilation. Once the runs are completed the software checks for verification by performing a file comparison on the new output file and themore » old output file. Any differences between any of the files will cause a verification error. Due to the manner in which the verification is completed a verification error does not necessarily indicate a problem. This indicates that a closer look at the output files is needed to determine the cause of the error.« less

1D-3D coupling for hydraulic system transient simulations

NASA Astrophysics Data System (ADS)

Wang, Chao; Nilsson, Håkan; Yang, Jiandong; Petit, Olivier

2017-01-01

This work describes a coupling between the 1D method of characteristics (MOC) and the 3D finite volume method of computational fluid dynamics (CFD). The coupling method is applied to compressible flow in hydraulic systems. The MOC code is implemented as a set of boundary conditions in the OpenFOAM open source CFD software. The coupling is realized by two linear equations originating from the characteristics equation and the Riemann constant equation, respectively. The coupling method is validated using three simple water hammer cases and several coupling configurations. The accuracy and robustness are investigated with respect to the mesh size ratio across the interface, and 3D flow features close to the interface. The method is finally applied to the transient flow caused by the closing and opening of a knife valve (gate) in a pipe, where the flow is driven by the difference in free surface elevation between two tanks. A small region surrounding the moving gate is resolved by CFD, using a dynamic mesh library, while the rest of the system is modeled by MOC. Minor losses are included in the 1D region, corresponding to the contraction of the flow from the upstream tank into the pipe, a separate stationary flow regulation valve, and a pipe bend. The results are validated with experimental data. A 1D solution is provided for comparison, using the static gate characteristics obtained from steady-state CFD simulations.

Simulation of Grouting Process in Rock Masses Under a Dam Foundation Characterized by a 3D Fracture Network

NASA Astrophysics Data System (ADS)

Deng, Shaohui; Wang, Xiaoling; Yu, Jia; Zhang, Yichi; Liu, Zhen; Zhu, Yushan

2018-06-01

Grouting plays a crucial role in dam safety. Due to the concealment of grouting activities, complexity of fracture distribution in rock masses and rheological properties of cement grout, it is difficult to analyze the effects of grouting. In this paper, a computational fluid dynamics (CFD) simulation approach of dam foundation grouting based on a 3D fracture network model is proposed. In this approach, the 3D fracture network model, which is based on an improved bootstrap sampling method and established by VisualGeo software, can provide a reliable and accurate geometric model for CFD simulation of dam foundation grouting. Based on the model, a CFD simulation is performed, in which the Papanastasiou regularized model is used to express the grout rheological properties, and the volume of fluid technique is utilized to capture the grout fronts. Two sets of tests are performed to verify the effectiveness of the Papanastasiou regularized model. When applying the CFD simulation approach for dam foundation grouting, three technical issues can be solved: (1) collapsing potential of the fracture samples, (2) inconsistencies in the geometric model in actual fractures under complex geological conditions, and (3) inappropriate method of characterizing the rheological properties of cement grout. The applicability of the proposed approach is demonstrated by an illustrative case study—a hydropower station dam foundation in southwestern China.

Next-Generation Lightweight Mirror Modeling Software

NASA Technical Reports Server (NTRS)

Arnold, William R., Sr.; Fitzgerald, Mathew; Rosa, Rubin Jaca; Stahl, Phil

2013-01-01

The advances in manufacturing techniques for lightweight mirrors, such as EXELSIS deep core low temperature fusion, Corning's continued improvements in the Frit bonding process and the ability to cast large complex designs, combined with water-jet and conventional diamond machining of glasses and ceramics has created the need for more efficient means of generating finite element models of these structures. Traditional methods of assembling 400,000 + element models can take weeks of effort, severely limiting the range of possible optimization variables. This paper will introduce model generation software developed under NASA sponsorship for the design of both terrestrial and space based mirrors. The software deals with any current mirror manufacturing technique, single substrates, multiple arrays of substrates, as well as the ability to merge submodels into a single large model. The modeler generates both mirror and suspension system elements, suspensions can be created either for each individual petal or the whole mirror. A typical model generation of 250,000 nodes and 450,000 elements only takes 5-10 minutes, much of that time being variable input time. The program can create input decks for ANSYS, ABAQUS and NASTRAN. An archive/retrieval system permits creation of complete trade studies, varying cell size, depth, and petal size, suspension geometry with the ability to recall a particular set of parameters and make small or large changes with ease. The input decks created by the modeler are text files which can be modified by any editor, all the key shell thickness parameters are accessible and comments in deck identify which groups of elements are associated with these parameters. This again makes optimization easier. With ANSYS decks, the nodes representing support attachments are grouped into components; in ABAQUS these are SETS and in NASTRAN as GRIDPOINT SETS, this make integration of these models into large telescope or satellite models possible

Next Generation Lightweight Mirror Modeling Software

NASA Technical Reports Server (NTRS)

Arnold, William; Fitzgerald, Matthew; Stahl, Philip

2013-01-01

The advances in manufacturing techniques for lightweight mirrors, such as EXELSIS deep core low temperature fusion, Corning's continued improvements in the Frit bonding process and the ability to cast large complex designs, combined with water-jet and conventional diamond machining of glasses and ceramics has created the need for more efficient means of generating finite element models of these structures. Traditional methods of assembling 400,000 + element models can take weeks of effort, severely limiting the range of possible optimization variables. This paper will introduce model generation software developed under NASA sponsorship for the design of both terrestrial and space based mirrors. The software deals with any current mirror manufacturing technique, single substrates, multiple arrays of substrates, as well as the ability to merge submodels into a single large model. The modeler generates both mirror and suspension system elements, suspensions can be created either for each individual petal or the whole mirror. A typical model generation of 250,000 nodes and 450,000 elements only takes 5-10 minutes, much of that time being variable input time. The program can create input decks for ANSYS, ABAQUS and NASTRAN. An archive/retrieval system permits creation of complete trade studies, varying cell size, depth, and petal size, suspension geometry with the ability to recall a particular set of parameters and make small or large changes with ease. The input decks created by the modeler are text files which can be modified by any editor, all the key shell thickness parameters are accessible and comments in deck identify which groups of elements are associated with these parameters. This again makes optimization easier. With ANSYS decks, the nodes representing support attachments are grouped into components; in ABAQUS these are SETS and in NASTRAN as GRIDPOINT SETS, this make integration of these models into large telescope or satellite models possible.

Next Generation Lightweight Mirror Modeling Software

NASA Technical Reports Server (NTRS)

Arnold, William R., Sr.; Fitzgerald, Mathew; Rosa, Rubin Jaca; Stahl, H. Philip

2013-01-01

The advances in manufacturing techniques for lightweight mirrors, such as EXELSIS deep core low temperature fusion, Corning's continued improvements in the Frit bonding process and the ability to cast large complex designs, combined with water-jet and conventional diamond machining of glasses and ceramics has created the need for more efficient means of generating finite element models of these structures. Traditional methods of assembling 400,000 + element models can take weeks of effort, severely limiting the range of possible optimization variables. This paper will introduce model generation software developed under NASA sponsorship for the design of both terrestrial and space based mirrors. The software deals with any current mirror manufacturing technique, single substrates, multiple arrays of substrates, as well as the ability to merge submodels into a single large model. The modeler generates both mirror and suspension system elements, suspensions can be created either for each individual petal or the whole mirror. A typical model generation of 250,000 nodes and 450,000 elements only takes 5-10 minutes, much of that time being variable input time. The program can create input decks for ANSYS, ABAQUS and NASTRAN. An archive/retrieval system permits creation of complete trade studies, varying cell size, depth, and petal size, suspension geometry with the ability to recall a particular set of parameters and make small or large changes with ease. The input decks created by the modeler are text files which can be modified by any editor, all the key shell thickness parameters are accessible and comments in deck identify which groups of elements are associated with these parameters. This again makes optimization easier. With ANSYS decks, the nodes representing support attachments are grouped into components; in ABAQUS these are SETS and in NASTRAN as GRIDPOINT SETS, this make integration of these models into large telescope or satellite models easier.

Increase of Gas-Turbine Plant Efficiency by Optimizing Operation of Compressors

NASA Astrophysics Data System (ADS)

Matveev, V.; Goriachkin, E.; Volkov, A.

2018-01-01

The article presents optimization method for improving of the working process of axial compressors of gas turbine engines. Developed method allows to perform search for the best geometry of compressor blades automatically by using optimization software IOSO and CFD software NUMECA Fine/Turbo. The calculation of the compressor parameters was performed for work and stall point of its performance map on each optimization step. Study was carried out for seven-stage high-pressure compressor and three-stage low-pressure compressors. As a result of optimization, improvement of efficiency was achieved for all investigated compressors.

[Mechanism of the dentino-enamel junction on the resist-crack propagation of human teeth by the finite element method].

PubMed

Jingjing, Zheng; Tiezhou, Hou; Hong, Tao; Xueyan, Guo; Cui, Wu

2014-10-01

This study aims to identify the crack tip stress intensity factor of the propagation process, crack propagation path, and the changes in the shape of the crack tip by the finite element method. The finite element model of dentino-enamel junction was established with ANSYS software, and the length of the initial crack in the single edge was set to 0.1 mm. The lower end of the sample was fixed. The tensile load of 1 MPa with frequency of 5 Hz was applied to the upper end. The stress intensity factor, deflection angle, and changes in the shape of the crack tip in the crack propagation were calculated by ANSYS. The stress intensity factor suddenly and continuously decreased in dentino-enamel junction as the crack extended. A large skewed angle appeared, and the stress on crack tip was reduced. The dentino-enamel junction on human teeth may resist crack propagation through stress reduction.

Numerical simulation of temperature at drilling micro-hole on moving CO2 laser irradiated sticking plaster

NASA Astrophysics Data System (ADS)

Rao, Zhiming; He, Zhifang; Du, Jianqiang; Zhang, Xinyou; Ai, Guoping; Zhang, Chunqiang; Wu, Tao

2012-03-01

This paper applied numerical simulation of temperature by using finite element analysis software Ansys to study a model of drilling on sticking plaster. The continuous CO2 laser doing uniform linear motion and doing uniform circular motion irradiated sticking plaster to vaporize. The sticking plaster material was chosen as the thermal conductivity, the heat capacity and the density. For temperatures above 450 °C, sticking plaster would be vaporized. Based on the mathematical model of heat transfer, the process of drilling sticking plaster by laser beams could be simulated by Ansys. The simulation results showed the distribution of the temperature at the surface of the sticking plaster with the time of vaporizing at CO2 laser to do uniform linear motion and to do uniform circular motion. The temperature of sticking plaster CO2 laser to do uniform linear motion was higher than CO2 laser to do uniform circular motion in the same condition.

Design and Simulation of an Electrothermal Actuator Based Rotational Drive

NASA Astrophysics Data System (ADS)

Beeson, Sterling; Dallas, Tim

2008-10-01

As a participant in the Micro and Nano Device Engineering (MANDE) Research Experience for Undergraduates program at Texas Tech University, I learned how MEMS devices operate and the limits of their operation. Using specialized AutoCAD-based design software and the ANSYS simulation program, I learned the MEMS fabrication process used at Sandia National Labs, the design limitations of this process, the abilities and drawbacks of micro devices, and finally, I redesigned a MEMS device called the Chevron Torsional Ratcheting Actuator (CTRA). Motion is achieved through electrothermal actuation. The chevron (bent-beam) actuators cause a ratcheting motion on top of a hub-less gear so that as voltage is applied the CTRA spins. The voltage applied needs to be pulsed and the frequency of the pulses determine the angular frequency of the device. The main objective was to design electromechanical structures capable of transforming the electrical signals into mechanical motion without overheating. The design was optimized using finite element analysis in ANSYS allowing multi-physics simulations of our model system.

Simulation study of air and water cooled photovoltaic panel using ANSYS

NASA Astrophysics Data System (ADS)

Syafiqah, Z.; Amin, N. A. M.; Irwan, Y. M.; Majid, M. S. A.; Aziz, N. A.

2017-10-01

Demand for alternative energy is growing due to decrease of fossil fuels sources. One of the promising and popular renewable energy technology is a photovoltaic (PV) technology. During the actual operation of PV cells, only around 15% of solar irradiance is converted to electricity, while the rest is converted into heat. The electrical efficiency decreases with the increment in PV panel’s temperature. This electrical energy is referring to the open-circuit voltage (Voc), short-circuit current (Isc) and output power generate. This paper examines and discusses the PV panel with water and air cooling system. The air cooling system was installed at the back of PV panel while water cooling system at front surface. The analyses of both cooling systems were done by using ANSYS CFX and PSPICE software. The highest temperature of PV panel without cooling system is 66.3 °C. There is a decrement of 19.2% and 53.2% in temperature with the air and water cooling system applied to PV panel.

Observation of the wing deformation and the CFD study of cicada

NASA Astrophysics Data System (ADS)

Dai, Hu; Mohd Adam Das, Shahrizan; Luo, Haoxiang

2011-11-01

We studied the wing properties and kinematics of cicada when the 13-year species emerged in amazingly large numbers in middle Tennessee during May 2011. Using a high-speed camera, we recorded the wing motion of the insect and then reconstructed the three-dimensional wing kinematics using a video digitization software. Like many other insects, the deformation of the cicada wing is asymmetric between the downstroke and upstroke half cycles, and this particular deformation pattern would benefit production of the lift and propulsive forces. Both two-dimensional and three-dimensional CFD studies are carried out based on the reconstructed wing motion. The implication of the study on the role of the aerodynamic force in the wing deformation will be discussed. This work is sponsored by the NSF.

Stability Analysis of a mortar cover ejected at various Mach numbers and angles of attack

NASA Astrophysics Data System (ADS)

Schwab, Jane; Carnasciali, Maria-Isabel; Andrejczyk, Joe; Kandis, Mike

2011-11-01

This study utilized CFD software to predict the aerodynamic coefficient of a wedge-shaped mortar cover which is ejected from a spacecraft upon deployment of its Parachute Recovery System (PRS). Concern over recontact or collision between the mortar cover and spacecraft served as the impetus for this study in which drag and moment coefficients were determined at Mach numbers from 0.3 to 1.6 at 30-degree increments. These CFD predictions were then used as inputs to a two-dimensional, multi-body, three-DoF trajectory model to calculate the relative motion of the mortar cover and spacecraft. Based upon those simulations, the study concluded a minimal/zero risk of collision with either the spacecraft or PRS. Sponsored by Pioneer Aerospace.

CFD Modeling of Boron Removal from Liquid Silicon with Cold Gases and Plasma

NASA Astrophysics Data System (ADS)

Vadon, Mathieu; Sortland, Øyvind; Nuta, Ioana; Chatillon, Christian; Tansgtad, Merete; Chichignoud, Guy; Delannoy, Yves

2018-03-01

The present study focuses on a specific step of the metallurgical path of purification to provide solar-grade silicon: the removal of boron through the injection of H2O(g)-H2(g)-Ar(g) (cold gas process) or of Ar-H2-O2 plasma (plasma process) on stirred liquid silicon. We propose a way to predict silicon and boron flows from the liquid silicon surface by using a CFD model (©Ansys Fluent) combined with some results on one-dimensional diffusive-reactive models to consider the formation of silica aerosols in a layer above the liquid silicon. The comparison of the model with experimental results on cold gas processes provided satisfying results for cases with low and high concentrations of oxidants. This confirms that the choices of thermodynamic data of HBO(g) and the activity coefficient of boron in liquid silicon are suitable and that the hypotheses regarding similar diffusion mechanisms at the surface for HBO(g) and SiO(g) are appropriate. The reasons for similar diffusion mechanisms need further enquiry. We also studied the effect of pressure and geometric variations in the cold gas process. For some cases with high injection flows, the model slightly overestimates the boron extraction rate, and the overestimation increases with increasing injection flow. A single plasma experiment from SIMaP (France) was modeled, and the model results fit the experimental data on purification if we suppose that aerosols form, but it is not enough to draw conclusions about the formation of aerosols for plasma experiments.

Computational fluid dynamic (CFD) analysis on ALUDRA SR-10 UAV with parachute recovery system

NASA Astrophysics Data System (ADS)

Saim, R.; Mohd, S.; Shamsudin, S. S.; Zulkifli, M. F.; Omar, Z.; Subari@Rahmat, Z.; Masrom, M. F. Mohd; Zaki, Y.

2017-09-01

In an operation, belly landing is mostly applied as recovery method especially on research Unmanned Aerial Vehicle (UAV) such as Aludra SR-10. This type of landing method may encounter tough landing on hard soil and gravel which create high impact load on the aircraft. The impact may cause structural or system damage which costly to be repaired. Nowadays, Parachute Recovery System (PRS) recently used in numerous different tasks such as landing purpose to replace belly landing technique. Parachute use in this system to slow down flying or falling UAV to a safe landing by opening the canopy to increase aerodynamic drag. This paper was described the Computational Fluid Dynamic (CFD) analysis on ALUDRA SR-10 model with two different conditions i.e. the UAV equipped with and without parachute in order to identify the changes of aerodynamic characteristics. This simulation studies using solid models of aircraft and hemisphere parachute and was carried out by using ANSYS 16.0 Fluent under steady and turbulent flow and was modelled using the k-epsilon (k-ε) turbulence model. This simulation was limited to determine the drag force and drag coefficient. The obtained result showed that implementation of parachute increase 0.25 drag coefficient of the aircraft that is from 0.93 to 1.18. Subsequent to the reduction of descent rate caused by the parachute, the drag force of the aircraft increase by 0.76N. These increasing of drag force of the aircraft will produce lower terminal velocity which is expected to reduce the impact force on the aircraft during landing.

CFD Modeling of Boron Removal from Liquid Silicon with Cold Gases and Plasma

NASA Astrophysics Data System (ADS)

Vadon, Mathieu; Sortland, Øyvind; Nuta, Ioana; Chatillon, Christian; Tansgtad, Merete; Chichignoud, Guy; Delannoy, Yves

2018-06-01

The present study focuses on a specific step of the metallurgical path of purification to provide solar-grade silicon: the removal of boron through the injection of H2O(g)-H2(g)-Ar(g) (cold gas process) or of Ar-H2-O2 plasma (plasma process) on stirred liquid silicon. We propose a way to predict silicon and boron flows from the liquid silicon surface by using a CFD model (©Ansys Fluent) combined with some results on one-dimensional diffusive-reactive models to consider the formation of silica aerosols in a layer above the liquid silicon. The comparison of the model with experimental results on cold gas processes provided satisfying results for cases with low and high concentrations of oxidants. This confirms that the choices of thermodynamic data of HBO(g) and the activity coefficient of boron in liquid silicon are suitable and that the hypotheses regarding similar diffusion mechanisms at the surface for HBO(g) and SiO(g) are appropriate. The reasons for similar diffusion mechanisms need further enquiry. We also studied the effect of pressure and geometric variations in the cold gas process. For some cases with high injection flows, the model slightly overestimates the boron extraction rate, and the overestimation increases with increasing injection flow. A single plasma experiment from SIMaP (France) was modeled, and the model results fit the experimental data on purification if we suppose that aerosols form, but it is not enough to draw conclusions about the formation of aerosols for plasma experiments.

Toward an Efficient Icing CFD Process Using an Interactive Software Toolkit: Smagglce 2D

NASA Technical Reports Server (NTRS)

Vickerman, Mary B.; Choo, Yung K.; Schilling, Herbert W.; Baez, Marivell; Braun, Donald C.; Cotton, Barbara J.

2001-01-01

Two-dimensional CID analysis for iced airfoils can be a labor-intensive task. The software toolkit SmaggIce 2D is being developed to help streamline the CID process and provide the unique features needed for icing. When complete, it will include a combination of partially automated and fully interactive tools for all aspects of the tasks leading up to the flow analysis: geometry preparation, domain decomposition. block boundary demoralization. gridding, and linking with a flow solver. It also includes tools to perform ice shape characterization, an important aid in determining the relationship between ice characteristics and their effects on aerodynamic performance. Completed tools, work-in-progress, and planned features of the software toolkit are presented here.

Smagglce: Surface Modeling and Grid Generation for Iced Airfoils: Phase 1 Results

NASA Technical Reports Server (NTRS)

Vickerman, Mary B.; Choo, Yung K.; Braun, Donald C.; Baez, Marivell; Gnepp, Steven

1999-01-01

SmaggIce (Surface Modeling and Grid Generation for Iced Airfoils) is a software toolkit used in the process of aerodynamic performance prediction of iced airfoils with grid-based Computational Fluid Dynamics (CFD). It includes tools for data probing, boundary smoothing, domain decomposition, and structured grid generation and refinement. SmaggIce provides the underlying computations to perform these functions, a GUI (Graphical User Interface) to control and interact with those functions, and graphical displays of results, it is being developed at NASA Glenn Research Center. This paper discusses the overall design of SmaggIce as well as what has been implemented in Phase 1. Phase 1 results provide two types of software tools: interactive ice shape probing and interactive ice shape control. The ice shape probing tools will provide aircraft icing engineers and scientists with an interactive means to measure the physical characteristics of ice shapes. On the other hand, the ice shape control features of SmaggIce will allow engineers to examine input geometry data, correct or modify any deficiencies in the geometry, and perform controlled systematic smoothing to a level that will make the CFD process manageable.

Comparison of Computational and Experimental Results for a Transonic Variable-Speed Power-Turbine Blade Operating with Low Inlet Turbulence Levels

NASA Technical Reports Server (NTRS)

Booth, David; Flegel, Ashlie

2015-01-01

A computational assessment of the aerodynamic performance of the midspan section of a variable-speed power-turbine blade is described. The computation comprises a periodic single blade that represents the 2-D Midspan section VSPT blade that was tested in the NASA Glenn Research Center Transonic Turbine Blade Cascade Facility. A commercial, off-the-shelf (COTS) software package, Pointwise and CFD++, was used for the grid generation and RANS and URANS computations. The CFD code, which offers flexibility in terms of turbulence and transition modeling options, was assessed in terms of blade loading, loss, and turning against test data from the transonic tunnel. Simulations were assessed at positive and negative incidence angles that represent the turbine cruise and take-off design conditions. The results indicate that the secondary flow induced at the positive incidence cruise condition results in a highly loaded case and transitional flow on the blade is observed. The negative incidence take-off condition is unloaded and the flow is very two-dimensional. The computational results demonstrate the predictive capability of the gridding technique and COTS software for a linear transonic turbine blade cascade with large incidence angle variation.

Comparison of Computational and Experimental Results for a Transonic Variable-speed Power-Turbine Blade Operating with Low Inlet Turbulence Levels

NASA Technical Reports Server (NTRS)

Booth, David T.; Flegel, Ashlie B.

2015-01-01

A computational assessment of the aerodynamic performance of the midspan section of a variable-speed power-turbine blade is described. The computation comprises a periodic single blade that represents the 2-D Midspan section VSPT blade that was tested in the NASA Glenn Research Center Transonic Turbine Blade Cascade Facility. A commercial, off-the-shelf (COTS) software package, Pointwise and CFD++, was used for the grid generation and RANS and URANS computations. The CFD code, which offers flexibility in terms of turbulence and transition modeling options, was assessed in terms of blade loading, loss, and turning against test data from the transonic tunnel. Simulations were assessed at positive and negative incidence angles that represent the turbine cruise and take-off design conditions. The results indicate that the secondary flow induced at the positive incidence cruise condition results in a highly loaded case and transitional flow on the blade is observed. The negative incidence take-off condition is unloaded and the flow is very two-dimensional. The computational results demonstrate the predictive capability of the gridding technique and COTS software for a linear transonic turbine blade cascade with large incidence angle variation.

Tracking Debris Shed by a Space-Shuttle Launch Vehicle

NASA Technical Reports Server (NTRS)

Stuart, Phillip C.; Rogers, Stuart E.

2009-01-01

The DEBRIS software predicts the trajectories of debris particles shed by a space-shuttle launch vehicle during ascent, to aid in assessing potential harm to the space-shuttle orbiter and crew. The user specifies the location of release and other initial conditions for a debris particle. DEBRIS tracks the particle within an overset grid system by means of a computational fluid dynamics (CFD) simulation of the local flow field and a ballistic simulation that takes account of the mass of the particle and its aerodynamic properties in the flow field. The computed particle trajectory is stored in a file to be post-processed by other software for viewing and analyzing the trajectory. DEBRIS supplants a prior debris tracking code that took .15 minutes to calculate a single particle trajectory: DEBRIS can calculate 1,000 trajectories in .20 seconds on a desktop computer. Other improvements over the prior code include adaptive time-stepping to ensure accuracy, forcing at least one step per grid cell to ensure resolution of all CFD-resolved flow features, ability to simulate rebound of debris from surfaces, extensive error checking, a builtin suite of test cases, and dynamic allocation of memory.

Visualization in aerospace research with a large wall display system

NASA Astrophysics Data System (ADS)

Matsuo, Yuichi

2002-05-01

National Aerospace Laboratory of Japan has built a large- scale visualization system with a large wall-type display. The system has been operational since April 2001 and comprises a 4.6x1.5-meter (15x5-foot) rear projection screen with 3 BARCO 812 high-resolution CRT projectors. The reason we adopted the 3-gun CRT projectors is support for stereoscopic viewing, ease with color/luminosity matching and accuracy of edge-blending. The system is driven by a new SGI Onyx 3400 server of distributed shared-memory architecture with 32 CPUs, 64Gbytes memory, 1.5TBytes FC RAID disk and 6 IR3 graphics pipelines. Software is another important issue for us to make full use of the system. We have introduced some applications available in a multi- projector environment such as AVS/MPE, EnSight Gold and COVISE, and been developing some software tools that create volumetric images with using SGI graphics libraries. The system is mainly used for visualization fo computational fluid dynamics (CFD) simulation sin aerospace research. Visualized CFD results are of our help for designing an improved configuration of aerospace vehicles and analyzing their aerodynamic performances. These days we also use it for various collaborations among researchers.

Effect of boundary conditions on thermal plume growth

NASA Astrophysics Data System (ADS)

Kondrashov, A.; Sboev, I.; Rybkin, K.

2016-07-01

We have investigated the influence of boundary conditions on the growth rate of convective plumes. Temperature and rate fields were studied in a rectangular convective cell heated by a spot heater. The results of the full-scale test were compared with the numerical data calculated using the ANSYS CFX software package. The relationship between the heat plume growth rate and heat boundary conditions, the width and height of the cell, size of heater for different kinds of liquid was established.

Achieving better cooling of turbine blades using numerical simulation methods

NASA Astrophysics Data System (ADS)

Inozemtsev, A. A.; Tikhonov, A. S.; Sendyurev, C. I.; Samokhvalov, N. Yu.

2013-02-01

A new design of the first-stage nozzle vane for the turbine of a prospective gas-turbine engine is considered. The blade's thermal state is numerically simulated in conjugate statement using the ANSYS CFX 13.0 software package. Critical locations in the blade design are determined from the distribution of heat fluxes, and measures aimed at achieving more efficient cooling are analyzed. Essentially lower (by 50-100°C) maximal temperature of metal has been achieved owing to the results of the performed work.

Research on Characteristics of New Energy Dissipation With Symmetrical Structure

NASA Astrophysics Data System (ADS)

Ming, Wen; Huang, Chun-mei; Huang, Hao-wen; Wang, Xin-fang

2018-03-01

Utilizing good energy consumption capacity of arc steel bar, a new energy dissipation with symmetrical structure was proposed in this article. On the base of collection experimental data of damper specimen Under low cyclic reversed loading, finite element models were built by using ANSYS software, and influences of parameter change (Conduction rod diameter, Actuation plate thickness, Diameter of arc steel rod, Curved bars initial bending) on energy dissipation performance were analyzed. Some useful conclusions which can lay foundations for practical application were drawn.

Analysis of Wood Structure Connections Using Cylindrical Steel and Carbon Fiber Dowel Pins

NASA Astrophysics Data System (ADS)

Vodiannikov, Mikhail A.; Kashevarova, Galina G., Dr.

2017-06-01

In this paper, the results of the statistical analysis of corrosion processes and moisture saturation of glued laminated timber structures and their joints in corrosive environment are shown. This paper includes calculation results for dowel connections of wood structures using steel and carbon fiber reinforced plastic cylindrical dowel pins in accordance with applicable regulatory documents by means of finite element analysis in ANSYS software, as well as experimental findings. Dependence diagrams are shown; comparative analysis of the results obtained is conducted.

Automated Seat Cushion for Pressure Ulcer Prevention Using Real-Time Mapping, Offloading, and Redistribution of Interface Pressure

DTIC Science & Technology

2016-10-01

testing as well as finite element simulation. Automation and control testing has been completed on a 5x5 array of bubble actuators to verify pressure...mechanical behavior at varying loads and internal pressures both by experimental testing as well as finite element simulation. Automation and control...A finite element (FE) model of the bubble actuator was developed in the commercial software ANSYS in order to determine the deformation of the

Electronic Biometric Transmission Specification. Version 1.2

DTIC Science & Technology

2006-11-08

Prescribed by ANSI Std Z39-18 Electronic Biometric Transmission Specification DIN: DOD_BTF_TS_EBTS_ Nov06_01.02.00 i Revision History Revision...contains: • the ORI • a Greenwich Mean (a.k.a. Zulu or UTC) date/time stamp • a code for the software used at the point of collection/transmission...long names and would generally include the tribe name. Subfield 1 Item 1 Character Type AS Characters 1 to 50 Special Characters: Any 7-bit non

Neural-Network-Development Program

NASA Technical Reports Server (NTRS)

Phillips, Todd A.

1993-01-01

NETS, software tool for development and evaluation of neural networks, provides simulation of neural-network algorithms plus computing environment for development of such algorithms. Uses back-propagation learning method for all of networks it creates. Enables user to customize patterns of connections between layers of network. Also provides features for saving, during learning process, values of weights, providing more-precise control over learning process. Written in ANSI standard C language. Machine-independent version (MSC-21588) includes only code for command-line-interface version of NETS 3.0.

Fatigue analysis of assembled marine floating platform for special purposes under complex water environments

NASA Astrophysics Data System (ADS)

Ma, Guang-ying; Yao, Yun-long

2018-03-01

In this paper, the fatigue lives of a new type of assembled marine floating platform for special purposes were studied. Firstly, by using ANSYS AQWA software, the hydrodynamic model of the platform was established. Secondly, the structural stresses under alternating change loads were calculated under complex water environments, such as wind, wave, current and ice. The minimum fatigue lives were obtained under different working conditions. The analysis results showed that the fatigue life of the platform structure can meet the requirements

Improvement of calculation method for electrical parameters of short network of ore-thermal furnaces

NASA Astrophysics Data System (ADS)

Aliferov, A. I.; Bikeev, R. A.; Goreva, L. P.

2017-10-01

The paper describes a new calculation method for active and inductive resistance of split interleaved current leads packages in ore-thermal electric furnaces. The method is developed on basis of regression analysis of dependencies of active and inductive resistances of the packages on their geometrical parameters, mutual disposition and interleaving pattern. These multi-parametric calculations have been performed with ANSYS software. The proposed method allows solving split current lead electrical parameters minimization and balancing problems for ore-thermal furnaces.

Automated Euler and Navier-Stokes Database Generation for a Glide-Back Booster

NASA Technical Reports Server (NTRS)

Chaderjian, Neal M.; Rogers, Stuart E.; Aftosmis, Mike J.; Pandya, Shishir A.; Ahmad, Jasim U.; Tejnil, Edward

2004-01-01

The past two decades have seen a sustained increase in the use of high fidelity Computational Fluid Dynamics (CFD) in basic research, aircraft design, and the analysis of post-design issues. As the fidelity of a CFD method increases, the number of cases that can be readily and affordably computed greatly diminishes. However, computer speeds now exceed 2 GHz, hundreds of processors are currently available and more affordable, and advances in parallel CFD algorithms scale more readily with large numbers of processors. All of these factors make it feasible to compute thousands of high fidelity cases. However, there still remains the overwhelming task of monitoring the solution process. This paper presents an approach to automate the CFD solution process. A new software tool, AeroDB, is used to compute thousands of Euler and Navier-Stokes solutions for a 2nd generation glide-back booster in one week. The solution process exploits a common job-submission grid environment, the NASA Information Power Grid (IPG), using 13 computers located at 4 different geographical sites. Process automation and web-based access to a MySql database greatly reduces the user workload, removing much of the tedium and tendency for user input errors. The AeroDB framework is shown. The user submits/deletes jobs, monitors AeroDB's progress, and retrieves data and plots via a web portal. Once a job is in the database, a job launcher uses an IPG resource broker to decide which computers are best suited to run the job. Job/code requirements, the number of CPUs free on a remote system, and queue lengths are some of the parameters the broker takes into account. The Globus software provides secure services for user authentication, remote shell execution, and secure file transfers over an open network. AeroDB automatically decides when a job is completed. Currently, the Cart3D unstructured flow solver is used for the Euler equations, and the Overflow structured overset flow solver is used for the Navier-Stokes equations. Other codes can be readily included into the AeroDB framework.

CAPRI: Using a Geometric Foundation for Computational Analysis and Design

NASA Technical Reports Server (NTRS)

Haimes, Robert

2002-01-01

CAPRI (Computational Analysis Programming Interface) is a software development tool intended to make computerized design, simulation and analysis faster and more efficient. The computational steps traditionally taken for most engineering analysis (Computational Fluid Dynamics (CFD), structural analysis, etc.) are: Surface Generation, usually by employing a Computer Aided Design (CAD) system; Grid Generation, preparing the volume for the simulation; Flow Solver, producing the results at the specified operational point; Post-processing Visualization, interactively attempting to understand the results. It should be noted that the structures problem is more tractable than CFD; there are fewer mesh topologies used and the grids are not as fine (this problem space does not have the length scaling issues of fluids). For CFD, these steps have worked well in the past for simple steady-state simulations at the expense of much user interaction. The data was transmitted between phases via files. In most cases, the output from a CAD system could go IGES files. The output from Grid Generators and Solvers do not really have standards though there are a couple of file formats that can be used for a subset of the gridding (i.e. PLOT3D) data formats and the upcoming CGNS). The user would have to patch up the data or translate from one format to another to move to the next step. Sometimes this could take days. Instead of the serial approach to analysis, CAPRI takes a geometry centric approach. CAPRI is a software building tool-kit that refers to two ideas: (1) A simplified, object-oriented, hierarchical view of a solid part integrating both geometry and topology definitions, and (2) programming access to this part or assembly and any attached data. The connection to the geometry is made through an Application Programming Interface (API) and not a file system.

STAR-CCM+ Verification and Validation Plan

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

Pointer, William David

2016-09-30

The commercial Computational Fluid Dynamics (CFD) code STAR-CCM+ provides general purpose finite volume method solutions for fluid dynamics and energy transport. This document defines plans for verification and validation (V&V) of the base code and models implemented within the code by the Consortium for Advanced Simulation of Light water reactors (CASL). The software quality assurance activities described herein are port of the overall software life cycle defined in the CASL Software Quality Assurance (SQA) Plan [Sieger, 2015]. STAR-CCM+ serves as the principal foundation for development of an advanced predictive multi-phase boiling simulation capability within CASL. The CASL Thermal Hydraulics Methodsmore » (THM) team develops advanced closure models required to describe the subgrid-resolution behavior of secondary fluids or fluid phases in multiphase boiling flows within the Eulerian-Eulerian framework of the code. These include wall heat partitioning models that describe the formation of vapor on the surface and the forces the define bubble/droplet dynamic motion. The CASL models are implemented as user coding or field functions within the general framework of the code. This report defines procedures and requirements for V&V of the multi-phase CFD capability developed by CASL THM. Results of V&V evaluations will be documented in a separate STAR-CCM+ V&V assessment report. This report is expected to be a living document and will be updated as additional validation cases are identified and adopted as part of the CASL THM V&V suite.« less

Facilitating higher-fidelity simulations of axial compressor instability and other turbomachinery flow conditions

NASA Astrophysics Data System (ADS)

Herrick, Gregory Paul

The quest to accurately capture flow phenomena with length-scales both short and long and to accurately represent complex flow phenomena within disparately sized geometry inspires a need for an efficient, high-fidelity, multi-block structured computational fluid dynamics (CFD) parallel computational scheme. This research presents and demonstrates a more efficient computational method by which to perform multi-block structured CFD parallel computational simulations, thus facilitating higher-fidelity solutions of complicated geometries (due to the inclusion of grids for "small'' flow areas which are often merely modeled) and their associated flows. This computational framework offers greater flexibility and user-control in allocating the resource balance between process count and wall-clock computation time. The principal modifications implemented in this revision consist of a "multiple grid block per processing core'' software infrastructure and an analytic computation of viscous flux Jacobians. The development of this scheme is largely motivated by the desire to simulate axial compressor stall inception with more complete gridding of the flow passages (including rotor tip clearance regions) than has been previously done while maintaining high computational efficiency (i.e., minimal consumption of computational resources), and thus this paradigm shall be demonstrated with an examination of instability in a transonic axial compressor. However, the paradigm presented herein facilitates CFD simulation of myriad previously impractical geometries and flows and is not limited to detailed analyses of axial compressor flows. While the simulations presented herein were technically possible under the previous structure of the subject software, they were much less computationally efficient and thus not pragmatically feasible; the previous research using this software to perform three-dimensional, full-annulus, time-accurate, unsteady, full-stage (with sliding-interface) simulations of rotating stall inception in axial compressors utilized tip clearance periodic models, while the scheme here is demonstrated by a simulation of axial compressor stall inception utilizing gridded rotor tip clearance regions. As will be discussed, much previous research---experimental, theoretical, and computational---has suggested that understanding clearance flow behavior is critical to understanding stall inception, and previous computational research efforts which have used tip clearance models have begged the question, "What about the clearance flows?''. This research begins to address that question.

The Development of Duct for a Horizontal Axis Turbine Using CFD

NASA Astrophysics Data System (ADS)

Ghani, Mohamad Pauzi Abdul; Yaacob, Omar; Aziz, Azliza Abdul

2010-06-01

Malaysia is heavily dependent on the fossil fuels to satisfy its energy demand. Nowadays, renewable energy which has attracted great interest is marine current energy, which extracted by a device called a device called marine current turbine. This energy resource has agreat potential to be exploited on a large scale because of its predictability and intensity. This paper will focus on developing a Horizontal Axis Marine Current Turbine (HAMCT) rotor to extract marine current energy suitable for Malaysian sea conditions. This work incorporates the characteristic of Malaysia's ocean of shallow water and low speed current in developing the turbines. The HAMCT rotor will be developed and simulated using CAD and CFD software for various combination of inlet and oulet duct design. The computer simulation results of the HAMCT being developed will be presented.

The application of CFD to the modelling of fires in complex geometries

NASA Astrophysics Data System (ADS)

Burns, A. D.; Clarke, D. S.; Guilbert, P.; Jones, I. P.; Simcox, S.; Wilkes, N. S.

The application of Computational Fluid Dynamics (CFD) to industrial safety is a challenging activity. In particular it involves the interaction of several different physical processes, including turbulence, combustion, radiation, buoyancy, compressible flow and shock waves in complex three-dimensional geometries. In addition, there may be multi-phase effects arising, for example, from sprinkler systems for extinguishing fires. The FLOW3D software (1-3) from Computational Fluid Dynamics Services (CFDS) is in widespread use in industrial safety problems, both within AEA Technology, and also by CFDS's commercial customers, for example references (4-13). This paper discusses some other applications of FLOW3D to safety problems. These applications illustrate the coupling of the gas flows with radiation models and combustion models, particularly for complex geometries where simpler radiation models are not applicable.

Design type air engine Di Pietro

NASA Astrophysics Data System (ADS)

Zwierzchowski, Jaroslaw

The article presents a pneumatic engine constructed by Angelo Di Pietro. 3D solid models of pneumatic engine components were presented therein. A directional valve is a key element of the control system. The valve functions as a camshaft distributing air to particular engine chambers. The construction designed by Angelo Di Pietro is modern and innovative. A pneumatic engine requires low pressure to start rotary movement. With the use of CFD software, the fields of velocity vectors' distribution were determined. Moreover, the author determined the distribution of pressure values in engine inlet and outlet channels. CFD model studies on engine operation were conducted for chosen stages of operating cycles. On the basis of simulation tests that were conducted, the values of flow rates for the engine were determined. The distribution of pressure values made it possible to evaluate the torque value on the rotating shaft.

Analysis of impact of general-purpose graphics processor units in supersonic flow modeling

NASA Astrophysics Data System (ADS)

Emelyanov, V. N.; Karpenko, A. G.; Kozelkov, A. S.; Teterina, I. V.; Volkov, K. N.; Yalozo, A. V.

2017-06-01

Computational methods are widely used in prediction of complex flowfields associated with off-normal situations in aerospace engineering. Modern graphics processing units (GPU) provide architectures and new programming models that enable to harness their large processing power and to design computational fluid dynamics (CFD) simulations at both high performance and low cost. Possibilities of the use of GPUs for the simulation of external and internal flows on unstructured meshes are discussed. The finite volume method is applied to solve three-dimensional unsteady compressible Euler and Navier-Stokes equations on unstructured meshes with high resolution numerical schemes. CUDA technology is used for programming implementation of parallel computational algorithms. Solutions of some benchmark test cases on GPUs are reported, and the results computed are compared with experimental and computational data. Approaches to optimization of the CFD code related to the use of different types of memory are considered. Speedup of solution on GPUs with respect to the solution on central processor unit (CPU) is compared. Performance measurements show that numerical schemes developed achieve 20-50 speedup on GPU hardware compared to CPU reference implementation. The results obtained provide promising perspective for designing a GPU-based software framework for applications in CFD.

Visual analysis of fluid dynamics at NASA's numerical aerodynamic simulation facility

NASA Technical Reports Server (NTRS)

Watson, Velvin R.

1991-01-01

A study aimed at describing and illustrating visualization tools used in Computational Fluid Dynamics (CFD) and indicating how these tools are likely to change by showing a projected resolution of the human computer interface is presented. The following are outlined using a graphically based test format: the revolution of human computer environments for CFD research; comparison of current environments; current environments with the ideal; predictions for the future CFD environments; what can be done to accelerate the improvements. The following comments are given: when acquiring visualization tools, potential rapid changes must be considered; environmental changes over the next ten years due to human computer interface cannot be fathomed; data flow packages such as AVS, apE, Explorer and Data Explorer are easy to learn and use for small problems, excellent for prototyping, but not so efficient for large problems; the approximation techniques used in visualization software must be appropriate for the data; it has become more cost effective to move jobs that fit on workstations and run only memory intensive jobs on the supercomputer; use of three dimensional skills will be maximized when the three dimensional environment is built in from the start.

Cryogenic Pressure Control Modeling for Ellipsoidal Space Tanks

NASA Technical Reports Server (NTRS)

Lopez, Alfredo; Grayson, Gary D.; Chandler, Frank O.; Hastings, Leon J.; Heyadat, Ali

2007-01-01

A computational fluid dynamics (CFD) model is developed to simulate pressure control of an ellipsoidal-shaped liquid hydrogen tank under external heating in normal gravity. Pressure control is provided by an axial jet thermodynamic vent system (TVS) centered within the vessel that injects cooler liquid into the tank, mixing the contents and reducing tank pressure. The two-phase cryogenic tank model considers liquid hydrogen in its own vapor with liquid density varying with temperature only and a fully compressible ullage. The axisymmetric model is developed using a custom version of the commercially available FLOW-31) software. Quantitative model validation is ,provided by engineering checkout tests performed at Marshall Space Flight Center in 1999 in support of the Solar Thermal Upper Stage_ Technology Demonstrator (STUSTD) program. The engineering checkout tests provide cryogenic tank self-pressurization test data at various heat leaks and tank fill levels. The predicted self-pressurization rates, ullage and liquid temperatures at discrete locations within the STUSTD tank are in good agreement with test data. The work presented here advances current CFD modeling capabilities for cryogenic pressure control and helps develop a low cost CFD-based design process for space hardware.

Modeling and validation of heat and mass transfer in individual coffee beans during the coffee roasting process using computational fluid dynamics (CFD).

PubMed

Alonso-Torres, Beatriz; Hernández-Pérez, José Alfredo; Sierra-Espinoza, Fernando; Schenker, Stefan; Yeretzian, Chahan

2013-01-01

Heat and mass transfer in individual coffee beans during roasting were simulated using computational fluid dynamics (CFD). Numerical equations for heat and mass transfer inside the coffee bean were solved using the finite volume technique in the commercial CFD code Fluent; the software was complemented with specific user-defined functions (UDFs). To experimentally validate the numerical model, a single coffee bean was placed in a cylindrical glass tube and roasted by a hot air flow, using the identical geometrical 3D configuration and hot air flow conditions as the ones used for numerical simulations. Temperature and humidity calculations obtained with the model were compared with experimental data. The model predicts the actual process quite accurately and represents a useful approach to monitor the coffee roasting process in real time. It provides valuable information on time-resolved process variables that are otherwise difficult to obtain experimentally, but critical to a better understanding of the coffee roasting process at the individual bean level. This includes variables such as time-resolved 3D profiles of bean temperature and moisture content, and temperature profiles of the roasting air in the vicinity of the coffee bean.

Simulation model of darrieus turbine using software CFD (Computating Fluid Dinamyc) in Bedono Village of Demak district

NASA Astrophysics Data System (ADS)

Margiantono, Agus; Nurhayati, Titik

2018-05-01

One area in Central Java that has the potential to develop a tidal power plant is the village Bedono, of Demak regency. In the area there are places with sea currents accelerating as sea water moves towards the mouth of the river which is then used for this study site with coordinates 6 ° 55'29.0 "S 110 ° 29'11.4" E. In this study, the Darrieus type H type offshore turbine, developed by NACA (National Advisory Committee for Aeronautics), is NACA 0018 which is a special blade for marine turbine applications. Simulation using Computational Fluid Dynamics (CFD) program with the condition of research location such as sea depth, sea water velocity, gravity force and seawater period used as the variable. From the simulation results using CFD obtained the highest sea water flow velocity in Bedono village occurred at 14-16 at 2.5m / sec and the lowest at 22-24 at 0,530m / s. The greatest boost of simulation results was obtained at the highest current velocity of 2.5 m / s from 631,115N and torque was 315,558 Nm.

Numerical Simulations For the F-16XL Aircraft Configuration

NASA Technical Reports Server (NTRS)

Elmiligui, Alaa A.; Abdol-Hamid, Khaled; Cavallo, Peter A.; Parlette, Edward B.

2014-01-01

Numerical simulations of flow around the F-16XL are presented as a contribution to the Cranked Arrow Wing Aerodynamic Project International II (CAWAPI-II). The NASA Tetrahedral Unstructured Software System (TetrUSS) is used to perform numerical simulations. This CFD suite, developed and maintained by NASA Langley Research Center, includes an unstructured grid generation program called VGRID, a postprocessor named POSTGRID, and the flow solver USM3D. The CRISP CFD package is utilized to provide error estimates and grid adaption for verification of USM3D results. A subsonic high angle-of-attack case flight condition (FC) 25 is computed and analyzed. Three turbulence models are used in the calculations: the one-equation Spalart-Allmaras (SA), the two-equation shear stress transport (SST) and the ke turbulence models. Computational results, and surface static pressure profiles are presented and compared with flight data. Solution verification is performed using formal grid refinement studies, the solution of Error Transport Equations, and adaptive mesh refinement. The current study shows that the USM3D solver coupled with CRISP CFD can be used in an engineering environment in predicting vortex-flow physics on a complex configuration at flight Reynolds numbers.

Feasibility of using the Massively Parallel Processor for large eddy simulations and other Computational Fluid Dynamics applications

NASA Technical Reports Server (NTRS)

Bruno, John

1984-01-01

The results of an investigation into the feasibility of using the MPP for direct and large eddy simulations of the Navier-Stokes equations is presented. A major part of this study was devoted to the implementation of two of the standard numerical algorithms for CFD. These implementations were not run on the Massively Parallel Processor (MPP) since the machine delivered to NASA Goddard does not have sufficient capacity. Instead, a detailed implementation plan was designed and from these were derived estimates of the time and space requirements of the algorithms on a suitably configured MPP. In addition, other issues related to the practical implementation of these algorithms on an MPP-like architecture were considered; namely, adaptive grid generation, zonal boundary conditions, the table lookup problem, and the software interface. Performance estimates show that the architectural components of the MPP, the Staging Memory and the Array Unit, appear to be well suited to the numerical algorithms of CFD. This combined with the prospect of building a faster and larger MMP-like machine holds the promise of achieving sustained gigaflop rates that are required for the numerical simulations in CFD.

A CFD study on the effectiveness of trees to disperse road traffic emissions at a city scale

NASA Astrophysics Data System (ADS)

Jeanjean, A. P. R.; Hinchliffe, G.; McMullan, W. A.; Monks, P. S.; Leigh, R. J.

2015-11-01

This paper focuses on the effectiveness of trees at dispersing road traffic emissions on a city scale. CFD simulations of air-pollutant concentrations were performed using the OpenFOAM software platform using the k-ε model. Results were validated against the CODASC wind tunnel database before being applied to a LIDAR database of buildings and trees representing the City of Leicester (UK). Most other CFD models in the literature typically use idealised buildings to model wind flow and pollution dispersion. However, the methodology used in this study uses real buildings and trees data from LIDAR to reconstruct a 3D representation of Leicester City Centre. It focuses on a 2 × 2 km area which is on a scale larger than those usually used in other CFD studies. Furthermore, the primary focus of this study is on the interaction of trees with wind flow dynamics. It was found that in effect, trees have a regionally beneficial impact on road traffic emissions by increasing turbulence and reducing ambient concentrations of road traffic emissions by 7% at pedestrian height on average. This was an important result given that previous studies generally concluded that trees trapped pollution by obstructing wind flow in street canyons. Therefore, this study is novel both in its methodology and subsequent results, highlighting the importance of combining local and regional scale models for assessing the impact of trees in urban planning.

Propulsion Simulations with the Unstructured-Grid CFD Tool TetrUSS

NASA Technical Reports Server (NTRS)

Deere, Karen A.; Pandya, Mohagna J.

2002-01-01

A computational investigation has been completed to assess the capability of the NASA Tetrahedral Unstructured Software System (TetrUSS) for simulation of exhaust nozzle flows. Three configurations were chosen for this study: (1) a fluidic jet effects model, (2) an isolated nacelle with a supersonic cruise nozzle, and (3) a fluidic pitchthrust- vectoring nozzle. These configurations were chosen because existing data provided a means for measuring the ability of the TetrUSS flow solver USM3D for simulating complex nozzle flows. Fluidic jet effects model simulations were compared with structured-grid CFD (computational fluid dynamics) data at Mach numbers from 0.3 to 1.2 at nozzle pressure ratios up to 7.2. Simulations of an isolated nacelle with a supersonic cruise nozzle were compared with wind tunnel experimental data and structured-grid CFD data at Mach numbers of 0.9 and 1.2, with a nozzle pressure ratio of 5. Fluidic pitch-thrust-vectoring nozzle simulations were compared with static experimental data and structured-grid CFD data at static freestream conditions and nozzle pressure ratios from 3 to 10. A fluidic injection case was computed with the third configuration at a nozzle pressure ratio of 4.6 and a secondary pressure ratio of 0.7. Results indicate that USM3D with the S-A turbulence model provides accurate exhaust nozzle simulations at on-design conditions, but does not predict internal shock location at overexpanded conditions or pressure recovery along a boattail at transonic conditions.

Distribution of stress on TMJ disc induced by use of chincup therapy: assessment by the finite element method.

PubMed

Calçada, Flávio Siqueira; Guimarães, Antônio Sérgio; Teixeira, Marcelo Lucchesi; Takamatsu, Flávio Atsushi

2017-01-01

To assess the distribution of stress produced on TMJ disc by chincup therapy, by means of the finite element method. a simplified three-dimensional TMJ disc model was developed by using Rhinoceros 3D software, and exported to ANSYS software. A 4.9N load was applied on the inferior surface of the model at inclinations of 30, 40, and 50 degrees to the mandibular plane (GoMe). ANSYS was used to analyze stress distribution on the TMJ disc for the different angulations, by means of finite element method. The results showed that the tensile and compressive stresses concentrations were higher on the inferior surface of the model. More presence of tensile stress was found in the middle-anterior region of the model and its location was not altered in the three directions of load application. There was more presence of compressive stress in the middle and mid-posterior regions, but when a 50o inclined load was applied, concentration in the middle region was prevalent. Tensile and compressive stresses intensities progressively diminished as the load was more vertically applied. stress induced by the chincup therapy is mainly located on the inferior surface of the model. Loads at greater angles to the mandibular plane produced distribution of stresses with lower intensity and a concentration of compressive stresses in the middle region. The simplified three-dimensional model proved useful for assessing the distribution of stresses on the TMJ disc induced by the chincup therapy.

Extruded upper first molar intrusion: Comparison between unilateral and bilateral miniscrew anchorage.

PubMed

Sugii, Mari Miura; Barreto, Bruno de Castro Ferreira; Francisco Vieira-Júnior, Waldemir; Simone, Katia Regina Izola; Bacchi, Ataís; Caldas, Ricardo Armini

2018-01-01

The aim of his study was to evaluate the stress on tooth and alveolar bone caused by orthodontic intrusion forces in a supraerupted upper molar, by using a three-dimensional Finite Element Method (FEM). A superior maxillary segment was modeled in the software SolidWorks 2010 (SolidWorks Corporation, Waltham, MA, USA) containing: cortical and cancellous bone, supraerupted first molar, periodontal tissue and orthodontic components. A finite element model has simulated intrusion forces of 4N onto a tooth, directed to different mini-screw locations. Three different intrusion mechanics vectors were simulated: anchoring on a buccal mini-implant; anchoring on a palatal mini-implant and the association of both anchorage systems. All analyses were performed considering the minimum principal stress and total deformation. Qualitative analyses exhibited stress distribution by color maps. Quantitative analysis was performed with a specific software for reading and solving numerical equations (ANSYS Workbench 14, Ansys, Canonsburg, Pennsylvania, USA). Intrusion forces applied from both sides (buccal and palatal) resulted in a more homogeneous stress distribution; no high peak of stress was detected and it has allowed a vertical resultant movement. Buccal or palatal single-sided forces resulted in concentrated stress zones with higher values and tooth tipping to respective force side. Unilateral forces promoted higher stress in root apex and higher dental tipping. The bilateral forces promoted better distribution without evidence of dental tipping. Bilateral intrusion technique suggested lower probability of root apex resorption.

[Three-dimensional finite element study on the change of glossopharyngeum in patient with obstructive sleep apnea hypopnea syndrome during titrated mandible advancement].

PubMed

Yang, Suixing; Feng, Jing; Zhang, Zuo; Qu, Aili; Gong, Miao; Tang, Jie; Fan, Junheng; Li, Songqing; Zhao, Yanling

2013-04-01

To construct a three-dimensional finite element model of the upper airway and adjacent structure of an obstructive sleep apnea hypopnea syndrome (OSAHS) patient for biomechanical analysis. And to study the influence of glossopharyngeum of an OSAHS patient with three-dimensional finite element model during titrated mandible advancement. DICOM format image information of an OSAHS patient's upper airway was obtained by thin-section CT scanning and digital image processing were utilized to construct a three-dimensional finite element model by Mimics 10.0, Imageware 10.0 and Ansys software. The changes and the law of glossopharyngeum were observed by biomechanics and morphology after loading with titrated mandible advancement. A three-dimensional finite element model of the adjacent upper airway structure of OSAHS was established successfully. After loading, the transverse diameter of epiglottis tip of glossopharyngeum increased significantly, although the sagittal diameter decreased correspondingly. The principal stress was mainly distributed in anterior wall of the upper airway. The location of principal stress concentration did not change significantly with the increasing of distance. The stress of glossopharyngeum increased during titrated mandible advancement. A more precise three-dimensional finite model of upper airway and adjacent structure of an OSAHS patient is established and improved efficiency by Mimics, Imageware and Ansys software. The glossopharyngeum of finite element model of OSAHS is analyzed by titrated mandible advancement and can effectively show the relationship between mandible advancement and the glossopharyngeum.

Radiopacity Evaluation of Gutta-Percha Points in Thinner Samples than the ANSI/ADA Recommendation.

PubMed

Petry, Bruna Lucian; Bodanezi, Augusto; Baldasso, Flávia Emi Razera; Delai, Débora; Larentis, Naiara Leites; Fontanella, Vania Regina Camargo; Kopper, Patrícia Maria Poli

2017-01-01

The aim of this study was to evaluate the radiopacity of different gutta-percha points (Endo Points®, Dentsply®, Tanari®, Meta®, Roeko® and Odous®) in samples of 1 mm thick as established by ANSI/ADA Specification #57 and ISO 6876/2001, in comparison with thinner samples. Twelve test specimens for each material, four for each thickness (0.3, 0.6, and 1 mm and diameter of 8 mm), were laminated and compressed between two polished glass plates until the desirable thickness. Digital radiographs were obtained along with a graduated aluminum stepwedge varying from 1 to 10 mm in thickness. The X-ray unit was set at 70 kVp, 10 mA and 0.4 s exposure time, at a focal distance of 36 cm. One calibrated observer quantified the average values of pixels with Adobe Photoshop® software. Data were analyzed using ANOVA and Tukey tests, at 5% significance level. At 0.6 and 1 mm thickness, all the tested materials showed radiopacity higher than 3 mm of aluminum (reference value). At 0.3 mm thickness, Odous and Tanari presented significantly less radiopacity than the reference, and the other materials showed similar radiopacity to the reference. The study concluded that the materials demonstrated different radiopacities and all had values above the minimum recommended by ANSI/ADA specification #57, being Odous and Tanari less radiopaque than the reference value in thinner samples (0.3mm).

Optimal design of the rotor geometry of line-start permanent magnet synchronous motor using the bat algorithm

NASA Astrophysics Data System (ADS)

Knypiński, Łukasz

2017-12-01

In this paper an algorithm for the optimization of excitation system of line-start permanent magnet synchronous motors will be presented. For the basis of this algorithm, software was developed in the Borland Delphi environment. The software consists of two independent modules: an optimization solver, and a module including the mathematical model of a synchronous motor with a self-start ability. The optimization module contains the bat algorithm procedure. The mathematical model of the motor has been developed in an Ansys Maxwell environment. In order to determine the functional parameters of the motor, additional scripts in Visual Basic language were developed. Selected results of the optimization calculation are presented and compared with results for the particle swarm optimization algorithm.

Analysis of artery blood flow before and after angioplasty

NASA Astrophysics Data System (ADS)

Tomaszewski, Michał; Baranowski, Paweł; Małachowski, Jerzy; Damaziak, Krzysztof; Bukała, Jakub

2018-01-01

The study presents a comparison of results obtained from numerical simulations of blood flow in two different arteries. One of them was considered to be narrowed in order to simulate an arteriosclerosis obstructing the blood flow in the vessel, whereas the second simulates the vessel after angioplasty treatment. During the treatment, a biodegradable stent is inserted into the artery, which prevents the vessel walls from collapsing. The treatment was simulated through the use of numerical simulation using the finite element method. The final mesh geometry obtained from the analysis was exported to the dedicated software in order to create geometry in which a flow domain inside the artery with the stent was created. The flow analysis was conducted in ANSYS Fluent software with non-deformable vessel walls.

A Mathematical Model for the Exhaust Gas Temperature Profile of a Diesel Engine

NASA Astrophysics Data System (ADS)

Brito, C. H. G.; Maia, C. B.; Sodré, J. R.

2015-09-01

This work presents a heat transfer model for the exhaust gas of a diesel power generator to determine the gas temperature profile in the exhaust pipe. The numerical methodology to solve the mathematical model was developed using a finite difference method approach for energy equation resolution and determination of temperature profiles considering turbulent fluid flow and variable fluid properties. The simulation was carried out for engine operation under loads from 0 kW to 40 kW. The model was compared with results obtained using the multidimensional Ansys CFX software, which was applied to solve the governor equations of turbulent fluid flow. The results for the temperature profiles in the exhaust pipe show a good proximity between the mathematical model developed and the multidimensional software.

Characteristics study of the gears by the CAD/CAE

NASA Astrophysics Data System (ADS)

Wang, P. Y.; Chang, S. L.; Lee, B. Y.; Nguyen, D. H.; Cao, C. W.

2017-09-01

Gears are the most important transmission component in machines. The rapid development of the machines in industry requires a shorter time of the analysis process. In traditional, the gears are analyzed by setting up the complete mathematical model firstly, considering the profile of cutter and coordinate systems relationship between the machine and the cutter. It is a really complex and time-consuming process. Recently, the CAD/CAE software is well developed and useful in the mechanical design. In this paper, the Autodesk Inventor® software is introduced to model the spherical gears firstly, and then the models can also be transferred into ANSYS Workbench for the finite element analysis. The proposed process in this paper is helpful to the engineers to speed up the analyzing process of gears in the design stage.

Method of experimental and calculation determination of dissipative properties of carbon

NASA Astrophysics Data System (ADS)

Kazakova, Olga I.; Smolin, Igor Yu.; Bezmozgiy, Iosif M.

2017-12-01

This paper describes the process of definition of relations between the damping ratio and strain/state levels in a material. For these purposes, the experimental-calculation approach was applied. The experimental research was performed on plane composite specimens. The tests were accompanied by finite element modeling using the ANSYS software. Optimization was used as a tool for FEM property setting and for finding the above-mentioned relations. A difference between the calculation and experimental results was accepted as objective functions of this optimization. The optimization cycle was implemented using the pSeven DATADVANCE software platform. The developed approach makes it possible to determine the relations between the damping ratio and strain/state levels in the material, which can be used for computer modeling of the structure response under dynamic loading.

The Safety Analysis of Shipborne Ammunition in Fire Environment

NASA Astrophysics Data System (ADS)

Ren, Junpeng; Wang, Xudong; Yue, Pengfei

2017-12-01

The safety of Ammunition has always been the focus of national military science and technology issues. And fire is one of the major safety threats to the ship’s ammunition storage environment, In this paper, Mk-82 shipborne aviation bomb has been taken as the study object, simulated the whole process of fire by using the FDS (Fire Detection System) software. According to the simulation results of FDS, ANSYS software was used to simulate the temperature field of Mk-82 carrier-based aviation bomb under fire environment, and the safety of aviation bomb in fire environment was analyzed. The result shows that the aviation bombs under the fire environment can occur the combustion or explosion after 70s constant cook-off, and it was a huge threat to the ship security.

Numerical simulation of nonequilibrium flows by using the state-to-state approach in commercial software

NASA Astrophysics Data System (ADS)

Kunova, O. V.; Shoev, G. V.; Kudryavtsev, A. N.

2017-01-01

Nonequilibrium flows of a two-component oxygen mixture O2/O behind a shock wave are studied with due allowance for the state-to-state vibrational and chemical kinetics. The system of gas-dynamic equations is supplemented with kinetic equations including contributions of VT (TV)-exchange and dissociation processes. A method of the numerical solution of this system with the use of the ANSYS Fluent commercial software package is proposed, which is used in a combination with the authors' code that takes into account nonequilibrium kinetics. The computed results are compared with parameters obtained by solving the problem in the shock-fitting formulation. The vibrational temperature is compared with experimental data. The numerical tool proposed in the present paper is applied to study the flow around a cylinder.

Optomechanical design software for segmented mirrors

NASA Astrophysics Data System (ADS)

Marrero, Juan

2016-08-01

The software package presented in this paper, still under development, was born to help analyzing the influence of the many parameters involved in the design of a large segmented mirror telescope. In summary, it is a set of tools which were added to a common framework as they were needed. Great emphasis has been made on the graphical presentation, as scientific visualization nowadays cannot be conceived without the use of a helpful 3d environment, showing the analyzed system as close to reality as possible. Use of third party software packages is limited to ANSYS, which should be available in the system only if the FEM results are needed. Among the various functionalities of the software, the next ones are worth mentioning here: automatic 3d model construction of a segmented mirror from a set of parameters, geometric ray tracing, automatic 3d model construction of a telescope structure around the defined mirrors from a set of parameters, segmented mirror human access assessment, analysis of integration tolerances, assessment of segments collision, structural deformation under gravity and thermal variation, mirror support system analysis including warping harness mechanisms, etc.

[Establishment of a 3D finite element model of human skull using MSCT images and mimics software].

PubMed

Huang, Ping; Li, Zheng-dong; Shao, Yu; Zou, Dong-hua; Liu, Ning-guo; Li, Li; Chen, Yuan-yuan; Wan, Lei; Chen, Yi-jiu

2011-02-01

To establish a human 3D finite element skull model, and to explore its value in biomechanics analysis. The cadaveric head was scanned and then 3D skull model was created using Mimics software based on 2D CT axial images. The 3D skull model was optimized by preprocessor along with creation of the surface and volume meshes. The stress changes, after the head was struck by an object or the head hit the ground directly, were analyzed using ANSYS software. The original 3D skull model showed a large number of triangles with a poor quality and high similarity with the real head, while the optimized model showed high quality surface and volume meshes with a small number of triangles comparatively. The model could show the local and global stress changes effectively. The human 3D skull model can be established using MSCT and Mimics software and provides a good finite element model for biomechanics analysis. This model may also provide a base for the study of head stress changes following different forces.

Accumulation and transport of microbial-size particles in a pressure protected model burn unit: CFD simulations and experimental evidence

PubMed Central

2011-01-01

Background Controlling airborne contamination is of major importance in burn units because of the high susceptibility of burned patients to infections and the unique environmental conditions that can accentuate the infection risk. In particular the required elevated temperatures in the patient room can create thermal convection flows which can transport airborne contaminates throughout the unit. In order to estimate this risk and optimize the design of an intensive care room intended to host severely burned patients, we have relied on a computational fluid dynamic methodology (CFD). Methods The study was carried out in 4 steps: i) patient room design, ii) CFD simulations of patient room design to model air flows throughout the patient room, adjacent anterooms and the corridor, iii) construction of a prototype room and subsequent experimental studies to characterize its performance iv) qualitative comparison of the tendencies between CFD prediction and experimental results. The Electricité De France (EDF) open-source software Code_Saturne® (http://www.code-saturne.org) was used and CFD simulations were conducted with an hexahedral mesh containing about 300 000 computational cells. The computational domain included the treatment room and two anterooms including equipment, staff and patient. Experiments with inert aerosol particles followed by time-resolved particle counting were conducted in the prototype room for comparison with the CFD observations. Results We found that thermal convection can create contaminated zones near the ceiling of the room, which can subsequently lead to contaminate transfer in adjacent rooms. Experimental confirmation of these phenomena agreed well with CFD predictions and showed that particles greater than one micron (i.e. bacterial or fungal spore sizes) can be influenced by these thermally induced flows. When the temperature difference between rooms was 7°C, a significant contamination transfer was observed to enter into the positive pressure room when the access door was opened, while 2°C had little effect. Based on these findings the constructed burn unit was outfitted with supplemental air exhaust ducts over the doors to compensate for the thermal convective flows. Conclusions CFD simulations proved to be a particularly useful tool for the design and optimization of a burn unit treatment room. Our results, which have been confirmed qualitatively by experimental investigation, stressed that airborne transfer of microbial size particles via thermal convection flows are able to bypass the protective overpressure in the patient room, which can represent a potential risk of cross contamination between rooms in protected environments. PMID:21371304

Accumulation and transport of microbial-size particles in a pressure protected model burn unit: CFD simulations and experimental evidence.

PubMed

Beauchêne, Christian; Laudinet, Nicolas; Choukri, Firas; Rousset, Jean-Luc; Benhamadouche, Sofiane; Larbre, Juliette; Chaouat, Marc; Benbunan, Marc; Mimoun, Maurice; Lajonchère, Jean-Patrick; Bergeron, Vance; Derouin, Francis

2011-03-03

Controlling airborne contamination is of major importance in burn units because of the high susceptibility of burned patients to infections and the unique environmental conditions that can accentuate the infection risk. In particular the required elevated temperatures in the patient room can create thermal convection flows which can transport airborne contaminates throughout the unit. In order to estimate this risk and optimize the design of an intensive care room intended to host severely burned patients, we have relied on a computational fluid dynamic methodology (CFD). The study was carried out in 4 steps: i) patient room design, ii) CFD simulations of patient room design to model air flows throughout the patient room, adjacent anterooms and the corridor, iii) construction of a prototype room and subsequent experimental studies to characterize its performance iv) qualitative comparison of the tendencies between CFD prediction and experimental results. The Electricité De France (EDF) open-source software Code_Saturne® (http://www.code-saturne.org) was used and CFD simulations were conducted with an hexahedral mesh containing about 300 000 computational cells. The computational domain included the treatment room and two anterooms including equipment, staff and patient. Experiments with inert aerosol particles followed by time-resolved particle counting were conducted in the prototype room for comparison with the CFD observations. We found that thermal convection can create contaminated zones near the ceiling of the room, which can subsequently lead to contaminate transfer in adjacent rooms. Experimental confirmation of these phenomena agreed well with CFD predictions and showed that particles greater than one micron (i.e. bacterial or fungal spore sizes) can be influenced by these thermally induced flows. When the temperature difference between rooms was 7°C, a significant contamination transfer was observed to enter into the positive pressure room when the access door was opened, while 2°C had little effect. Based on these findings the constructed burn unit was outfitted with supplemental air exhaust ducts over the doors to compensate for the thermal convective flows. CFD simulations proved to be a particularly useful tool for the design and optimization of a burn unit treatment room. Our results, which have been confirmed qualitatively by experimental investigation, stressed that airborne transfer of microbial size particles via thermal convection flows are able to bypass the protective overpressure in the patient room, which can represent a potential risk of cross contamination between rooms in protected environments.

Sandia Compact Sensor Node (SCSN) v. 1.0

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

HARRINGTON, JOHN

2009-01-07

The SCSN communication protocol is implemented in software and incorporates elements of Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), and Carrier Sense Multiple Access (CSMA) to reduce radio message collisions, latency, and power consumption. Alarm messages are expeditiously routed to a central node as a 'star' network with minimum overhead. Other messages can be routed along network links between any two nodes so that peer-to-peer communication is possible. Broadcast messages can be composed that flood the entire network or just specific portions with minimal radio traffic and latency. Two-way communication with sensor nodes, which sleep most ofmore » the time to conserve battery life, can occur at seven second intervals. SCSN software also incorporates special algorithms to minimize superfluous radio traffic that can result from excessive intrusion alarm messages. A built-in seismic detector is implemented with a geophone and software that distinguishes between pedestrian and vehicular targets. Other external sensors can be attached to a SCSN using supervised interface lines that are controlled by software. All software is written in the ANSI C language for ease of development, maintenance, and portability.« less

40 CFR 211.206-2 - Alternative test data.

Code of Federal Regulations, 2013 CFR

2013-07-01

... according to ANSI STD Z24.22-1957 or ANSI STD S3.19-1974 to determine the mean attenuation and standard... based on the ANSI STD Z24.22-1957 measurement procedure must state in the supporting information... are based on ANSI STD -Z24.22-1957. (b) Manufacturers who initially use available data based on ANSI...

40 CFR 211.206-2 - Alternative test data.

Code of Federal Regulations, 2014 CFR

2014-07-01

... according to ANSI STD Z24.22-1957 or ANSI STD S3.19-1974 to determine the mean attenuation and standard... based on the ANSI STD Z24.22-1957 measurement procedure must state in the supporting information... are based on ANSI STD -Z24.22-1957. (b) Manufacturers who initially use available data based on ANSI...

40 CFR 211.206-2 - Alternative test data.

Code of Federal Regulations, 2011 CFR

2011-07-01

... according to ANSI STD Z24.22-1957 or ANSI STD S3.19-1974 to determine the mean attenuation and standard... based on the ANSI STD Z24.22-1957 measurement procedure must state in the supporting information... are based on ANSI STD -Z24.22-1957. (b) Manufacturers who initially use available data based on ANSI...

40 CFR 211.206-2 - Alternative test data.

Code of Federal Regulations, 2012 CFR

2012-07-01

... according to ANSI STD Z24.22-1957 or ANSI STD S3.19-1974 to determine the mean attenuation and standard... based on the ANSI STD Z24.22-1957 measurement procedure must state in the supporting information... are based on ANSI STD -Z24.22-1957. (b) Manufacturers who initially use available data based on ANSI...

ACTE Wing Loads Analysis

NASA Technical Reports Server (NTRS)

Horn, Nicholas R.

2015-01-01

The Adaptive Compliant Trailing Edge (ACTE) project modified a Gulfstream III (GIII) aircraft with a new flexible flap that creates a seamless transition between the flap and the wing. As with any new modification, it is crucial to ensure that the aircraft will not become overstressed in flight. To test this, Star CCM a computational fluid dynamics (CFD) software program was used to calculate aerodynamic data for the aircraft at given flight conditions.

Numerical simulation of heat fluxes in a two-temperature plasma at shock tube walls

NASA Astrophysics Data System (ADS)

Kuznetsov, E. A.; Poniaev, S. A.

2015-12-01

Numerical simulation of a two-temperature three-component Xenon plasma flow is presented. A solver based on the OpenFOAM CFD software package is developed. The heat flux at the shock tube end wall is calculated and compared with experimental data. It is shown that the heat flux due to electrons can be as high as 14% of the total heat flux.

Pilot-in-the Loop CFD Method Development

DTIC Science & Technology

2016-10-20

State University. All software supporting piloted simulations must run at real time speeds or faster. This requirement drives the number of...objects in the environment. In turn, this flowfield affects the local aerodynamics of the main rotor blade sections, affecting blade air loads, and...model, empirical models of ground effect and rotor / airframe interactions) are disabled when running in fully coupled mode, so as to not “double count

CFD Analysis of Thermal Control System Using NX Thermal and Flow

NASA Technical Reports Server (NTRS)

Fortier, C. R.; Harris, M. F. (Editor); McConnell, S. (Editor)

2014-01-01

The Thermal Control Subsystem (TCS) is a key part of the Advanced Plant Habitat (APH) for the International Space Station (ISS). The purpose of this subsystem is to provide thermal control, mainly cooling, to the other APH subsystems. One of these subsystems, the Environmental Control Subsystem (ECS), controls the temperature and humidity of the growth chamber (GC) air to optimize the growth of plants in the habitat. The TCS provides thermal control to the ECS with three cold plates, which use Thermoelectric Coolers (TECs) to heat or cool water as needed to control the air temperature in the ECS system. In order to optimize the TCS design, pressure drop and heat transfer analyses were needed. The analysis for this system was performed in Siemens NX Thermal/Flow software (Version 8.5). NX Thermal/Flow has the ability to perform 1D or 3D flow solutions. The 1D flow solver can be used to represent simple geometries, such as pipes and tubes. The 1D flow method also has the ability to simulate either fluid only or fluid and wall regions. The 3D flow solver is similar to other Computational Fluid Dynamic (CFD) software. TCS performance was analyzed using both the 1D and 3D solvers. Each method produced different results, which will be evaluated and discussed.

Stirling Analysis Comparison of Commercial vs. High-Order Methods

NASA Technical Reports Server (NTRS)

Dyson, Rodger W.; Wilson, Scott D.; Tew, Roy C.; Demko, Rikako

2007-01-01

Recently, three-dimensional Stirling engine simulations have been accomplished utilizing commercial Computational Fluid Dynamics software. The validations reported can be somewhat inconclusive due to the lack of precise time accurate experimental results from engines, export control/ proprietary concerns, and the lack of variation in the methods utilized. The last issue may be addressed by solving the same flow problem with alternate methods. In this work, a comprehensive examination of the methods utilized in the commercial codes is compared with more recently developed high-order methods. Specifically, Lele's Compact scheme and Dyson s Ultra Hi-Fi method will be compared with the SIMPLE and PISO methods currently employed in CFD-ACE, FLUENT, CFX, and STAR-CD (all commercial codes which can in theory solve a three-dimensional Stirling model although sliding interfaces and their moving grids limit the effective time accuracy). We will initially look at one-dimensional flows since the current standard practice is to design and optimize Stirling engines with empirically corrected friction and heat transfer coefficients in an overall one-dimensional model. This comparison provides an idea of the range in which commercial CFD software for modeling Stirling engines may be expected to provide accurate results. In addition, this work provides a framework for improving current one-dimensional analysis codes.

Stirling Analysis Comparison of Commercial Versus High-Order Methods

NASA Technical Reports Server (NTRS)

Dyson, Rodger W.; Wilson, Scott D.; Tew, Roy C.; Demko, Rikako

2005-01-01

Recently, three-dimensional Stirling engine simulations have been accomplished utilizing commercial Computational Fluid Dynamics software. The validations reported can be somewhat inconclusive due to the lack of precise time accurate experimental results from engines, export control/proprietary concerns, and the lack of variation in the methods utilized. The last issue may be addressed by solving the same flow problem with alternate methods. In this work, a comprehensive examination of the methods utilized in the commercial codes is compared with more recently developed high-order methods. Specifically, Lele's compact scheme and Dyson's Ultra Hi-Fi method will be compared with the SIMPLE and PISO methods currently employed in CFD-ACE, FLUENT, CFX, and STAR-CD (all commercial codes which can in theory solve a three-dimensional Stirling model with sliding interfaces and their moving grids limit the effective time accuracy). We will initially look at one-dimensional flows since the current standard practice is to design and optimize Stirling engines with empirically corrected friction and heat transfer coefficients in an overall one-dimensional model. This comparison provides an idea of the range in which commercial CFD software for modeling Stirling engines may be expected to provide accurate results. In addition, this work provides a framework for improving current one-dimensional analysis codes.

Turbulence Resolving Flow Simulations of a Francis Turbine in Part Load using Highly Parallel CFD Simulations

NASA Astrophysics Data System (ADS)

Krappel, Timo; Riedelbauch, Stefan; Jester-Zuerker, Roland; Jung, Alexander; Flurl, Benedikt; Unger, Friedeman; Galpin, Paul

2016-11-01

The operation of Francis turbines in part load conditions causes high fluctuations and dynamic loads in the turbine and especially in the draft tube. At the hub of the runner outlet a rotating vortex rope within a low pressure zone arises and propagates into the draft tube cone. The investigated part load operating point is at about 72% discharge of best efficiency. To reduce the possible influence of boundary conditions on the solution, a flow simulation of a complete Francis turbine is conducted consisting of spiral case, stay and guide vanes, runner and draft tube. As the flow has a strong swirling component for the chosen operating point, it is very challenging to accurately predict the flow and in particular the flow losses in the diffusor. The goal of this study is to reach significantly better numerical prediction of this flow type. This is achieved by an improved resolution of small turbulent structures. Therefore, the Scale Adaptive Simulation SAS-SST turbulence model - a scale resolving turbulence model - is applied and compared to the widely used RANS-SST turbulence model. The largest mesh contains 300 million elements, which achieves LES-like resolution throughout much of the computational domain. The simulations are evaluated in terms of the hydraulic losses in the machine, evaluation of the velocity field, pressure oscillations in the draft tube and visual comparisons of turbulent flow structures. A pre-release version of ANSYS CFX 17.0 is used in this paper, as this CFD solver has a parallel performance up to several thousands of cores for this application which includes a transient rotor-stator interface to support the relative motion between the runner and the stationary portions of the water turbine.

Analysis of materials used for Greenhouse roof covering - structure using CFD

NASA Astrophysics Data System (ADS)

Subin, M. C.; Savio Lourence, Jason; Karthikeyan, Ram; Periasamy, C.

2018-04-01

Greenhouse is widely used to create a suitable environment for the growth of plant. During summer, high temperatures cause harm to the plant. This work calculates characteristics required to optimize the above-mentioned parameters using different roof structure covering materials for the greenhouse. Moreover, this work also presents a simulation of the cooling and heating system. In addition, a computer model based on Ansys Fluent has been using to predict the temperature profiles inside the greenhouse. Greenhouse roof structure shading may have a time-dependent effect the production, water and nutrient uptake in plants. An experiment was conducted in the emirate of Dubai in United Arab Emirates to discover the impact of different materials in order to have an optimal plant growth zone and yield production. These structures were poly ethylene and poly carbonate sheets of 2 different configurations. Results showed that poly carbonate sheets configuration of optimal thickness has given a high result in terms of yield production. Therefore, there is a need for appropriate material selection of greenhouse roof structure in this area of UAE. Major parameters and properties need to be considered while selecting a greenhouse roof structure are the resistance to solar radiation, weathering, thermal as well as mechanical properties and good abrasion resistance. In the present study, an experiment has been conducted to find out the material suitability of the greenhouse roof structure in terms of developing proper ambient conditions especially to minimize the energy lose by reducing the HVAC and lighting expenses. The configuration verified using the CFD, so it has been concluded that polycarbonate can be safely used in the greenhouse than other roof structure material having white or green colour.

Using Fluid Dynamics and Field Experiments to Improve Vehicle-based Wind Measurements for Environmental Monitoring

NASA Astrophysics Data System (ADS)

Hanlon, T.; Bourlon, E.; Jensen, N.; Risk, D. A.

2017-12-01

Vehicle-based measurements of wind speed and direction are presently used for a range of applications, including gas plume detection. Theoretically, vehicle-based measurements could also be integrated with fixed-site measurements to add spatial richness in weather and atmospheric observing systems, but the quality and accuracy of such measurements is currently not well understood. Our research objective for this field-simulation study was to understand how anemometer placement and the vehicle's external air flow field affect measurement accuracy of vehicle-mounted anemometers. We used a truck-mounted anemometer to investigate wind measurements at different vehicle speeds and anemometer placements. We conducted field tests on a square 3.2 km route in flat, treeless terrain and positioned stationary sonic anemometers at each corner. We drove the route in replicate under varying wind conditions and vehicle speeds, and with multiple sonic anemometer placements on the vehicle. The vehicle-based anemometer measurements were corrected to remove the vehicle speed and course vector. In the lab, Computational Fluid Dynamic (CFD) simulations were generated in Ansys FLUENT to model the external flow fields at the locations of measurement under varying vehicle speed and yaw angle. In field trials we observed that vehicle-based measurements differed from stationary measurements by a different magnitude in each of the upwind, downwind and crosswind directions. The difference from stationary anemometers increased with vehicle speed, suggesting the vehicle's flow field does indeed impact the accuracy of vehicle-based anemometer measurements. We used the CFD simulations to develop a quantitative understanding of fluid flow around the vehicle, and to develop speed-based corrections that were applied to the field data. We were also able to make recommendations for anemometer placement. This study demonstrates the importance of applying aerodynamics-based correction factors to vehicle based wind measurements.

Numerical simulation of temperature field in K9 glass irradiated by ultraviolet pulse laser

NASA Astrophysics Data System (ADS)

Wang, Xi; Fang, Xiaodong

2015-10-01

The optical component of photoelectric system was easy to be damaged by irradiation of high power pulse laser, so the effect of high power pulse laser irradiation on K9 glass was researched. A thermodynamic model of K9 glass irradiated by ultraviolet pulse laser was established using the finite element software ANSYS. The article analyzed some key problems in simulation process of ultraviolet pulse laser damage of K9 glass based on ANSYS from the finite element models foundation, meshing, loading of pulse laser, setting initial conditions and boundary conditions and setting the thermal physical parameters of material. The finite element method (FEM) model was established and a numerical analysis was performed to calculate temperature field in K9 glass irradiated by ultraviolet pulse laser. The simulation results showed that the temperature of irradiation area exceeded the melting point of K9 glass, while the incident laser energy was low. The thermal damage dominated in the damage mechanism of K9 glass, the melting phenomenon should be much more distinct.

Fluid structure interaction dynamic analysis of a mixed-flow waterjet pump

NASA Astrophysics Data System (ADS)

Pan, X. W.; Y Pan, Z.; Huang, D.; Shen, Z. H.

2013-12-01

In order to avoid resonance of a mixed-flow waterjet pump at run time and calculate the stress and deformation of the pump rotor in the flow field, a one-way fluid structure interaction method was applied to simulate the pump rotor using ANSYS CFX and ANSYS Workbench software. The natural frequencies and mode shapes of the pump rotor in the air and in the flow field were analyzed, and the stress and deformation of the impeller were obtained at different flow rates. The obtained numerical results indicated that the mode shapes were similar both in the air and in the flow field, but the pump rotor's natural frequency in the flow field was slightly smaller than that in the air; the difference of the pump rotor's natural frequency varied lightly at different flow rates, and all frequencies at different flow rates were higher than the safe frequency, the pump rotor under the effect of prestress rate did not occur resonance; The maximum stress was on the blade near the hub and the maximum deformation on the blade tip at different flow rates.

Determination of the temperature distribution in a minichannel using ANSYS CFX and a procedure based on the Trefftz functions

NASA Astrophysics Data System (ADS)

Maciejewska, Beata; Błasiak, Sławomir; Piasecka, Magdalena

This work discusses the mathematical model for laminar-flow heat transfer in a minichannel. The boundary conditions in the form of temperature distributions on the outer sides of the channel walls were determined from experimental data. The data were collected from the experimental stand the essential part of which is a vertical minichannel 1.7 mm deep, 16 mm wide and 180 mm long, asymmetrically heated by a Haynes-230 alloy plate. Infrared thermography allowed determining temperature changes on the outer side of the minichannel walls. The problem was analysed numerically through either ANSYS CFX software or special calculation procedures based on the Finite Element Method and Trefftz functions in the thermal boundary layer. The Trefftz functions were used to construct the basis functions. Solutions to the governing differential equations were approximated with a linear combination of Trefftz-type basis functions. Unknown coefficients of the linear combination were calculated by minimising the functional. The results of the comparative analysis were represented in a graphical form and discussed.

A Virtual Aluminum Reduction Cell

NASA Astrophysics Data System (ADS)

Zhang, Hongliang; Zhou, Chenn Q.; Wu, Bing; Li, Jie

2013-11-01

The most important component in the aluminum industry is the aluminum reduction cell; it has received considerable interests and resources to conduct research to improve its productivity and energy efficiency. The current study focused on the integration of numerical simulation data and virtual reality technology to create a scientifically and practically realistic virtual aluminum reduction cell by presenting complex cell structures and physical-chemical phenomena. The multiphysical field simulation models were first built and solved in ANSYS software (ANSYS Inc., Canonsburg, PA, USA). Then, the methodology of combining the simulation results with virtual reality was introduced, and a virtual aluminum reduction cell was created. The demonstration showed that a computer-based world could be created in which people who are not analysis experts can see the detailed cell structure in a context that they can understand easily. With the application of the virtual aluminum reduction cell, even people who are familiar with aluminum reduction cell operations can gain insights that make it possible to understand the root causes of observed problems and plan design changes in much less time.

Analysis of the Articulated Total Body (ATB) and Mathematical Dynamics Model (MADYMO) Software Suites for Modeling Anthropomorphic Test Devices (ATDs) in Blast Environments

DTIC Science & Technology

2013-05-01

REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 ...valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1 . REPORT DATE (DD-MM-YYYY) May 2013 2. REPORT TYPE Final 3. DATES...area code) (410) 278-7386 Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std. Z39.18 iii Contents List of Figures v List of Tables v 1

Pulsatile blood flow in elastic artery with model aneurysm

NASA Astrophysics Data System (ADS)

Nikolov, N.; Radev, St.; Tabakova, S.

2017-11-01

The mathematical modeling and numerical simulations are expected to play an important role to predict the genesis of different cardiovascular diseases, such as the formation and rupture of aneurysms. In the present work, the numerical solutions of the oscillatory blood flow are constructed for an elastic artery with a model aneurysm by use of the software ANSYS. It is observed that the artery elastic strain behaves in a different way: stably or unstably depending on the different combinations between the flow parameter (outlet pressure) and the elastic modulus of the artery wall.

The Mechanical Design Optimization of a High Field HTS Solenoid

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

Lalitha, SL; Gupta, RC

2015-06-01

This paper describes the conceptual design optimization of a large aperture, high field (24 T at 4 K) solenoid for a 1.7 MJ superconducting magnetic energy storage device. The magnet is designed to be built entirely of second generation (2G) high temperature superconductor tape with excellent electrical and mechanical properties at the cryogenic temperatures. The critical parameters that govern the magnet performance are examined in detail through a multiphysics approach using ANSYS software. The analysis results formed the basis for the performance specification as well as the construction of the magnet.

Numerical Simulations for Distribution Characteristics of Internal Forces on Segments of Tunnel Linings

NASA Astrophysics Data System (ADS)

Li, Shouju; Shangguan, Zichang; Cao, Lijuan

A procedure based on FEM is proposed to simulate interaction between concrete segments of tunnel linings and soils. The beam element named as Beam 3 in ANSYS software was used to simulate segments. The ground loss induced from shield tunneling and segment installing processes is simulated in finite element analysis. The distributions of bending moment, axial force and shear force on segments were computed by FEM. The commutated internal forces on segments will be used to design reinforced bars on shield linings. Numerically simulated ground settlements agree with observed values.

Ada 9X overview

NASA Technical Reports Server (NTRS)

Weller, David G.

1992-01-01

The current version of Ada has been an ANSI standard since 1983. In 1988, the Ada Joint Program Office was tasked with reevaluating the language and proposing changes to the standard. Since that time, the world has seen a tremendous explosion in object-oriented languages, as well as other growing fields such as distributed computing and support for very large software systems. The speaker will discuss new features being added to the next version of Ada, currently called Ada 9X, and what transition issues must be considered for current Ada projects.

User’s Manual for a Prototype Binding of ANSI-Standard SQL to Ada Supporting the SAME Methodology for the Software Technology for Adaptable, Reliable Systems (STARS) Program

DTIC Science & Technology

1990-06-30

declaring all of the valid enumeration values for a domain of type enumeration. Example-> In type color_vals is (red, blue , green), color_vals is the name...Color Vals is (red, white, blue ); package Fifth is new domainl.generateenum domain (ColorVals, Colors, enumeration, nullandnotnull); Resulting...generated domain definition-> type colorsnotnull is (red, white, blue ); package colors_ops is new sqlenumeration_pkg(colors notnull); type colors_type is

FPGA based control system for space instrumentation

NASA Astrophysics Data System (ADS)

Di Giorgio, Anna M.; Cerulli Irelli, Pasquale; Nuzzolo, Francesco; Orfei, Renato; Spinoglio, Luigi; Liu, Giovanni S.; Saraceno, Paolo

2008-07-01

The prototype for a general purpose FPGA based control system for space instrumentation is presented, with particular attention to the instrument control application software. The system HW is based on the LEON3FT processor, which gives the flexibility to configure the chip with only the necessary HW functionalities, from simple logic up to small dedicated processors. The instrument control SW is developed in ANSI C and for time critical (<10μs) commanding sequences implements an internal instructions sequencer, triggered via an interrupt service routine based on a HW high priority interrupt.

On the mechanics of cerebral aneurysms: experimental research and numerical simulation

NASA Astrophysics Data System (ADS)

Parshin, D. V.; Kuianova, I. O.; Yunoshev, A. S.; Ovsyannikov, K. S.; Dubovoy, A. V.

2017-10-01

This research extends existing experimental data for CA tissues [1, 2] and presents the preliminary results of numerical calculations. Experiments were performed to measure aneurysm wall stiffness and the data obtained was analyzed. To reconstruct the geometry of the CAs, DICOM images of real patients with aneurysms and ITK Snap [3] were used. In addition, numerical calculations were performed in ANSYS (commercial software, License of Lavrentyev Institute of Hydrodynamics). The results of these numerical calculations show a high level of agreement with experimental data from previous literature.

Fault-Tree Compiler

NASA Technical Reports Server (NTRS)

Butler, Ricky W.; Boerschlein, David P.

1993-01-01

Fault-Tree Compiler (FTC) program, is software tool used to calculate probability of top event in fault tree. Gates of five different types allowed in fault tree: AND, OR, EXCLUSIVE OR, INVERT, and M OF N. High-level input language easy to understand and use. In addition, program supports hierarchical fault-tree definition feature, which simplifies tree-description process and reduces execution time. Set of programs created forming basis for reliability-analysis workstation: SURE, ASSIST, PAWS/STEM, and FTC fault-tree tool (LAR-14586). Written in PASCAL, ANSI-compliant C language, and FORTRAN 77. Other versions available upon request.

Comparison of effects of different screw materials in the triangle fixation of femoral neck fractures.

PubMed

Gok, Kadir; Inal, Sermet; Gok, Arif; Gulbandilar, Eyyup

2017-05-01

In this study, biomechanical behaviors of three different screw materials (stainless steel, titanium and cobalt-chromium) have analyzed to fix with triangle fixation under axial loading in femoral neck fracture and which material is best has been investigated. Point cloud obtained after scanning the human femoral model with the three dimensional (3D) scanner and this point cloud has been converted to 3D femoral model by Geomagic Studio software. Femoral neck fracture was modeled by SolidWorks software for only triangle configuration and computer-aided numerical analyses of three different materials have been carried out by AnsysWorkbench finite element analysis (FEA) software. The loading, boundary conditions and material properties have prepared for FEA and Von-Misses stress values on upper and lower proximity of the femur and screws have been calculated. At the end of numerical analyses, the best advantageous screw material has calculated as titanium because it creates minimum stress at the upper and lower proximity of the fracture line.

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

Zitney, S.E.

This paper highlights the use of the CAPE-OPEN (CO) standard interfaces in the Advanced Process Engineering Co-Simulator (APECS) developed at the National Energy Technology Laboratory (NETL). The APECS system uses the CO unit operation, thermodynamic, and reaction interfaces to provide its plug-and-play co-simulation capabilities, including the integration of process simulation with computational fluid dynamics (CFD) simulation. APECS also relies heavily on the use of a CO COM/CORBA bridge for running process/CFD co-simulations on multiple operating systems. For process optimization in the face of multiple and some time conflicting objectives, APECS offers stochastic modeling and multi-objective optimization capabilities developed to complymore » with the CO software standard. At NETL, system analysts are applying APECS to a wide variety of advanced power generation systems, ranging from small fuel cell systems to commercial-scale power plants including the coal-fired, gasification-based FutureGen power and hydrogen production plant.« less

Computational Analysis of the Transonic Dynamics Tunnel Using FUN3D

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

Chwalowski, Pawel; Quon, Eliot; Brynildsen, Scott E.

This paper presents results from an explanatory two-year effort of applying Computational Fluid Dynamics (CFD) to analyze the empty-tunnel flow in the NASA Langley Research Center Transonic Dynamics Tunnel (TDT). The TDT is a continuous-flow, closed circuit, 16- x 16-foot slotted-test-section wind tunnel, with capabilities to use air or heavy gas as a working fluid. In this study, experimental data acquired in the empty tunnel using the R-134a test medium was used to calibrate the computational data. The experimental calibration data includes wall pressures, boundary-layer profiles, and the tunnel centerline Mach number profiles. Subsonic and supersonic flow regimes were considered,more » focusing on Mach 0.5, 0.7 and Mach 1.1 in the TDT test section. This study discusses the computational domain, boundary conditions, and initial conditions selected in the resulting steady-state analyses using NASA's FUN3D CFD software.« less

Quantitative comparison of hemodynamics in simulated and 3D angiography models of cerebral aneurysms by use of computational fluid dynamics.

PubMed

Saho, Tatsunori; Onishi, Hideo

2015-07-01

In this study, we evaluated hemodynamics using simulated models and determined how cerebral aneurysms develop in simulated and patient-specific models based on medical images. Computational fluid dynamics (CFD) was analyzed by use of OpenFOAM software. Flow velocity, stream line, and wall shear stress (WSS) were evaluated in a simulated model aneurysm with known geometry and in a three-dimensional angiographic model. The ratio of WSS at the aneurysm compared with that at the basilar artery was 1:10 in simulated model aneurysms with a diameter of 10 mm and 1:18 in the angiographic model, indicating similar tendencies. Vortex flow occurred in both model aneurysms, and the WSS decreased in larger model aneurysms. The angiographic model provided accurate CFD information, and the tendencies of simulated and angiographic models were similar. These findings indicate that hemodynamic effects are involved in the development of aneurysms.

Computational Analysis of the Transonic Dynamics Tunnel Using FUN3D

NASA Technical Reports Server (NTRS)

Chwalowski, Pawel; Quon, Eliot; Brynildsen, Scott E.

2016-01-01

This paper presents results from an exploratory two-year effort of applying Computational Fluid Dynamics (CFD) to analyze the empty-tunnel flow in the NASA Langley Research Center Transonic Dynamics Tunnel (TDT). The TDT is a continuous-flow, closed circuit, 16- x 16-foot slotted-test-section wind tunnel, with capabilities to use air or heavy gas as a working fluid. In this study, experimental data acquired in the empty tunnel using the R-134a test medium was used to calibrate the computational data. The experimental calibration data includes wall pressures, boundary-layer profiles, and the tunnel centerline Mach number profiles. Subsonic and supersonic flow regimes were considered, focusing on Mach 0.5, 0.7 and Mach 1.1 in the TDT test section. This study discusses the computational domain, boundary conditions, and initial conditions selected and the resulting steady-state analyses using NASA's FUN3D CFD software.

Performance of Reynolds Averaged Navier-Stokes Models in Predicting Separated Flows: Study of the Hump Flow Model Problem

NASA Technical Reports Server (NTRS)

Cappelli, Daniele; Mansour, Nagi N.

2012-01-01

Separation can be seen in most aerodynamic flows, but accurate prediction of separated flows is still a challenging problem for computational fluid dynamics (CFD) tools. The behavior of several Reynolds Averaged Navier-Stokes (RANS) models in predicting the separated ow over a wall-mounted hump is studied. The strengths and weaknesses of the most popular RANS models (Spalart-Allmaras, k-epsilon, k-omega, k-omega-SST) are evaluated using the open source software OpenFOAM. The hump ow modeled in this work has been documented in the 2004 CFD Validation Workshop on Synthetic Jets and Turbulent Separation Control. Only the baseline case is treated; the slot flow control cases are not considered in this paper. Particular attention is given to predicting the size of the recirculation bubble, the position of the reattachment point, and the velocity profiles downstream of the hump.

gpuSPHASE-A shared memory caching implementation for 2D SPH using CUDA

NASA Astrophysics Data System (ADS)

Winkler, Daniel; Meister, Michael; Rezavand, Massoud; Rauch, Wolfgang

2017-04-01

Smoothed particle hydrodynamics (SPH) is a meshless Lagrangian method that has been successfully applied to computational fluid dynamics (CFD), solid mechanics and many other multi-physics problems. Using the method to solve transport phenomena in process engineering requires the simulation of several days to weeks of physical time. Based on the high computational demand of CFD such simulations in 3D need a computation time of years so that a reduction to a 2D domain is inevitable. In this paper gpuSPHASE, a new open-source 2D SPH solver implementation for graphics devices, is developed. It is optimized for simulations that must be executed with thousands of frames per second to be computed in reasonable time. A novel caching algorithm for Compute Unified Device Architecture (CUDA) shared memory is proposed and implemented. The software is validated and the performance is evaluated for the well established dambreak test case.

Numerical investigation of a heat transfer characteristics of an impingement cooling system with non-uniform temperature on a cooled surface

NASA Astrophysics Data System (ADS)

Marzec, K.; Kucaba-Pietal, A.

2016-09-01

A series of numerical analysis have been performed to investigate heat transfer characteristics of an impingement cooling array of ten jets directed to the flat surface with different heat flux qw(x). A three-dimensional finite element model was used to solve equations of heat and mass transfer. The study focused on thermal stresses reduction on a cooled surface and aims at answering the question how the Nusselt number distribution on the cooled surface is affected by various inlet flow parameters for different heat flux distributions. The setup consists of a cylindrical plenum with an inline array of ten impingement jets. Simulation has been performed using the Computational Fluid Dynamics (CFD) code Ansys CFX. The k - ω shear stress transport (SST) turbulence model is used in calculations. The numerical analysis of the different mesh density results in good convergence of the GCI index, what excluded mesh size dependency. The physical model is simplified by using the steady state analysis and the incompressible and viscous flow of the fluid.

Prediction of dynamic and aerodynamic characteristics of the centrifugal fan with forward curved blades

NASA Astrophysics Data System (ADS)

Polanský, Jiří; Kalmár, László; Gášpár, Roman

2013-12-01

The main aim of this paper is determine the centrifugal fan with forward curved blades aerodynamic characteristics based on numerical modeling. Three variants of geometry were investigated. The first, basic "A" variant contains 12 blades. The geometry of second "B" variant contains 12 blades and 12 semi-blades with optimal length [1]. The third, control variant "C" contains 24 blades without semi-blades. Numerical calculations were performed by CFD Ansys. Another aim of this paper is to compare results of the numerical simulation with results of approximate numerical procedure. Applied approximate numerical procedure [2] is designated to determine characteristics of the turbulent flow in the bladed space of a centrifugal-flow fan impeller. This numerical method is an extension of the hydro-dynamical cascade theory for incompressible and inviscid fluid flow. Paper also partially compares results from the numerical simulation and results from the experimental investigation. Acoustic phenomena observed during experiment, during numerical simulation manifested as deterioration of the calculation stability, residuals oscillation and thus also as a flow field oscillation. Pressure pulsations are evaluated by using frequency analysis for each variant and working condition.

Decreasing the exhaust outlet temperatures on a class III bus with the lowest impact on the exhaust backpressure and the fuel consumption

NASA Astrophysics Data System (ADS)

Aslan, E.; Ozturk, Y.; Dileroglu, S.

2017-07-01

The focus of this study is to determine the most appropriate exhaust tail pipe form among three different type of designs with respect to their temperature loss efficiency for a 9.5m intercity bus equipped with an Euro VI diesel engine and an automated transmission. To provide lower temperatures at the exhaust outlet, mentioned designs were submitted on to a CFD simulation using Ansys Fluent 17.1, while for manufactured products, temperature measurement tests were conducted in an environmental chamber with Omega K-type thermocouples, and Flir T420 thermal camera was used to monitor outer surface temperature distributions to make a comparison between theoretical and practical results. In order to obtain these practical results, actual tests were performed in an environmental chamber with a constant ambient temperature during the vehicle exhaust emission system regeneration process. In conclusion, an exhaust tail pipe design with a diffuser having a circular contraction and expansion forms is designated since it was the most optimized option in terms of temperature loss efficiency, inconsiderable exhaust backpressure increase and manufacturing costs.

Homogenous and heterogeneous combustion in the secondary chamber of a straw-fired batch boiler

NASA Astrophysics Data System (ADS)

Szubel, Mateusz; Adamczyk, Wojciech; Basista, Grzegorz; Filipowicz, Mariusz

Currently, the attention of the producers of biomass batch boilers is mostly focused on the problem of the total efficiency of energy conversion, CO emissions as well as particulate matter emissions. Due to the regulations of the European Union, the emissions referred to above have to be kept at certain levels because of health considerations, but also because of the necessity to increase the efficiency of the devices. The paper presents the process of analysis of a straw-fired small-scale boiler. In this study, the early stage CFD model presented in a previous paper [1] has been improved and evaluated. Based on [2], an additional set of specimens participating in homogeneous gas reactions was assumed to describe the combustion process sufficiently. Associated Arrhenius parameters have been applied for the description of these reactions. ANSYS Fluent 16 has been used to perform the analysis and the analysis was focused on the CO emissions level as well as on the impact of the modelling approach on the result of the computing. Moreover, losses related to incomplete combustion have been calculated for each of the considered cases.

Lattice Boltzmann Model of 3D Multiphase Flow in Artery Bifurcation Aneurysm Problem

PubMed Central

Abas, Aizat; Mokhtar, N. Hafizah; Ishak, M. H. H.; Abdullah, M. Z.; Ho Tian, Ang

2016-01-01

This paper simulates and predicts the laminar flow inside the 3D aneurysm geometry, since the hemodynamic situation in the blood vessels is difficult to determine and visualize using standard imaging techniques, for example, magnetic resonance imaging (MRI). Three different types of Lattice Boltzmann (LB) models are computed, namely, single relaxation time (SRT), multiple relaxation time (MRT), and regularized BGK models. The results obtained using these different versions of the LB-based code will then be validated with ANSYS FLUENT, a commercially available finite volume- (FV-) based CFD solver. The simulated flow profiles that include velocity, pressure, and wall shear stress (WSS) are then compared between the two solvers. The predicted outcomes show that all the LB models are comparable and in good agreement with the FVM solver for complex blood flow simulation. The findings also show minor differences in their WSS profiles. The performance of the parallel implementation for each solver is also included and discussed in this paper. In terms of parallelization, it was shown that LBM-based code performed better in terms of the computation time required. PMID:27239221