STE thrust chamber technology: Main injector technology program and nozzle Advanced Development Program (ADP)

NASA Technical Reports Server (NTRS)

1993-01-01

The purpose of the STME Main Injector Program was to enhance the technology base for the large-scale main injector-combustor system of oxygen-hydrogen booster engines in the areas of combustion efficiency, chamber heating rates, and combustion stability. The initial task of the Main Injector Program, focused on analysis and theoretical predictions using existing models, was complemented by the design, fabrication, and test at MSFC of a subscale calorimetric, 40,000-pound thrust class, axisymmetric thrust chamber operating at approximately 2,250 psi and a 7:1 expansion ratio. Test results were used to further define combustion stability bounds, combustion efficiency, and heating rates using a large injector scale similar to the Pratt & Whitney (P&W) STME main injector design configuration including the tangential entry swirl coaxial injection elements. The subscale combustion data was used to verify and refine analytical modeling simulation and extend the database range to guide the design of the large-scale system main injector. The subscale injector design incorporated fuel and oxidizer flow area control features which could be varied; this allowed testing of several design points so that the STME conditions could be bracketed. The subscale injector design also incorporated high-reliability and low-cost fabrication techniques such as a one-piece electrical discharged machined (EDMed) interpropellant plate. Both subscale and large-scale injectors incorporated outer row injector elements with scarfed tip features to allow evaluation of reduced heating rates to the combustion chamber.

Vacuum Plasma Spray of CuCrNb Alloy for Advanced Liquid - Fuel Combustion Chambers

NASA Technical Reports Server (NTRS)

Zimmerman, Frank

2000-01-01

The copper-8 atomic percent chromium-4 atomic percent niobium (CuCrNb) alloy was developed by Glenn Research Center (formally Lewis Research Center) as an improved alloy for combustion chamber liners. In comparison to NARloy-Z, the baseline (as in Space Shuttle Main Engine) alloy for such liners, CuCrNb demonstrates mechanical and thermophysical properties equivalent to NARloy-Z, but at temperatures 100 C to 150 C (180 F to 270 F) higher. Anticipated materials related benefits include decreasing the thrust cell liner weight 5% to 20%, increasing the service life at least two fold over current combustion chamber design, and increasing the safety margins available to designers. By adding an oxidation and thermal barrier coating to the liner, the combustion chamber can operate at even higher temperatures. For all these benefits, however, this alloy cannot be formed using conventional casting and forging methods because of the levels of chromium and niobium, which exceed their solubility limit in copper. Until recently, the only forming process that maintains the required microstructure of CrNb intermetallics is powder metallurgy formation of a billet from powder stock, followed by extrusion. This severely limits its usefulness in structural applications, particularly the complex shapes required for combustion chamber liners. Vacuum plasma spray (VPS) has been demonstrated as a method to form structural articles including small combustion chambers from the CuCrNb alloy. In addition, an oxidation and thermal barrier layer can be formed integrally on the hot wall of the liner that improve performance and extend service life. This paper discusses the metallurgy and thermomechanical properties of VPS formed CuCrNb versus the baseline powder metallurgy process, and the manufacturing of small combustion chamber liners at Marshall Space Flight Center using the VPS process. The benefits to advanced propulsion initiatives of using VPS to fabricate combustion chamber liners

An Overview of Combustion Mechanisms and Flame Structures for Advanced Solid Propellants

NASA Technical Reports Server (NTRS)

Beckstead, M. W.

2000-01-01

Ammonium perchlorate (AP) and cyclotretamethylenetetranitramine (HMX) are two solid ingredients often used in modern solid propellants. Although these two ingredients have very similar burning rates as monopropellants, they lead to significantly different characteristics when combined with binders to form propellants. Part of the purpose of this paper is to relate the observed combustion characteristics to the postulated flame structures and mechanisms for AP and HMX propellants that apparently lead to these similarities and differences. For AP composite, the primary diffusion flame is more energetic than the monopropellant flame, leading to an increase in burning rate over the monopropellant rate. In contrast the HMX primary diffusion flame is less energetic than the HMX monopropellant flame and ultimately leads to a propellant rate significantly less than the monopropellant rate in composite propellants. During the past decade the search for more energetic propellants and more environmentally acceptable propellants is leading to the development of propellants based on ingredients other than AP and HMX. The objective of this paper is to utilize the more familiar combustion characteristics of AP and HMX containing propellants to project the combustion characteristics of propellants made up of more advanced ingredients. The principal conclusion reached is that most advanced ingredients appear to burn by combustion mechanisms similar to HMX containing propellants rather than AP propellants.

SSME Main Combustion Chamber (MCC) hot oil dewaxing

NASA Technical Reports Server (NTRS)

Akpati, Anthony U.

1995-01-01

In an attempt to comply with the changing environmental regulations, a process was developed for the replacement of perchloroethylene in the dewaxing of the Space Shuttle Main Engine (SSME) Main Combustion Chamber (MCC) and other associated hardware filled with the Rigidax (R) casting compound. Rigidax (R) is a hard blue-dyed, calcium carbonate filled thermoplastic casting compound (melting point 77 C) that is melted and poured into hardware cavities to prevent contamination during material removal processes, i.e. machining, grinding, drilling, and deburring. Additionally, it serves as a maskant for designated areas during electroforming processes. Laboratory testing was conducted to evaluate seven alternate fluids for the replacement of perchloroethylene in the dewaxing process. Based upon successful laboratory results, a mineral oil was selected for testing on actual hardware. The final process developed involves simultaneous immersion and flushing of the MCC channels using a distinct eight stage process. A nonvolatile hydrocarbon analysis of a solvent flush sample is performed to determine the hardware cleanliness for comparison to the previous perchloroethylene dewaxing process.

SSME Main Combustion Chamber (MCC) 'Hot Oil' Dewaxing

NASA Technical Reports Server (NTRS)

Akpati, Anthony U.

1994-01-01

In an attempt to comply with the changing environmental regulations, a process was developed for the replacement of perchloroethylene in the dewaxing of the Space Shuttle Main Engine (SSME) Main Combustion Chamber (MCC) and other associated hardware filled with the Rigidax(registered mark) casting compound. Rigidax(registered mark) is a hard blue-dyed, calcium carbonate filled thermoplastic casting compound (melting point 77 C) that is melted and poured into hardware cavities to prevent contamination during material removal processes, i.e. machining, grinding, drilling, and deburring. Additionally, it serves as a maskant for designated areas during electroforming processes. Laboratory testing was conducted to evaluate seven alternate fluids for the replacement of perchloroethylene in the dewaxing process. Based upon successful laboratory results, a mineral oil was selected for testing on actual hardware. The final process developed involves simultaneous immersion and flushing of the MCC channels using a distinct eight stage process. A nonvolatile hydrocarbon analysis of a solvent flush sample is performed to determine the hardware cleanliness for comparison to the previous perchloroethylene dewaxing process.

Combustion characteristics and influential factors of isooctane active-thermal atmosphere combustion assisted by two-stage reaction of n-heptane

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

Lu, Xingcai; Ji, Libin; Ma, Junjun

2011-02-15

This paper presents an experimental study on the isooctane active-thermal atmosphere combustion (ATAC) which is assisted by two-stage reaction of n-heptane. The active-thermal atmosphere is created by low- and high-temperature reactions of n-heptane which is injected at intake port, and isooctane is directly injected into combustion chamber near the top dead center. The effects of isooctane injection timing, active-thermal atmosphere intensity, overall equivalence ratio, and premixed ratio on combustion characteristics and emissions are investigated. The experimental results reveal that, the isooctane ignition and combustion can be classified to thermal atmosphere combustion, active atmosphere combustion, and active-thermal atmosphere combustion respectively accordingmore » to the extent of n-heptane oxidation as well as effects of isooctane quenching and charge cooling. n-Heptane equivalence ratio, isooctane equivalence ratio and isooctane delivery advance angle are major control parameters. In one combustion cycle, the isooctane ignited and burned after those of n-heptane, and then this combustion phenomenon can also be named as dual-fuel sequential combustion (DFSC). The ignition timing of the overall combustion event is mainly determined by n-heptane equivalence ratio and can be controlled in flexibility by simultaneously adjusting isooctane equivalence ratio. The isooctane ignition regime, overall thermal efficiency, and NO{sub x} emissions show strong sensitivity to the fuel delivery advance angle between 20 CA BTDC and 25 CA BTDC. (author)« less

Advanced Booster Liquid Engine Combustion Stability

NASA Technical Reports Server (NTRS)

Tucker, Kevin; Gentz, Steve; Nettles, Mindy

2015-01-01

Combustion instability is a phenomenon in liquid rocket engines caused by complex coupling between the time-varying combustion processes and the fluid dynamics in the combustor. Consequences of the large pressure oscillations associated with combustion instability often cause significant hardware damage and can be catastrophic. The current combustion stability assessment tools are limited by the level of empiricism in many inputs and embedded models. This limited predictive capability creates significant uncertainty in stability assessments. This large uncertainty then increases hardware development costs due to heavy reliance on expensive and time-consuming testing.

Operating manual for coaxial injection combustion model. [for the space shuttle main engine

NASA Technical Reports Server (NTRS)

Sutton, R. D.; Schuman, M. D.; Chadwick, W. D.

1974-01-01

An operating manual for the coaxial injection combustion model (CICM) is presented as the final report for an eleven month effort designed to provide improvement, to verify, and to document the comprehensive computer program for analyzing the performance of thrust chamber operation with gas/liquid coaxial jet injection. The effort culminated in delivery of an operation FORTRAN IV computer program and associated documentation pertaining to the combustion conditions in the space shuttle main engine. The computer program is structured for compatibility with the standardized Joint Army-Navy-NASA-Air Force (JANNAF) performance evaluation procedure. Use of the CICM in conjunction with the JANNAF procedure allows the analysis of engine systems using coaxial gas/liquid injection.

Advanced main combustion chamber program

NASA Technical Reports Server (NTRS)

1991-01-01

The topics presented are covered in viewgraph form and include the following: investment of low cost castings; usage of SSME program; usage of MSFC personnel for design effort; and usage of concurrent engineering techniques.

NASA Engineers Test Combustion Chamber to Advance 3-D Printed Rocket Engine Design

NASA Image and Video Library

2016-12-08

A series of test firings like this one in late August brought a group of engineers at NASA's Marshall Space Flight Center in Huntsville, Alabama, a big step closer to their goal of a 100-percent 3-D printed rocket engine, said Andrew Hanks, test lead for the additively manufactured demonstration engine project. The main combustion chamber, fuel turbopump, fuel injector, valves and other components used in the tests were of the team's new design, and all major engine components except the main combustion chamber were 3-D printed. (NASA/MSFC)

Comparison of ash behavior of different fuels in fluidised bed combustion using advanced fuel analysis and global equilibrium calculations

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

Zevenhoven-Onderwater, M.; Blomquist, J.P.; Skrifvars, B.J.

1999-07-01

The behavior of different ashes is predicted by means of a combination of an advanced fuel analysis and global equilibrium calculations. In order to cover a broad spectrum of fuels a coal, a peat, a forest residue and Salix (i.e. willow) are studied. The latter was taken with and without soil contamination, i.e. with a high and low content of silica , respectively. It is shown that mineral matter in fossil and biomass fuels can be present in the matrix of the fuel itself or as included minerals. Using an advanced fuel analysis, i.e. a fractionation method, this mineral contentmore » can be divided into four fractions. The first fraction mainly contains those metal ions, that can be leached out of the fuel by water and mainly contains alkali sulfates, carbonates and chlorides. The second fraction mainly consists of those ions leached out by ammonium acetate and covers those ions, that are connected to the organic matrix. The third fraction contains the metals leached out by hydrochloric acid and contains earth alkali carbonates and sulfates as well as pyrites. The rest fraction contains those minerals, that are not leached out by any of the above mentioned solvents, such as silicates. A global equilibrium analysis is used to predict the thermal and chemical behavior of the combined first and second fractions and of the combined third and rest fractions under pressurized and/or atmospheric combustion conditions. Results of both the fuel analysis and the global equilibrium analysis are discussed and practical implications for combustion processes are pointed out.« less

Microstructure of wave propagation during combustion synthesis of advanced materials: Experiments and theory

NASA Astrophysics Data System (ADS)

Hwang, Stephen

Combustion synthesis (CS) is an attractive method for producing advanced materials, including ceramics, intermetallics, and composites. In this process, after initiation by an external heat source, a highly exothermic reaction propagates through the sample in a self-sustained combustion wave. The process offers the possibility of producing materials with novel structures and properties. At conventional magnifications and imaging rates, the combustion wave appears to propagate in a planar, steady manner. However, using higher magnifications (>400X) and imaging rates (1000 frames/sec), fluctuations in the shape and propagation of the combustion front were observed. These variations in local conditions (i.e., the microstructure of the combustion wave) can influence the microstructure and properties of materials produced by combustion synthesis. In this work, the microstructure of wave propagation during combustion synthesis is investigated experimentally and theoretically. Using microscopic high-speed imaging, the spatial and temporal fluctuations of the combustion front shape and propagation were investigated. New image analysis methods were developed to characterize the heterogeneity of the combustion front quantitatively. The initial organization of the reaction medium was found to affect the heterogeneity of the combustion wave. Moreover, at the microscopic level, two different regimes of combustion propagation were observed. In the quasihomogeneous mechanism, the microstructure of the combustion wave resembles what is viewed macroscopically, and steady, planar propagation is observed. In the relay-race mechanism, while planar at the macroscopic level, the combustion front profiles are irregularly shaped, with arc-shaped convexities and concavities at the microscopic level. Also, the reaction front propagates as a series of rapid jumps and hesitations. Based on the combustion wave microstructure, new criteria were developed to determine the boundaries between

Some Factors Affecting Combustion in an Internal-Combustion Engine

NASA Technical Reports Server (NTRS)

Rothrock, A M; Cohn, Mildred

1936-01-01

An investigation of the combustion of gasoline, safety, and diesel fuels was made in the NACA combustion apparatus under conditions of temperature that permitted ignition by spark with direct fuel injection, in spite of the compression ratio of 12.7 employed. The influence of such variables as injection advance angle, jacket temperature, engine speed, and spark position was studied. The most pronounced effect was that an increase in the injection advance angle (beyond a certain minimum value) caused a decrease in the extent and rate of combustion. In almost all cases combustion improved with increased temperature. The results show that at low air temperatures the rates of combustion vary with the volatility of the fuel, but that at high temperatures this relationship does not exist and the rates depend to a greater extent on the chemical nature of the fuel.

High Thermal Conductivity NARloy-Z-Diamond Composite Combustion Chamber Liner For Advanced Rocket Engines

NASA Technical Reports Server (NTRS)

Bhat, Biliyar N.; Ellis, David; Singh, Jogender

2014-01-01

Advanced high thermal conductivity materials research conducted at NASA Marshall Space Flight Center (MSFC) with state of the art combustion chamber liner material NARloy-Z showed that its thermal conductivity can be increased significantly by adding diamond particles and sintering it at high temperatures. For instance, NARloy-Z containing 40 vol. percent diamond particles, sintered at 975C to full density by using the Field assisted Sintering Technology (FAST) showed 69 percent higher thermal conductivity than baseline NARloy-Z. Furthermore, NARloy-Z-40vol. percent D is 30 percent lighter than NARloy-Z and hence the density normalized thermal conductivity is 140 percent better. These attributes will improve the performance and life of the advanced rocket engines significantly. By one estimate, increased thermal conductivity will directly translate into increased turbopump power up to 2X and increased chamber pressure for improved thrust and ISP, resulting in an expected 20 percent improvement in engine performance. Follow on research is now being conducted to demonstrate the benefits of this high thermal conductivity NARloy-Z-D composite for combustion chamber liner applications in advanced rocket engines. The work consists of a) Optimizing the chemistry and heat treatment for NARloy-Z-D composite, b) Developing design properties (thermal and mechanical) for the optimized NARloy-Z-D, c) Fabrication of net shape subscale combustion chamber liner, and d) Hot fire testing of the liner for performance. FAST is used for consolidating and sintering NARlo-Z-D. The subscale cylindrical liner with built in channels for coolant flow is also fabricated near net shape using the FAST process. The liner will be assembled into a test rig and hot fire tested in the MSFC test facility to determine performance. This paper describes the development of this novel high thermal conductivity NARloy-Z-D composite material, and the advanced net shape technology to fabricate the combustion

Study of advanced rotary combustion engines for commuter aircraft

NASA Technical Reports Server (NTRS)

Berkowitz, M.; Jones, C.; Myers, D.

1983-01-01

Performance, weight, size, and maintenance data for advanced rotary aircraft engines suitable for comparative commuter aircraft system evaluation studies of alternate engine candidates are provided. These are turbocharged, turbocompounded, direct injected, stratified charge rotary engines. Hypothetical engines were defined (an RC4-74 at 895 kW and an RC6-87 at 1490 kW) based on the technologies and design approaches used in the highly advanced engine of a study of advanced general aviation rotary engines. The data covers the size range of shaft power from 597 kW (800 hp) to 1865 kW (2500 hp) and is in the form of drawings, tables, curves and written text. These include data on internal geometry and configuration, installation information, turbocharging and turbocompounding arrangements, design features and technologies, engine cooling, fuels, scaling for weight size BSFC and heat rejection for varying horsepower, engine operating and performance data, and TBO and maintenance requirements. The basic combustion system was developed and demonstrated; however the projected power densities and performance efficiencies require increases in engine internal pressures, thermal loading, and rotative speed.

Laboratory Demonstrations for PDE and Metals Combustion at NASA MSFC's Advanced Propulsion Laboratory

NASA Technical Reports Server (NTRS)

2000-01-01

Report provides status reporting on activities under order no. H-30549 for the period December 1 through December 31, 1999. Details the activities of the contract in the coordination of planned conduct of experiments at the MSFC Advanced Propulsion Laboratory in pulse detonation MHD power production and metals combustion.

Advanced Chemical Modeling for Turbulent Combustion Simulations

DTIC Science & Technology

2012-05-03

premixed combustion. The chemistry work proposes a method for defining jet fuel surrogates, describes how different sub- mechanisms can be incorporated...Chemical Modeling For Turbulent Combustion Simulations Final Report submitted by: Heinz Pitsch (PI) Stanford University Mechanical Engineering Flow Physics...predict the combustion characteristics of fuel oxidation and pollutant emissions from engines . The relevant fuel chemistry must be accurately modeled

Microgravity Combustion Diagnostics Workshop

NASA Technical Reports Server (NTRS)

Santoro, Gilbert J. (Editor); Greenberg, Paul S. (Editor); Piltch, Nancy D. (Editor)

1988-01-01

Through the Microgravity Science and Applications Division (MSAD) of the Office of Space Science and Applications (OSSA) at NASA Headquarters, a program entitled, Advanced Technology Development (ATD) was promulgated with the objective of providing advanced technologies that will enable the development of future microgravity science and applications experimental flight hardware. Among the ATD projects one, Microgravity Combustion Diagnostics (MCD), has the objective of developing advanced diagnostic techniques and technologies to provide nonperturbing measurements of combustion characteristics and parameters that will enhance the scientific integrity and quality of microgravity combustion experiments. As part of the approach to this project, a workshop was held on July 28 and 29, 1987, at the NASA Lewis Research Center. A small group of laser combustion diagnosticians met with a group of microgravity combustion experimenters to discuss the science requirements, the state-of-the-art of laser diagnostic technology, and plan the direction for near-, intermediate-, and long-term programs. This publication describes the proceedings of that workshop.

Fabrication of High Thermal Conductivity NARloy-Z-Diamond Composite Combustion Chamber Liner for Advanced Rocket Engines

NASA Technical Reports Server (NTRS)

Bhat, Biliyar N.; Greene, Sandra E.; Singh, Jogender

2016-01-01

NARloy-Z alloy (Cu-3 percent, Ag-0.5 percent, Zr) is a state of the art alloy currently used for fabricating rocket engine combustion chamber liners. Research conducted at NASA-MSFC and Penn State – Applied Research Laboratory has shown that thermal conductivity of NARloy-Z can be increased significantly by adding diamonds to form a composite (NARloy-Z-D). NARloy-Z-D is also lighter than NARloy-Z. These attributes make this advanced composite material an ideal candidate for fabricating combustion chamber liner for an advanced rocket engine. Increased thermal conductivity will directly translate into increased turbopump power and increased chamber pressure for improved thrust and specific impulse. This paper describes the process development for fabricating a subscale high thermal conductivity NARloy-Z-D combustion chamber liner using Field Assisted Sintering Technology (FAST). The FAST process uses a mixture of NARloy-Z and diamond powders which is sintered under pressure at elevated temperatures. Several challenges were encountered, i.e., segregation of diamonds, machining the super hard NARloy-Z-D composite, net shape fabrication and nondestructive examination. The paper describes how these challenges were addressed. Diamonds coated with copper (CuD) appear to give the best results. A near net shape subscale combustion chamber liner is being fabricated by diffusion bonding cylindrical rings of NARloy-Z-CuD using the FAST process.

Mechanistic Studies Of Combustion And Structure Formation During Combustion Synthesis Of Advanced Materials: Phase Separation Mechanism For Bio-Alloys

NASA Technical Reports Server (NTRS)

Varma, A.; Lau, C.; Mukasyan, A.

2003-01-01

Among all implant materials, Co-Cr-Mo alloys demonstrate perhaps the most useful balance of resistance to corrosion, fatigue and wear, along with strength and biocompatibility [1]. Currently, these widely used alloys are produced by conventional furnace technology. Owing to high melting points of the main alloy elements (e.g. Tm.p.(Co) 1768 K), high-temperature furnaces and long process times (several hours) are required. Therefore, attempts to develop more efficient and flexible methods for production of such alloys with superior properties are of great interest. The synthesis of materials using combustion phenomena is an advanced approach in powder metallurgy [2]. The process is characterized by unique conditions involving extremely fast heating rates (up to 10(exp 6 K/s), high temperatures (up to 3500 K), and short reaction times (on the order of seconds). As a result, combustion synthesis (CS) offers several attractive advantages over conventional metallurgical processing and alloy development technologies. The foremost is that solely the heat of chemical reaction (instead of an external source) supplies the energy for the synthesis. Also, simple equipment, rather than energy-intensive high-temperature furnaces, is sufficient. This work was devoted to experiments on CS of Co-based alloys by utilizing thermite (metal oxide-reducing metal) reactions, where phase separation subsequently produces materials with tailored compositions and properties. Owing to high reaction exothermicity, the CS process results in a significant increase of temperature (up to 3000 C), which is higher than melting points of all products. Since the products differ in density, phase separation may be a gravitydriven process: the heavy (metallic phase) settles while the light (slag) phase floats. The goal was to determine if buoyancy is indeed the major mechanism that controls phase segregation.

Main Chamber and Preburner Injector Technology

NASA Technical Reports Server (NTRS)

Santoro, Robert J.; Merkle, Charles L.

1999-01-01

This document reports the experimental and analytical research carried out at the Penn State Propulsion Engineering Research Center in support of NASA's plan to develop advanced technologies for future single stage to orbit (SSTO) propulsion systems. The focus of the work is on understanding specific technical issues related to bi-propellant and tri-propellant thrusters. The experiments concentrate on both cold flow demonstrations and hot-fire uni-element tests to demonstrate concepts that can be incorporated into hardware design and development. The analysis is CFD-based and is intended to support the design and interpretation of the experiments and to extrapolate findings to full-scale designs. The research is divided into five main categories that impact various SSTO development scenarios. The first category focuses on RP-1/gaseous hydrogen (GH2)/gaseous oxygen (GO2) tri-propellant combustion with specific emphasis on understanding the benefits of hydrogen addition to RP-1/oxygen combustion and in developing innovative injector technology. The second category investigates liquid oxygen (LOX)/GH2 combustion at main chamber near stoichiometric conditions to improve understanding of existing LOX/GH2 rocket systems. The third and fourth categories investigate the technical issues related with oxidizer-rich and fuel-rich propulsive concepts, issues that are necessary for developing the full-flow engine cycle. Here, injector technology issues for both LOX/GH2 and LOX/RP-1 propellants are examined. The last category, also related to the full-flow engine cycle, examines injector technology needs for GO2/GH2 propellant combustion at near-stoichiometric conditions for main chamber application.

Method and apparatus for advanced staged combustion utilizing forced internal recirculation

DOEpatents

Rabovitser, Iosif K.; Knight, Richard A.; Cygan, David F.; Nester, Serguei; Abbasi, Hamid A.

2003-12-16

A method and apparatus for combustion of a fuel in which a first-stage fuel and a first-stage oxidant are introduced into a combustion chamber and ignited, forming a primary combustion zone. At least about 5% of the total heat output produced by combustion of the first-stage fuel and the first-stage oxidant is removed from the primary combustion zone, forming cooled first-stage combustion products. A portion of the cooled first-stage combustion products from a downstream region of the primary combustion zone is recirculated to an upstream region of primary combustion zone. A second-stage fuel is introduced into the combustion chamber downstream of the primary combustion zone and ignited, forming a secondary combustion zone. At least about 5% of the heat from the secondary combustion zone is removed. In accordance with one embodiment, a third-stage oxidant is introduced into the combustion chamber downstream of the secondary combustion zone, forming a tertiary combustion zone.

Some Effects of Injection Advance Angle, Engine-Jacket Temperature, and Speed on Combustion in a Compression-Ignition Engine

NASA Technical Reports Server (NTRS)

Rothrock, A M; Waldron, C D

1936-01-01

An optical indicator and a high-speed motion-picture camera capable of operating at the rate of 2,000 frames per second were used to record simultaneously the pressure development and the flame formation in the combustion chamber of the NACA combustion apparatus. Tests were made at engine speeds of 570 and 1,500 r.p.m. The engine-jacket temperature was varied from 100 degrees to 300 degrees F. And the injection advance angle from 13 degrees after top center to 120 degrees before top center. The results show that the course of the combustion is largely controlled by the temperature and pressure of the air in the chamber from the time the fuel is injected until the time at which combustion starts and by the ignition lag. The conclusion is presented that in a compression-ignition engine with a quiescent combustion chamber the ignition lag should be the longest that can be used without excessive rates of pressure rise; any further shortening of the ignition lag decreased the effective combustion of the engine.

Development of Kinetic Mechanisms for Next-Generation Fuels and CFD Simulation of Advanced Combustion Engines

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

Pitz, William J.; McNenly, Matt J.; Whitesides, Russell

Predictive chemical kinetic models are needed to represent next-generation fuel components and their mixtures with conventional gasoline and diesel fuels. These kinetic models will allow the prediction of the effect of alternative fuel blends in CFD simulations of advanced spark-ignition and compression-ignition engines. Enabled by kinetic models, CFD simulations can be used to optimize fuel formulations for advanced combustion engines so that maximum engine efficiency, fossil fuel displacement goals, and low pollutant emission goals can be achieved.

State of the art and future needs in S.I. engine combustion

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

Maly, R.R.

1994-12-31

The paper reviews, in short, the state-of-the-art in SI engine combustion by addressing its main features: mixture formation, ignition, homogeneous combustion, pollutant formation, knock, and engine modeling. Necessary links between fundamental and practical work are clarified and discussed along with advanced diagnostics and simulation tools. The needs for further work are identified, the most important one being integration of all fundamental and practical resources to meet R and D requirements for future engines.

Advanced Monitoring to Improve Combustion Turbine/Combined Cycle Reliability, Availability & Maintainability

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

Leonard Angello

2005-09-30

Power generators are concerned with the maintenance costs associated with the advanced turbines that they are purchasing. Since these machines do not have fully established Operation and Maintenance (O&M) track records, power generators face financial risk due to uncertain future maintenance costs. This risk is of particular concern, as the electricity industry transitions to a competitive business environment in which unexpected O&M costs cannot be passed through to consumers. These concerns have accelerated the need for intelligent software-based diagnostic systems that can monitor the health of a combustion turbine in real time and provide valuable information on the machine's performancemore » to its owner/operators. EPRI, Impact Technologies, Boyce Engineering, and Progress Energy have teamed to develop a suite of intelligent software tools integrated with a diagnostic monitoring platform that, in real time, interpret data to assess the 'total health' of combustion turbines. The 'Combustion Turbine Health Management System' (CTHMS) will consist of a series of 'Dynamic Link Library' (DLL) programs residing on a diagnostic monitoring platform that accepts turbine health data from existing monitoring instrumentation. CTHMS interprets sensor and instrument outputs, correlates them to a machine's condition, provide interpretative analyses, project servicing intervals, and estimate remaining component life. In addition, the CTHMS enables real-time anomaly detection and diagnostics of performance and mechanical faults, enabling power producers to more accurately predict critical component remaining useful life and turbine degradation.« less

Fuel Effects on Ignition and Their Impact on Advanced Combustion Engines (Poster)

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

Taylor, J.; Li, H.; Neill, S.

The objective of this report is to develop a pathway to use easily measured ignition properties as metrics for characterizing fuels in advanced combustion engine research--correlate IQT{trademark} measured parameters with engine data. In HCCL engines, ignition timing depends on the reaction rates throughout compression stroke: need to understand sensitivity to T, P, and [O{sub 2}]; need to rank fuels based on more than one set of conditions; and need to understand how fuel composition (molecular species) affect ignition properties.

Computational Combustion

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

Westbrook, C K; Mizobuchi, Y; Poinsot, T J

2004-08-26

Progress in the field of computational combustion over the past 50 years is reviewed. Particular attention is given to those classes of models that are common to most system modeling efforts, including fluid dynamics, chemical kinetics, liquid sprays, and turbulent flame models. The developments in combustion modeling are placed into the time-dependent context of the accompanying exponential growth in computer capabilities and Moore's Law. Superimposed on this steady growth, the occasional sudden advances in modeling capabilities are identified and their impacts are discussed. Integration of submodels into system models for spark ignition, diesel and homogeneous charge, compression ignition engines, surfacemore » and catalytic combustion, pulse combustion, and detonations are described. Finally, the current state of combustion modeling is illustrated by descriptions of a very large jet lifted 3D turbulent hydrogen flame with direct numerical simulation and 3D large eddy simulations of practical gas burner combustion devices.« less

Internal combustion engine

DOEpatents

Baker, Quentin A.; Mecredy, Henry E.; O'Neal, Glenn B.

1991-01-01

An improved engine is provided that more efficiently consumes difficult fuels such as coal slurries or powdered coal. The engine includes a precombustion chamber having a portion thereof formed by an ignition plug. The precombustion chamber is arranged so that when the piston is proximate the head, the precombustion chamber is sealed from the main cylinder or the main combustion chamber and when the piston is remote from the head, the precombustion chamber and main combustion chamber are in communication. The time for burning of fuel in the precombustion chamber can be regulated by the distance required to move the piston from the top dead center position to the position wherein the precombustion chamber and main combustion chamber are in communication.

Development of Computational Capabilities to Predict the Corrosion Wastage of Boiler Tubes in Advanced Combustion Systems

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

Kung, Steven; Rapp, Robert

A comprehensive corrosion research project consisting of pilot-scale combustion testing and long-term laboratory corrosion study has been successfully performed. A pilot-scale combustion facility available at Brigham Young University was selected and modified to enable burning of pulverized coals under the operating conditions typical for advanced coal-fired utility boilers. Eight United States (U.S.) coals were selected for this investigation, with the test conditions for all coals set to have the same heat input to the combustor. In addition, the air/fuel stoichiometric ratio was controlled so that staged combustion was established, with the stoichiometric ratio maintained at 0.85 in the burner zonemore » and 1.15 in the burnout zone. The burner zone represented the lower furnace of utility boilers, while the burnout zone mimicked the upper furnace areas adjacent to the superheaters and reheaters. From this staged combustion, approximately 3% excess oxygen was attained in the combustion gas at the furnace outlet. During each of the pilot-scale combustion tests, extensive online measurements of the flue gas compositions were performed. In addition, deposit samples were collected at the same location for chemical analyses. Such extensive gas and deposit analyses enabled detailed characterization of the actual combustion environments existing at the lower furnace walls under reducing conditions and those adjacent to the superheaters and reheaters under oxidizing conditions in advanced U.S. coal-fired utility boilers. The gas and deposit compositions were then carefully simulated in a series of 1000-hour laboratory corrosion tests, in which the corrosion performances of different commercial candidate alloys and weld overlays were evaluated at various temperatures for advanced boiler systems. Results of this laboratory study led to significant improvement in understanding of the corrosion mechanisms operating on the furnace walls as well as superheaters and

Robust Low Cost Aerospike/RLV Combustion Chamber by Advanced Vacuum Plasma Process

NASA Technical Reports Server (NTRS)

Holmes, Richard; Ellis, David; McKechnie

1999-01-01

Next-generation, regeneratively cooled rocket engines will require materials that can withstand high temperatures while retaining high thermal conductivity. At the same time, fabrication techniques must be cost efficient so that engine components can be manufactured within the constraints of a shrinking NASA budget. In recent years, combustion chambers of equivalent size to the Aerospike chamber have been fabricated at NASA-Marshall Space Flight Center (MSFC) using innovative, relatively low-cost, vacuum-plasma-spray (VPS) techniques. Typically, such combustion chambers are made of the copper alloy NARloy-Z. However, current research and development conducted by NASA-Lewis Research Center (LeRC) has identified a Cu-8Cr-4Nb alloy which possesses excellent high-temperature strength, creep resistance, and low cycle fatigue behavior combined with exceptional thermal stability. In fact, researchers at NASA-LeRC have demonstrated that powder metallurgy (P/M) Cu-8Cr-4Nb exhibits better mechanical properties at 1,200 F than NARloy-Z does at 1,000 F. The objective of this program was to develop and demonstrate the technology to fabricate high-performance, robust, inexpensive combustion chambers for advanced propulsion systems (such as Lockheed-Martin's VentureStar and NASA's Reusable Launch Vehicle, RLV) using the low-cost, VPS process to deposit Cu-8Cr-4Nb with mechanical properties that match or exceed those of P/M Cu-8Cr-4Nb. In addition, oxidation resistant and thermal barrier coatings can be incorporated as an integral part of the hot wall of the liner during the VPS process. Tensile properties of Cu-8Cr-4Nb material produced by VPS are reviewed and compared to material produced previously by extrusion. VPS formed combustion chamber liners have also been prepared and will be reported on following scheduled hot firing tests at NASA-Lewis.

Application of Multivariable Model Predictive Advanced Control for a 2×310T/H CFB Boiler Unit

NASA Astrophysics Data System (ADS)

Weijie, Zhao; Zongllao, Dai; Rong, Gou; Wengan, Gong

When a CFB boiler is in automatic control, there are strong interactions between various process variables and inverse response characteristics of bed temperature control target. Conventional Pill control strategy cannot deliver satisfactory control demand. Kalman wave filter technology is used to establish a non-linear combustion model, based on the CFB combustion characteristics of bed fuel inventory, heating values, bed lime inventory and consumption. CFB advanced combustion control utilizes multivariable model predictive control technology to optimize primary and secondary air flow, bed temperature, air flow, fuel flow and heat flux. In addition to providing advanced combustion control to 2×310t/h CFB+1×100MW extraction condensing turbine generator unit, the control also provides load allocation optimization and advanced control for main steam pressure, combustion and temperature. After the successful implementation, under 10% load change, main steam pressure varied less than ±0.07MPa, temperature less than ±1°C, bed temperature less than ±4°C, and air flow (O2) less than ±0.4%.

The combustion behavior of diesel/CNG mixtures in a constant volume combustion chamber

NASA Astrophysics Data System (ADS)

Firmansyah; Aziz, A. R. A.; Heikal, M. R.

2015-12-01

The stringent emissions and needs to increase fuel efficiency makes controlled auto-ignition (CAI) based combustion an attractive alternative for the new combustion system. However, the combustion control is the main obstacles in its development. Reactivity controlled compression ignition (RCCI) that employs two fuels with significantly different in reactivity proven to be able to control the combustion. The RCCI concept applied in a constant volume chamber fuelled with direct injected diesel and compressed natural gas (CNG) was tested. The mixture composition is varied from 0 - 100% diesel/CNG at lambda 1 with main data collection are pressure profile and combustion images. The results show that diesel-CNG mixture significantly shows better combustion compared to diesel only. It is found that CNG is delaying the diesel combustion and at the same time assisting in diesel distribution inside the chamber. This combination creates a multipoint ignition of diesel throughout the chamber that generate very fast heat release rate and higher maximum pressure. Furthermore, lighter yellow color of the flame indicates lower soot production in compared with diesel combustion.

Microwave-Assisted Ignition for Improved Internal Combustion Engine Efficiency

NASA Astrophysics Data System (ADS)

DeFilippo, Anthony Cesar

The ever-present need for reducing greenhouse gas emissions associated with transportation motivates this investigation of a novel ignition technology for internal combustion engine applications. Advanced engines can achieve higher efficiencies and reduced emissions by operating in regimes with diluted fuel-air mixtures and higher compression ratios, but the range of stable engine operation is constrained by combustion initiation and flame propagation when dilution levels are high. An advanced ignition technology that reliably extends the operating range of internal combustion engines will aid practical implementation of the next generation of high-efficiency engines. This dissertation contributes to next-generation ignition technology advancement by experimentally analyzing a prototype technology as well as developing a numerical model for the chemical processes governing microwave-assisted ignition. The microwave-assisted spark plug under development by Imagineering, Inc. of Japan has previously been shown to expand the stable operating range of gasoline-fueled engines through plasma-assisted combustion, but the factors limiting its operation were not well characterized. The present experimental study has two main goals. The first goal is to investigate the capability of the microwave-assisted spark plug towards expanding the stable operating range of wet-ethanol-fueled engines. The stability range is investigated by examining the coefficient of variation of indicated mean effective pressure as a metric for instability, and indicated specific ethanol consumption as a metric for efficiency. The second goal is to examine the factors affecting the extent to which microwaves enhance ignition processes. The factors impacting microwave enhancement of ignition processes are individually examined, using flame development behavior as a key metric in determining microwave effectiveness. Further development of practical combustion applications implementing microwave

Thermally Stratified Compression Ignition: A new advanced low temperature combustion mode with load flexibility

DOE PAGES

Lawler, Benjamin; Splitter, Derek; Szybist, James; ...

2017-03-01

We introduce a new advanced combustion mode, called Thermally Stratified Compression Ignition (TSCI), which uses direct water injection to control both the average temperature and the temperature distribution prior to ignition, thereby providing cycle-to-cycle control over the start and rate of heat release in Low Temperature Combustion (LTC). Experiments were conducted to fundamentally understand the effects of water injection on heat release in LTC. Our results show that water injection retards the start of combustion due to the latent heat of vaporization of the injected water. Furthermore, for start of water injection timings between 20 and 70 degrees before topmore » dead center, combustion is significantly elongated compared to without water injection. The 10–90% burn duration with 6.6 and 9.0 mg of water per cycle was 77% and 146% longer than without water injection, respectively. Forced thermal stratification result from a direct water injection which reduces the heat release rate by local evaporative cooling. Finally, the load limits with and without water injection were determined experimentally. Without water injection, the load range was 2.3–3.6 bar gross IMEP. By using water injection to control heat release, the load range in TSCI was 2.3–8.4 bar gross IMEP, which is a range expansion of over 350%. These results demonstrate that direct water injection can provide significant improvements to both controllability and the range of operability of LTC, thereby resolving the major challenges associated with HCCI.« less

Diesel engine emissions and combustion predictions using advanced mixing models applicable to fuel sprays

NASA Astrophysics Data System (ADS)

Abani, Neerav; Reitz, Rolf D.

2010-09-01

An advanced mixing model was applied to study engine emissions and combustion with different injection strategies ranging from multiple injections, early injection and grouped-hole nozzle injection in light and heavy duty diesel engines. The model was implemented in the KIVA-CHEMKIN engine combustion code and simulations were conducted at different mesh resolutions. The model was compared with the standard KIVA spray model that uses the Lagrangian-Drop and Eulerian-Fluid (LDEF) approach, and a Gas Jet spray model that improves predictions of liquid sprays. A Vapor Particle Method (VPM) is introduced that accounts for sub-grid scale mixing of fuel vapor and more accurately and predicts the mixing of fuel-vapor over a range of mesh resolutions. The fuel vapor is transported as particles until a certain distance from nozzle is reached where the local jet half-width is adequately resolved by the local mesh scale. Within this distance the vapor particle is transported while releasing fuel vapor locally, as determined by a weighting factor. The VPM model more accurately predicts fuel-vapor penetrations for early cycle injections and flame lift-off lengths for late cycle injections. Engine combustion computations show that as compared to the standard KIVA and Gas Jet spray models, the VPM spray model improves predictions of in-cylinder pressure, heat released rate and engine emissions of NOx, CO and soot with coarse mesh resolutions. The VPM spray model is thus a good tool for efficiently investigating diesel engine combustion with practical mesh resolutions, thereby saving computer time.

Thermally Stratified Compression Ignition: A new advanced low temperature combustion mode with load flexibility

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

Lawler, Benjamin; Splitter, Derek; Szybist, James

We introduce a new advanced combustion mode, called Thermally Stratified Compression Ignition (TSCI), which uses direct water injection to control both the average temperature and the temperature distribution prior to ignition, thereby providing cycle-to-cycle control over the start and rate of heat release in Low Temperature Combustion (LTC). Experiments were conducted to fundamentally understand the effects of water injection on heat release in LTC. Our results show that water injection retards the start of combustion due to the latent heat of vaporization of the injected water. Furthermore, for start of water injection timings between 20 and 70 degrees before topmore » dead center, combustion is significantly elongated compared to without water injection. The 10–90% burn duration with 6.6 and 9.0 mg of water per cycle was 77% and 146% longer than without water injection, respectively. Forced thermal stratification result from a direct water injection which reduces the heat release rate by local evaporative cooling. Finally, the load limits with and without water injection were determined experimentally. Without water injection, the load range was 2.3–3.6 bar gross IMEP. By using water injection to control heat release, the load range in TSCI was 2.3–8.4 bar gross IMEP, which is a range expansion of over 350%. These results demonstrate that direct water injection can provide significant improvements to both controllability and the range of operability of LTC, thereby resolving the major challenges associated with HCCI.« less

Main Chamber Injectors for Advanced Hydrocarbon Booster Engines

NASA Technical Reports Server (NTRS)

Long, Matthew R.; Bazarov, Vladimir G.; Anderson, William E.

2003-01-01

Achieving the highest possible specific impulse has long been a key driver for space launch systems. Recently, more importance has been placed on the need for increased reliability and streamlined launch operations. These general factors along with more specific mission requirements have provided a new focus that is centered on the oxidizer rich staged combustion (ORSC) cycle. Despite a history of use in Russia that extends back to the 1960's, a proven design methodology for ORSC cycle engines does not exist in the West. This lack of design expertise extends to the main chamber injector, a critical subcomponent that largely determines the engine performance and main chamber life. The goals of the effort described here are to establish an empirical knowledge base to provide a fundamental understanding of main chamber injectors and for verification of an injector design methodology for the ORSC cycle. The design of a baseline injector element, derived from information on Russian engines in the open literature, is presented. The baseline injector comprises a gaseous oxidizer core flow and an annular swirling fuel flow. Sets of equations describing the steady-state and the dynamic characteristics of the injector are presented; these equations, which form the basis of the design analysis methodology, will be verified in tests later this year. On-going cold flow studies, using nitrogen and water as simulants, are described which indicate highly atomized and symmetric sprays.

Annual Report: DOE Advanced Combustion Systems & Fuels R&D; Light-Duty Diesel Combustion

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

Busch, Stephen

Despite compliance issues in previous years, automakers have demonstrated that the newest generation of diesel power trains are capable of meeting all federal and state regulations (EPA, 2016). Diesels continue to be a cost-effective, efficient, powerful propulsion source for many light- and medium-duty vehicle applications (Martec, 2016). Even modest reductions in the fuel consumption of light- and medium duty diesel vehicles in the U.S. will eliminate millions of tons of CO2 emissions per year. Continued improvement of diesel combustion systems will play an important role in reducing fleet fuel consumption, but these improvements will require an unprecedented scientific understanding ofmore » how changes in engine design and calibration affect the mixture preparation, combustion, and pollutant formation processes that take place inside the cylinder. The focus of this year’s research is to provide insight into the physical mechanisms responsible for improved thermal efficiency observed with a stepped-lip piston. Understanding how piston design can influence efficiency will help engineers develop and optimize new diesel combustion systems.« less

Aerothermal environment induced by mismatch at the SSME main combustion chamber-nozzle joint

NASA Technical Reports Server (NTRS)

Mcconnaughey, H. V.; O'Farrell, J. M.; Olive, T. A.; Brown, G. B.; Holt, J. B.

1990-01-01

The computational study reported here is motivated by a Space Shuttle main engine hardware problem detected in post-flight and post-test inspections. Of interest are the potential for hot gas ingestion into the joint (G15) at the main combustion chamber-to-nozzle interface and the effect of particular goemetric nonuniformities on that gas ingestion. The flowfield in the G15 region involves supersonic flow past a rounded forward facing step preceded by a deep narrow cavity. This paper describes the physical problem associated with joint G15 and computational investigations of the G15 aerothermal environment. The associated flowfield was simulated in two and three space dimensions using the United Solutions Algorithm (USA) computational fluid dynamics code series. A benchmark calculation of experimentally measured supersonic flow over of a square cavity was performed to demonstrate the accuracy of the USA code in analyzing flows similar to the G15 computational flowfield. The G15 results demonstrate the mechanism for hot gas ingestion into the joint and reveal the sensitivity to salient geometric nonuniformities.

Multiuser Droplet Combustion Apparatus Developed to Conduct Combustion Experiments

NASA Technical Reports Server (NTRS)

Myhre, Craig A.

2001-01-01

A major portion of the energy produced in the world today comes from the combustion or burning of liquid hydrocarbon fuels in the form of droplets. However, despite vigorous scientific examinations for over a century, researchers still lack a full understanding of many fundamental combustion processes of liquid fuels. Understanding how these fuel droplets ignite, spread, and extinguish themselves will help us develop more efficient ways of energy production and propulsion, as well as help us deal better with the problems of combustion-generated pollution and fire hazards associated with liquid combustibles. The ability to conduct more controlled experiments in space, without the complication of gravity, provides scientists with an opportunity to examine these complicated processes closely. The Multiuser Droplet Combustion Apparatus (MDCA) supports this continued research under microgravity conditions. The objectives are to improve understanding of fundamental droplet phenomena affected by gravity, to use research results to advance droplet combustion science and technology on Earth, and to address issues of fire hazards associated with liquid combustibles on Earth and in space. MDCA is a multiuser facility designed to accommodate different combustion science experiments. The modular approach permits the on-orbit replacement of droplet combustion principal investigator experiments such as different fuels, droplet-dispensing needles, and droplet-tethering mechanisms. Large components such as the avionics, diagnostics, and base-plate remain on the International Space Station to reduce the launch mass of new experiments. MDCA is also designed to operate in concert with ground systems on Earth to minimize the involvement of the crew during orbit.

Fabrication of High Thermal Conductivity NARloy-Z-Diamond Composite Combustion Chamber Liner for Advanced Rocket Engines

NASA Technical Reports Server (NTRS)

Bhat, Biliyar N.; Greene, Sandra E.; Singh, Jogender

2016-01-01

This paper describes the process development for fabricating a high thermal conductivity NARloy-Z-Diamond composite (NARloy-Z-D) combustion chamber liner for application in advanced rocket engines. The fabrication process is challenging and this paper presents some details of these challenges and approaches used to address them. Prior research conducted at NASA-MSFC and Penn State had shown that NARloy-Z-40%D composite material has significantly higher thermal conductivity than the state of the art NARloy-Z alloy. Furthermore, NARloy-Z-40 %D is much lighter than NARloy-Z. These attributes help to improve the performance of the advanced rocket engines. Increased thermal conductivity will directly translate into increased turbopump power, increased chamber pressure for improved thrust and specific impulse. Early work on NARloy-Z-D composites used the Field Assisted Sintering Technology (FAST, Ref. 1, 2) for fabricating discs. NARloy-Z-D composites containing 10, 20 and 40vol% of high thermal conductivity diamond powder were investigated. Thermal conductivity (TC) data. TC increased with increasing diamond content and showed 50% improvement over pure copper at 40vol% diamond. This composition was selected for fabricating the combustion chamber liner using the FAST technique.

Supercritical droplet combustion and related transport phenomena

NASA Technical Reports Server (NTRS)

Yang, Vigor; Hsieh, K. C.; Shuen, J. S.

1993-01-01

An overview of recent advances in theoretical analyses of supercritical droplet vaporization and combustion is conducted. Both hydrocarbon and cryogenic liquid droplets over a wide range of thermodynamic states are considered. Various important high-pressure effects on droplet behavior, such as thermodynamic non-ideality, transport anomaly, and property variation, are reviewed. Results indicate that the ambient gas pressure exerts significant control of droplet gasification and burning processes through its influence on fluid transport, gas-liquid interfacial thermodynamics, and chemical reactions. The droplet gasification rate increases progressively with pressure. However, the data for the overall burnout time exhibit a considerable change in the combustion mechanism at the criticl pressure, mainly as a result of reduced mass diffusivity and latent heat of vaporization with increased pressure. The influence of droplet size on the burning characteristics is also noted.

Beryllium particle combustion

NASA Technical Reports Server (NTRS)

Prentice, J. L.

1972-01-01

A two-year study of the combustion efficiency of single beryllium droplets burning in a variety of oxidizers (primarily mixtures of oxygen/argon and oxygen/nitrogen) is summarized. An advanced laser heating technique was used to acquire systematic quantitative data on the burning of single beryllium droplets at atmospheric pressure. The research confirmed the sensitivity of beryllium droplet combustion to the chemistry of environmental species and provides experimental documentation for the nitrogen-induced droplet fragmentation of burning beryllium droplets.

Energy Efficient Engine (E3) combustion system component technology performance report

NASA Technical Reports Server (NTRS)

Burrus, D. L.; Chahrour, C. A.; Foltz, H. L.; Sabla, P. E.; Seto, S. P.; Taylor, J. R.

1984-01-01

The Energy Efficient Engine (E3) combustor effort was conducted as part of the overall NASA/GE E3 Program. This effort included the selection of an advanced double-annular combustion system design. The primary intent of this effort was to evolve a design that meets the stringent emissions and life goals of the E3, as well as all of the usual performance requirements of combustion systems for modern turbofan engines. Numerous detailed design studies were conducted to define the features of the combustion system design. Development test hardware was fabricated, and an extensive testing effort was undertaken to evaluate the combustion system subcomponents in order to verify and refine the design. Technology derived from this effort was incorporated into the engine combustion hardware design. The advanced engine combustion system was then evaluated in component testing to verify the design intent. What evolved from this effort was an advanced combustion system capable of satisfying all of the combustion system design objectives and requirements of the E3.

Space Shuttle Main Engine: Advanced Health Monitoring System

NASA Technical Reports Server (NTRS)

Singer, Chirs

1999-01-01

The main gola of the Space Shuttle Main Engine (SSME) Advanced Health Management system is to improve flight safety. To this end the new SSME has robust new components to improve the operating margen and operability. The features of the current SSME health monitoring system, include automated checkouts, closed loop redundant control system, catastropic failure mitigation, fail operational/ fail-safe algorithms, and post flight data and inspection trend analysis. The features of the advanced health monitoring system include: a real time vibration monitor system, a linear engine model, and an optical plume anomaly detection system. Since vibration is a fundamental measure of SSME turbopump health, it stands to reason that monitoring the vibration, will give some idea of the health of the turbopumps. However, how is it possible to avoid shutdown, when it is not necessary. A sensor algorithm has been developed which has been exposed to over 400 test cases in order to evaluate the logic. The optical plume anomaly detection (OPAD) has been developed to be a sensitive monitor of engine wear, erosion, and breakage.

Combustion and Heat Transfer Studies Utilizing Advanced Diagnostics: Combustion Studies

DTIC Science & Technology

1992-11-01

Research Zone With Combustion," Turbulent Shear Flows. VoL 5. pp. 337- and Development Center, Aero Propulsion and Power 346, Springer Verlg, New ...200 words) A long-term goal of the Air Force is to develop near-stoichiometric gas turbine combustors that will burn broad-specification fuels, and...laboratory combustors. Two novel methods for CARS slit function were developed ; these made possible precise and unambiguous measurements of flame

Recent Advances In Science Support For Isolated Droplet Combustion Experiments

NASA Technical Reports Server (NTRS)

Dryer, F. L.; Kazakov, A.; Urban, B. D.; Kroenlein, K.

2003-01-01

In a joint program involving Prof. F.A. Williams of the University of California, San Diego and Dr. V. Nayagam of the National Center for Microgravity Research, the combustion characteristics of isolated liquid fuel droplets of n-heptane, n-decane, methanol, methanol-water, ethanol and ethanol-water having initial diameters between about 1 mm and 6 mm continues to be investigated. The objectives of the work are to improve fundamental knowledge of droplet combustion dynamics for pure fuels and fuel-water mixtures through microgravity experiments and theoretical analyses. The Princeton contributions support the engineering design, data analysis, and data interpretation requirements for the study of initially single component, spherically symmetric, isolated droplet combustion studies through experiments and numerical modeling. UCSD contributions are described in a companion communication in this conference. The Princeton effort also addresses the analyses of Fiber Supported Droplet Combustion (FSDC) experiments conducted with the above fuels and collaborative work with others who are investigating droplet combustion in the presence of steady convection. A thorough interpretation of droplet burning behavior for n-heptane and n-decane over a relatively wide range of conditions also involves the influences of sooting on the combustion behavior, and this particular aspect on isolated burning of droplets is under consideration in a collaborative program underway with Drexel University. This collaboration is addressed in another communication at this conference. The one-dimensional, time-dependent, numerical modeling approach that we have continued to evolve for analyzing isolated, quiescent droplet combustion data has been further applied to investigate several facets of isolated droplet burning of simple alcohols, n-heptane, and n-decane. Some of the new results are described below.

Nitrogen enriched combustion of a natural gas internal combustion engine to reduce NO.sub.x emissions

DOEpatents

Biruduganti, Munidhar S.; Gupta, Sreenath Borra; Sekar, R. Raj; McConnell, Steven S.

2008-11-25

A method and system for reducing nitrous oxide emissions from an internal combustion engine. An input gas stream of natural gas includes a nitrogen gas enrichment which reduces nitrous oxide emissions. In addition ignition timing for gas combustion is advanced to improve FCE while maintaining lower nitrous oxide emissions.

Active Combustion Control for Aircraft Gas-Turbine Engines-Experimental Results for an Advanced, Low-Emissions Combustor Prototype

NASA Technical Reports Server (NTRS)

DeLaat, John C.; Kopasakis, George; Saus, Joseph R.; Chang, Clarence T.; Wey, Changlie

2012-01-01

Lean combustion concepts for aircraft engine combustors are prone to combustion instabilities. Mitigation of instabilities is an enabling technology for these low-emissions combustors. NASA Glenn Research Center s prior activity has demonstrated active control to suppress a high-frequency combustion instability in a combustor rig designed to emulate an actual aircraft engine instability experience with a conventional, rich-front-end combustor. The current effort is developing further understanding of the problem specifically as applied to future lean-burning, very low-emissions combustors. A prototype advanced, low-emissions aircraft engine combustor with a combustion instability has been identified and previous work has characterized the dynamic behavior of that combustor prototype. The combustor exhibits thermoacoustic instabilities that are related to increasing fuel flow and that potentially prevent full-power operation. A simplified, non-linear oscillator model and a more physics-based sectored 1-D dynamic model have been developed to capture the combustor prototype s instability behavior. Utilizing these models, the NASA Adaptive Sliding Phasor Average Control (ASPAC) instability control method has been updated for the low-emissions combustor prototype. Active combustion instability suppression using the ASPAC control method has been demonstrated experimentally with this combustor prototype in a NASA combustion test cell operating at engine pressures, temperatures, and flows. A high-frequency fuel valve was utilized to perturb the combustor fuel flow. Successful instability suppression was shown using a dynamic pressure sensor in the combustor for controller feedback. Instability control was also shown with a pressure feedback sensor in the lower temperature region upstream of the combustor. It was also demonstrated that the controller can prevent the instability from occurring while combustor operation was transitioning from a stable, low-power condition to

Low emission internal combustion engine

DOEpatents

Karaba, Albert M.

1979-01-01

A low emission, internal combustion compression ignition engine having a cylinder, a piston movable in the cylinder and a pre-combustion chamber communicating with the cylinder near the top thereof and in which low emissions of NO.sub.x are achieved by constructing the pre-combustion chamber to have a volume of between 70% and 85% of the combined pre-chamber and main combustion chamber volume when the piston is at top dead center and by variably controlling the initiation of fuel injection into the pre-combustion chamber.

Promoted Combustion Test Data Re-Examined

NASA Technical Reports Server (NTRS)

Lewis, Michelle; Jeffers, Nathan; Stoltzfus, Joel

2010-01-01

Promoted combustion testing of metallic materials has been performed by NASA since the mid-1980s to determine the burn resistance of materials in oxygen-enriched environments. As the technolo gy has advanced, the method of interpreting, presenting, and applying the promoted combustion data has advanced as well. Recently NASA changed the bum criterion from 15 cm (6 in.) to 3 cm (1.2 in.). This new burn criterion was adopted for ASTM G 124, Standard Test Method for Determining the Combustion Behavior- of Metallic Materials in Oxygen-Enriched Atmospheres. Its effect on the test data and the latest method to display the test data will be discussed. Two specific examples that illustrate how this new criterion affects the burn/no-bum thresholds of metal alloys will also be presented.

National Combustion Code: Parallel Performance

NASA Technical Reports Server (NTRS)

Babrauckas, Theresa

2001-01-01

This report discusses the National Combustion Code (NCC). The NCC is an integrated system of codes for the design and analysis of combustion systems. The advanced features of the NCC meet designers' requirements for model accuracy and turn-around time. The fundamental features at the inception of the NCC were parallel processing and unstructured mesh. The design and performance of the NCC are discussed.

Priorities for Microgravity Combustion Research and Goals for Workshop Discussions

NASA Technical Reports Server (NTRS)

Faeth, Gerard M.

1993-01-01

Several concerns motivate fundamental research: combustion-generated pollutants are re-emerging as a major problem, new combustion technologies are needed for effective energy utilization, municipal and hazardous waste incineration are needed to replace landfills and storage, new combustion technologies are needed for advanced aircraft and spacecraft propulsion systems, and current understanding of fires and explosion hazards is limited - particularly for space-craft environments. Thus, it is of interest to determine how experimentation using microgravity facilities can advance research relevant to these problems.

Advanced CFD modelling of air and recycled flue gas staging in a waste wood-fired grate boiler for higher combustion efficiency and greater environmental benefits.

PubMed

Rajh, Boštjan; Yin, Chungen; Samec, Niko; Hriberšek, Matjaž; Kokalj, Filip; Zadravec, Matej

2018-07-15

Grate-fired boilers are commonly used to burn biomass/wastes for heat and power production. In spite of the recent breakthrough in integration of advanced secondary air systems in grate boilers, grate-firing technology needs to be advanced for higher efficiency and lower emissions. In this paper, innovative staging of combustion air and recycled flue gas in a 13 MW th waste wood-fired grate boiler is comprehensively studied based on a numerical model that has been previously validated. In particular, the effects of the jet momentum, position and orientation of the combustion air and recycled flue gas streams on in-furnace mixing, combustion and pollutant emissions from the boiler are examined. It is found that the optimized air and recycled flue gas jets remarkably enhance mixing and heat transfer, result in a more uniform temperature and velocity distribution, extend the residence time of the combustibles in the hot zone and improve burnout in the boiler. Optimizing the air and recycled flue gas jet configuration can reduce carbon monoxide emission from the boiler by up to 86%, from the current 41.0 ppm to 5.7 ppm. The findings of this study can serve as useful guidelines for novel design and optimization of the combustion air supply and flue gas recycling for grate boilers of this type. Copyright © 2018 Elsevier Ltd. All rights reserved.

Modeling aerosol emissions from the combustion of composite materials

NASA Technical Reports Server (NTRS)

Roop, J. A.; Caldwell, D. J.; Kuhlmann, K. J.

1994-01-01

The use of advanced composite materials (ACM) in the B-2 bomber, composite armored vehicle, and F-22 advanced tactical fighter has rekindled interest concerning the health risk of burned or burning ACM. The objective of this work was to determine smoke production from burning ACM and its toxicity. A commercial version of the UPITT II combustion toxicity method developed at the University of Pittsburgh, and subsequently refined through a US Army-funded basic research project, was used to established controlled combustion conditions which were selected to evaluate real-world exposure scenarios. Production and yield of toxic species varied with the combustion conditions. Previous work with this method showed that the combustion conditions directly influenced the toxicity of the decomposition products from a variety of materials.

Combustion devices technology team - An overview and status of STME-related activities

NASA Technical Reports Server (NTRS)

Tucker, P. K.; Croteau-Gillespie, Margie

1992-01-01

The Consortium for CFD applications in propulsion technology has been formed at NASA/Marshall Space Flight Center. The combustion devices technology team is one of the three teams that constitute the Consortium. While generally aiming to advance combustion devices technology for rocket propulsion, the team's efforts for the last 1 and 1/2 years have been focused on issues relating to the Space Transportation Main Engine (STME) nozzle. The nozzle design uses hydrogen-rich turbine exhaust to cool the wall in a film/dump scheme. This method of cooling presents challenges and associated risks for the nozzle designers and the engine/vehicle integrators. Within the nozzle itself, a key concern is the ability to effectively and efficiently film cool the wall. From the National Launch System vehicle base standpoint, there are concerns with dumping combustible gases at the nozzle exit and their potential adverse effects on the base thermal environment. The Combustion Team has developed and is implementing plans to use validated CFD tools to aid in risk mitigation for both areas.

Advancements in Dual-Pump Broadband CARS for Supersonic Combustion Measurements

NASA Technical Reports Server (NTRS)

Tedder, Sarah Augusta Umberger

2010-01-01

Space- and time-resolved measurements of temperature and species mole fractions of nitrogen, oxygen, and hydrogen were obtained with a dual-pump coherent anti-Stokes Raman spectroscopy (CARS) system in hydrogen-fueled supersonic combustion free jet flows. These measurements were taken to provide time-resolved fluid properties of turbulent supersonic combustion for use in the creation and verification of computational fluid dynamic (CFD) models. CFD models of turbulent supersonic combustion flow currently facilitate the design of air-breathing supersonic combustion ramjet (scramjet) engines. Measurements were made in supersonic axi-symmetric free jets of two scales. First, the measurement system was tested in a laboratory environment using a laboratory-scale burner (approx.10 mm at nozzle exit). The flow structures of the laboratory-burner were too small to be resolved with the CARS measurements volume, but the composition and temperature of the jet allowed the performance of the system to be evaluated. Subsequently, the system was tested in a burner that was approximately 6 times larger, whose length scales are better resolved by the CARS measurement volume. During both these measurements, weaknesses of the CARS system, such as sensitivity to vibrations and beam steering and inability to measure temperature or species concentrations in hydrogen fuel injection regions were indentified. Solutions were then implemented in improved CARS systems. One of these improved systems is a dual-pump broadband CARS technique called, Width Increased Dual-pump Enhanced CARS (WIDECARS). The two lowest rotational energy levels of hydrogen detectable by WIDECARS are H2 S(3) and H2 S(4). The detection of these lines gives the system the capability to measure temperature and species concentrations in regions of the flow containing pure hydrogen fuel at room temperature. WIDECARS is also designed for measurements of all the major species (except water) in supersonic combustion flows

Assessment of the National Combustion Code

NASA Technical Reports Server (NTRS)

Liu, nan-Suey; Iannetti, Anthony; Shih, Tsan-Hsing

2007-01-01

The advancements made during the last decade in the areas of combustion modeling, numerical simulation, and computing platform have greatly facilitated the use of CFD based tools in the development of combustion technology. Further development of verification, validation and uncertainty quantification will have profound impact on the reliability and utility of these CFD based tools. The objectives of the present effort are to establish baseline for the National Combustion Code (NCC) and experimental data, as well as to document current capabilities and identify gaps for further improvements.

Combustion physics

NASA Astrophysics Data System (ADS)

Jones, A. R.

1985-11-01

Over 90% of our energy comes from combustion. By the year 2000 the figure will still be 80%, even allowing for nuclear and alternative energy sources. There are many familiar examples of combustion use, both domestic and industrial. These range from the Bunsen burner to large flares, from small combustion chambers, such as those in car engines, to industrial furnaces for steel manufacture or the generation of megawatts of electricity. There are also fires and explosions. The bountiful energy release from combustion, however, brings its problems, prominent among which are diminishing fuel resources and pollution. Combustion science is directed towards finding ways of improving efficiency and reducing pollution. One may ask, since combustion is a chemical reaction, why physics is involved: the answer is in three parts. First, chemicals cannot react unless they come together. In most flames the fuel and air are initially separate. The chemical reaction in the gas phase is very fast compared with the rate of mixing. Thus, once the fuel and air are mixed the reaction can be considered to occur instantaneously and fluid mechanics limits the rate of burning. Secondly, thermodynamics and heat transfer determine the thermal properties of the combustion products. Heat transfer also plays a role by preheating the reactants and is essential to extracting useful work. Fluid mechanics is relevant if work is to be performed directly, as in a turbine. Finally, physical methods, including electric probes, acoustics, optics, spectroscopy and pyrometry, are used to examine flames. The article is concerned mainly with how physics is used to improve the efficiency of combustion.

Gravitational Effects on Combustion Synthesis of Advanced Porous Materials

NASA Technical Reports Server (NTRS)

Zhang, X.; Moore, J. J.; Schowengerdt, F. D.; Thorne, K.

2000-01-01

Combustion Synthesis (self-Propagating high-temperature synthesis-(SHS)) of porous Ti-TiB(x), composite materials has been studied with respect to the sensitivity to the SHS reaction parameters of stoichiometry, green density, gasifying agents, ambient pressure, diluents and gravity. The main objective of this research program is to engineer the required porosity and mechanical properties into the composite materials to meet the requirements of a consumer, such as for the application of bone replacement materials. Gravity serves to restrict the gas expansion and the liquid movement during SHS reaction. As a result, gravitational forces affect the microstructure and properties of the SHS products. Reacting these SHS systems in low gravity in the KC-135 aircraft has extended the ability to form porous products. This paper will emphasize the effects of gravity (low g, 1g and 2g) on the SHS reaction process, and the microstructure and properties of the porous composite. Some of biomedical results are also discussed.

Biofuels combustion.

PubMed

Westbrook, Charles K

2013-01-01

This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acids and used primarily to replace or supplement conventional diesel fuels. Research efforts on so-called second- and third-generation biofuels are discussed briefly.

A Review of LOX/Kerosene Combustion Instability in American and Russian Combustion Devices in Application to Next-Generation Launch Technology

NASA Technical Reports Server (NTRS)

Rocker, Marvin; Nesman, Tomas E.; Hulka, James R.; Dougherty, N. Sam

2003-01-01

The Next-Generation Launch Technology (NGLT) project was introduced with its objectives. To meet the objectives, NASA has directed aerospace industry to perform advances and risk reduction of relevant technologies, including propulsion. Originally, the propulsion industry focused on producing both LOWLH2 and LOWkerosene flight engine technology demonstrators. These flight engine technology demonstrators were briefly reviewed. NASA recently redirected this focus to Lowkerosene only. Discussion of LOWkerosene combustion devices was and is prefaced by grave concerns about combustion instability. These concerns have prompted a review of LOWkerosene combustion instability in American and Russian combustion devices. In the review of the Russian propulsion industry's experience in eliminating LOWkerosene combustion instabilities, the history of principal Russian rocket scientists and their role in the development of LOXkerosene combustion devices is presented. The innovative methods implemented by the Russians of eliminations combustion instabilities in LOXkerosene combustion devices were reviewed. The successful elimination of these combustion instabilities has resulted in two generations of Russian-produced, high-performance LOWkerosene combustion devices.

Advanced High Pressure O2/H2 Technology

NASA Technical Reports Server (NTRS)

Morea, S. F. (Editor); Wu, S. T. (Editor)

1985-01-01

Activities in the development of advanced high pressure oxygen-hydrogen stage combustion rocket engines are reported. Particular emphasis is given to the Space Shuttle main engine. The areas of engine technology discussed include fracture and fatigue in engine components, manufacturing and producibility engineering, materials, bearing technology, structure dynamics, fluid dynamics, and instrumentation technology.

Combustion synthesis of advanced materials. [using in-situ infiltration technique

NASA Technical Reports Server (NTRS)

Moore, J. J.; Feng, H. J.; Perkins, N.; Readey, D. W.

1992-01-01

The combustion synthesis of ceramic-metal composites using an in-situ liquid infiltration technique is described. The effect of varying the reactants and their stoichiometry to provide a range of reactant and product species i.e. solids, liquids and gases, with varying physical properties e.g. thermal conductivity, on the microstructure and morphology of synthesized products is also described. Alternatively, conducting the combustion synthesis reaction in a reactive gas environment is also discussed, in which advantages can be gained from the synergistic effects of combustion synthesis and vapor phase transport. In each case, the effect of the presence or absence of gravity (density) driven fluid flow and vapor transport is discussed as is the potential for producing new and perhaps unique materials by conducting these SHS reactions under microgravity conditions.

Biofuels combustion*

DOE PAGES

Westbrook, Charles K.

2013-01-04

This review describes major features of current research in renewable fuels derived from plants and from fatty acids. Recent and ongoing fundamental studies of biofuel molecular structure, oxidation reactions, and biofuel chemical properties are reviewed, in addition to combustion applications of biofuels in the major types of engines in which biofuels are used. Biofuels and their combustion are compared with combustion features of conventional petroleum-based fuels. Two main classes of biofuels are described, those consisting of small, primarily alcohol, fuels (particularly ethanol, n-butanol, and iso-pentanol) that are used primarily to replace or supplement gasoline and those derived from fatty acidsmore » and used primarily to replace or supplement conventional diesel fuels. As a result, research efforts on so-called second- and third-generation biofuels are discussed briefly.« less

14th congress of combustion by-products and their health effects-origin, fate, and health effects of combustion-related air pollutants in the coming era of bio-based energy sources.

PubMed

Weidemann, Eva; Andersson, Patrik L; Bidleman, Terry; Boman, Christoffer; Carlin, Danielle J; Collina, Elena; Cormier, Stephania A; Gouveia-Figueira, Sandra C; Gullett, Brian K; Johansson, Christer; Lucas, Donald; Lundin, Lisa; Lundstedt, Staffan; Marklund, Stellan; Nording, Malin L; Ortuño, Nuria; Sallam, Asmaa A; Schmidt, Florian M; Jansson, Stina

2016-04-01

The 14th International Congress on Combustion By-Products and Their Health Effects was held in Umeå, Sweden from June 14th to 17th, 2015. The Congress, mainly sponsored by the National Institute of Environmental Health Sciences Superfund Research Program and the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning, focused on the "Origin, fate and health effects of combustion-related air pollutants in the coming era of bio-based energy sources". The international delegates included academic and government researchers, engineers, scientists, policymakers and representatives of industrial partners. The Congress provided a unique forum for the discussion of scientific advances in this research area since it addressed in combination the health-related issues and the environmental implications of combustion by-products. The scientific outcomes of the Congress included the consensus opinions that: (a) there is a correlation between human exposure to particulate matter and increased cardiac and respiratory morbidity and mortality; (b) because currently available data does not support the assessment of differences in health outcomes between biomass smoke and other particulates in outdoor air, the potential human health and environmental impacts of emerging air-pollution sources must be addressed. Assessment will require the development of new approaches to characterize combustion emissions through advanced sampling and analytical methods. The Congress also concluded the need for better and more sustainable e-waste management and improved policies, usage and disposal methods for materials containing flame retardants.

Coal-water slurry fuel internal combustion engine and method for operating same

DOEpatents

McMillian, Michael H.

1992-01-01

An internal combustion engine fueled with a coal-water slurry is described. About 90 percent of the coal-water slurry charge utilized in the power cycle of the engine is directly injected into the main combustion chamber where it is ignited by a hot stream of combustion gases discharged from a pilot combustion chamber of a size less than about 10 percent of the total clearance volume of main combustion chamber with the piston at top dead center. The stream of hot combustion gases is provided by injecting less than about 10 percent of the total coal-water slurry charge into the pilot combustion chamber and using a portion of the air from the main combustion chamber that has been heated by the walls defining the pilot combustion chamber as the ignition source for the coal-water slurry injected into the pilot combustion chamber.

The Effects of Gravity on Combustion and Structure Formation During Combustion Synthesis in Gasless Systems

NASA Technical Reports Server (NTRS)

Varma, Arvind; Mukasyan, Alexander; Pelekh, Aleksey

1997-01-01

There have been relatively few publications examining the role of gravity during combustion synthesis (CS), mostly involving thermite systems. The main goal of this research was to study the influence of gravity on the combustion characteristics of heterogeneous gasless systems. In addition, some aspects of microstructure formation processes which occur during gasless CS were also studied. Four directions for experimental investigation have been explored: (1) the influence of gravity force on the characteristic features of heterogeneous combustion wave propagation (average velocity, instantaneous velocities, shape of combustion front); (2) the combustion of highly porous mixtures (with porosity greater than that for loose powders), which cannot be obtained in normal gravity; (3) the effect of gravity on sample expansion during combustion, in order to produce highly porous materials under microgravity conditions; and (4) the effect of gravity on the structure formation mechanism during the combustion synthesis of poreless composite materials.

Preliminary tests of an advanced high-temperature combustion system

NASA Technical Reports Server (NTRS)

Wear, J. D.; Trout, A. M.; Smith, J. M.; Jacobs, R. E.

1983-01-01

A combustion system has been developed to operate efficiently and with good durability at inlet pressures to 4.05 MPa (40 atm), inlet air temperatures to 900 K, and exhaust gas temperatures to 2480 K. A preliminary investigation of this system was conducted at inlet pressures to 0.94 MPa (9 atm), a nominal inlet air temperature of 560 K, and exhaust gas temperatures to 2135 K. A maximum combustion efficiency of 98.5 percent was attained at a fuel-air ratio of 0.033; the combustion efficiency decreased to about 90 percent as the fuel-air ratio was increased to 0.058. An average liner metal temperature of 915 K, 355 kelvins greater than the nominal inlet air temperature, was reached with an average exhaust gas temperature of 2090 K. The maximum local metal temperature at this condition was about 565 kelvins above the nominal inlet air temperature and decreased to 505 kelvins above with increasing combustor pressure. Tests to determine the isothermal total pressure loss of the combustor showed a liner loss of 1.1 percent and a system loss of 6.5 percent.

JANNAF 37th Combustion Subcommittee Meeting. Volume 1

NASA Technical Reports Server (NTRS)

Fry, Ronald S. (Editor); Gannaway, Mary T. (Editor)

2000-01-01

This volume, the first of two volumes is a compilation of 59 unclassified/unlimited-distribution technical papers presented at the Joint Army-Navy-NASA-Air Force (JANNAF) 37th Combustion Subcommittee (CS) meeting held jointly with the 25th Airbreathing Propulsion Subcommittee (APS), 19th Propulsion Systems Hazards Subcommittee (PSHS), and 1st Modeling and Simulation Subcommittee (MSS) meetings. The meeting was held 13-17 November 2000 at the Naval Postgraduate School and Hyatt Regency Hotel, Monterey, California. Topics covered at the CS meeting include: a keynote address on the Future Combat Systems, and review of a new JANNAF Modeling and Simulation Subcommittee, and technical papers on gun propellant burning rate, gun tube erosion, advanced gun propulsion concepts, ETC guns, novel gun propellants; liquid, hybrid and novel propellant combustion; solid propellant combustion kinetics, GAP, ADN and RDX combustion, sandwich combustion, metal combustion, combustion instability, and motor combustion instability.

Ames Hybrid Combustion Facility

NASA Technical Reports Server (NTRS)

Zilliac, Greg; Karabeyoglu, Mustafa A.; Cantwell, Brian; Hunt, Rusty; DeZilwa, Shane; Shoffstall, Mike; Soderman, Paul T.; Bencze, Daniel P. (Technical Monitor)

2003-01-01

The report summarizes the design, fabrication, safety features, environmental impact, and operation of the Ames Hybrid-Fuel Combustion Facility (HCF). The facility is used in conducting research into the scalability and combustion processes of advanced paraffin-based hybrid fuels for the purpose of assessing their applicability to practical rocket systems. The facility was designed to deliver gaseous oxygen at rates between 0.5 and 16.0 kg/sec to a combustion chamber operating at pressures ranging from 300 to 900. The required run times were of the order of 10 to 20 sec. The facility proved to be robust and reliable and has been used to generate a database of regression-rate measurements of paraffin at oxygen mass flux levels comparable to those of moderate-sized hybrid rocket motors.

Droplet Combustion Experiment movie

NASA Technical Reports Server (NTRS)

2003-01-01

The Droplet Combustion Experiment (DCE) was designed to investigate the fundamental combustion aspects of single, isolated droplets under different pressures and ambient oxygen concentrations for a range of droplet sizes varying between 2 and 5 mm. The DCE principal investigator was Forman Williams, University of California, San Diego. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1 mission (STS-83, April 4-8 1997; the shortened mission was reflown as MSL-1R on STS-94). Advanced combustion experiments will be a part of investigations plarned for the International Space Station. (1.1 MB, 12-second MPEG, screen 320 x 240 pixels; downlinked video, higher quality not available)A still JPG composite of this movie is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300164.html.

500 MW demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide emissions from coal-fired boilers

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

Sorge, J.N.; Larrimore, C.L.; Slatsky, M.D.

1997-12-31

This paper discusses the technical progress of a US Department of Energy Innovative Clean Coal Technology project demonstrating advanced wall-fired combustion techniques for the reduction of nitrogen oxide (NOx) emissions from coal-fired boilers. The primary objectives of the demonstration is to determine the long-term NOx reduction performance of advanced overfire air (AOFA), low NOx burners (LNB), and advanced digital control optimization methodologies applied in a stepwise fashion to a 500 MW boiler. The focus of this paper is to report (1) on the installation of three on-line carbon-in-ash monitors and (2) the design and results to date from the advancedmore » digital control/optimization phase of the project.« less

Temporal evolution of ultrafine particles and of alveolar deposited surface area from main indoor combustion and non-combustion sources in a model room.

PubMed

Manigrasso, Maurizio; Vitali, Matteo; Protano, Carmela; Avino, Pasquale

2017-11-15

Aerosol number size distributions, PM mass concentrations, alveolar deposited surface areas (ADSAs) and VOC concentrations were measured in a model room when aerosol was emitted by sources frequently encountered in indoor environments. Both combustion and non-combustion sources were considered. The most intense aerosol emission occurred when combustion sources were active (as high as 4.1×10 7 particlescm -3 for two meat grilling sessions; the first with exhaust ventilation, the second without). An intense spike generation of nucleation particles occurred when appliances equipped with brush electric motors were operating (as high as 10 6 particlescm -3 on switching on an electric drill). Average UFP increments over the background value were highest for electric appliances (5-12%) and lowest for combustion sources (as low as -24% for tobacco cigarette smoke). In contrast, average increments in ADSA were highest for combustion sources (as high as 3.2×10 3 μm 2 cm -3 for meat grilling without exhaust ventilation) and lowest for electric appliances (20-90μm 2 cm -3 ). The health relevance of such particles is associated to their ability to penetrate cellular structures and elicit inflammatory effects mediated through oxidative stress in a way dependent on their surface area. The highest VOC concentrations were measured (PID probe) for cigarette smoke (8ppm) and spray air freshener (10ppm). The highest PM mass concentration (PM 1 ) was measured for citronella candle burning (as high as 7.6mgm -3 ). Copyright © 2017 Elsevier B.V. All rights reserved.

Combustion synthesis of complex oxides

NASA Astrophysics Data System (ADS)

Ming, Qimin

Advanced ceramic materials have numerous applications in electronic engineering, chemical engineering, and semiconductor industry. The synthesis of these materials at an economical cost is the bottleneck in the application of these materials. Self-propagating High-temperature Synthesis (SHS) is a new technique for producing these materials for exothermic systems by a combustion wave that propagates and produces high purity products. The full potential of SHS to produce advanced materials has not yet been utilized. In this study, we used SHS to prepare two types of complex oxides: La 1-xSrxCrO3, La0.89Sr0.1 MnO3, powders, used to make interconnect and cathode of solid oxide fuel cells; and chromium- and gallium-doped La1-xSr xFeO3-delta, mixed ionic and electronic conductive powders used to manufacture ceramic membranes for oxygen separation. A thermodynamic feasibility analysis shows that the oxidation of Cr is the main source of heat generation of La1-xSrxCrO 3, which maintains a stable reaction front. Replacing part of the metallic Cr in the reaction mixture by its oxides decreases the combustion temperature and front propagating velocity and modifies the product morphology. The oxygen needed for the Cr oxidation is provided by the decomposition of CrO3 , SrO2, or NaClO4. The predicted and observed combustion temperatures are in reasonable agreement. TG/DTA analyses of La1-xSrxCrO3 indicated that SHS stability was strongly affected by the transport of oxygen between the two regions, in which oxygen was generated by the decomposition of either NaClO4 or CrO3 and that in which it was consumed by the oxidation of Cr. Partial melting at the high combustion temperature during SHS of La 1-xSrxMnO3 increased product homogeneity. The electrical conductivity at 1000°C in air of SHS-produced cathode material (of 180 O-1·cm-1) matches that of the commercial product made by other processes. However, the SHS process provides much higher productivity and decreases processing

Introductory lecture. Advanced laser spectroscopy in combustion chemistry: from elementary steps to practical devices.

PubMed

Wolfrum, J

2001-01-01

In recent years a large number of linear and nonlinear laser-based diagnostic techniques for nonintrusive measurements of species concentrations, temperatures, and gas velocities in a wide pressure and temperature range with high temporal and spatial resolution have been developed and have become extremely valuable tools to study many aspects of combustion. Beside the nonintrusive diagnostics of technical combustion devices the kinetics and microscopic dynamics of elementary chemical combustion reactions can be investigated in great detail by laser spectroscopy. These investigations show, that a small number of relatively simple elementary steps like H + O2-->OH + O, H2O2-->2OH, O + N2-->NO + N, NH2 + NO-->H2O + N2, OH + N2H control a large variety of combustion phenomena and pollutant formation processes. Laminar flames are ideal objects to develop the application of laser spectroscopic methods for practical combustion systems and to test and improve the gas-phase reaction mechanism in combustion models. Nonintrusive laser point and field measurements are of basic importance in the validation and further development of turbulent combustion models. Nonlinear laser spectroscopic techniques using infrared-visible sum-frequency generation can now bridge the pressure and materials gap to provide kinetic data for catalytic combustion. Finally, the potential of laser techniques for active combustion control in municipal waste incinerators is illustrated.

Combustion Science for Cleaner Fuels

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

Ahmed, Musahid

2014-10-17

Musahid Ahmed discusses how he and his team use the Advanced Light Source (ALS) to study combustion chemistry at our '8 Big Ideas' Science at the Theater event on October 8th, 2014, in Oakland, California.

Combustion Science for Cleaner Fuels

ScienceCinema

Ahmed, Musahid

2018-01-16

Musahid Ahmed discusses how he and his team use the Advanced Light Source (ALS) to study combustion chemistry at our '8 Big Ideas' Science at the Theater event on October 8th, 2014, in Oakland, California.

Main propulsion system design recommendations for an advanced Orbit Transfer Vehicle

NASA Technical Reports Server (NTRS)

Redd, L.

1985-01-01

Various main propulsion system configurations of an advanced OTV are evaluated with respect to the probability of nonindependent failures, i.e., engine failures that disable the entire main propulsion system. Analysis of the life-cycle cost (LCC) indicates that LCC is sensitive to the main propulsion system reliability, vehicle dry weight, and propellant cost; it is relatively insensitive to the number of missions/overhaul, failures per mission, and EVA and IVA cost. In conclusion, two or three engines are recommended in view of their highest reliability, minimum life-cycle cost, and fail operational/fail safe capability.

Ultra-lean combustion at high inlet temperatures

NASA Technical Reports Server (NTRS)

Anderson, D. N.

1981-01-01

Combustion at inlet air temperatures of 1100 to 1250 K was studied for application to advanced automotive gas turbine engines. Combustion was initiated by the hot environment, and therefore no external ignition source was used. Combustion was stabilized without a flameholder. The tests were performed in a 12 cm diameter test section at a pressure of 2.5 x 10 to the 5th power Pa, with reference velocities of 32 to 60 m/sec and at maximum combustion temperatures of 1350 to 1850 K. Number 2 diesel fuel was injected by means of a multiple source fuel injector. Unburned hydrocarbons emissions were negligible for all test conditions. Nitrogen oxides emissions were less than 1.9 g NO2/kg fuel for combustion temperatures below 1680 K. Carbon monoxide emissions were less than 16 g CO/kg fuel for combustion temperatures greater than 1600 K, inlet air temperatures higher than 1150 K, and residence times greater than 4.3 microseconds.

Method of combustion for dual fuel engine

DOEpatents

Hsu, Bertrand D.; Confer, Gregory L.; Shen, Zujing; Hapeman, Martin J.; Flynn, Paul L.

1993-12-21

Apparatus and a method of introducing a primary fuel, which may be a coal water slutty, and a high combustion auxiliary fuel, which may be a conventional diesel oil, into an internal combustion diesel engine comprises detecting the load conditions of the engine, determining the amount of time prior to the top dead center position of the piston to inject the main fuel into the combustion chamber, and determining the relationship of the timing of the injection of the auxiliary fuel into the combustion chamber to achieve a predetermined specific fuel consumption, a predetermined combustion efficiency, and a predetermined peak cylinder firing pressure.

Thermodynamic analysis of the advanced zero emission power plant

NASA Astrophysics Data System (ADS)

Kotowicz, Janusz; Job, Marcin

2016-03-01

The paper presents the structure and parameters of advanced zero emission power plant (AZEP). This concept is based on the replacement of the combustion chamber in a gas turbine by the membrane reactor. The reactor has three basic functions: (i) oxygen separation from the air through the membrane, (ii) combustion of the fuel, and (iii) heat transfer to heat the oxygen-depleted air. In the discussed unit hot depleted air is expanded in a turbine and further feeds a bottoming steam cycle (BSC) through the main heat recovery steam generator (HRSG). Flue gas leaving the membrane reactor feeds the second HRSG. The flue gas consist mainly of CO2 and water vapor, thus, CO2 separation involves only the flue gas drying. Results of the thermodynamic analysis of described power plant are presented.

Fuel properties to enable lifted-flame combustion

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

Kurtz, Eric

The Fuel Properties to Enable Lifted-Flame Combustion project responded directly to solicitation DE-FOA-0000239 AOI 1A, Fuels and Lubricants for Advanced Combustion Regimes. This subtopic was intended to encompass clean and highly-efficient, liquid-fueled combustion engines to achieve extremely low engine-out nitrogen oxides (NOx) and particulate matter (PM) as a target and similar efficiency as state-of-the-art direct injection diesel engines. The intent of this project was to identify how fuel properties can be used to achieve controllable Leaner Lifted Flame Combustion (LLFC) with low NOx and PM emissions. Specifically, this project was expected to identify and test key fuel properties to enablemore » LLFC and their compatibility with current fuel systems and to enhance combustion models to capture the effect of fuel properties on advanced combustion. Successful demonstration of LLFC may reduce the need for after treatment devices, thereby reducing costs and improving thermal efficiency. The project team consisted of key technical personnel from Ford Motor Company (FMC), the University of Wisconsin-Madison (UW), Sandia National Laboratories (SNL) and Lawrence Livermore National Laboratories (LLNL). Each partner had key roles in achieving project objectives. FMC investigated fuel properties relating to LLFC and sooting tendency. Together, FMC and UW developed and integrated 3D combustion models to capture fuel property combustion effects. FMC used these modeling results to develop a combustion system and define fuel properties to support a single-cylinder demonstration of fuel-enabled LLFC. UW investigated modeling the flame characteristics and emissions behavior of different fuels, including those with different cetane number and oxygen content. SNL led spray combustion experiments to quantify the effect of key fuel properties on combustion characteristics critical for LLFC, as well as single cylinder optical engine experiments to improve fundamental

Combustion Stability Characteristics of the Project Morpheus Liquid Oxygen / Liquid Methane Main Engine

NASA Technical Reports Server (NTRS)

Melcher, John C.; Morehead, Robert L.

2014-01-01

The project Morpheus liquid oxygen (LOX) / liquid methane (LCH4) main engine is a Johnson Space Center (JSC) designed 5,000 lbf-thrust, 4:1 throttling, pressure-fed cryogenic engine using an impinging element injector design. The engine met or exceeded all performance requirements without experiencing any in- ight failures, but the engine exhibited acoustic-coupled combustion instabilities during sea-level ground-based testing. First tangential (1T), rst radial (1R), 1T1R, and higher order modes were triggered by conditions during the Morpheus vehicle derived low chamber pressure startup sequence. The instability was never observed to initiate during mainstage, even at low power levels. Ground-interaction acoustics aggravated the instability in vehicle tests. Analysis of more than 200 hot re tests on the Morpheus vehicle and Stennis Space Center (SSC) test stand showed a relationship between ignition stability and injector/chamber pressure. The instability had the distinct characteristic of initiating at high relative injection pressure drop at low chamber pressure during the start sequence. Data analysis suggests that the two-phase density during engine start results in a high injection velocity, possibly triggering the instabilities predicted by the Hewitt stability curves. Engine ignition instability was successfully mitigated via a higher-chamber pressure start sequence (e.g., 50% power level vs 30%) and operational propellant start temperature limits that maintained \\cold LOX" and \\warm methane" at the engine inlet. The main engine successfully demonstrated 4:1 throttling without chugging during mainstage, but chug instabilities were observed during some engine shutdown sequences at low injector pressure drop, especially during vehicle landing.

Advanced exergoenvironmental analysis of a near-zero emission power plant with chemical looping combustion.

PubMed

Petrakopoulou, Fontina; Tsatsaronis, George; Morosuk, Tatiana

2012-03-06

Carbon capture and storage (CCS) from power plants can be used to mitigate CO(2) emissions from the combustion of fossil fuels. However, CCS technologies are energy intensive, decreasing the operating efficiency of a plant and increasing its costs. Recently developed advanced exergy-based analyses can uncover the potential for improvement of complex energy conversion systems, as well as qualify and quantify plant component interactions. In this paper, an advanced exergoenvironmental analysis is used for the first time as means to evaluate an oxy-fuel power plant with CO(2) capture. The environmental impacts of each component are split into avoidable/unavoidable and endogenous/exogenous parts. In an effort to minimize the environmental impact of the plant operation, we focus on the avoidable part of the impact (which is also split into endogenous and exogenous parts) and we seek ways to decrease it. The results of the advanced exergoenvironmental analysis show that the majority of the environmental impact related to the exergy destruction of individual components is unavoidable and endogenous. Thus, the improvement potential is rather limited, and the interactions of the components are of lower importance. The environmental impact of construction of the components is found to be significantly lower than that associated with their operation; therefore, our suggestions for improvement focus on measures concerning the reduction of exergy destruction and pollutant formation.

Terascale Cluster for Advanced Turbulent Combustion Simulations

DTIC Science & Technology

2008-07-25

the system We have given the name CATS (for Combustion And Turbulence Simulator) to the terascale system that was obtained through this grant. CATS ...lnfiniBand interconnect. CATS includes an interactive login node and a file server, each holding in excess of 1 terabyte of file storage. The 35 active...compute nodes of CATS enable us to run up to 140-core parallel MPI batch jobs; one node is reserved to run the scheduler. CATS is operated and

An investigation of late-combustion soot burnout in a DI diesel engine using simultaneous planar imaging of soot and OH radical

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

John E. Dec; Peter L. Kelly-Zion

Diesel engine design continues to be driven by the need to improve performance while at the same time achieving further reductions in emissions. The development of new designs to accomplish these goals requires an understanding of how the emissions are produced in the engine. Laser-imaging diagnostics are uniquely capable of providing this information, and the understanding of diesel combustion and emissions formation has been advanced considerably in recent years by their application. However, previous studies have generally focused on the early and middle stages of diesel combustion. These previous laser-imaging studies do provide important insight into the soot formation andmore » oxidation processes during the main combustion event. They indicate that prior to the end of injection, soot formation is initiated by fuel-rich premixed combustion (equivalence ratio > 4) near the upstream limit of the luminous portion of the reacting fuel jet. The soot is then oxidized at the diffusion flame around the periphery of the luminous plume. Under typical diesel engine conditions, the diffusion flame does not burn the remaining fuel and soot as rapidly as it is supplied, resulting in an expanding region of rich combustion products and soot. This is evident in natural emission images by the increasing size of the luminous soot cloud prior to the end of injection. Hence, the amount of soot in the combustion chamber typically increases until shortly after the end of fuel injection, at which time the main soot formation period ends and the burnout phase begins. Sampling valve and two-color pyrometry data indicate that the vast majority (more than 90%) of the soot formed is oxidized before combustion ends; however, it is generally thought that a small fraction of this soot from the main combustion zones is not consumed and is the source of tail pipe soot emissions.« less

Method of combustion for dual fuel engine

DOEpatents

Hsu, B.D.; Confer, G.L.; Zujing Shen; Hapeman, M.J.; Flynn, P.L.

1993-12-21

Apparatus and a method of introducing a primary fuel, which may be a coal water slurry, and a high combustion auxiliary fuel, which may be a conventional diesel oil, into an internal combustion diesel engine comprises detecting the load conditions of the engine, determining the amount of time prior to the top dead center position of the piston to inject the main fuel into the combustion chamber, and determining the relationship of the timing of the injection of the auxiliary fuel into the combustion chamber to achieve a predetermined specific fuel consumption, a predetermined combustion efficiency, and a predetermined peak cylinder firing pressure. 19 figures.

Microgravity combustion of dust suspensions

NASA Technical Reports Server (NTRS)

Lee, John H. S.; Peraldi, Olivier; Knystautas, Rom

1993-01-01

Unlike the combustion of homogeneous gas mixtures, there are practically no reliable fundamental data (i.e., laminar burning velocity, flammability limits, quenching distance, minimum ignition energy) for the combustion of heterogeneous dust suspensions. Even the equilibrium thermodynamic data such as the constant pressure volume combustion pressure and the constant pressure adiabatic flame temperature are not accurately known for dust mixtures. This is mainly due to the problem of gravity sedimentation. In normal gravity, turbulence, convective flow, electric and acoustic fields are required to maintain a dust in suspension. These external influences have a dominating effect on the combustion processes. Microgravity offers a unique environment where a quiescent dust cloud can in principle be maintained for a sufficiently long duration for almost all combustion experiments (dust suspensions are inherently unstable due to Brownian motion and particle aggregation). Thus, the microgravity duration provided by drop towers, parabolic flights, and the space shuttle, can all be exploited for different kinds of dust combustion experiments. The present paper describes some recent studies on microgravity combustion of dust suspension carried out on the KC-135 and the Caravelle aircraft. The results reported are obtained from three parabolic flight campaigns.

Wind-tunnel evaluation of an advanced main-rotor blade design for a utility-class helicopter

NASA Technical Reports Server (NTRS)

Yeager, William T., Jr.; Mantay, Wayne R.; Wilbur, Matthew L.; Cramer, Robert G., Jr.; Singleton, Jeffrey D.

1987-01-01

An investigation was conducted in the Langley Transonic Dynamics Tunnel to evaluate differences between an existing utility-class main-rotor blade and an advanced-design main-rotor blade. The two rotor blade designs were compared with regard to rotor performance oscillatory pitch-link loads, and 4-per-rev vertical fixed-system loads. Tests were conducted in hover and over a range of simulated full-scale gross weights and density altitude conditions at advance ratios from 0.15 to 0.40. Results indicate that the advanced blade design offers performance improvements over the baseline blade in both hover and forward flight. Pitch-link oscillatory loads for the baseline rotor were more sensitive to the test conditions than those of the advanced rotor. The 4-per-rev vertical fixed-system load produced by the advanced blade was larger than that produced by the baseline blade at all test conditions.

Droplet Combustion Experiment Operates

NASA Technical Reports Server (NTRS)

2003-01-01

Fuel ignites and burns in the Droplet Combustion Experiment (DCE) on STS-94 on July 12, 1997, MET:11/07:00 (approximate). DCE used various fuels -- in drops ranging from 1 mm (0.04 inches) to 5 mm (0.2 inches) -- and mixtures of oxidizers and inert gases to learn more about the physics of combustion in the simplest burning configuration, a sphere. The DCE was designed to investigate the fundamental combustion aspects of single, isolated droplets under different pressures and ambient oxygen concentrations for a range of droplet sizes varying between 2 and 5 mm. The experiment elapsed time is shown at the bottom of the composite image. The DCE principal investigator was Forman Williams, University of California, San Diego. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). Advanced combustion experiments will be a part of investigations plarned for the International Space Station. (119KB JPEG, 658 x 982 pixels; downlinked video, higher quality not available) The MPG from which this composite was made is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300171.html.

Sound quality assessment of Diesel combustion noise using in-cylinder pressure components

NASA Astrophysics Data System (ADS)

Payri, F.; Broatch, A.; Margot, X.; Monelletta, L.

2009-01-01

The combustion process in direct injection (DI) Diesel engines is an important source of noise, and it is thus the main reason why end-users could be reluctant to drive vehicles powered with this type of engine. This means that the great potential of Diesel engines for environment preservation—due to their lower consumption and the subsequent reduction of CO2 emissions—may be lost. Moreover, the advanced combustion concepts—e.g. the HCCI (homogeneous charge compression ignition)—developed to comply with forthcoming emissions legislation, while maintaining the efficiency of current engines, are expected to be noisier because they are characterized by a higher amount of premixed combustion. For this reason many efforts have been dedicated by car manufacturers in recent years to reduce the overall level and improve the sound quality of engine noise. Evaluation procedures are required, both for noise levels and sound quality, that may be integrated in the global engine development process in a timely and cost-effective manner. In previous published work, the authors proposed a novel method for the assessment of engine noise level. A similar procedure is applied in this paper to demonstrate the suitability of combustion indicators for the evaluation of engine noise quality. These indicators, which are representative of the peak velocity of fuel burning and the resonance in the combustion chamber, are well correlated with the combustion noise mark obtained from jury testing. Quite good accuracy in the prediction of the engine noise quality has been obtained with the definition of a two-component regression, which also permits the identification of the combustion process features related to the resulting noise quality, so that corrective actions may be proposed.

Combustion inorganic transformations

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

Benson, S.A.; Sweeny, P.G.; Abrahamson, H.B.

1988-04-01

The overall goal of the project is to develop a unified picture of the physical and chemical changes that occur in coal inorganic matter during combustion. The research is centered on two main tasks. Task 3.2A deals with the use of laser-induced fluorescence spectroscopy (LIFS) to study the release of sodium from various model compounds and coal during combustion in a flame. The vaporized or released sodium is considered to be an important factor in the formation of ash fouling deposits in full-scale utility boilers. Task 3.2B will study changes in the morphology and chemical associations of inorganic components inmore » coals during combustion in a drop-tube furnace designed to simulate the time-temperature profile of a pulverized coal-fired utility boiler. Results are described. 18 refs., 51 figs., 28 tabs.« less

Potential Commercial Applications from Combustion and Fire Research in Space

NASA Technical Reports Server (NTRS)

Friedman, Robert; Lyons, Valerie J.

1996-01-01

The near-zero (microgravity) environment of orbiting spacecraft minimizes buoyant flows, greatly simplifying combustion processes and isolating important phenomena ordinarily concealed by the overwhelming gravity-driven forces and flows. Fundamental combustion understanding - the focus to date of the NASA microgravity-combustion program - has greatly benefited from analyses and experiments conducted in the microgravity environment. Because of the economic and commercial importance of combustion in practice, there is strong motivation to seek wider applications for the microgravity-combustion findings. This paper reviews selected technology developments to illustrate some emerging applications. Topics cover improved fire-safety technology in spacecraft and terrestrial systems, innovative combustor designs for aerospace and ground propulsion, applied sensors and controls for combustion processes, and self-sustaining synthesis techniques for advanced materials.

Active Combustion Control for Aircraft Gas Turbine Engines

NASA Technical Reports Server (NTRS)

DeLaat, John C.; Breisacher, Kevin J.; Saus, Joseph R.; Paxson, Daniel E.

2000-01-01

Lean-burning combustors are susceptible to combustion instabilities. Additionally, due to non-uniformities in the fuel-air mixing and in the combustion process, there typically exist hot areas in the combustor exit plane. These hot areas limit the operating temperature at the turbine inlet and thus constrain performance and efficiency. Finally, it is necessary to optimize the fuel-air ratio and flame temperature throughout the combustor to minimize the production of pollutants. In recent years, there has been considerable activity addressing Active Combustion Control. NASA Glenn Research Center's Active Combustion Control Technology effort aims to demonstrate active control in a realistic environment relevant to aircraft engines. Analysis and experiments are tied to aircraft gas turbine combustors. Considerable progress has been shown in demonstrating technologies for Combustion Instability Control, Pattern Factor Control, and Emissions Minimizing Control. Future plans are to advance the maturity of active combustion control technology to eventual demonstration in an engine environment.

Low emission U-fired boiler combustion system

DOEpatents

Ake, Terence; Beittel, Roderick; Lisauskas, Robert A.; Reicker, Eric

2000-01-01

At least one main combustion chamber contains at least one pulverized coal burner. Each pulverized coal burner is operatively arranged for minimizing NO.sub.X production and for maintaining a predetermined operating temperature to liquefy ash within the combustion chamber. The combustion chamber includes a slag drain for removing slag from the combustion chamber. A slag screen is positioned in a generally U-shaped furnace flow pattern. The slag screen is positioned between the combustion chamber and a radiant furnace. The radiant furnace includes a reburning zone for in-furnace No.sub.X reduction. The reburning zone extends between a reburning fuel injection source and at least one overfire air injection port for injecting air.

Investigating co-combustion characteristics of bamboo and wood.

PubMed

Liang, Fang; Wang, Ruijuan; Jiang, Changle; Yang, Xiaomeng; Zhang, Tao; Hu, Wanhe; Mi, Bingbing; Liu, Zhijia

2017-11-01

To investigate co-combustion characteristics of bamboo and wood, moso bamboo and masson pine were torrefied and mixed with different blend ratios. The combustion process was examined by thermogravimetric analyzer (TGA). The results showed the combustion process of samples included volatile emission and oxidation combustion as well as char combustion. The main mass loss of biomass blends occurred at volatile emission and oxidation combustion stage, while that of torrefied biomass occurred at char combustion stage. With the increase of bamboo content, characteristic temperatures decreased. Compared with untreated biomass, torrefied biomass had a higher initial and burnout temperature. With the increase of heating rates, combustion process of samples shifted to higher temperatures. Compared with non-isothermal models, activation energy obtained from isothermal model was lower. The result is helpful to promote development of co-combustion of bamboo and masson pine wastes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Test Results of the Modified Space Shuttle Main Engine at the Marshall Space Flight Center Technology Test Bed Facility

NASA Technical Reports Server (NTRS)

Cook, J.; Dumbacher, D.; Ise, M.; Singer, C.

1990-01-01

A modified space shuttle main engine (SSME), which primarily includes an enlarged throat main combustion chamber with the acoustic cavities removed and a main injector with the stability control baffles removed, was tested. This one-of-a-kind engine's design changes are being evaluated for potential incorporation in the shuttle flight program in the mid-1990's. Engine testing was initiated on September 15, 1988 and has accumulated 1,915 seconds and 19 starts. Testing is being conducted to characterize the engine system performance, combustion stability with the baffle-less injector, and both low pressure oxidizer turbopump (LPOTP) and high pressure oxidizer turbopump (HPOTP) for suction performance. These test results are summarized and compared with the SSME flight configuration data base. Testing of this new generation SSME is the first product from the technology test bed (TTB). Figure test plans for the TTB include the highly instrumented flight configuration SSME and advanced liquid propulsion technology items.

Combustion Dynamics and Control for Ultra Low Emissions in Aircraft Gas-Turbine Engines

NASA Technical Reports Server (NTRS)

DeLaat, John C.

2011-01-01

Future aircraft engines must provide ultra-low emissions and high efficiency at low cost while maintaining the reliability and operability of present day engines. The demands for increased performance and decreased emissions have resulted in advanced combustor designs that are critically dependent on efficient fuel/air mixing and lean operation. However, all combustors, but most notably lean-burning low-emissions combustors, are susceptible to combustion instabilities. These instabilities are typically caused by the interaction of the fluctuating heat release of the combustion process with naturally occurring acoustic resonances. These interactions can produce large pressure oscillations within the combustor and can reduce component life and potentially lead to premature mechanical failures. Active Combustion Control which consists of feedback-based control of the fuel-air mixing process can provide an approach to achieving acceptable combustor dynamic behavior while minimizing emissions, and thus can provide flexibility during the combustor design process. The NASA Glenn Active Combustion Control Technology activity aims to demonstrate active control in a realistic environment relevant to aircraft engines by providing experiments tied to aircraft gas turbine combustors. The intent is to allow the technology maturity of active combustion control to advance to eventual demonstration in an engine environment. Work at NASA Glenn has shown that active combustion control, utilizing advanced algorithms working through high frequency fuel actuation, can effectively suppress instabilities in a combustor which emulates the instabilities found in an aircraft gas turbine engine. Current efforts are aimed at extending these active control technologies to advanced ultra-low-emissions combustors such as those employing multi-point lean direct injection.

An Extended Combustion Model for the Aircraft Turbojet Engine

NASA Astrophysics Data System (ADS)

Rotaru, Constantin; Andres-Mihăilă, Mihai; Matei, Pericle Gabriel

2014-08-01

The paper consists in modelling and simulation of the combustion in a turbojet engine in order to find optimal characteristics of the burning process and the optimal shape of combustion chambers. The main focus of this paper is to find a new configuration of the aircraft engine combustion chambers, namely an engine with two main combustion chambers, one on the same position like in classical configuration, between compressor and turbine and the other, placed behind the turbine but not performing the role of the afterburning. This constructive solution could allow a lower engine rotational speed, a lower temperature in front of the first stage of the turbine and the possibility to increase the turbine pressure ratio by extracting the flow stream after turbine in the inner nozzle. Also, a higher thermodynamic cycle efficiency and thrust in comparison to traditional constant-pressure combustion gas turbine engines could be obtained.

Thermogravimetric-mass spectrometric analysis on combustion of lignocellulosic biomass.

PubMed

López-González, D; Fernandez-Lopez, M; Valverde, J L; Sanchez-Silva, L

2013-09-01

Combustion characteristics of biomass main components and three lignocellulosic biomass (fir wood, eucalyptus wood and pine bark) were investigated by thermogravimetric analysis coupled with mass spectrometry. The combustion of biomass was divided into two main steps, devolatilization and char oxidation stage. Heating rate effect was also studied. Generally, the higher the heating rate, the higher the decomposition temperature. Furthermore, the weight loss rate decreased due to particle temperature gradients. Combustion kinetics were studied. Models based on reaction order (Oi), nucleation (Ni) and diffusion (Di) achieved the best fitting to the experimental data. Cellulose oxidation presented the highest activation energies. CO, CO2 and H2O were the main components evolved from combustion. Additionally, light hydrocarbons (CH4 and C2H5) were also present. Finally, nitrogen compounds were in a higher proportion than sulfur compounds being released as primary amines and NOx. Copyright © 2013 Elsevier Ltd. All rights reserved.

Thermal ignition combustion system

DOEpatents

Kamo, R.; Kakwani, R.M.; Valdmanis, E.; Woods, M.E.

1988-04-19

The thermal ignition combustion system comprises means for providing walls defining an ignition chamber, the walls being made of a material having a thermal conductivity greater than 20 W/m C and a specific heat greater than 480 J/kg C with the ignition chamber being in constant communication with the main combustion chamber, means for maintaining the temperature of the walls above a threshold temperature capable of causing ignition of a fuel, and means for conducting fuel to the ignition chamber. 8 figs.

Thermal ignition combustion system

DOEpatents

Kamo, Roy; Kakwani, Ramesh M.; Valdmanis, Edgars; Woods, Melvins E.

1988-01-01

The thermal ignition combustion system comprises means for providing walls defining an ignition chamber, the walls being made of a material having a thermal conductivity greater than 20 W/m.degree. C. and a specific heat greater than 480 J/kg.degree. C. with the ignition chamber being in constant communication with the main combustion chamber, means for maintaining the temperature of the walls above a threshold temperature capable of causing ignition of a fuel, and means for conducting fuel to the ignition chamber.

AST Combustion Workshop: Diagnostics Working Group Report

NASA Technical Reports Server (NTRS)

Locke, Randy J.; Hicks, Yolanda R.; Hanson, Ronald K.

1996-01-01

A workshop was convened under NASA's Advanced Subsonics Technologies (AST) Program. Many of the principal combustion diagnosticians from industry, academia, and government laboratories were assembled in the Diagnostics/Testing Subsection of this workshop to discuss the requirements and obstacles to the successful implementation of advanced diagnostic techniques to the test environment of the proposed AST combustor. The participants, who represented the major relevant areas of advanced diagnostic methods currently applied to combustion and related fields, first established the anticipated AST combustor flowfield conditions. Critical flow parameters were then examined and prioritized as to their importance to combustor/fuel injector design and manufacture, environmental concerns, and computational interests. Diagnostic techniques were then evaluated in terms of current status, merits and obstacles for each flow parameter. All evaluations are presented in tabular form and recommendations are made on the best-suited diagnostic method to implement for each flow parameter in order of applicability and intrinsic value.

Combustion of interacting droplet arrays in a microgravity environment

NASA Technical Reports Server (NTRS)

Dietrich, Daniel L.

1995-01-01

This research program involves the study of one and two dimensional arrays of droplets in a buoyant-free environment. The purpose of the work is to extend the database and theories that exist for single droplets into the regime where droplet interactions are important. The eventual goal being to use the results of this work as inputs to models on spray combustion where droplets seldom burn individually; instead the combustion history of a droplet is strongly influenced by the presence of the neighboring droplets. Throughout the course of the work, a number of related aspects of isolated droplet combustion have also been investigated. This paper will review our progress in microgravity droplet array combustion, advanced diagnostics (specifically L2) applied to isolated droplet combustion, and radiative extinction large droplet flames. A small-scale droplet combustion experiment being developed for the Space Shuttle will also be described.

Coal Combustion Science quarterly progress report, April--June 1992

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

Hardesty, D.R.; Hurt, R.H.; Baxter, L.L.

1992-09-01

The objective of this work is to support the Office of Fossil Energy in executing research on coal combustion science. This project consists of basic research on coal combustion that supports both the Pittsburgh Energy Technology Center (PETC) Direct Utilization Advanced Research and Technology Development Program, and the International Energy Agency (IEA) Coal Combustion Science Project. Specific tasks include: The characterization of the physical and chemical processes that constitute the early devolatilization phase of coal combustion: Characterization of the combustion behavior of selected coals under conditions relevant to industria pulverized coal-fired furnaces; and to establish a quantitative understanding of themore » mechanisms and rates of transformation, fragmentation, and deposition of mineral matter in coal combustion environments as a function of coal type, particle size and temperature, the initial forms and distributions of mineral species in the unreacted coal, and the local gas temperature and composition.« less

Sandia and General Motors: Advancing Clean Combustion Engines with

Science.gov Websites

Quantitative Risk Assessment Technical Reference for Hydrogen Compatibility of Materials Hydrogen Battery Abuse Testing Laboratory Center for Infrastructure Research and Innovation Combustion Research Facility Joint BioEnergy Institute Close Energy Research Programs ARPA-E Basic Energy Sciences Materials

Combustion characteristics and design of hot water boiler

NASA Astrophysics Data System (ADS)

Liu, Xuemin; Yang, Dinghua; Lu, Junfu; Guan, Jian; Qi, Guoli

2017-03-01

In order to understand the combustion characteristics of biomass, a detailed comparison with coal was made. There are many differences between biomass and coal in combustion characteristics. The burning rate of biomass is much higher than coal. The burning rate of biomass char is also higher than coal char. During biomass combustion, HCl, SO2 and NO x emissions mainly concentrate in volatile combustion stage, while CO2 emission mainly concentrates in char combustion stage. The slagging tendency of biomass ash is severer than coal ash and the adhesive force of biomass ash is higher. However, the wearing tendency of biomass ash is minor. Aiming at the particularity of biomass fuels, this paper briefly introduces the design of biomass hot water boilers. On this basis, a 2.8 MW biomass hot water boiler was developed and tested under the loads of 1.7 MW and 2.8MW. The running results show that the carbon content of bottom slag significantly decreases as the load increases. The boiler efficiency is higher than 85% under both loads.

NCC: A Multidisciplinary Design/Analysis Tool for Combustion Systems

NASA Technical Reports Server (NTRS)

Liu, Nan-Suey; Quealy, Angela

1999-01-01

A multi-disciplinary design/analysis tool for combustion systems is critical for optimizing the low-emission, high-performance combustor design process. Based on discussions between NASA Lewis Research Center and the jet engine companies, an industry-government team was formed in early 1995 to develop the National Combustion Code (NCC), which is an integrated system of computer codes for the design and analysis of combustion systems. NCC has advanced features that address the need to meet designer's requirements such as "assured accuracy", "fast turnaround", and "acceptable cost". The NCC development team is comprised of Allison Engine Company (Allison), CFD Research Corporation (CFDRC), GE Aircraft Engines (GEAE), NASA Lewis Research Center (LeRC), and Pratt & Whitney (P&W). This development team operates under the guidance of the NCC steering committee. The "unstructured mesh" capability and "parallel computing" are fundamental features of NCC from its inception. The NCC system is composed of a set of "elements" which includes grid generator, main flow solver, turbulence module, turbulence and chemistry interaction module, chemistry module, spray module, radiation heat transfer module, data visualization module, and a post-processor for evaluating engine performance parameters. Each element may have contributions from several team members. Such a multi-source multi-element system needs to be integrated in a way that facilitates inter-module data communication, flexibility in module selection, and ease of integration.

Combustion of Biosolids in a Bubbling Fluidized Bed, Part 1: Main Ash-Forming Elements and Ash Distribution with a Focus on Phosphorus.

PubMed

Skoglund, Nils; Grimm, Alejandro; Ohman, Marcus; Boström, Dan

2014-02-20

This is the first in a series of three papers describing combustion of biosolids in a 5-kW bubbling fluidized bed, the ash chemistry, and possible application of the ash produced as a fertilizing agent. This part of the study aims to clarify whether the distribution of main ash forming elements from biosolids can be changed by modifying the fuel matrix, the crystalline compounds of which can be identified in the raw materials and what role the total composition may play for which compounds are formed during combustion. The biosolids were subjected to low-temperature ashing to investigate which crystalline compounds that were present in the raw materials. Combustion experiments of two different types of biosolids were conducted in a 5-kW benchscale bubbling fluidized bed at two different bed temperatures and with two different additives. The additives were chosen to investigate whether the addition of alkali (K 2 CO 3 ) and alkaline-earth metal (CaCO 3 ) would affect the speciation of phosphorus, so the molar ratios targeted in modified fuels were P:K = 1:1 and P:K:Ca = 1:1:1, respectively. After combustion the ash fractions were collected, the ash distribution was determined and the ash fractions were analyzed with regards to elemental composition (ICP-AES and SEM-EDS) and part of the bed ash was also analyzed qualitatively using XRD. There was no evidence of zeolites in the unmodified fuels, based on low-temperature ashing. During combustion, the biosolid pellets formed large bed ash particles, ash pellets, which contained most of the total ash content (54%-95% (w/w)). This ash fraction contained most of the phosphorus found in the ash and the only phosphate that was identified was a whitlockite, Ca 9 (K,Mg,Fe)(PO 4 ) 7 , for all fuels and fuel mixtures. With the addition of potassium, cristobalite (SiO 2 ) could no longer be identified via X-ray diffraction (XRD) in the bed ash particles and leucite (KAlSi 2 O 6 ) was formed. Most of the alkaline-earth metals

Combustion of Biosolids in a Bubbling Fluidized Bed, Part 1: Main Ash-Forming Elements and Ash Distribution with a Focus on Phosphorus

PubMed Central

2014-01-01

This is the first in a series of three papers describing combustion of biosolids in a 5-kW bubbling fluidized bed, the ash chemistry, and possible application of the ash produced as a fertilizing agent. This part of the study aims to clarify whether the distribution of main ash forming elements from biosolids can be changed by modifying the fuel matrix, the crystalline compounds of which can be identified in the raw materials and what role the total composition may play for which compounds are formed during combustion. The biosolids were subjected to low-temperature ashing to investigate which crystalline compounds that were present in the raw materials. Combustion experiments of two different types of biosolids were conducted in a 5-kW benchscale bubbling fluidized bed at two different bed temperatures and with two different additives. The additives were chosen to investigate whether the addition of alkali (K2CO3) and alkaline-earth metal (CaCO3) would affect the speciation of phosphorus, so the molar ratios targeted in modified fuels were P:K = 1:1 and P:K:Ca = 1:1:1, respectively. After combustion the ash fractions were collected, the ash distribution was determined and the ash fractions were analyzed with regards to elemental composition (ICP-AES and SEM-EDS) and part of the bed ash was also analyzed qualitatively using XRD. There was no evidence of zeolites in the unmodified fuels, based on low-temperature ashing. During combustion, the biosolid pellets formed large bed ash particles, ash pellets, which contained most of the total ash content (54%–95% (w/w)). This ash fraction contained most of the phosphorus found in the ash and the only phosphate that was identified was a whitlockite, Ca9(K,Mg,Fe)(PO4)7, for all fuels and fuel mixtures. With the addition of potassium, cristobalite (SiO2) could no longer be identified via X-ray diffraction (XRD) in the bed ash particles and leucite (KAlSi2O6) was formed. Most of the alkaline-earth metals calcium and

Spray combustion model improvement study, 1

NASA Technical Reports Server (NTRS)

Chen, C. P.; Kim, Y. M.; Shang, H. M.

1993-01-01

This study involves the development of numerical and physical modeling in spray combustion. These modeling efforts are mainly motivated to improve the physical submodels of turbulence, combustion, atomization, dense spray effects, and group vaporization. The present mathematical formulation can be easily implemented in any time-marching multiple pressure correction methodologies such as MAST code. A sequence of validation cases includes the nonevaporating, evaporating and_burnin dense_sprays.

Numerical simulations of turbulent jet ignition and combustion

NASA Astrophysics Data System (ADS)

Validi, Abdoulahad; Irannejad, Abolfazl; Jaberi, Farhad

2013-11-01

The ignition and combustion of a homogeneous lean hydrogen-air mixture by a turbulent jet flow of hot combustion products injected into a colder gas mixture are studied by a high fidelity numerical model. Turbulent jet ignition can be considered as an efficient method for starting and controlling the reaction in homogeneously charged combustion systems used in advanced internal combustion and gas turbine engines. In this work, we study in details the physics of turbulent jet ignition in a fundamental flow configuration. The flow and combustion are modeled with the hybrid large eddy simulation/filtered mass density function (LES/FMDF) approach, in which the filtered form the compressible Navier-Stokes equations are solved with a high-order finite difference scheme for the turbulent velocity and the FMDF transport equations are solved with a Lagrangian stochastic method to obtain the scalar (temperature and species mass fractions) field. The hydrogen oxidation is described by a detailed reaction mechanism with 37 elementary reactions and 9 species.

Coal Combustion Science quarterly progress report, April--June 1992. Task 1, Coal devolatilization: Task 2, Coal char combustion; Task 3, Fate of mineral matter

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

Hardesty, D.R.; Hurt, R.H.; Baxter, L.L.

1992-09-01

The objective of this work is to support the Office of Fossil Energy in executing research on coal combustion science. This project consists of basic research on coal combustion that supports both the Pittsburgh Energy Technology Center (PETC) Direct Utilization Advanced Research and Technology Development Program, and the International Energy Agency (IEA) Coal Combustion Science Project. Specific tasks include: The characterization of the physical and chemical processes that constitute the early devolatilization phase of coal combustion: Characterization of the combustion behavior of selected coals under conditions relevant to industria pulverized coal-fired furnaces; and to establish a quantitative understanding of themore » mechanisms and rates of transformation, fragmentation, and deposition of mineral matter in coal combustion environments as a function of coal type, particle size and temperature, the initial forms and distributions of mineral species in the unreacted coal, and the local gas temperature and composition.« less

National Combustion Code Used To Study the Hydrogen Injector Design for Gas Turbines

NASA Technical Reports Server (NTRS)

Iannetti, Anthony C.; Norris, Andrew T.; Shih, Tsan-Hsing

2005-01-01

Hydrogen, in the gas state, has been proposed to replace Jet-A (the fuel used for commercial jet engines) as a fuel for gas turbine combustion. For the combustion of hydrogen and oxygen only, water is the only product and the main greenhouse gas, carbon dioxide, is not produced. This is an obvious benefit of using hydrogen as a fuel. The situation is not as simple when air replaces oxygen in the combustion process. (Air is mainly a mixture of oxygen, nitrogen, and argon. Other components comprise a very small part of air and will not be mentioned.) At the high temperatures found in the combustion process, oxygen reacts with nitrogen, and this produces nitrogen oxide compounds, or NOx--the main component of atmospheric smog. The production of NOx depends mainly on two variables: the temperature at which combustion occurs, and the length of time that the products of combustion stay, or reside, in the combustor. Starting from a lean (excess air) air-to-fuel ratio, the goal of this research was to minimize hot zones caused by incomplete premixing and to keep the residence time short while producing a stable flame. The minimization of these two parameters will result in low- NOx hydrogen combustion.

Advanced Health Management System for the Space Shuttle Main Engine

NASA Technical Reports Server (NTRS)

Davidson, Matt; Stephens, John

2004-01-01

Boeing-Canoga Park (BCP) and NASA-Marshall Space Flight Center (NASA-MSFC) are developing an Advanced Health Management System (AHMS) for use on the Space Shuttle Main Engine (SSME) that will improve Shuttle safety by reducing the probability of catastrophic engine failures during the powered ascent phase of a Shuttle mission. This is a phased approach that consists of an upgrade to the current Space Shuttle Main Engine Controller (SSMEC) to add turbomachinery synchronous vibration protection and addition of a separate Health Management Computer (HMC) that will utilize advanced algorithms to detect and mitigate predefined engine anomalies. The purpose of the Shuttle AHMS is twofold; one is to increase the probability of successfully placing the Orbiter into the intended orbit, and the other is to increase the probability of being able to safely execute an abort of a Space Transportation System (STS) launch. Both objectives are achieved by increasing the useful work envelope of a Space Shuttle Main Engine after it has developed anomalous performance during launch and the ascent phase of the mission. This increase in work envelope will be the result of two new anomaly mitigation options, in addition to existing engine shutdown, that were previously unavailable. The added anomaly mitigation options include engine throttle-down and performance correction (adjustment of engine oxidizer to fuel ratio), as well as enhanced sensor disqualification capability. The HMC is intended to provide the computing power necessary to diagnose selected anomalous engine behaviors and for making recommendations to the engine controller for anomaly mitigation. Independent auditors have assessed the reduction in Shuttle ascent risk to be on the order of 40% with the combined system and a three times improvement in mission success.

Distributed ignition method and apparatus for a combustion engine

DOEpatents

Willi, Martin L.; Bailey, Brett M.; Fiveland, Scott B.; Gong, Weidong

2006-03-07

A method and apparatus for operating an internal combustion engine is provided. The method comprises the steps of introducing a primary fuel into a main combustion chamber of the engine, introducing a pilot fuel into the main combustion chamber of the engine, determining an operating load of the engine, determining a desired spark plug ignition timing based on the engine operating load, and igniting the primary fuel and pilot fuel with a spark plug at the desired spark plug ignition timing. The method is characterized in that the octane number of the pilot fuel is lower than the octane number of the primary fuel.

Injection system used into SI engines for complete combustion and reduction of exhaust emissions in the case of alcohol and petrol alcohol mixtures feed

NASA Astrophysics Data System (ADS)

Ispas, N.; Cofaru, C.; Aleonte, M.

2017-10-01

Internal combustion engines still play a major role in today transportation but increasing the fuel efficiency and decreasing chemical emissions remain a great goal of the researchers. Direct injection and air assisted injection system can improve combustion and can reduce the concentration of the exhaust gas pollutes. Advanced air-to-fuel and combustion air-to-fuel injection system for mixtures, derivatives and alcohol gasoline blends represent a major asset in reducing pollutant emissions and controlling combustion processes in spark-ignition engines. The use of these biofuel and biofuel blending systems for gasoline results in better control of spark ignition engine processes, making combustion as complete as possible, as well as lower levels of concentrations of pollutants in exhaust gases. The main purpose of this paper was to provide most suitable tools for ensure the proven increase in the efficiency of spark ignition engines, making them more environmentally friendly. The conclusions of the paper allow to highlight the paths leading to a better use of alcohols (biofuels) in internal combustion engines of modern transport units.

Consequences of sludge composition on combustion performance derived from thermogravimetry analysis

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

Li, Meiyan; Xiao, Benyi; Wang, Xu

Highlights: • Volatiles, particularly proteins, play a key role in sludge combustion. • Sludge combustion performance varies with different sludge organic concentrations. • Carbohydrates significantly affect the combustion rate in the second stage. • Combustion performance of digested sludge is more negative compared with others. - Abstract: Wastewater treatment plants produce millions of tons of sewage sludge. Sewage sludge is recognized as a promising feedstock for power generation via combustion and can be used for energy crisis adaption. We aimed to investigate the quantitative effects of various sludge characteristics on the overall sludge combustion process performance. Different types of sewagemore » sludge were derived from numerous wastewater treatment plants in Beijing for further thermogravimetric analysis. Thermogravimetric–differential thermogravimetric curves were used to compare the performance of the studied samples. Proximate analytical data, organic compositions, elementary composition, and calorific value of the samples were determined. The relationship between combustion performance and sludge composition was also investigated. Results showed that the performance of sludge combustion was significantly affected by the concentration of protein, which is the main component of volatiles. Carbohydrates and lipids were not correlated with combustion performance, unlike protein. Overall, combustion performance varied with different sludge organic composition. The combustion rate of carbohydrates was higher than those of protein and lipid, and carbohydrate weight loss mainly occurred during the second stage (175–300 °C). Carbohydrates have a substantial effect on the rate of system combustion during the second stage considering the specific combustion feature. Additionally, the combustion performance of digested sewage sludge is more negative than the others.« less

Microgravity Combustion Science: 1995 Program Update

NASA Technical Reports Server (NTRS)

Ross, Howard D. (Editor); Gokoglu, Suleyman A. (Editor); Friedman, Robert (Editor)

1995-01-01

Microgravity greatly benefits the study of fundamental combustion processes. In this environment, buoyancy-induced flow is nearly eliminated, weak or normally obscured forces and flows can be isolated, gravitational settling or sedimentation is nearly eliminated, and temporal and spatial scales can be expanded. This document reviews the state of knowledge in microgravity combustion science with the emphasis on NASA-sponsored developments in the current period of 1992 to early 1995. The subjects cover basic research in gaseous premixed and diffusion-flame systems, flame structure and sooting, liquid droplets and pools, and solid-surface ignition and flame spread. They also cover applied research in combustion synthesis of ceramic-metal composites, advanced diagnostic instrumentation, and on-orbit fire safety. The review promotes continuing research by describing the opportunities for Principal Investigator participation through the NASA Research Announcement program and the available NASA Lewis Research Center ground-based facilities and spaceflight accommodations. This review is compiled by the members and associates of the NASA Lewis Microgravity Combustion Branch, and it serves as an update of two previous overview reports.

Combustion-derived substances in deep basins of Puget Sound: historical inputs from fossil fuel and biomass combustion.

PubMed

Kuo, Li-Jung; Louchouarn, Patrick; Herbert, Bruce E; Brandenberger, Jill M; Wade, Terry L; Crecelius, Eric

2011-04-01

Reconstructions of 250 years historical inputs of two distinct types of black carbon (soot/graphitic black carbon (GBC) and char-BC) were conducted on sediment cores from two basins of the Puget Sound, WA. Signatures of polycyclic aromatic hydrocarbons (PAHs) were also used to support the historical reconstructions of BC to this system. Down-core maxima in GBC and combustion-derived PAHs occurred in the 1940s in the cores from the Puget Sound Main Basin, whereas in Hood Canal such peak was observed in the 1970s, showing basin-specific differences in inputs of combustion byproducts. This system showed relatively higher inputs from softwood combustion than the northeastern U.S. The historical variations in char-BC concentrations were consistent with shifts in climate indices, suggesting an influence of climate oscillations on wildfire events. Environmental loading of combustion byproducts thus appears as a complex function of urbanization, fuel usage, combustion technology, environmental policies, and climate conditions. Copyright © 2010 Elsevier Ltd. All rights reserved.

Gasoline Combustion Fundamentals DOE FY17 Report

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

Ekoto, Isaac W.

Advanced automotive gasoline engines that leverage a combination of reduced heat transfer, throttling, and mechanical losses; shorter combustion durations; and higher compression and mixture specific heat ratios are needed to meet aggressive DOE VTP fuel economy and pollutant emission targets. Central challenges include poor combustion stability at low-power conditions when large amounts of charge dilution are introduced and high sensitivity of conventional inductive coil ignition systems to elevated charge motion and density for boosted high-load operation. For conventional spark ignited operation, novel low-temperature plasma (LTP) or pre-chamber based ignition systems can improve dilution tolerances while maintaining good performance characteristics atmore » elevated charge densities. Moreover, these igniters can improve the control of advanced compression ignition (ACI) strategies for gasoline at low to moderate loads. The overarching research objective of the Gasoline Combustion Fundamentals project is to investigate phenomenological aspects related to enhanced ignition. The objective is accomplished through targeted experiments performed in a single-cylinder optically accessible research engine or an in-house developed optically accessible spark calorimeter (OASC). In situ optical diagnostics and ex situ gas sampling measurements are performed to elucidate important details of ignition and combustion processes. Measurements are further used to develop and validate complementary high-fidelity ignition simulations. The primary project audience is automotive manufacturers, Tier 1 suppliers, and technology startups—close cooperation has resulted in the development and execution of project objectives that address crucial mid- to long-range research challenges.« less

Real time identification of the internal combustion engine combustion parameters based on the vibration velocity signal

NASA Astrophysics Data System (ADS)

Zhao, Xiuliang; Cheng, Yong; Wang, Limei; Ji, Shaobo

2017-03-01

Accurate combustion parameters are the foundations of effective closed-loop control of engine combustion process. Some combustion parameters, including the start of combustion, the location of peak pressure, the maximum pressure rise rate and its location, can be identified from the engine block vibration signals. These signals often include non-combustion related contributions, which limit the prompt acquisition of the combustion parameters computationally. The main component in these non-combustion related contributions is considered to be caused by the reciprocating inertia force excitation (RIFE) of engine crank train. A mathematical model is established to describe the response of the RIFE. The parameters of the model are recognized with a pattern recognition algorithm, and the response of the RIFE is predicted and then the related contributions are removed from the measured vibration velocity signals. The combustion parameters are extracted from the feature points of the renovated vibration velocity signals. There are angle deviations between the feature points in the vibration velocity signals and those in the cylinder pressure signals. For the start of combustion, a system bias is adopted to correct the deviation and the error bound of the predicted parameters is within 1.1°. To predict the location of the maximum pressure rise rate and the location of the peak pressure, algorithms based on the proportion of high frequency components in the vibration velocity signals are introduced. Tests results show that the two parameters are able to be predicted within 0.7° and 0.8° error bound respectively. The increase from the knee point preceding the peak value point to the peak value in the vibration velocity signals is used to predict the value of the maximum pressure rise rate. Finally, a monitoring frame work is inferred to realize the combustion parameters prediction. Satisfactory prediction for combustion parameters in successive cycles is achieved, which

Consequences of sludge composition on combustion performance derived from thermogravimetry analysis.

PubMed

Li, Meiyan; Xiao, Benyi; Wang, Xu; Liu, Junxin

2015-01-01

Wastewater treatment plants produce millions of tons of sewage sludge. Sewage sludge is recognized as a promising feedstock for power generation via combustion and can be used for energy crisis adaption. We aimed to investigate the quantitative effects of various sludge characteristics on the overall sludge combustion process performance. Different types of sewage sludge were derived from numerous wastewater treatment plants in Beijing for further thermogravimetric analysis. Thermogravimetric-differential thermogravimetric curves were used to compare the performance of the studied samples. Proximate analytical data, organic compositions, elementary composition, and calorific value of the samples were determined. The relationship between combustion performance and sludge composition was also investigated. Results showed that the performance of sludge combustion was significantly affected by the concentration of protein, which is the main component of volatiles. Carbohydrates and lipids were not correlated with combustion performance, unlike protein. Overall, combustion performance varied with different sludge organic composition. The combustion rate of carbohydrates was higher than those of protein and lipid, and carbohydrate weight loss mainly occurred during the second stage (175-300°C). Carbohydrates have a substantial effect on the rate of system combustion during the second stage considering the specific combustion feature. Additionally, the combustion performance of digested sewage sludge is more negative than the others. Copyright © 2014 Elsevier Ltd. All rights reserved.

Construction of combustion models for rapeseed methyl ester bio-diesel fuel for internal combustion engine applications.

PubMed

Golovitchev, Valeri I; Yang, Junfeng

2009-01-01

Bio-diesel fuels are non-petroleum-based diesel fuels consisting of long chain alkyl esters produced by the transesterification of vegetable oils, that are intended for use (neat or blended with conventional fuels) in unmodified diesel engines. There have been few reports of studies proposing theoretical models for bio-diesel combustion simulations. In this study, we developed combustion models based on ones developed previously. We compiled the liquid fuel properties, and the existing detailed mechanism of methyl butanoate ester (MB, C(5)H(10)O(2)) oxidation was supplemented by sub-mechanisms for two proposed fuel constituent components, C(7)H(16) and C(7)H(8)O (and then, by mp2d, C(4)H(6)O(2) and propyne, C(3)H(4)) to represent the combustion model for rapeseed methyl ester described by the chemical formula, C(19)H(34)O(2) (or C(19)H(36)O(2)). The main fuel vapor thermal properties were taken as those of methyl palmitate C(19)H(36)O(2) in the NASA polynomial form of the Burcat database. The special global reaction was introduced to "crack" the main fuel into its constituent components. This general reaction included 309 species and 1472 reactions, including soot and NO(x) formation processes. The detailed combustion mechanism was validated using shock-tube ignition-delay data under diesel engine conditions. For constant volume and diesel engine (Volvo D12C) combustion modeling, this mechanism could be reduced to 88 species participating in 363 reactions.

Aviation combustion toxicology: an overview.

PubMed

Chaturvedi, Arvind K

2010-01-01

Aviation combustion toxicology is a subspecialty of the field of aerospace toxicology, which is composed of aerospace and toxicology. The term aerospace, that is, the environment extending above and beyond the surface of the Earth, is also used to represent the combined fields of aeronautics and astronautics. Aviation is another term interchangeably used with aerospace and aeronautics and is explained as the science and art of operating powered aircraft. Toxicology deals with the adverse effects of substances on living organisms. Although toxicology borrows knowledge from biology, chemistry, immunology, pathology, physiology, and public health, the most closely related field to toxicology is pharmacology. Economic toxicology, environmental toxicology, and forensic toxicology, including combustion toxicology, are the three main branches of toxicology. In this overview, a literature search for the period of 1960-2007 was performed and information related to aviation combustion toxicology collected. The overview included introduction; combustion, fire, and smoke; smoke gas toxicity; aircraft material testing; fire gases and their interactive effects; result interpretation; carboxyhemoglobin and blood cyanide ion levels; pyrolytic products of aircraft engine oils, fluids, and lubricants; and references. This review is anticipated to be an informative resource for aviation combustion toxicology and fire-related casualties.

Volatile Reaction Products From Silicon-Based Ceramics in Combustion Environments Identified

NASA Technical Reports Server (NTRS)

Opila, Elizabeth J.

1997-01-01

Silicon-based ceramics and composites are prime candidates for use as components in the hot sections of advanced aircraft engines. These materials must have long-term durability in the combustion environment. Because water vapor is always present as a major product of combustion in the engine environment, its effect on the durability of silicon-based ceramics must be understood. In combustion environments, silicon-based ceramics react with water vapor to form a surface silica (SiO2) scale. This SiO2 scale, in turn, has been found to react with water vapor to form volatile hydroxides. Studies to date have focused on how water vapor reacts with high-purity silicon carbide (SiC) and SiO2 in model combustion environments. Because the combustion environment in advanced aircraft engines is expected to contain about 10-percent water vapor at 10-atm total pressure, the durability of SiC and SiO2 in gas mixtures containing 0.1- to 1-atm water vapor is of interest. The reactions of SiC and SiO2 with water vapor were monitored by measuring weight changes of sample coupons in a 0.5-atm water vapor/0.5-atm oxygen gas mixture with thermogravimetric analysis.

Economics of electron beam and electrical discharge processing for post-combustion NO(x) control in internal combustion engines

NASA Astrophysics Data System (ADS)

Penetrante, B. M.

1993-08-01

The physics and chemistry of non-thermal plasma processing for post-combustion NO(x) control in internal combustion engines are discussed. A comparison of electron beam and electrical discharge processing is made regarding their power consumption, radical production, NO(x) removal mechanisms, and by-product formation. Pollution control applications present a good opportunity for transferring pulsed power techniques to the commercial sector. However, unless advances are made to drastically reduce the price and power consumption of electron beam sources and pulsed power systems, these plasma techniques will not become commercially competitive with conventional thermal or surface-catalytic methods.

Measure Guideline: Combustion Safety for Natural Draft Appliances Through Appliance Zone Isolation

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

Fitzgerald, J.; Bohac, D.

2014-04-01

This measure guideline covers how to assess and carry out the isolation of natural draft combustion appliances from the conditioned space of low-rise residential buildings. It deals with combustion appliances located either within the living space in enclosed closets or side rooms or outside the living space in an adjacent area like an attic or garage. This subset of houses does not require comprehensive combustion safety tests and simplified prescriptive procedures can be used to address safety concerns. This allows residential energy retrofit contractors inexperienced in advanced combustion safety testing to effectively address combustion safety issues and allow energy retrofitsmore » including tightening and changes to distribution and ventilation systems to proceed.« less

Development and application of noninvasive technology for study of combustion in a combustion chamber of gas turbine engine

NASA Astrophysics Data System (ADS)

Inozemtsev, A. A.; Sazhenkov, A. N.; Tsatiashvili, V. V.; Abramchuk, T. V.; Shipigusev, V. A.; Andreeva, T. P.; Gumerov, A. R.; Ilyin, A. N.; Gubaidullin, I. T.

2015-05-01

The paper formulates the issue of development of experimental base with noninvasive optical-electronic tools for control of combustion in a combustion chamber of gas turbine engine. The design and specifications of a pilot sample of optronic system are explained; this noninvasive system was created in the framework of project of development of main critical technologies for designing of aviation gas turbine engine PD-14. The testbench run data are presented.

Review of Combustion Stability Characteristics of Swirl Coaxial Element Injectors

NASA Technical Reports Server (NTRS)

Hulka, J. R.; Casiano, M. J.

2013-01-01

Liquid propellant rocket engine injectors using coaxial elements where the center liquid is swirled have become more common in the United States over the past several decades, although primarily for technology or advanced development programs. Currently, only one flight engine operates with this element type in the United States (the RL10 engine), while the element type is very common in Russian (and ex-Soviet) liquid propellant rocket engines. In the United States, the understanding of combustion stability characteristics of swirl coaxial element injectors is still very limited, despite the influx of experimental and theoretical information from Russia. The empirical and theoretical understanding is much less advanced than for the other prevalent liquid propellant rocket injector element types, the shear coaxial and like-on-like paired doublet. This paper compiles, compares and explores the combustion stability characteristics of swirl coaxial element injectors tested in the United States, dating back to J-2 and RL-10 development, and extending to very recent programs at the NASA MSFC using liquid oxygen and liquid methane and kerosene propellants. Included in this study are several other relatively recent design and test programs, including the Space Transportation Main Engine (STME), COBRA, J-2X, and the Common Extensible Cryogenic Engine (CECE). A presentation of the basic data characteristics is included, followed by an evaluation by several analysis techniques, including those included in Rocket Combustor Interactive Design and Analysis Computer Program (ROCCID), and methodologies described by Hewitt and Bazarov.

Specifics of phytomass combustion in small experimental device

NASA Astrophysics Data System (ADS)

Lenhard, Richard; Mičieta, Jozef; Jandačka, Jozef; Gavlas, Stanislav

2015-05-01

A wood pellet combustion carries out with high efficiency and comfort in modern pellet boilers. These facts help to increase the amount of installed pellet boilers in households. The combustion process quality depends besides the combustion conditions also on the fuel quality. The wood pellets, which don`t contain the bark and branches represent the highest quality. Because of growing pellet demand, an herbal biomass (phytomass), which is usually an agricultural by-product becomes economically attractive for pellet production. Although the phytomass has the net calorific value relatively slightly lower than the wood biomass, it is often significantly worse in view of the combustion process and an emission production. The combustion of phytomass pellets causes various difficulties in small heat sources, mainly due to a sintering of fuel residues. We want to avoid the ash sintering by a lowering of temperature in the combustion chamber below the ash sintering temperature of phytomass via the modification of a burner design. For research of the phytomass combustion process in the small boilers is constructed the experimental combustion device. There will investigate the impact of cooling intensity of the combustion chamber on the combustion process and emissions. Arising specific requirements from the measurement will be the basis for the design of the pellet burner and for the setting of operating parameters to the trouble-free phytomass combustion was guaranteed.

Droplet Combustion Experiment on STS-94

NASA Technical Reports Server (NTRS)

2003-01-01

Fuel ignites and burns in the Droplet Combustion Experiment (DCE) on STS-94 on July 12, 1997, MET:11/07:00 (approximate). DCE used various fuels -- in drops ranging from 1 mm (0.04 inches) to 5 mm (0.2 inches) -- and mixtures of oxidizers and inert gases to learn more about the physics of combustion in the simplest burning configuration, a sphere. The DCE was designed to investigate the fundamental combustion aspects of single, isolated droplets under different pressures and ambient oxygen concentrations for a range of droplet sizes varying between 2 and 5 mm. The experiment elapsed time is shown at the bottom of the composite image. The DCE principal investigator was Forman Williams, University of California, San Diego. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). Advanced combustion experiments will be a part of investigations plarned for the International Space Station. (1.3MB, 13-second MPEG, screen 320 x 240 pixels; downlinked video, higher quality not available) A still JPG composite of this movie is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300170.html.

Progress in Advanced Spray Combustion Code Integration

NASA Technical Reports Server (NTRS)

Liang, Pak-Yan

1993-01-01

A multiyear project to assemble a robust, muitiphase spray combustion code is now underway and gradually building up to full speed. The overall effort involves several university and government research teams as well as Rocketdyne. The first part of this paper will give an overview of the respective roles of the different participants involved, the master strategy, the evolutionary milestones, and an assessment of the state-of-the-art of various key components. The second half of this paper will highlight the progress made to date in extending the baseline Navier-Stokes solver to handle multiphase, multispecies, chemically reactive sub- to supersonic flows. The major hurdles to overcome in order to achieve significant speed ups are delineated and the approaches to overcoming them will be discussed.

Combustion and Engine-Core Noise

NASA Astrophysics Data System (ADS)

Ihme, Matthias

2017-01-01

The implementation of advanced low-emission aircraft engine technologies and the reduction of noise from airframe, fan, and jet exhaust have made noise contributions from an engine core increasingly important. Therefore, meeting future ambitious noise-reduction goals requires the consideration of engine-core noise. This article reviews progress on the fundamental understanding, experimental analysis, and modeling of engine-core noise; addresses limitations of current techniques; and identifies opportunities for future research. After identifying core-noise contributions from the combustor, turbomachinery, nozzles, and jet exhaust, they are examined in detail. Contributions from direct combustion noise, originating from unsteady combustion, and indirect combustion noise, resulting from the interaction of flow-field perturbations with mean-flow variations in turbine stages and nozzles, are analyzed. A new indirect noise-source contribution arising from mixture inhomogeneities is identified by extending the theory. Although typically omitted in core-noise analysis, the impact of mean-flow variations and nozzle-upstream perturbations on the jet-noise modulation is examined, providing potential avenues for future core-noise mitigation.

Review of Membrane Oxygen Enrichment for Efficient Combustion

NASA Astrophysics Data System (ADS)

Ariono, Danu; Kusuma Wardani, Anita

2017-07-01

Oxygen enrichment from air is a simple way of increasing the efficiency of combustion process, as in oxy-combustion. Oxy-combustion has become one of the most attracting combustion technologies because of its potential to address both pollutant reduction and CO2 capture. In oxy-combustion, the fuel and recycled flue gas are combusted with oxygen enriched air (OEA). By using OEA, many benefits can be obtained, such as increasing available heat, improving ignition characteristics, flue gas reduction, increasing productivity, energy efficiency, turndown ratio, and flame stability. Membrane-based gas separation for OEA production becomes an attractive technology over the conventional technology due to the some advantages, including low capital cost, low energy consumption, compact size, and modularity. A single pass through membrane usually can enrich O2 concentration in the air up to 35% and a 50% concentration can be achieved with a double pass of membrane. The use of OEA in the combustion process eliminates the presence of nitrogen in the flue gas. Hence, the flue gas is mainly composed of CO2 and condensable water that can be easily separated. This paper gives an overview of oxy-combustion with membrane technology for oxygen enrichment process. Special attention is given to OEA production and the effect of OEA to the efficiency of combustion.

Practical internal combustion engine laser spark plug development

NASA Astrophysics Data System (ADS)

Myers, Michael J.; Myers, John D.; Guo, Baoping; Yang, Chengxin; Hardy, Christopher R.

2007-09-01

Fundamental studies on laser ignition have been performed by the US Department of Energy under ARES (Advanced Reciprocating Engines Systems) and by the California Energy Commission under ARICE (Advanced Reciprocating Internal Combustion Engine). These and other works have reported considerable increases in fuel efficiencies along with substantial reductions in green-house gas emissions when employing laser spark ignition. Practical commercial applications of this technology require low cost high peak power lasers. The lasers must be small, rugged and able to provide stable laser beam output operation under adverse mechanical and environmental conditions. New DPSS (Diode Pumped Solid State) lasers appear to meet these requirements. In this work we provide an evaluation of HESP (High Efficiency Side Pumped) DPSS laser design and performance with regard to its application as a practical laser spark plug for use in internal combustion engines.

External combustion engine having a combustion expansion chamber

NASA Astrophysics Data System (ADS)

Duva, Anthony W.

1993-03-01

This patent application discloses an external combustion engine having a combustion expansion chamber. The engine includes a combustion chamber for generating a high-pressure, energized gas from a monopropellant fuel, and a cylinder for receiving the energized gas through a rotary valve to perform work on a cylinder disposed therein. A baffle plate is positioned between the combustion area and expansion area for reducing the pressure of the gas. The combustion area and expansion area are separated by a baffle plate having a flow area which is sufficiently large to eliminate the transmission of pressure pulsations from the combustion area to the expansion area while being small enough to provide for substantially complete combustion in the combustion area. The engine is particularly well suited for use in a torpedo.

Combustion synthesis of ceramic-metal composite materials in microgravity

NASA Technical Reports Server (NTRS)

Moore, John

1995-01-01

Combustion synthesis, self-propagating high temperature synthesis (SHS) or reactive synthesis provides an attractive alternative to conventional methods of producing advanced materials since this technology is based on the ability of highly exothermic reactions to be self sustaining and, therefore, energetically efficient. The exothermic SHS reaction is initiated at the ignition temperature, T(sub ig), and generates heat which is manifested in a maximum or combustion temperature, T(sub c), which can exceed 3000 K . Such high combustion temperatures are capable of melting and/or volatilizing reactant and product species and, therefore, present an opportunity for producing structure and property modification and control through liquid-solid, vapor-liquid-solid, and vapor-solid transformations.

National Jet Fuels Combustion Program - overall program integration and analysis, Area #7.

DOT National Transportation Integrated Search

2017-01-01

The goal of this study is to develop, conduct, and analyze advanced laser and optical measurements in the referee combustor (WPAFB, Bldg. 490, RC 152) selected by the ASCENT National Fuel Combustion Program. We will conduct advanced spatially resolve...

Space Shuttle main engine product improvement

NASA Technical Reports Server (NTRS)

Lucci, A. D.; Klatt, F. P.

1985-01-01

The current design of the Space Shuttle Main Engine has passed 11 certification cycles, amassed approximately a quarter million seconds of engine test time in 1200 tests and successfully launched the Space Shuttle 17 times of 51 engine launches through May 1985. Building on this extensive background, two development programs are underway at Rocketdyne to improve the flow of hot gas through the powerhead and evaluate the changes to increase the performance margins in the engine. These two programs, called Phase II+ and Technology Test Bed Precursor program are described. Phase II+ develops a two-tube hot-gas manifold that improves the component environment. The Precursor program will evaluate a larger throat main combustion chamber, conduct combustion stability testing of a baffleless main injector, fabricate an experimental weld-free heat exchanger tube, fabricate and test a high pressure oxidizer turbopump with an improved inlet, and develop and test methods for reducing temperature transients at start and shutdown.

Combustion Devices CFD Team Analyses Review

NASA Technical Reports Server (NTRS)

Rocker, Marvin

2008-01-01

A variety of CFD simulations performed by the Combustion Devices CFD Team at Marshall Space Flight Center will be presented. These analyses were performed to support Space Shuttle operations and Ares-1 Crew Launch Vehicle design. Results from the analyses will be shown along with pertinent information on the CFD codes and computational resources used to obtain the results. Six analyses will be presented - two related to the Space Shuttle and four related to the Ares I-1 launch vehicle now under development at NASA. First, a CFD analysis of the flow fields around the Space Shuttle during the first six seconds of flight and potential debris trajectories within those flow fields will be discussed. Second, the combusting flows within the Space Shuttle Main Engine's main combustion chamber will be shown. For the Ares I-1, an analysis of the performance of the roll control thrusters during flight will be described. Several studies are discussed related to the J2-X engine to be used on the upper stage of the Ares I-1 vehicle. A parametric study of the propellant flow sequences and mixture ratios within the GOX/GH2 spark igniters on the J2-X is discussed. Transient simulations will be described that predict the asymmetric pressure loads that occur on the rocket nozzle during the engine start as the nozzle fills with combusting gases. Simulations of issues that affect temperature uniformity within the gas generator used to drive the J-2X turbines will described as well, both upstream of the chamber in the injector manifolds and within the combustion chamber itself.

Selected results from combustion research at the Lewis Research Center

NASA Technical Reports Server (NTRS)

Jones, R. E.

1981-01-01

Combustion research at Lewis is organized to provide a balanced program responsive to national needs and the gas turbine industry. The results of this research is a technology base that assists the gas turbine engine manufacturers in developing new and improved combustion systems for advanced civil and military engines with significant improvements in performance, durability, fuel flexibility and control of exhaust emissions. Research efforts consist of fundamentals and modeling, and applied component and combustor research.

Computational fluid dynamics combustion analysis evaluation

NASA Technical Reports Server (NTRS)

Kim, Y. M.; Shang, H. M.; Chen, C. P.; Ziebarth, J. P.

1992-01-01

This study involves the development of numerical modelling in spray combustion. These modelling efforts are mainly motivated to improve the computational efficiency in the stochastic particle tracking method as well as to incorporate the physical submodels of turbulence, combustion, vaporization, and dense spray effects. The present mathematical formulation and numerical methodologies can be casted in any time-marching pressure correction methodologies (PCM) such as FDNS code and MAST code. A sequence of validation cases involving steady burning sprays and transient evaporating sprays will be included.

Fiber-Supported Droplet Combustion Experiment-2

NASA Technical Reports Server (NTRS)

Colantonio, Renato O.

1998-01-01

A major portion of the energy produced in the world today comes from the burning of liquid hydrocarbon fuels in the form of droplets. Understanding the fundamental physical processes involved in droplet combustion is not only important in energy production but also in propulsion, in the mitigation of combustion-generated pollution, and in the control of the fire hazards associated with handling liquid combustibles. Microgravity makes spherically symmetric combustion possible, allowing investigators to easily validate their droplet models without the complicating effects of gravity. The Fiber-Supported Droplet Combustion (FSDC-2) investigation was conducted in the Microgravity Glovebox facility of the shuttles' Spacelab during the reflight of the Microgravity Science Laboratory (MSL- 1R) on STS-94 in July 1997. FSDC-2 studied fundamental phenomena related to liquid fuel droplet combustion in air. Pure fuels and mixtures of fuels were burned as isolated single and duo droplets with and without forced air convection. FSDC-2 is sponsored by the NASA Lewis Research Center, whose researchers are working in cooperation with several investigators from industry and academia. The rate at which a droplet burns is important in many commercial applications. The classical theory of droplet burning assumes that, for an isolated, spherically symmetric, single-fuel droplet, the gas-phase combustion processes are much faster than the droplet surface regression rate and that the liquid phase is at a uniform temperature equal to the boiling point. Recent, more advanced models predict that both the liquid and gas phases are unsteady during a substantial portion of the droplet's burning history, thus affecting the instantaneous and average burning rates, and that flame radiation is a dominant mechanism that can extinguish flames in a microgravity environment. FSDC-2 has provided well-defined, symmetric droplet burning data including radiative emissions to validate these theoretical

Numerical analysis of exhaust jet secondary combustion in hypersonic flow field

NASA Astrophysics Data System (ADS)

Yang, Tian-Peng; Wang, Jiang-Feng; Zhao, Fa-Ming; Fan, Xiao-Feng; Wang, Yu-Han

2018-05-01

The interaction effect between jet and control surface in supersonic and hypersonic flow is one of the key problems for advanced flight control system. The flow properties of exhaust jet secondary combustion in a hypersonic compression ramp flow field were studied numerically by solving the Navier-Stokes equations with multi-species and combustion reaction effects. The analysis was focused on the flow field structure and the force amplification factor under different jet conditions. Numerical results show that a series of different secondary combustion makes the flow field structure change regularly, and the temperature increases rapidly near the jet exit.

Regenerative combustion device

DOEpatents

West, Phillip B.

2004-03-16

A regenerative combustion device having a combustion zone, and chemicals contained within the combustion zone, such as water, having a first equilibrium state, and a second combustible state. Means for transforming the chemicals from the first equilibrium state to the second combustible state, such as electrodes, are disposed within the chemicals. An igniter, such as a spark plug or similar device, is disposed within the combustion zone for igniting combustion of the chemicals in the second combustible state. The combustion products are contained within the combustion zone, and the chemicals are selected such that the combustion products naturally chemically revert into the chemicals in the first equilibrium state following combustion. The combustion device may thus be repeatedly reused, requiring only a brief wait after each ignition to allow the regeneration of combustible gasses within the head space.

Effect of oxy-combustion flue gas on mercury oxidation.

PubMed

Fernández-Miranda, Nuria; Lopez-Anton, M Antonia; Díaz-Somoano, Mercedes; Martínez-Tarazona, M Rosa

2014-06-17

This study evaluates the effect of the gases present in a typical oxy-coal combustion atmosphere on mercury speciation and compares it with the mercury speciation produced in conventional air combustion atmospheres. The work was performed at laboratory scale at 150 °C. It was found that the minor constituents (SO2, NOx, and HCl) significantly modify the percentages of Hg(2+) in the gas. The influence of these species on mercury oxidation was demostrated when they were tested individually and also when they were blended in different gas compositions, although the effect was different to the sum of their individual effects. Of the minor constituents, NOx were the main species involved in oxidation of mercury. Moreover, it was found that a large concentration of H2O vapor also plays an important role in mercury oxidation. Around 50% of the total mercury was oxidized in atmospheres with H2O vapor concentrations typical of oxy-combustion conditions. When the atmospheres have similar concentrations of SO2, NO, NO2, HCl, and H2O, the proportion of Hg(0)/Hg(2+) is similar regardless of whether CO2 (oxy-fuel combustion) or N2 (air combustion) are the main components of the gas.

Indirect combustion noise of auxiliary power units

NASA Astrophysics Data System (ADS)

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

2013-08-01

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

Molecular structure of photosynthetic microbial biofuels for improved engine combustion and emissions characteristics.

PubMed

Hellier, Paul; Purton, Saul; Ladommatos, Nicos

2015-01-01

The metabolic engineering of photosynthetic microbes for production of novel hydrocarbons presents an opportunity for development of advanced designer biofuels. These can be significantly more sustainable, throughout the production-to-consumption lifecycle, than the fossil fuels and crop-based biofuels they might replace. Current biofuels, such as bioethanol and fatty acid methyl esters, have been developed primarily as drop-in replacements for existing fossil fuels, based on their physical properties and autoignition characteristics under specific combustion regimes. However, advances in the genetic engineering of microalgae and cyanobacteria, and the application of synthetic biology approaches offer the potential of designer strains capable of producing hydrocarbons and oxygenates with specific molecular structures. Furthermore, these fuel molecules can be designed for higher efficiency of energy release and lower exhaust emissions during combustion. This paper presents a review of potential fuel molecules from photosynthetic microbes and the performance of these possible fuels in modern internal combustion engines, highlighting which modifications to the molecular structure of such fuels may enhance their suitability for specific combustion regimes.

Molecular Structure of Photosynthetic Microbial Biofuels for Improved Engine Combustion and Emissions Characteristics

PubMed Central

Hellier, Paul; Purton, Saul; Ladommatos, Nicos

2015-01-01

The metabolic engineering of photosynthetic microbes for production of novel hydrocarbons presents an opportunity for development of advanced designer biofuels. These can be significantly more sustainable, throughout the production-to-consumption lifecycle, than the fossil fuels and crop-based biofuels they might replace. Current biofuels, such as bioethanol and fatty acid methyl esters, have been developed primarily as drop-in replacements for existing fossil fuels, based on their physical properties and autoignition characteristics under specific combustion regimes. However, advances in the genetic engineering of microalgae and cyanobacteria, and the application of synthetic biology approaches offer the potential of designer strains capable of producing hydrocarbons and oxygenates with specific molecular structures. Furthermore, these fuel molecules can be designed for higher efficiency of energy release and lower exhaust emissions during combustion. This paper presents a review of potential fuel molecules from photosynthetic microbes and the performance of these possible fuels in modern internal combustion engines, highlighting which modifications to the molecular structure of such fuels may enhance their suitability for specific combustion regimes. PMID:25941673

Combustion Stability Characteristics of the Project Morpheus Liquid Oxygen/Liquid Methane Main Engine

NASA Technical Reports Server (NTRS)

Melcher, J. C.; Morehead, Robert L.

2014-01-01

The Project Morpheus liquid oxygen (LOX) / liquid methane rocket engines demonstrated acousticcoupled combustion instabilities during sea-level ground-based testing at the NASA Johnson Space Center (JSC) and Stennis Space Center (SSC). High-amplitude, 1T, 1R, 1T1R (and higher order) modes appear to be triggered by injector conditions. The instability occurred during the Morpheus-specific engine ignition/start sequence, and did demonstrate the capability to propagate into mainstage. However, the instability was never observed to initiate during mainstage, even at low power levels. The Morpheus main engine is a JSC-designed 5,000 lbf-thrust, 4:1 throttling, pressure-fed cryogenic engine using an impinging element injector design. Two different engine designs, named HD4 and HD5, and two different builds of the HD4 engine all demonstrated similar instability characteristics. Through the analysis of more than 200 hot fire tests on the Morpheus vehicle and SSC test stand, a relationship between ignition stability and injector/chamber pressure was developed. The instability has the distinct characteristic of initiating at high relative injection pressure drop (dP) at low chamber pressure (Pc); i.e., instabilities initiated at high dP/Pc at low Pc during the start sequence. The high dP/Pc during start results during the injector /chamber chill-in, and is enhanced by hydraulic flip in the injector orifice elements. Because of the fixed mixture ratio of the existing engine design (the main valves share a common actuator), it is not currently possible to determine if LOX or methane injector dP/Pc were individual contributors (i.e., LOX and methane dP/Pc typically trend in the same direction within a given test). The instability demonstrated initiation characteristic of starting at or shortly after methane injector chillin. Colder methane (e.g., sub-cooled) at the injector inlet prior to engine start was much more likely to result in an instability. A secondary effect of LOX

Characteristics of oily sludge combustion in circulating fluidized beds.

PubMed

Zhou, Lingsheng; Jiang, Xiumin; Liu, Jianguo

2009-10-15

Incineration of oily sludge in circulating fluidized beds may be an effective way for its management in some cases. The objective of the present paper is to investigate combustion characteristics of oily sludge, which would be helpful and useful for the design and simulation of a circulating fluidized bed. Firstly, the pyrolysis and combustion of oily sludge were studied through some thermal analyses, which included the thermogravimetric (TG) analysis and the differential thermal analytical (DTA) analysis. It was found that the combustion of oily sludge might be the combustion of its pyrolysis products. Secondly, an experiment for measuring of main components of the volatile from oily sludge pyrolysis was carried out. Some mathematic correlations about the compositions of volatile from oily sludge devolatilization were achieved from the experimental results. Finally, the combustion characteristics of oily sludge was studied in a lab-scale circulating fluidized bed, which could obtain some information about the location of release and combustion of the volatiles.

Fuel Droplet Burning During Droplet Combustion Experiment

NASA Technical Reports Server (NTRS)

2003-01-01

Fuel ignites and burns in the Droplet Combustion Experiment (DCE) on STS-94 on July 4 1997, MET:2/05:40 (approximate). The DCE was designed to investigate the fundamental combustion aspects of single, isolated droplets under different pressures and ambient oxygen concentrations for a range of droplet sizes varying between 2 and 5 mm. DCE used various fuels -- in drops ranging from 1 mm (0.04 inches) to 5 mm (0.2 inches) -- and mixtures of oxidizers and inert gases to learn more about the physics of combustion in the simplest burning configuration, a sphere. The experiment elapsed time is shown at the bottom of the composite image. The DCE principal investigator was Forman Williams, University of California, San Diego. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). Advanced combustion experiments will be a part of investigations plarned for the International Space Station. (1.4MB, 13-second MPEG, screen 320 x 240 pixels; downlinked video, higher quality not available)A still JPG composite of this movie is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300168.html.

Combustion characteristics of gas turbine alternative fuels

NASA Technical Reports Server (NTRS)

Rollbuhler, R. James

1987-01-01

An experimental investigation was conducted to obtain combustion performance values for specific heavyend, synthetic hydrocarbon fuels. A flame tube combustor modified to duplicate an advanced gas turbine engine combustor was used for the tests. Each fuel was tested at steady-state operating conditions over a range of mass flow rates, fuel-to-air mass ratio, and inlet air temperatures. The combustion pressure, as well as the hardware, were kept nearly constant over the program test phase. Test results were obtained in regards to geometric temperature pattern factors as a function of combustor wall temperatures, the combustion gas temperature, and the combustion emissions, both as affected by the mass flow rate and fuel-to-air ratio. The synthetic fuels were reacted in the combustor such that for most tests their performance was as good, if not better, than the baseline gasoline or diesel fuel tests. The only detrimental effects were that at high inlet air temperature conditions, fuel decomposition occurred in the fuel atomizing nozzle passages resulting in blockage. And the nitrogen oxide emissions were above EPA limits at low flow rate and high operating temperature conditions.

National Jet Fuels Combustion Program - Area #6 : Referee Swirl-Stabilized Combustor Evaluation/Support.

DOT National Transportation Integrated Search

2017-01-01

The goal of this study is to develop, conduct, and analyze advanced laser and optical measurements in the referee combustor (WPAFB, Bldg. 490, RC 152) selected by the ASCENT National Fuel Combustion Program. We will conduct advanced spatially resolve...

A practical approach in porous medium combustion for domestic application: A review

NASA Astrophysics Data System (ADS)

Ismail, A. K.; Ibrahim, N. H.; Shamsuddin, K. A.; Abdullah, M. Z.; Zubair, M.

2018-05-01

Combustion in porous media has been widely studied. Many application involving the combustion of porous media has been reported in various way with most consider on numerical works and industrial application. Besides, recent application of porous medium combustion for domestic is the topic of interest among researchers. In this paper, a review was conducted on the combustion of porous media in term of practical application for domestic consumers. Details on the type of fuel used including bio fuel and their system have been search thoroughly. Most of the system have utilized compressed air system to provide lean combustion in domestic application. Some self-aspirating system of porous medium burner was also reported. The application of new technology such as cogeneration by using thermoelectric cells in tandem with porous medium combustion is also revised according to recent work which have already been published. Besides, the recent advances which include coating of porous material is also considered at the end of this paper.

The study of PDF turbulence models in combustion

NASA Technical Reports Server (NTRS)

Hsu, Andrew T.

1991-01-01

The accurate prediction of turbulent combustion is still beyond reach for today's computation techniques. It is the consensus of the combustion profession that the predictions of chemically reacting flow were poor if conventional turbulence models were used. The main difficulty lies in the fact that the reaction rate is highly nonlinear, and the use of averaged temperature, pressure, and density produces excessively large errors. The probability density function (PDF) method is the only alternative at the present time that uses local instant values of the temperature, density, etc. in predicting chemical reaction rate, and thus it is the only viable approach for turbulent combustion calculations.

Physicochemical characterization of fine particles from small-scale wood combustion

NASA Astrophysics Data System (ADS)

Lamberg, Heikki; Nuutinen, Kati; Tissari, Jarkko; Ruusunen, Jarno; Yli-Pirilä, Pasi; Sippula, Olli; Tapanainen, Maija; Jalava, Pasi; Makkonen, Ulla; Teinilä, Kimmo; Saarnio, Karri; Hillamo, Risto; Hirvonen, Maija-Riitta; Jokiniemi, Jorma

2011-12-01

Emissions from small-scale wood combustion appliances are of special interest since fine particles have been consistently associated with adverse health effects. It has been reported that the physicochemical characteristics of the emitted particles affect also their toxic properties but the mechanisms behind these phenomena and the causative role of particles from wood combustion sources are still mostly unknown. Combustion situations vary significantly in small-scale appliances, especially in batch combustion. Combustion behaviour is affected by fuel properties, appliance type and operational practice. Particle samples were collected from six appliances representing different combustion situations in small-scale combustion. These appliances were five wood log fuelled stoves, including one stove equipped with modern combustion technology, three different conventional combustion appliances and one sauna stove. In addition, a modern small-scale pellet boiler represented advanced continuous combustion technology. The aim of the study was to analyze gas composition and fine particle properties over different combustion situations. Fine particle (PM 1) emissions and their chemical constituents emerging from different combustion situations were compared and this physicochemical data was combined with the toxicological data on cellular responses induced by the same particles (see Tapanainen et al., 2011). There were significant differences in the particle emissions from different combustion situations. Overall, the efficient combustion in the pellet boiler produced the smallest emissions whereas inefficient batch combustion in a sauna stove created the largest emissions. Improved batch combustion with air-staging produced about 2.5-fold PM 1 emissions compared to the modern pellet boiler (50.7 mg MJ -1 and 19.7 mg MJ -1, respectively), but the difference in the total particulate PAH content was 750-fold (90 μg MJ -1 and 0.12 μg MJ -1, respectively). Improved batch

Co-Optimization of Internal Combustion Engines and Biofuels

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

McCormick, Robert L.

2016-03-08

The development of advanced engines has significant potential advantages in reduced aftertreatment costs for air pollutant emission control, and just as importantly for efficiency improvements and associated greenhouse gas emission reductions. There are significant opportunities to leverage fuel properties to create more optimal engine designs for both advanced spark-ignition and compression-ignition combustion strategies. The fact that biofuel blendstocks offer a potentially low-carbon approach to fuel production, leads to the idea of optimizing the entire fuel production-utilization value chain as a system from the standpoint of life cycle greenhouse gas emissions. This is a difficult challenge that has yet to bemore » realized. This presentation will discuss the relationship between chemical structure and critical fuel properties for more efficient combustion, survey the properties of a range of biofuels that may be produced in the future, and describe the ongoing challenges of fuel-engine co-optimization.« less

Spray combustion experiments and numerical predictions

NASA Technical Reports Server (NTRS)

Mularz, Edward J.; Bulzan, Daniel L.; Chen, Kuo-Huey

1993-01-01

The next generation of commercial aircraft will include turbofan engines with performance significantly better than those in the current fleet. Control of particulate and gaseous emissions will also be an integral part of the engine design criteria. These performance and emission requirements present a technical challenge for the combustor: control of the fuel and air mixing and control of the local stoichiometry will have to be maintained much more rigorously than with combustors in current production. A better understanding of the flow physics of liquid fuel spray combustion is necessary. This paper describes recent experiments on spray combustion where detailed measurements of the spray characteristics were made, including local drop-size distributions and velocities. Also, an advanced combustor CFD code has been under development and predictions from this code are compared with experimental results. Studies such as these will provide information to the advanced combustor designer on fuel spray quality and mixing effectiveness. Validation of new fast, robust, and efficient CFD codes will also enable the combustor designer to use them as additional design tools for optimization of combustor concepts for the next generation of aircraft engines.

Large eddy simulation modelling of combustion for propulsion applications.

PubMed

Fureby, C

2009-07-28

Predictive modelling of turbulent combustion is important for the development of air-breathing engines, internal combustion engines, furnaces and for power generation. Significant advances in modelling non-reactive turbulent flows are now possible with the development of large eddy simulation (LES), in which the large energetic scales of the flow are resolved on the grid while modelling the effects of the small scales. Here, we discuss the use of combustion LES in predictive modelling of propulsion applications such as gas turbine, ramjet and scramjet engines. The LES models used are described in some detail and are validated against laboratory data-of which results from two cases are presented. These validated LES models are then applied to an annular multi-burner gas turbine combustor and a simplified scramjet combustor, for which some additional experimental data are available. For these cases, good agreement with the available reference data is obtained, and the LES predictions are used to elucidate the flow physics in such devices to further enhance our knowledge of these propulsion systems. Particular attention is focused on the influence of the combustion chemistry, turbulence-chemistry interaction, self-ignition, flame holding burner-to-burner interactions and combustion oscillations.

Commercial investments in Combustion research aboard ISS

NASA Astrophysics Data System (ADS)

Schowengerdt, F. D.

2000-01-01

The Center for Commercial Applications of Combustion in Space (CCACS) at the Colorado School of Mines is working with a number of companies planning commercial combustion research to be done aboard the International Space Station (ISS). This research will be conducted in two major ISS facilities, SpaceDRUMS™ and the Fluids and Combustion Facility. SpaceDRUMS™, under development by Guigne Technologies, Ltd., of St. John's Newfoundland, is a containerless processing facility employing active acoustic sample positioning. It is capable of processing the large samples needed in commercial research and development with virtually complete vibration isolation from the space station. The Fluids and Combustion Facility (FCF), being developed by NASA-Glenn Research Center in Cleveland, is a general-purpose combustion furnace designed to accommodate a wide range of scientific experiments. SpaceDRUMS™ will be the first commercial hardware to be launched to ISS. Launch is currently scheduled for UF-1 in 2001. The CCACS research to be done in SpaceDRUMS™ includes combustion synthesis of glass-ceramics and porous materials. The FCF is currently scheduled to be launched to ISS aboard UF-3 in 2002. The CCACS research to be done in the FCF includes water mist fire suppression, catalytic combustion and flame synthesis of ceramic powders. The companies currently planning to be involved in the research include Guigne International, Ltd., Technology International, Inc., Coors Ceramics Company, TDA Research, Advanced Refractory Technologies, Inc., ADA Technologies, Inc., ITN Energy Systems, Inc., Innovative Scientific Solutions, Inc., Princeton Instruments, Inc., Environmental Engineering Concepts, Inc., and Solar Turbines, Inc. Together, these companies are currently investing almost $2 million in cash and in-kind annually toward the seven commercial projects within CCACS. Total private investment in CCACS research to date is over $7 million. .

Development and Hot-fire Testing of Additively Manufactured Copper Combustion Chambers for Liquid Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Gradl, Paul R.; Greene, Sandy Elam; Protz, Christopher S.; Ellis, David L.; Lerch, Bradley A.; Locci, Ivan E.

2017-01-01

NASA and industry partners are working towards fabrication process development to reduce costs and schedules associated with manufacturing liquid rocket engine components with the goal of reducing overall mission costs. One such technique being evaluated is powder-bed fusion or selective laser melting (SLM), commonly referred to as additive manufacturing (AM). The NASA Low Cost Upper Stage Propulsion (LCUSP) program was designed to develop processes and material characterization for GRCop-84 (a NASA Glenn Research Center-developed copper, chrome, niobium alloy) commensurate with powder-bed AM, evaluate bimetallic deposition, and complete testing of a full scale combustion chamber. As part of this development, the process has been transferred to industry partners to enable a long-term supply chain of monolithic copper combustion chambers. To advance the processes further and allow for optimization with multiple materials, NASA is also investigating the feasibility of bimetallic AM chambers. In addition to the LCUSP program, NASA has completed a series of development programs and hot-fire tests to demonstrate SLM GRCop-84 and other AM techniques. NASA's efforts include a 4K lbf thrust liquid oxygen/methane (LOX/CH4) combustion chamber and subscale thrust chambers for 1.2K lbf LOX/hydrogen (H2) applications that have been designed and fabricated with SLM GRCop-84. The same technologies for these lower thrust applications are being applied to 25-35K lbf main combustion chamber (MCC) designs. This paper describes the design, development, manufacturing and testing of these numerous combustion chambers, and the associated lessons learned throughout their design and development processes.

Method and apparatus for detecting combustion instability in continuous combustion systems

DOEpatents

Benson, Kelly J.; Thornton, Jimmy D.; Richards, George A.; Straub, Douglas L.

2006-08-29

An apparatus and method to sense the onset of combustion stability is presented. An electrode is positioned in a turbine combustion chamber such that the electrode is exposed to gases in the combustion chamber. A control module applies a voltage potential to the electrode and detects a combustion ionization signal and determines if there is an oscillation in the combustion ionization signal indicative of the occurrence of combustion stability or the onset of combustion instability. A second electrode held in a coplanar but spaced apart manner by an insulating member from the electrode provides a combustion ionization signal to the control module when the first electrode fails. The control module broadcasts a notice if the parameters indicate the combustion process is at the onset of combustion instability or broadcasts an alarm signal if the parameters indicate the combustion process is unstable.

Combustible structural composites and methods of forming combustible structural composites

DOEpatents

Daniels, Michael A [Idaho Falls, ID; Heaps, Ronald J [Idaho Falls, ID; Steffler, Eric D [Idaho Falls, ID; Swank, William D [Idaho Falls, ID

2011-08-30

Combustible structural composites and methods of forming same are disclosed. In an embodiment, a combustible structural composite includes combustible material comprising a fuel metal and a metal oxide. The fuel metal is present in the combustible material at a weight ratio from 1:9 to 1:1 of the fuel metal to the metal oxide. The fuel metal and the metal oxide are capable of exothermically reacting upon application of energy at or above a threshold value to support self-sustaining combustion of the combustible material within the combustible structural composite. Structural-reinforcing fibers are present in the composite at a weight ratio from 1:20 to 10:1 of the structural-reinforcing fibers to the combustible material. Other embodiments and aspects are disclosed.

Combustible structural composites and methods of forming combustible structural composites

DOEpatents

Daniels, Michael A.; Heaps, Ronald J.; Steffler, Eric D.; Swank, W. David

2013-04-02

Combustible structural composites and methods of forming same are disclosed. In an embodiment, a combustible structural composite includes combustible material comprising a fuel metal and a metal oxide. The fuel metal is present in the combustible material at a weight ratio from 1:9 to 1:1 of the fuel metal to the metal oxide. The fuel metal and the metal oxide are capable of exothermically reacting upon application of energy at or above a threshold value to support self-sustaining combustion of the combustible material within the combustible structural composite. Structural-reinforcing fibers are present in the composite at a weight ratio from 1:20 to 10:1 of the structural-reinforcing fibers to the combustible material. Other embodiments and aspects are disclosed.

Advanced Laser-Based Techniques for Gas-Phase Diagnostics in Combustion and Aerospace Engineering.

PubMed

Ehn, Andreas; Zhu, Jiajian; Li, Xuesong; Kiefer, Johannes

2017-03-01

Gaining information of species, temperature, and velocity distributions in turbulent combustion and high-speed reactive flows is challenging, particularly for conducting measurements without influencing the experimental object itself. The use of optical and spectroscopic techniques, and in particular laser-based diagnostics, has shown outstanding abilities for performing non-intrusive in situ diagnostics. The development of instrumentation, such as robust lasers with high pulse energy, ultra-short pulse duration, and high repetition rate along with digitized cameras exhibiting high sensitivity, large dynamic range, and frame rates on the order of MHz, has opened up for temporally and spatially resolved volumetric measurements of extreme dynamics and complexities. The aim of this article is to present selected important laser-based techniques for gas-phase diagnostics focusing on their applications in combustion and aerospace engineering. Applicable laser-based techniques for investigations of turbulent flows and combustion such as planar laser-induced fluorescence, Raman and Rayleigh scattering, coherent anti-Stokes Raman scattering, laser-induced grating scattering, particle image velocimetry, laser Doppler anemometry, and tomographic imaging are reviewed and described with some background physics. In addition, demands on instrumentation are further discussed to give insight in the possibilities that are offered by laser flow diagnostics.

Combustion dynamics in cryogenic rocket engines: Research programme at DLR Lampoldshausen

NASA Astrophysics Data System (ADS)

Hardi, Justin S.; Traudt, Tobias; Bombardieri, Cristiano; Börner, Michael; Beinke, Scott K.; Armbruster, Wolfgang; Nicolas Blanco, P.; Tonti, Federica; Suslov, Dmitry; Dally, Bassam; Oschwald, Michael

2018-06-01

The Combustion Dynamics group in the Rocket Propulsion Department at the German Aerospace Center (DLR), Lampoldshausen, strives to advance the understanding of dynamic processes in cryogenic rocket engines. Leveraging the test facilities and experimental expertise at DLR Lampoldshausen, the group has taken a primarily experimental approach to investigating transient flows, ignition, and combustion instabilities for over one and a half decades. This article provides a summary of recent achievements, and an overview of current and planned research activities.

Overview of Microgravity Combustion Research at NASA Lewis Research Center and its Potential Commercial Impact

NASA Technical Reports Server (NTRS)

Lyons, Valerie; Friedman, Robert

1996-01-01

The near-zero (microgravity) environment of orbiting spacecraft minimizes buoyant flows, greatly simplifying combustion processes and isolating important phenomena ordinarily concealed by the overwhelming gravity-driven forces and flows. Fundamental combustion understanding has greatly benefited from analyses and experiments conducted in the microgravity environment. Because of the economic and commercial importance of combustion in practice, there is strong motivation to seek wider applications for the microgravity-combustion findings. This paper reviews selected technology developments to illustrate some emerging applications. Topics cover improved fire-safety technology in spacecraft and terrestrial systems, innovative combustor designs for aerospace and ground propulsion, applied sensors and controls for combustion processes, and self-sustaining synthesis techniques for advanced materials.

Advanced Laser Based Measurements in Porous Media Combustion

NASA Technical Reports Server (NTRS)

Tedder, Sarah A.

2009-01-01

We present measurements using dual-pump dual-broadband coherent anti-Stokes Raman scattering spectroscopy (DP-DBB-CARS) inside a porous media burner. This work continues our previous measurements in such combustion systems. The existing setup was significantly modified with the aim of providing improved data quality and data rate, reduction of interferences and additional species information. These changes are presented and discussed in detail. The CARS technique was expanded to a dual-pump dual-broadband CARS system which in principle enables acquisition of temperatures together with relative H2/N2- and O2/N2- species concentrations. Experimental complexity was reduced by the use of a modified spectrometer enabling the detection of both signals, vibrational and rotational CARS, with only one detection system.

Numerical Modeling of Turbulent Combustion

NASA Technical Reports Server (NTRS)

Ghoneim, A. F.; Chorin, A. J.; Oppenheim, A. K.

1983-01-01

The work in numerical modeling is focused on the use of the random vortex method to treat turbulent flow fields associated with combustion while flame fronts are considered as interfaces between reactants and products, propagating with the flow and at the same time advancing in the direction normal to themselves at a prescribed burning speed. The latter is associated with the generation of specific volume (the flame front acting, in effect, as the locus of volumetric sources) to account for the expansion of the flow field due to the exothermicity of the combustion process. The model was applied to the flow in a channel equipped with a rearward facing step. The results obtained revealed the mechanism of the formation of large scale turbulent structure in the wake of the step, while it showed the flame to stabilize on the outer edges of these eddies.

500 MW demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide (NOx) emissions from coal-fired boilers. Public design report (preliminary and final)

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

NONE

1996-07-01

This Public Design Report presents the design criteria of a DOE Innovative Clean Coal Technology (ICCT) project demonstrating advanced wall-fired combustion techniques for the reduction of NO{sub x} emissions from coal-fired boilers. The project is being conducted at Georgia Power Company`s Plant Hammond Unit 4 (500 MW) near Rome, Georgia. The technologies being demonstrated at this site include Foster Wheeler Energy Corporation`s advanced overfire air system and Controlled Flow/Split Flame low NO{sub x} burner. This report provides documentation on the design criteria used in the performance of this project as it pertains to the scope involved with the low NO{submore » x} burners, advanced overfire systems, and digital control system.« less

Stress analysis of advanced attack helicopter composite main rotor blade root end lug

NASA Technical Reports Server (NTRS)

Baker, D. J.

1982-01-01

Stress analysis of the Advanced Attack Helicopter (AAH) composite main rotor blade root end lug is described. The stress concentration factor determined from a finite element analysis is compared to an empirical value used in the lug design. The analysis and test data indicate that the stress concentration is primarily a function of configuration and independent of the range of material properties typical of Kevlar-49/epoxy and glass epoxy.

Hot-Fire Test Results of an Oxygen/RP-2 Multi-Element Oxidizer-Rich Staged-Combustion Integrated Test Article

NASA Technical Reports Server (NTRS)

Hulka, J. R.; Protz, C. S.; Garcia, C. P.; Casiano, M. J.; Parton, J. A.

2016-01-01

As part of the Combustion Stability Tool Development project funded by the Air Force Space and Missile Systems Center, the NASA Marshall Space Flight Center was contracted to assemble and hot-fire test a multi-element integrated test article demonstrating combustion characteristics of an oxygen/hydrocarbon propellant oxidizer-rich staged-combustion engine thrust chamber. Such a test article simulates flow through the main injectors of oxygen/kerosene oxidizer-rich staged combustion engines such as the Russian RD-180 or NK-33 engines, or future U.S.-built engine systems such as the Aerojet-Rocketdyne AR-1 engine or the Hydrocarbon Boost program demonstration engine. For the thrust chamber assembly of the test article, several configurations of new main injectors, using relatively conventional gas-centered swirl coaxial injector elements, were designed and fabricated. The design and fabrication of these main injectors are described in a companion paper at this JANNAF meeting. New ablative combustion chambers were fabricated based on hardware previously used at NASA for testing at similar size and pressure. An existing oxygen/RP-1 oxidizer-rich subscale preburner injector from a previous NASA-funded program, along with existing and new inter-connecting hot gas duct hardware, were used to supply the oxidizer-rich combustion products to the oxidizer circuit of the main injector of the thrust chamber. Results from independent hot-fire tests of the preburner injector in a combustion chamber with a sonic throat are described in companion papers at this JANNAF conference. The resulting integrated test article - which includes the preburner, inter-connecting hot gas duct, main injector, and ablative combustion chamber - was assembled at Test Stand 116 at the East Test Area of the NASA Marshall Space Flight Center. The test article was well instrumented with static and dynamic pressure, temperature, and acceleration sensors to allow the collected data to be used for

Advanced optical diagnostics of multiphase combustion flow field using OH planar laser-induced fluorescence

NASA Astrophysics Data System (ADS)

Cho, Kevin Young-jin

High-repetition-rate (5 kHz, 10 kHz) OH planar laser induced fluorescence (PLIF) was used to investigate the combustion of liquid, gelled, and solid propellants. For the liquid monomethyl hydrazine (MMH) droplet combustion experiment in N2O/N2 using 5 kHz OH PLIF and visible imaging system, the OH profile and the droplet diameter were measured. The N2O partial pressure was varied by 20% and 40%, and the total pressure was varied by 103, 172, 276, 414, 552 kPa. The OH location indicated that the oxidation flame front is between the visible dual flame fronts. The results showed thicker flame sheet and higher burning rate for increased N2O concentration for a given pressure. The burning rate increased with increased pressure at 20% partial pressure N2O, and the burning rate decreased with increased pressure at 40% partial pressure N2O. This work provides experimental data for validating chemical kinetics models. For the gelled droplet combustion experiment using a 5 kHz OH PLIF system, speeds and locations of fuel jets emanating from the burning gelled droplets were quantified for the first time. MMH was gelled with organic gellant HPC at 3 wt.% and 6 wt.%, and burned in air at 35, 103, 172, 276, and 414 kPa. Different types of interaction of vapor jets and flame front were distinguished for the first time. For high jet speed, local extinction of the flame was observed. By analyzing the jet speed statistics, it was concluded that pressure and jet speed had an inverse relationship and gellant concentration and jet speed had a direct relationship. This work provides more fundamental insight into the physics of gelled fuel droplet combustion. A 3D OH PLIF system was assembled and demonstrated using a 10 kHz OH PLIF system and a galvanometric scanning mirror. This is the first time that a reacting flow field was imaged with a 3D optical technique using OH PLIF. A 3D scan time of 1 ms was achieved, with ten slices generated per sweep with 1000 Hz scan rate. Alternatively

A Method for Large Eddy Simulation of Acoustic Combustion Instabilities

NASA Astrophysics Data System (ADS)

Wall, Clifton; Pierce, Charles; Moin, Parviz

2002-11-01

A method for performing Large Eddy Simulation of acoustic combustion instabilities is presented. By extending the low Mach number pressure correction method to the case of compressible flow, a numerical method is developed in which the Poisson equation for pressure is replaced by a Helmholtz equation. The method avoids the acoustic CFL condition by using implicit time advancement, leading to large efficiency gains at low Mach number. The method also avoids artificial damping of acoustic waves. The numerical method is attractive for the simulation of acoustic combustion instabilities, since these flows are typically at low Mach number, and the acoustic frequencies of interest are usually low. Both of these characteristics suggest the use of larger time steps than those allowed by an acoustic CFL condition. The turbulent combustion model used is the Combined Conserved Scalar/Level Set Flamelet model of Duchamp de Lageneste and Pitsch for partially premixed combustion. Comparison of LES results to the experiments of Besson et al will be presented.

Flashback Detection Sensor for Hydrogen Augmented Natural Gas Combustion

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

Thornton, J.D.; Chorpening, B.T.; Sidwell, T.

2007-05-01

The use of hydrogen augmented fuel is being investigated by various researchers as a method to extend the lean operating limit, and potentially reduce thermal NOx formation in natural gas fired lean premixed (LPM) combustion systems. The resulting increase in flame speed during hydrogen augmentation, however, increases the propensity for flashback in LPM systems. Real-time in-situ monitoring of flashback is important for the development of control strategies for use of hydrogen augmented fuel in state-of-the-art combustion systems, and for the development of advanced hydrogen combustion systems. The National Energy Technology Laboratory (NETL) and Woodward Industrial Controls are developing a combustionmore » control and diagnostics sensor (CCADS), which has already been demonstrated as a useful sensor for in-situ monitoring of natural gas combustion, including detection of important combustion events such as flashback and lean blowoff. Since CCADS is a flame ionization sensor technique, the low ion concentration produced in pure hydrogen combustion raises concerns of whether CCADS can be used to monitor flashback in hydrogen augmented combustion. This paper discusses CCADS tests conducted at 0.2-0.6 MPa (2-6 atm), demonstrating flashback detection with fuel compositions up to 80% hydrogen (by volume) mixed with natural gas. NETL’s Simulation Validation (SimVal) combustor offers full optical access to pressurized combustion during these tests. The CCADS data and high-speed video show the reaction zone moves upstream into the nozzle as the hydrogen fuel concentration increases, as is expected with the increased flame speed of the mixture. The CCADS data and video also demonstrate the opportunity for using CCADS to provide the necessary in-situ monitor to control flashback and lean blowoff in hydrogen augmented combustion applications.« less

Capturing Cyclic Variability in EGR Dilute SI Combustion using Multi-Cycle RANS

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

Scarcelli, Riccardo; Sevik, James; Wallner, Thomas

Dilute combustion is an effective approach to increase the thermal efficiency of spark-ignition (SI) internal combustion engines (ICEs). However, high dilution levels typically result in large cycle-to-cycle variations (CCV) and poor combustion stability, therefore limiting the efficiency improvement. In order to extend the dilution tolerance of SI engines, advanced ignition systems are the subject of extensive research. When simulating the effect of the ignition characteristics on CCV, providing a numerical result matching the measured average in-cylinder pressure trace does not deliver useful information regarding combustion stability. Typically Large Eddy Simulations (LES) are performed to simulate cyclic engine variations, since Reynold-Averagedmore » Navier-Stokes (RANS) modeling is expected to deliver an ensemble-averaged result. In this paper it is shown that, when using RANS, the cyclic perturbations coming from different initial conditions at each cycle are not damped out even after many simulated cycles. As a result, multi-cycle RANS results feature cyclic variability. This allows evaluating the effect of advanced ignition sources on combustion stability but requires validation against the entire cycle-resolved experimental dataset. A single-cylinder GDI research engine is simulated using RANS and the numerical results for 20 consecutive engine cycles are evaluated for several operating conditions, including stoichiometric as well as EGR dilute operation. The effect of the ignition characteristics on CCV is also evaluated. Results show not only that multi-cycle RANS simulations can capture cyclic variability and deliver similar trends as the experimental data, but more importantly that RANS might be an effective, lower-cost alternative to LES for the evaluation of ignition strategies for combustion systems that operate close to the stability limit.« less

The combustion properties analysis of various liquid fuels based on crude oil and renewables

NASA Astrophysics Data System (ADS)

Grab-Rogalinski, K.; Szwaja, S.

2016-09-01

The paper presents results of investigation on combustion properties analysis of hydrocarbon based liquid fuels commonly used in the CI engine. The analysis was performed with aid of the CRU (Combustion Research Unit). CRU is the machine consisted of a constant volume combustion chamber equipped with one or two fuel injectors and a pressure sensor. Fuel can be injected under various both injection pressure and injection duration, also with two injector versions two stage combustion with pilot injection can be simulated, that makes it possible to introduce and modify additional parameter which is injection delay (defined as the time between pilot and main injection). On a basis of this investigation such combustion parameters as pressure increase, rate of heat release, ignition delay and combustion duration can be determined. The research was performed for the four fuels as follows: LFO, HFO, Biofuel from rape seeds and Glycerol under various injection parameters as well as combustion chamber thermodynamic conditions. Under these tests the change in such injection parameters as injection pressure, use of pilot injection, injection delay and injection duration, for main injection, were made. Moreover, fuels were tested under different conditions of load, what was determined by initial conditions (pressure and temperature) in the combustion chamber. Stored data from research allows to compare combustion parameters for fuels applied to tests and show this comparison in diagrams.

Assessing Spontaneous Combustion Instability with Nonlinear Time Series Analysis

NASA Technical Reports Server (NTRS)

Eberhart, C. J.; Casiano, M. J.

2015-01-01

Considerable interest lies in the ability to characterize the onset of spontaneous instabilities within liquid propellant rocket engine (LPRE) combustion devices. Linear techniques, such as fast Fourier transforms, various correlation parameters, and critical damping parameters, have been used at great length for over fifty years. Recently, nonlinear time series methods have been applied to deduce information pertaining to instability incipiency hidden in seemingly stochastic combustion noise. A technique commonly used in biological sciences known as the Multifractal Detrended Fluctuation Analysis has been extended to the combustion dynamics field, and is introduced here as a data analysis approach complementary to linear ones. Advancing, a modified technique is leveraged to extract artifacts of impending combustion instability that present themselves a priori growth to limit cycle amplitudes. Analysis is demonstrated on data from J-2X gas generator testing during which a distinct spontaneous instability was observed. Comparisons are made to previous work wherein the data were characterized using linear approaches. Verification of the technique is performed by examining idealized signals and comparing two separate, independently developed tools.

Dry low combustion system with means for eliminating combustion noise

DOEpatents

Verdouw, Albert J.; Smith, Duane; McCormick, Keith; Razdan, Mohan K.

2004-02-17

A combustion system including a plurality of axially staged tubular premixers to control emissions and minimize combustion noise. The combustion system includes a radial inflow premixer that delivers the combustion mixture across a contoured dome into the combustion chamber. The axially staged premixers having a twist mixing apparatus to rotate the fluid flow and cause improved mixing without causing flow recirculation that could lead to pre-ignition or flashback.

The Fluids And Combustion Facility Combustion Integrated Rack And The Multi-User Droplet Combustion Apparatus: Microgravity Combustion Science Using Modular Multi-User Hardware

NASA Technical Reports Server (NTRS)

OMalley, Terence F.; Myhre, Craig A.

2000-01-01

The Fluids and Combustion Facility (FCF) is a multi-rack payload planned for the International Space Station (ISS) that will enable the study of fluid physics and combustion science in a microgravity environment. The Combustion Integrated Rack (CIR) is one of two International Standard Payload Racks of the FCF and is being designed primarily to support combustion science experiments. The Multi-user Droplet Combustion Apparatus (MDCA) is a multi-user apparatus designed to accommodate four different droplet combustion science experiments and is the first payload for CIR. The CIR will function independently until the later launch of the Fluids Integrated Rack component of the FCF. This paper provides an overview of the capabilities and the development status of the CIR and MDCA.

46 CFR 58.01-55 - Tanks for flammable and combustible oil.

Code of Federal Regulations, 2011 CFR

2011-10-01

...-combustion machinery used for other than main propulsion, whose power output is equal to or greater than 500... AND AUXILIARY MACHINERY AND RELATED SYSTEMS General Requirements § 58.01-55 Tanks for flammable and combustible oil. (a) For the purposes of this section, a machinery space of category A is a space that...

46 CFR 58.01-55 - Tanks for flammable and combustible oil.

Code of Federal Regulations, 2013 CFR

2013-10-01

...-combustion machinery used for other than main propulsion, whose power output is equal to or greater than 500... AND AUXILIARY MACHINERY AND RELATED SYSTEMS General Requirements § 58.01-55 Tanks for flammable and combustible oil. (a) For the purposes of this section, a machinery space of category A is a space that...

46 CFR 58.01-55 - Tanks for flammable and combustible oil.

Code of Federal Regulations, 2012 CFR

2012-10-01

...-combustion machinery used for other than main propulsion, whose power output is equal to or greater than 500... AND AUXILIARY MACHINERY AND RELATED SYSTEMS General Requirements § 58.01-55 Tanks for flammable and combustible oil. (a) For the purposes of this section, a machinery space of category A is a space that...

46 CFR 58.01-55 - Tanks for flammable and combustible oil.

Code of Federal Regulations, 2014 CFR

2014-10-01

...-combustion machinery used for other than main propulsion, whose power output is equal to or greater than 500... AND AUXILIARY MACHINERY AND RELATED SYSTEMS General Requirements § 58.01-55 Tanks for flammable and combustible oil. (a) For the purposes of this section, a machinery space of category A is a space that...

46 CFR 58.01-55 - Tanks for flammable and combustible oil.

Code of Federal Regulations, 2010 CFR

2010-10-01

...-combustion machinery used for other than main propulsion, whose power output is equal to or greater than 500... AND AUXILIARY MACHINERY AND RELATED SYSTEMS General Requirements § 58.01-55 Tanks for flammable and combustible oil. (a) For the purposes of this section, a machinery space of category A is a space that...

Experimental studies on combustion of composite biomass pellets in fluidized bed.

PubMed

Guo, Feihong; Zhong, Zhaoping

2017-12-01

This work presents studies on the combustion of Composite Biomass Pellets (CBP S ) in fluidized bed using bauxite particles as the bed material. Prior to the combustion experiment, cold-flow characterization and thermogravimetric analysis are performed to investigate the effect of air velocity and combustion mechanism of CBP S . The cold-state test shows that CBPs and bauxite particles fluidize well in the fluidized bed. However, because of the presence of large CBPs, optimization of the fluidization velocity is rather challenging. CBPs can gather at the bottom of the fluidized bed at lower gas velocities. On the contrary, when the velocity is too high, they accumulate in the upper section of the fluidized bed. The suitable fluidization velocity for the system in this study was found to be between 1.5-2.0m/s. At the same time, it is found that the critical fluidization velocity and the pressure fluctuation of the two-component system increase with the increase of CBPs mass concentration. The thermogravimetric experiment verifies that the combustion of CBPs is a first-order reaction, and it is divided into three stages: (i) dehydration, (ii) release and combustion of the volatile and (iii) the coke combustion. The combustion of CBPs is mainly based on the stage of volatile combustion, and its activation energy is greater than that of char combustion. During the combustion test, CBP S are burned at a 10kg/h feed rate, while the excess air is varied from 25% to 100%. Temperatures of the bed and flue gas concentrations (O 2 , CO, SO 2 and NO) are recorded. CBPs can be burnt stably, and the temperature of dense phase is maintained at 765-780°C. With the increase of the air velocity, the main combustion region has a tendency to move up. While the combustion is stable, O 2 and CO 2 concentrations are maintained at about 7%, and 12%, respectively. The concentration of SO 2 in the flue gas after the initial stage of combustion is nearly zero. Furthermore, NO concentration

The Combustion Performance and Ingredient Ratio of Thermite

NASA Astrophysics Data System (ADS)

Jia, Shuan-zhu; Du, Shi-guo; Zhen, Jian-wei; Yang, Xin-hui

2017-12-01

Thermite was widely used because of its combustion properties and combustion products. However, due to the combustion heat, ignition performance, burning rate and the ratio of energy conversion of different components of thermite agent are very different. The requirements of the main realization in: (a) Its easy to ignite and not easy to extinguish; (b) Combustion and heat as much as possible High; (c) The burning speed should be appropriate. So the performance of these aspects is always being hot focus. In this paper, four aspects of the improve about combustion heat, ignition performance, burning rate and the ratio of energy conversion were analyzed through the aluminum alloy, the addition of aluminum, the addition of the third party, the change of the particle size and the compaction density. Finaly states the research direction in the future. The future of aluminum heat agent formula research focus will be: (a) A single aluminum heat agent the best proportion of the study; (b) The addition of different additives and additives (c) The exploration of alternatives that are more excellent performance will inevitably become a hot topic to improve the heat of combustion. Aluminum heat agent performance will be much superior, and the application will also be more extensive.

Internal combustion engine using premixed combustion of stratified charges

DOEpatents

Marriott, Craig D [Rochester Hills, MI; Reitz, Rolf D [Madison, WI

2003-12-30

During a combustion cycle, a first stoichiometrically lean fuel charge is injected well prior to top dead center, preferably during the intake stroke. This first fuel charge is substantially mixed with the combustion chamber air during subsequent motion of the piston towards top dead center. A subsequent fuel charge is then injected prior to top dead center to create a stratified, locally richer mixture (but still leaner than stoichiometric) within the combustion chamber. The locally rich region within the combustion chamber has sufficient fuel density to autoignite, and its self-ignition serves to activate ignition for the lean mixture existing within the remainder of the combustion chamber. Because the mixture within the combustion chamber is overall premixed and relatively lean, NO.sub.x and soot production are significantly diminished.

Predicting the ash behavior during biomass combustion in FBC conditions by combining advanced fuel analyses with thermodynamic multicomponent equilibrium calculations

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

Skrifvars, B.J.; Blomquist, J.P.; Hupa, M.

1998-12-31

Previous work at Aabo Akademi University has focused on identification and quantification of various sintering mechanisms which are relevant for problematic ash behavior during biomass combustion in fluidized bed combustion conditions, and on multi-component multi-phase thermodynamic phase equilibrium calculations of ash chemistry in these conditions. In both areas new information has been developed and useful modeling capabilities have been created. Based on the previous work, the authors now present a novel approach of using a combination of an advanced fuel analysis method and thermodynamic phase equilibrium calculations to predict the chemical and thermal behavior of the ash when firing biomass.more » Four different fuels [coal, forest residues, wood chips, and a mixture of forest residue and wood chips] were analyzed using the chemical fractionation analysis technique. Based on the results from these analyses, the authors formed two different ash fractions, (1) one fine sized fraction consisting of those elements found in the water and weak acid leach, and (2) a coarse ash particle fraction consisting of those elements found in the strong acid leach and non-leachable rest. The small sized ash fraction was then assumed to be carried up with the flue gases and consequently formed the base for any ash related problems in the flue gas channel. This fraction was therefore analyzed on its chemical and thermal behavior using multi-component multi-phase equilibrium calculations, by which the composition and the melting behavior was estimated as a function of the temperature. The amount of melt, which has earlier been found to be strongly related to problematic ash behavior, was finally expressed as a function of the temperature for the fraction. The coarse fraction was treated separately. Here the authors estimate the composition only. The paper discusses the results and their relevance to full scale combustion.« less

Preburner of Staged Combustion Rocket Engine

NASA Technical Reports Server (NTRS)

Yost, M. C.

1978-01-01

A regeneratively cooled LOX/hydrogen staged combustion assembly system with a 400:1 expansion area ratio nozzle utilizing an 89,000 Newton (20,000 pound) thrust regeneratively cooled thrust chamber and 175:1 tubular nozzle was analyzed, assembled, and tested. The components for this assembly include two spark/torch oxygen-hydrogen igniters, two servo-controlled LOX valves, a preburner injector, a preburner combustor, a main propellant injector, a regeneratively cooled combustion chamber, a regeneratively cooled tubular nozzle with an expansion area ratio of 175:1, an uncooled heavy-wall steel nozzle with an expansion area ratio of 400:1, and interconnecting ducting. The analytical effort was performed to optimize the thermal and structural characteristics of each of the new components and the ducting, and to reverify the capabilities of the previously fabricated components. The testing effort provided a demonstration of the preburner/combustor chamber operation, chamber combustion efficiency and stability, and chamber and nozzle heat transfer.

An important missing source of atmospheric carbonyl sulfide: Domestic coal combustion

NASA Astrophysics Data System (ADS)

Du, Qianqian; Zhang, Chenglong; Mu, Yujing; Cheng, Ye; Zhang, Yuanyuan; Liu, Chengtang; Song, Min; Tian, Di; Liu, Pengfei; Liu, Junfeng; Xue, Chaoyang; Ye, Can

2016-08-01

Carbonyl sulfide (COS), carbon monoxide (CO), and sulfur dioxide (SO2) emissions generated from prevailing domestic coal stoves fueled with raw bituminous coal were studied under alternation cycles of flaming and smoldering combustion. The measurements in the laboratory and the farmer's house indicated that COS and CO emissions mainly occurred under the condition of flame extinguishment after coal loading, whereas SO2 emissions were mainly generated through combustion with flame. The COS emission factors for the domestic stoves in the laboratory and the farmer's house were recorded as 0.57 ± 0.10 g COS kg-1 and 1.43 ± 0.32 g COS kg-1, being approximately a factor of 50 and 125 greater than that generated from coal power plants, respectively. Based on the COS emission factors measured in this study, COS emission from only domestic coal combustion in China would be at least 30.5 ± 5.6 Gg S yr-1 which was 1 magnitude greater than the current COS estimation from the total coal combustion in China.

Combustion noise

NASA Technical Reports Server (NTRS)

Strahle, W. C.

1977-01-01

A review of the subject of combustion generated noise is presented. Combustion noise is an important noise source in industrial furnaces and process heaters, turbopropulsion and gas turbine systems, flaring operations, Diesel engines, and rocket engines. The state-of-the-art in combustion noise importance, understanding, prediction and scaling is presented for these systems. The fundamentals and available theories of combustion noise are given. Controversies in the field are discussed and recommendations for future research are made.

Calculations of combustion response profiles and oscillations

NASA Technical Reports Server (NTRS)

Priem, Richard J.; Breisacher, Kevin J.

1993-01-01

The theory and procedures for determining the characteristics of pressure oscillations in rocket engines with prescribed burning rate oscillations are presented. Pressure and velocity oscillations calculated using this procedure are presented for the Space Shuttle Main Engine (SSME) to show the influence of baffles and absorbers on the burning rate oscillations required to achieve neutral stability. Results of calculations to determine local combustion responses using detailed physical models for injection, atomization, and vaporization with gas phase oscillations in baffled and unbaffled SSME combustors are presented. The contributions of the various physical phenomena occurring in a combustor to oscillations in combustion response were determined.

High Efficiency, Clean Combustion

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

Donald Stanton

2010-03-31

numerous challenges to reduce oil consumption and greenhouse gases, meet stringent emissions regulations, provide customer value, and improve safety. The HECC program successfully reduced engine fuel consumption and greenhouse gases while providing greater customer valve. The US EPA 2010 emissions standard poses a significant challenge for developing clean diesel powertrains that meet the DoE Vehicle Technologies Multi-Year Program Plan (MYPP) for fuel efficiency improvement while remaining affordable. Along with exhaust emissions, an emphasis on heavy duty vehicle fuel efficiency is being driven by increased energy costs as well as the potential regulation of greenhouse gases. An important element of the success of meeting emissions while significantly improving efficiency is leveraging Cummins component technologies such as fuel injection equipment, aftertreatment, turbomahcinery, electronic controls, and combustion systems. Innovation in component technology coupled with system integration is enabling Cummins to move forward with the development of high efficiency clean diesel products with a long term goal of reaching a 55% peak brake thermal efficiency for the engine plus aftertreatment system. The first step in developing high efficiency clean products has been supported by the DoE co-sponsored HECC program. The objectives of the HECC program are: (1) To design and develop advanced diesel engine architectures capable of achieving US EPA 2010 emission regulations while improving the brake thermal efficiency by 10% compared to the baseline (a state of the art 2007 production diesel engine). (2) To design and develop components and subsystems (fuel systems, air handling, controls, etc) to enable construction and development of multi-cylinder engines. (3) To perform an assessment of the commercial viability of the newly developed engine technology. (4) To specify fuel properties conducive to improvements in emissions, reliability, and fuel efficiency for engines using

Development and Hotfire Testing of Additively Manufactured Copper Combustion Chambers for Liquid Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Gradl, Paul R.; Greene, Sandy; Protz, Chris

2017-01-01

NASA and industry partners are working towards fabrication process development to reduce costs and schedules associated with manufacturing liquid rocket engine components with the goal of reducing overall mission costs. One such technique being evaluated is powder-bed fusion or selective laser melting (SLM), commonly referred to as additive manufacturing (AM). The NASA Low Cost Upper Stage Propulsion (LCUSP) program was designed to develop processes and material characterization for GRCop-84 (a NASA Glenn Research Center-developed copper, chrome, niobium alloy) commensurate with powder bed AM, evaluate bimetallic deposition, and complete testing of a full scale combustion chamber. As part of this development, the process has been transferred to industry partners to enable a long-term supply chain of monolithic copper combustion chambers. To advance the processes further and allow for optimization with multiple materials, NASA is also investigating the feasibility of bimetallic AM chambers. In addition to the LCUSP program, NASA’s Marshall Space Flight Center (MSFC) has completed a series of development programs and hot-fire tests to demonstrate SLM GRCop-84 and other AM techniques. MSFC’s efforts include a 4,000 pounds-force thrust liquid oxygen/methane (LOX/CH4) combustion chamber. Small thrust chambers for 1,200 pounds-force LOX/hydrogen (H2) applications have also been designed and fabricated with SLM GRCop-84. Similar chambers have also completed development with an Inconel 625 jacket bonded to the GRCop-84 material, evaluating direct metal deposition (DMD) laser- and arc-based techniques. The same technologies for these lower thrust applications are being applied to 25,000-35,000 pounds-force main combustion chamber (MCC) designs. This paper describes the design, development, manufacturing and testing of these numerous combustion chambers, and the associated lessons learned throughout their design and development processes.

Distributed Low Temperature Combustion: Fundamental Understanding of Combustion Regime Transitions

DTIC Science & Technology

2016-09-07

AFRL-AFOSR-UK-TR-2016-0021 Distributed Low Temperature Combustion 133024 Peter Lindstedt IMPERIAL COLLEGE OF SCIENCE TECHNOLOGY & MEDICINE Final...TYPE Final 3. DATES COVERED (From - To) 01 Feb 2013 to 31 Jul 2016 4. TITLE AND SUBTITLE Distributed Low Temperature Combustion: Fundamental...identification of five separate fluid states. 15. SUBJECT TERMS EOARD, Low Temperature Combustion, Combustion Regime Transitions 16. SECURITY

KINETIC MODELING OF NOX FORMATION AND DESTRUCTION AND COMBUSTIBLES BURNOUT

EPA Science Inventory

The report describes a model of the gas-phase chemistry involved in the combustion of simple hydrocarbon fuels and the interconversion of fixed nitrogen species. One focus of the work was on modeling the chemistry involved in reburning and other advanced NOx control strategies. A...

Combustion-wave ignition for rocket engines

NASA Technical Reports Server (NTRS)

Liou, Larry C.

1992-01-01

The combustion wave ignition concept was experimentally studied in order to verify its suitability for application in baffled sections of a large booster engine combustion chamber. Gaseous oxygen/gaseous methane (GOX/GH4) and gaseous oxygen/gaseous hydrogen (GOX/GH2) propellant combinations were evaluated in a subscale combustion wave ignition system. The system included four element tubes capable of carrying ignition energy simultaneously to four locations, simulating four baffled sections. Also, direct ignition of a simulated Main Combustion Chamber (MCC) was performed. Tests were conducted over a range of mixture ratios and tube geometries. Ignition was consistently attained over a wide range of mixture ratios. And at every ignition, the flame propagated through all four element tubes. For GOX/GH4, the ignition system ignited the MCC flow at mixture ratios from 2 to 10 and for GOX/GH2 the ratios is from 2 to 13. The ignition timing was found to be rapid and uniform. The total ignition delay when using the MCC was under 11 ms, with the tube-to-tube, as well as the run-to-run, variation under 1 ms. Tube geometries were found to have negligible effect on the ignition outcome and timing.

Advanced Optical Diagnostic Methods for Describing Fuel Injection and Combustion Flowfield Phenomena

NASA Technical Reports Server (NTRS)

Locke, Randy J.; Hicks, Yolanda R.; Anderson, Robert C.

2004-01-01

Over the past decade advanced optical diagnostic techniques have evolved and matured to a point where they are now widely applied in the interrogation of high pressure combusting flows. At NASA Glenn Research Center (GRC), imaging techniques have been used successfully in on-going work to develop the next generation of commercial aircraft gas turbine combustors. This work has centered on providing a means by which researchers and designers can obtain direct visual observation and measurements of the fuel injection/mixing/combustion processes and combustor flowfield in two- and three-dimensional views at actual operational conditions. Obtaining a thorough understanding of the chemical and physical processes at the extreme operating conditions of the next generation of combustors is critical to reducing emissions and increasing fuel efficiency. To accomplish this and other tasks, the diagnostic team at GRC has designed and constructed optically accessible, high pressurer high temperature flame tubes and sectar rigs capable of optically probing the 20-60 atm flowfields of these aero-combustors. Among the techniques employed at GRC are planar laser-induced fluorescence (PLIF) for imaging molecular species as well as liquid and gaseous fuel; planar light scattering (PLS) for imaging fuel sprays and droplets; and spontaneous Raman scattering for species and temperature measurement. Using these techniques, optical measurements never before possible have been made in the actual environments of liquid fueled gas turbines. 2-D mapping of such parameters as species (e.g. OH-, NO and kerosene-based jet fuel) distribution, injector spray angle, and fuel/air distribution are just some of the measurements that are now routinely made. Optical imaging has also provided prompt feedback to researchers regarding the effects of changes in the fuel injector configuration on both combustor performance and flowfield character. Several injector design modifications and improvements have

NOx formation in combustion of gaseous fuel in ejection burner

NASA Astrophysics Data System (ADS)

Rimár, Miroslav; Kulikov, Andrii

2016-06-01

The aim of this work is to prepare model for researching of the formation in combustion of gaseous fuels. NOx formation is one of the main ecological problems nowadays as nitrogen oxides is one of main reasons of acid rains. The ANSYS model was designed according to the calculation to provide full combustion and good mixing of the fuel and air. The current model is appropriate to research NOx formation and the influence of the different principles of NOx reduction method. Applying of designed model should spare both time of calculations and research and also money as you do not need to measure the burner characteristics.

Combustion behaviors of GO2/GH2 swirl-coaxial injector using non-intrusive optical diagnostics

NASA Astrophysics Data System (ADS)

GuoBiao, Cai; Jian, Dai; Yang, Zhang; NanJia, Yu

2016-06-01

This research evaluates the combustion behaviors of a single-element, swirl-coaxial injector in an atmospheric combustion chamber with gaseous oxygen and gaseous hydrogen (GO2/GH2) as the propellants. A brief simulated flow field schematic comparison between a shear-coaxial injector and the swirl-coaxial injector reveals the distribution characteristics of the temperature field and streamline patterns. Advanced optical diagnostics, i.e., OH planar laser-induced fluorescence and high-speed imaging, are simultaneously employed to determine the OH radical spatial distribution and flame fluctuations, respectively. The present study focuses on the flame structures under varying O/F mixing ratios and center oxygen swirl intensities. The combined use of several image-processing methods aimed at OH instantaneous images, including time-averaged, root-mean-square, and gradient transformation, provides detailed information regarding the distribution of the flow field. The results indicate that the shear layers anchored on the oxygen injector lip are the main zones of chemical heat release and that the O/F mixing ratio significantly affects the flame shape. Furthermore, with high-speed imaging, an intuitionistic ignition process and several consecutive steady-state images reveal that lean conditions make it easy to drive the combustion instabilities and that the center swirl intensity has a moderate influence on the flame oscillation strength. The results of this study provide a visualized analysis for future optimal swirl-coaxial injector designs.

Combustion energy frontier research center (CEFRC) final report (August 1, 2009 – July 31, 2016)

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

Law, Chung

The Combustion Energy Frontier Research Center (CEFRC) was established to tackle the single overarching grand challenge of energy sustainability, energy security and global warming: to develop a “validated, predictive, multi-scale, combustion modeling capability to optimize the design and operation of evolving fuels in advanced engines for transportation applications,” as identified in the DOE report on “Basic Energy Needs for Clean and Efficient Combustion of 21st Century Transportation Fuels”. The challenge is particularly daunting since energy conversion efficiencies and exhaust emissions are governed by coupled chemical and transport processes at multiple length scales ranging from electron excitation to molecular rearrangements tomore » nanoscale particulate formation to turbulent fuel/air mixing. To tackle this challenge, the CEFRC assembled a world-class team of 15 principal investigators, with the objectives to: 1) develop and test theoretical models to predict elementary reaction rates, molecule thermalization rates, chemical bond dissociation energies, and nonequilibrium transport properties using quantum chemistry calculations that account for strong electron correlation and multiple electronic potential energy surfaces; 2) develop automated kinetic mechanism generation, reduction, and error control methods for predicting alternative fuel including biofuel oxidation, fuel droplet decomposition, and NOx and particulate formation; 3) validate and improve the predictions of these models by measuring ignition delay times, species profiles, flame structures, burning limits, turbulence-kinetic coupling, and NOx and soot emissions at high-pressures and near-limit conditions, by using advanced experimental diagnostic techniques including multiple laser techniques, molecular beam sampling and synchrotron photoionization, and by conducting the measurements in high-pressure shock tubes, jet-stirred and flow reactors, flame bombs, counterflow flames, and

Advances in poultry litter disposal technology--a review.

PubMed

Kelleher, B P; Leahy, J J; Henihan, A M; O'Dwyer, T F; Sutton, D; Leahy, M J

2002-05-01

The land disposal of waste from the poultry industry and subsequent environmental implications has stimulated interest into cleaner and more useful disposal options. The review presented here details advances in the three main alternative disposal routes for poultry litter, specifically in the last decade. Results of experimental investigations into the optimisation of composting, anaerobic digestion and direct combustion are summarised. These technologies open up increased opportunities to market the energy and nutrients in poultry litter to agricultural and non-agricultural uses. Common problems experienced by the current technologies are the existence and fate of nitrogen as ammonia, pH and temperature levels, moisture content and the economics of alternative disposal methods. Further advancement of these technologies is currently receiving increased interest, both academically and commercially. However, significant financial incentives are required to attract the agricultural industry.

A Method for Large Eddy Simulation of Acoustic Combustion Instabilities

NASA Astrophysics Data System (ADS)

Wall, Clifton; Moin, Parviz

2003-11-01

A method for performing Large Eddy Simulation of acoustic combustion instabilities is presented. By extending the low Mach number pressure correction method to the case of compressible flow, a numerical method is developed in which the Poisson equation for pressure is replaced by a Helmholtz equation. The method avoids the acoustic CFL condition by using implicit time advancement, leading to large efficiency gains at low Mach number. The method also avoids artificial damping of acoustic waves. The numerical method is attractive for the simulation of acoustics combustion instabilities, since these flows are typically at low Mach number, and the acoustic frequencies of interest are usually low. Additionally, new boundary conditions based on the work of Poinsot and Lele have been developed to model the acoustic effect of a long channel upstream of the computational inlet, thus avoiding the need to include such a channel in the computational domain. The turbulent combustion model used is the Level Set model of Duchamp de Lageneste and Pitsch for premixed combustion. Comparison of LES results to the reacting experiments of Besson et al. will be presented.

Mercury (Hg) emissions from domestic biomass combustion for space heating.

PubMed

Huang, Jiaoyan; Hopke, Philip K; Choi, Hyun-Deok; Laing, James R; Cui, Huailue; Zananski, Tiffany J; Chandrasekaran, Sriraam Ramanathan; Rattigan, Oliver V; Holsen, Thomas M

2011-09-01

Three mercury (Hg) species (gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and fine particulate-bound mercury (PBM(2.5))) were measured in the stack of a small scale wood combustion chamber at 400°C, in the stack of an advanced wood boiler, and in two areas influenced by wood combustion. The low temperature process (lab-scale) emitted mostly GEM (∼99% when burning wood pellets and ∼95% when burning unprocessed wood). The high temperature wood boiler emitted a greater proportion of oxidized Hg (approximately 65%) than the low temperature system. In field measurements, mean PBM(2.5) concentrations at the rural and urban sites in winter were statistically significantly higher than in warmer seasons and were well correlated with Delta-C concentrations, a wood combustion indictor measured by an aethalometer (UV-absorbable carbon minus black carbon). Overall the results suggest that wood combustion may be an important source of oxidized mercury (mostly in the particulate phase) in northern climates in winter. Copyright © 2011 Elsevier Ltd. All rights reserved.

The effects of detailed chemistry and transport on microgravity droplet combustion

NASA Technical Reports Server (NTRS)

Marchese, A. J.; Lee, J. C.; Held, T. J.; Dryer, F. L.

1995-01-01

A brief overview of recent advances in the theoretical study of microgravity droplet combustion is presented. Much of this work has centered on the development and utilization of sphero-symmetric transient numerical models which consider detailed gas phase chemistry and transport as well as energy and/or species transport within a regressing condensed phase. Numerical results for microgravity combustion and vaporization of methanol, methanol/water, heptane, and heptane/hexadecane droplets are summarized along with refinements in chemical kinetics and the development of a new two-dimensional axi-symmetric model.

Source profiles and contributions of biofuel combustion for PM2.5, PM10 and their compositions, in a city influenced by biofuel stoves.

PubMed

Tian, Ying-Ze; Chen, Jia-Bao; Zhang, Lin-Lin; Du, Xin; Wei, Jin-Jin; Fan, Hui; Xu, Jiao; Wang, Hai-Ting; Guan, Liao; Shi, Guo-Liang; Feng, Yin-Chang

2017-12-01

Source and ambient samples were collected in a city in China that uses considerable biofuel, to assess influence of biofuel combustion and other sources on particulate matter (PM). Profiles and size distribution of biofuel combustion were investigated. Higher levels in source profiles, a significant increase in heavy-biomass ambient and stronger correlations of K + , Cl - , OC and EC suggest that they can be tracers of biofuel combustion. And char-EC/soot-EC (8.5 for PM 2.5 and 15.8 for PM 10 of source samples) can also be used to distinguish it. In source samples, water-soluble organic carbon (WSOC) were approximately 28.0%-68.8% (PM 2.5 ) and 27.2%-43.8% (PM 10 ) of OC. For size distribution, biofuel combustion mainly produces smaller particles. OC1, OC2, EC1 and EC2 abundances showed two peaks with one below 1 μm and one above 2 μm. An advanced three-way factory analysis model was applied to quantify source contributions to ambient PM 2.5 and PM 10 . Higher contributions of coal combustion, vehicular emission, nitrate and biofuel combustion occurred during the heavy-biomass period, and higher contributions of sulfate and crustal dust were observed during the light-biomass period. Mass and percentage contributions of biofuel combustion were significantly higher in heavy-biomass period. The biofuel combustion attributed above 45% of K + and Cl - , above 30% of EC and about 20% of OC. In addition, through analysis of source profiles and contributions, they were consistently evident that biofuel combustion and crustal dust contributed more to cation than to anion, while sulfate & SOC and nitrate showed stronger influence on anion than on cation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mathematical modelling of particle mixing effect on the combustion of municipal solid wastes in a packed-bed furnace.

PubMed

Yang, Yao Bin; Swithenbank, Jim

2008-01-01

Packed bed combustion is still the most common way to burn municipal solid wastes. In this paper, a dispersion model for particle mixing, mainly caused by the movement of the grate in a moving-burning bed, has been proposed and transport equations for the continuity, momentum, species, and energy conservation are described. Particle-mixing coefficients obtained from model tests range from 2.0x10(-6) to 3.0x10(-5)m2/s. A numerical solution is sought to simulate the combustion behaviour of a full-scale 12-tonne-per-h waste incineration furnace at different levels of bed mixing. It is found that an increase in mixing causes a slight delay in the bed ignition but greatly enhances the combustion processes during the main combustion period in the bed. A medium-level mixing produces a combustion profile that is positioned more at the central part of the combustion chamber, and any leftover combustible gases (mainly CO) enter directly into the most intensive turbulence area created by the opposing secondary-air jets and thus are consumed quickly. Generally, the specific arrangement of the impinging secondary-air jets dumps most of the non-uniformity in temperature and CO into the gas flow coming from the bed-top, while medium-level mixing results in the lowest CO emission at the furnace exit and the highest combustion efficiency in the bed.

Design and experimental investigation of an oxy-fuel combustion system for magnetohydrodynamic power extraction

NASA Astrophysics Data System (ADS)

Hernandez, Manuel Johannes

A general consensus in the scientific and research community is the need to restrict carbon emissions in energy systems. Therefore, extensive research efforts are underway to develop the next generation of energy systems. In the field of power generation, researchers are actively investigating novel methods to produce electricity in a cleaner, efficient form. Recently, Oxy-Combustion for magnetohydrodynamic power extraction has generated significant interest, since the idea was proposed as a method for clean power generation in coal and natural gas power plants. Oxy-combustion technologies have been proposed to provide high enthalpy, electrically conductive flows for direct conversion of electricity. Direct power extraction via magnetohydrodynamics (MHD) can occur as a consequence of the motion of "seeded" combustion products in the presence of magnetic fields. However, oxy-combustion technologies for MHD power extraction has not been demonstrated in the available literature. Furthermore, there are still fundamental unexplored questions remaining, associated with this technology, for MHD power extraction. In this present study, previous magnetohydrodynamic combustion technologies and technical issues in this field were assessed to develop a new combustion system for electrically conductive flows. The research aims were to fully understand the current-state-of-the-art of open-cycle magnetohydrodynamic technologies and present new future directions and concepts. The design criteria, methodology, and technical specifications of an advanced cooled oxy-combustion technology are presented in this dissertation. The design was based on a combined analytical, empirical, and numerical approach. Analytical one-dimensional (1D) design tools initiated design construction. Design variants were analyzed and vetted against performance criteria through the application of computational fluid dynamics modeling. CFD-generated flow fields permitted insightful visualization of the

Gasdynamic modeling and parametric study of mesoscale internal combustion swing engine/generator systems

NASA Astrophysics Data System (ADS)

Gu, Yongxian

The demand of portable power generation systems for both domestic and military applications has driven the advances of mesoscale internal combustion engine systems. This dissertation was devoted to the gasdynamic modeling and parametric study of the mesoscale internal combustion swing engine/generator systems. First, the system-level thermodynamic modeling for the swing engine/generator systems has been developed. The system performance as well as the potentials of both two- and four-stroke swing engine systems has been investigated based on this model. Then through parameterc studies, the parameters that have significant impacts on the system performance have been identified, among which, the burn time and spark advance time are the critical factors related to combustion process. It is found that the shorter burn time leads to higher system efficiency and power output and the optimal spark advance time is about half of the burn time. Secondly, the turbulent combustion modeling based on levelset method (G-equation) has been implemented into the commercial software FLUENT. Thereafter, the turbulent flame propagation in a generic mesoscale combustion chamber and realistic swing engine chambers has been studied. It is found that, in mesoscale combustion engines, the burn time is dominated by the mean turbulent kinetic energy in the chamber. It is also shown that in a generic mesoscale combustion chamber, the burn time depends on the longest distance between the initial ignition kernel to its walls and by changing the ignition and injection locations, the burn time can be reduced by a factor of two. Furthermore, the studies of turbulent flame propagation in real swing engine chambers show that the combustion can be enhanced through in-chamber turbulence augmentation and with higher engine frequency, the burn time is shorter, which indicates that the in-chamber turbulence can be induced by the motion of moving components as well as the intake gas jet flow. The burn time

An Overview of Low-Emission Combustion Research

NASA Technical Reports Server (NTRS)

DelRosario, Ruben

2014-01-01

An overview of research efforts at NASA Glenn Research Center (GRC) in low-emission combustion technology that have made a significant impact on the Nitrogen Oxides (NOx) emission reduction in aircraft propulsion will be presented. The technology advancements and their impact on aircraft emissions will be discussed in the context of NASAs Aeronautics Research Mission Directorate (ARMD) high-level goals in fuel burn, noise and emission reductions. The highlights of the research presented will show how the past and current efforts have laid the foundation for the engines that are flying today as well as how the continued technology advancements will significantly influence the next generation of aviation propulsion system designs.

Chemical kinetic simulation of kerosene combustion in an individual flame tube.

PubMed

Zeng, Wen; Liang, Shuang; Li, Hai-Xia; Ma, Hong-An

2014-05-01

The use of detailed chemical reaction mechanisms of kerosene is still very limited in analyzing the combustion process in the combustion chamber of the aircraft engine. In this work, a new reduced chemical kinetic mechanism for fuel n-decane, which selected as a surrogate fuel for kerosene, containing 210 elemental reactions (including 92 reversible reactions and 26 irreversible reactions) and 50 species was developed, and the ignition and combustion characteristics of this fuel in both shock tube and flat-flame burner were kinetic simulated using this reduced reaction mechanism. Moreover, the computed results were validated by experimental data. The calculated values of ignition delay times at pressures of 12, 50 bar and equivalence ratio is 1.0, 2.0, respectively, and the main reactants and main products mole fractions using this reduced reaction mechanism agree well with experimental data. The combustion processes in the individual flame tube of a heavy duty gas turbine combustor were simulated by coupling this reduced reaction mechanism of surrogate fuel n-decane and one step reaction mechanism of surrogate fuel C12H23 into the computational fluid dynamics software. It was found that this reduced reaction mechanism is shown clear advantages in simulating the ignition and combustion processes in the individual flame tube over the one step reaction mechanism.

Chemical kinetic simulation of kerosene combustion in an individual flame tube

PubMed Central

Zeng, Wen; Liang, Shuang; Li, Hai-xia; Ma, Hong-an

2013-01-01

The use of detailed chemical reaction mechanisms of kerosene is still very limited in analyzing the combustion process in the combustion chamber of the aircraft engine. In this work, a new reduced chemical kinetic mechanism for fuel n-decane, which selected as a surrogate fuel for kerosene, containing 210 elemental reactions (including 92 reversible reactions and 26 irreversible reactions) and 50 species was developed, and the ignition and combustion characteristics of this fuel in both shock tube and flat-flame burner were kinetic simulated using this reduced reaction mechanism. Moreover, the computed results were validated by experimental data. The calculated values of ignition delay times at pressures of 12, 50 bar and equivalence ratio is 1.0, 2.0, respectively, and the main reactants and main products mole fractions using this reduced reaction mechanism agree well with experimental data. The combustion processes in the individual flame tube of a heavy duty gas turbine combustor were simulated by coupling this reduced reaction mechanism of surrogate fuel n-decane and one step reaction mechanism of surrogate fuel C12H23 into the computational fluid dynamics software. It was found that this reduced reaction mechanism is shown clear advantages in simulating the ignition and combustion processes in the individual flame tube over the one step reaction mechanism. PMID:25685503

The combustion behavior of large scale lithium titanate battery

PubMed Central

Huang, Peifeng; Wang, Qingsong; Li, Ke; Ping, Ping; Sun, Jinhua

2015-01-01

Safety problem is always a big obstacle for lithium battery marching to large scale application. However, the knowledge on the battery combustion behavior is limited. To investigate the combustion behavior of large scale lithium battery, three 50 Ah Li(NixCoyMnz)O2/Li4Ti5O12 batteries under different state of charge (SOC) were heated to fire. The flame size variation is depicted to analyze the combustion behavior directly. The mass loss rate, temperature and heat release rate are used to analyze the combustion behavior in reaction way deeply. Based on the phenomenon, the combustion process is divided into three basic stages, even more complicated at higher SOC with sudden smoke flow ejected. The reason is that a phase change occurs in Li(NixCoyMnz)O2 material from layer structure to spinel structure. The critical temperatures of ignition are at 112–121°C on anode tab and 139 to 147°C on upper surface for all cells. But the heating time and combustion time become shorter with the ascending of SOC. The results indicate that the battery fire hazard increases with the SOC. It is analyzed that the internal short and the Li+ distribution are the main causes that lead to the difference. PMID:25586064

On the influence of singlet oxygen molecules on characteristics of HCCI combustion: A numerical study

NASA Astrophysics Data System (ADS)

Starik, A. M.; Kozlov, V. E.; Titova, N. S.

2013-08-01

Mechanisms of homogeneous charge compression ignition (HCCI) combustion enhancement are investigated numerically when excited O2(a 1Δg) molecules are produced at different points in the compression stroke. The analysis is conducted with the use of an extended kinetic model involving the submechanism of nitric oxide formation in the presence of singlet oxygen O2(a 1Δg) or O2(b 1Σg +) molecules in the methane-air mixture. It is demonstrated that the abundance of excited O2(a 1Δg) molecules in the mixture even in a small amounts intensifies the ignition and combustion and allows one to control the ignition event in the HCCI engine. Such a method of energy supply in the HCCI engine is much more effective in advancement of combustion timing than mere heating of the mixture, because it leads to acceleration of the chain-branching mechanism. The excitation of O2 molecules to the a 1Δg electronic state makes it possible to organise the successful combustion in the cylinder at diminished initial temperature of the mixture and increase the effective energy released during HCCI combustion. The advance in the value of this energy is much higher than the energy needed for the excitation of oxygen molecules. Moreover, in this case, the output concentration of NO and CO can be reduced significantly.

Tripropellant combustion process

NASA Technical Reports Server (NTRS)

Kmiec, T. D.; Carroll, R. G.

1988-01-01

The addition of small amounts of hydrogen to the combustion of LOX/hydrocarbon propellants in large rocket booster engines has the potential to enhance the system stability. Programs being conducted to evaluate the effects of hydrogen on the combustion of LOX/hydrocarbon propellants at supercritical pressures are described. Combustion instability has been a problem during the development of large hydrocarbon fueled rocket engines. At the higher combustion chamber pressures expected for the next generation of booster engines, the effect of unstable combustion could be even more destructive. The tripropellant engine cycle takes advantage of the superior cooling characteristics of hydrogen to cool the combustion chamber and a small amount of the hydrogen coolant can be used in the combustion process to enhance the system stability. Three aspects of work that will be accomplished to evaluate tripropellant combustion are described. The first is laboratory demonstration of the benefits through the evaluation of drop size, ignition delay and burning rate. The second is analytical modeling of the combustion process using the empirical relationship determined in the laboratory. The third is a subscale demonstration in which the system stability will be evaluated. The approach for each aspect is described and the analytical models that will be used are presented.

Morphology, composition, and mixing state of primary particles from combustion sources - crop residue, wood, and solid waste.

PubMed

Liu, Lei; Kong, Shaofei; Zhang, Yinxiao; Wang, Yuanyuan; Xu, Liang; Yan, Qin; Lingaswamy, A P; Shi, Zongbo; Lv, Senlin; Niu, Hongya; Shao, Longyi; Hu, Min; Zhang, Daizhou; Chen, Jianmin; Zhang, Xiaoye; Li, Weijun

2017-07-11

Morphology, composition, and mixing state of individual particles emitted from crop residue, wood, and solid waste combustion in a residential stove were analyzed using transmission electron microscopy (TEM). Our study showed that particles from crop residue and apple wood combustion were mainly organic matter (OM) in smoldering phase, whereas soot-OM internally mixed with K in flaming phase. Wild grass combustion in flaming phase released some Cl-rich-OM/soot particles and cardboard combustion released OM and S-rich particles. Interestingly, particles from hardwood (pear wood and bamboo) and softwood (cypress and pine wood) combustion were mainly soot and OM in the flaming phase, respectively. The combustion of foam boxes, rubber tires, and plastic bottles/bags in the flaming phase released large amounts of soot internally mixed with a small amount of OM, whereas the combustion of printed circuit boards and copper-core cables emitted large amounts of OM with Br-rich inclusions. In addition, the printed circuit board combustion released toxic metals containing Pb, Zn, Sn, and Sb. The results are important to document properties of primary particles from combustion sources, which can be used to trace the sources of ambient particles and to know their potential impacts in human health and radiative forcing in the air.

Elimination of High-Frequency Combustion Instability in the Fastrac Engine Thrust Chamber

NASA Technical Reports Server (NTRS)

Rocker, Marvin; Nesman, Thomas E.

1998-01-01

NASA's Marshall Space Flight Center(MSFC) has been tasked with developing a 60,000 pound thrust, pump-fed, LOX/RP-1 engine under the Advanced Space Transportation Program(ASTP). This government-led design has been designated the Fastrac engine. The X-34 vehicle will use the Fastrac engine as the main propulsion system. The X-34 will be a suborbital vehicle developed by the Orbital Sciences Corporation. The X-34 vehicle will be launched from an L-1011 airliner. After launch, the X-34 vehicle will be able to climb to altitudes up to 250,000 feet and reach speeds up to Mach 8, over a mission range of 500 miles. The overall length, wingspan, and gross takeoff weight of the X-34 vehicle are 58.3 feet, 27.7 feet and 45,000 pounds, respectively. This report summarizes the plan of achieving a Fastrac thrust chamber assembly(TCA) stable bomb test that meets the JANNAF standards, the Fastrac TCA design, and the combustion instabilities exhibited by the Fastrac TCA during testing at MSFC's test stand 116 as determined from high-frequency fluctuating pressure measurements. This report also summarizes the characterization of the combustion instabilities from the pressure measurements and the steps taken to eliminate the instabilities.

Progress towards an Optimization Methodology for Combustion-Driven Portable Thermoelectric Power Generation Systems

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

Krishnan, Shankar; Karri, Naveen K.; Gogna, Pawan K.

2012-03-13

Enormous military and commercial interests exist in developing quiet, lightweight, and compact thermoelectric (TE) power generation systems. This paper investigates design integration and analysis of an advanced TE power generation system implementing JP-8 fueled combustion and thermal recuperation. Design and development of a portable TE power system using a JP-8 combustor as a high temperature heat source and optimal process flows depend on efficient heat generation, transfer, and recovery within the system are explored. Design optimization of the system required considering the combustion system efficiency and TE conversion efficiency simultaneously. The combustor performance and TE sub-system performance were coupled directlymore » through exhaust temperatures, fuel and air mass flow rates, heat exchanger performance, subsequent hot-side temperatures, and cold-side cooling techniques and temperatures. Systematic investigation of this system relied on accurate thermodynamic modeling of complex, high-temperature combustion processes concomitantly with detailed thermoelectric converter thermal/mechanical modeling. To this end, this work reports on design integration of systemlevel process flow simulations using commercial software CHEMCADTM with in-house thermoelectric converter and module optimization, and heat exchanger analyses using COMSOLTM software. High-performance, high-temperature TE materials and segmented TE element designs are incorporated in coupled design analyses to achieve predicted TE subsystem level conversion efficiencies exceeding 10%. These TE advances are integrated with a high performance microtechnology combustion reactor based on recent advances at the Pacific Northwest National Laboratory (PNNL). Predictions from this coupled simulation established a basis for optimal selection of fuel and air flow rates, thermoelectric module design and operating conditions, and microtechnology heat-exchanger design criteria. This paper will discuss

Effect of Structural Parameters on the Combustion Performance of Platelet Engines

NASA Astrophysics Data System (ADS)

Liang, Yin; Liu, Weiqiang

2017-12-01

Numerical simulation was adopted to determine its flow and combustion characteristics by using gaseous methane and oxygen as the main propellants, the effects of nozzle space and expanding angle are examined for the single element splash platelet injector. Navier-Stokes (N-S) equations were solved for the gas-gas flow field with a reduced mechanism involving 9 species and 1 reaction. Results indicated that large corner recirculation zones are produced in the combustor head. This phenomenon consequently enhances mixing and stabilizes combustion, but non-uniformity in temperature contour is observed in the combustor head. Recirculation zone decreases as nozzle space increases, which induces the decrease of maximum temperature and high temperature regions, but it has little influence on the combustion efficiency and combustion length. The combustion length and maximum temperature decrease initially and then increase as expanding angle increases. Conversely, a D value of 2.4 mm and γ value of 60° are selected for the future works because of the shortest combustion length and minimum temperature of the injector faceplate.

Method and device for diagnosing and controlling combustion instabilities in internal combustion engines operating in or transitioning to homogeneous charge combustion ignition mode

DOEpatents

Wagner, Robert M [Knoxville, TN; Daw, Charles S [Knoxville, TN; Green, Johney B [Knoxville, TN; Edwards, Kevin D [Knoxville, TN

2008-10-07

This invention is a method of achieving stable, optimal mixtures of HCCI and SI in practical gasoline internal combustion engines comprising the steps of: characterizing the combustion process based on combustion process measurements, determining the ratio of conventional and HCCI combustion, determining the trajectory (sequence) of states for consecutive combustion processes, and determining subsequent combustion process modifications using said information to steer the engine combustion toward desired behavior.

Fluids and Combustion Facility-Combustion Integrated Rack

NASA Technical Reports Server (NTRS)

Francisco, David R.

1998-01-01

This paper describes in detail the concept of performing Combustion microgravity experiments in the Combustion Integrated Rack (CIR) of the Fluids and Combustion Facility (FCF) on the International Space Station (ISS). The extended duration microgravity environment of the ISS will enable microgravity research to enter into a new era of increased scientific and technological data return. The FCF is designed to increase the amount and quality of scientific and technological data and decrease the development cost of an individual experiment relative to the era of Space Shuttle experiments. This paper also describes how the FCF will cost effectively accommodate these experiments.

Comparing the greenhouse gas emissions from three alternative waste combustion concepts.

PubMed

Vainikka, Pasi; Tsupari, Eemeli; Sipilä, Kai; Hupa, Mikko

2012-03-01

Three alternative condensing mode power and combined heat and power (CHP) waste-to-energy concepts were compared in terms of their impacts on the greenhouse gas (GHG) emissions from a heat and power generation system. The concepts included (i) grate, (ii) bubbling fluidised bed (BFB) and (iii) circulating fluidised bed (CFB) combustion of waste. The BFB and CFB take advantage of advanced combustion technology which enabled them to reach electric efficiency up to 35% and 41% in condensing mode, respectively, whereas 28% (based on the lower heating value) was applied for the grate fired unit. A simple energy system model was applied in calculating the GHG emissions in different scenarios where coal or natural gas was substituted in power generation and mix of fuel oil and natural gas in heat generation by waste combustion. Landfilling and waste transportation were not considered in the model. GHG emissions were reduced significantly in all of the considered scenarios where the waste combustion concepts substituted coal based power generation. With the exception of condensing mode grate incinerator the different waste combustion scenarios resulted approximately in 1 Mton of fossil CO(2)-eq. emission reduction per 1 Mton of municipal solid waste (MSW) incinerated. When natural gas based power generation was substituted by electricity from the waste combustion significant GHG emission reductions were not achieved. Copyright © 2011 Elsevier Ltd. All rights reserved.

Bubble Combustion

NASA Technical Reports Server (NTRS)

Corrigan, Jackie

2004-01-01

A method of energy production that is capable of low pollutant emissions is fundamental to one of the four pillars of NASA s Aeronautics Blueprint: Revolutionary Vehicles. Bubble combustion, a new engine technology currently being developed at Glenn Research Center promises to provide low emissions combustion in support of NASA s vision under the Emissions Element because it generates power, while minimizing the production of carbon dioxide (CO2) and nitrous oxides (NOx), both known to be Greenhouse gases. and allows the use of alternative fuels such as corn oil, low-grade fuels, and even used motor oil. Bubble combustion is analogous to the inverse of spray combustion: the difference between bubble and spray combustion is that spray combustion is spraying a liquid in to a gas to form droplets, whereas bubble combustion involves injecting a gas into a liquid to form gaseous bubbles. In bubble combustion, the process for the ignition of the bubbles takes place on a time scale of less than a nanosecond and begins with acoustic waves perturbing each bubble. This perturbation causes the local pressure to drop below the vapor pressure of the liquid thus producing cavitation in which the bubble diameter grows, and upon reversal of the oscillating pressure field, the bubble then collapses rapidly with the aid of the high surface tension forces acting on the wall of the bubble. The rapid and violent collapse causes the temperatures inside the bubbles to soar as a result of adiabatic heating. As the temperatures rise, the gaseous contents of the bubble ignite with the bubble itself serving as its own combustion chamber. After ignition, this is the time in the bubble s life cycle where power is generated, and CO2, and NOx among other species, are produced. However, the pollutants CO2 and NOx are absorbed into the surrounding liquid. The importance of bubble combustion is that it generates power using a simple and compact device. We conducted a parametric study using CAVCHEM

The Diesel Combustion Collaboratory: Combustion Researchers Collaborating over the Internet

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

C. M. Pancerella; L. A. Rahn; C. Yang

2000-02-01

The Diesel Combustion Collaborator (DCC) is a pilot project to develop and deploy collaborative technologies to combustion researchers distributed throughout the DOE national laboratories, academia, and industry. The result is a problem-solving environment for combustion research. Researchers collaborate over the Internet using DCC tools, which include: a distributed execution management system for running combustion models on widely distributed computers, including supercomputers; web-accessible data archiving capabilities for sharing graphical experimental or modeling data; electronic notebooks and shared workspaces for facilitating collaboration; visualization of combustion data; and video-conferencing and data-conferencing among researchers at remote sites. Security is a key aspect of themore » collaborative tools. In many cases, the authors have integrated these tools to allow data, including large combustion data sets, to flow seamlessly, for example, from modeling tools to data archives. In this paper the authors describe the work of a larger collaborative effort to design, implement and deploy the DCC.« less

Status of the Combustion Devices Injector Technology Program at the NASA MSFC

NASA Technical Reports Server (NTRS)

Jones, Gregg; Protz, Christopher; Trinh, Huu; Tucker, Kevin; Nesman, Tomas; Hulka, James

2005-01-01

To support the NASA Space Exploration Mission, an in-house program called Combustion Devices Injector Technology (CDIT) is being conducted at the NASA Marshall Space Flight Center (MSFC) for the fiscal year 2005. CDIT is focused on developing combustor technology and analysis tools to improve reliability and durability of upper-stage and in-space liquid propellant rocket engines. The three areas of focus include injector/chamber thermal compatibility, ignition, and combustion stability. In the compatibility and ignition areas, small-scale single- and multi-element hardware experiments will be conducted to demonstrate advanced technological concepts as well as to provide experimental data for validation of computational analysis tools. In addition, advanced analysis tools will be developed to eventually include 3-dimensional and multi- element effects and improve capability and validity to analyze heat transfer and ignition in large, multi-element injectors.

Modeling internal ballistics of gas combustion guns.

PubMed

Schorge, Volker; Grossjohann, Rico; Schönekess, Holger C; Herbst, Jörg; Bockholdt, Britta; Ekkernkamp, Axel; Frank, Matthias

2016-05-01

Potato guns are popular homemade guns which work on the principle of gas combustion. They are usually constructed for recreational rather than criminal purposes. Yet some serious injuries and fatalities due to these guns are reported. As information on the internal ballistics of homemade gas combustion-powered guns is scarce, it is the aim of this work to provide an experimental model of the internal ballistics of these devices and to investigate their basic physical parameters. A gas combustion gun was constructed with a steel tube as the main component. Gas/air mixtures of acetylene, hydrogen, and ethylene were used as propellants for discharging a 46-mm caliber test projectile. Gas pressure in the combustion chamber was captured with a piezoelectric pressure sensor. Projectile velocity was measured with a ballistic speed measurement system. The maximum gas pressure, the maximum rate of pressure rise, the time parameters of the pressure curve, and the velocity and path of the projectile through the barrel as a function of time were determined according to the pressure-time curve. The maximum gas pressure was measured to be between 1.4 bar (ethylene) and 4.5 bar (acetylene). The highest maximum rate of pressure rise was determined for hydrogen at (dp/dt)max = 607 bar/s. The muzzle energy was calculated to be between 67 J (ethylene) and 204 J (acetylene). To conclude, this work provides basic information on the internal ballistics of homemade gas combustion guns. The risk of injury to the operator or bystanders is high, because accidental explosions of the gun due to the high-pressure rise during combustion of the gas/air mixture may occur.

Control Strategies for HCCI Mixed-Mode Combustion

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

Wagner, Robert M; Edwards, Kevin Dean

2010-03-01

, presentation, and meetings as necessary to maintain progress. Delphi provided substantial support through modeling, hardware, data exchange, and technical consultation. This CRADA was also successful at establishing important next steps to further expanding the use of an HCCI engine for improved fuel efficiency and emissions. These topics will be address in a follow-on CRADA. The objectives are: (1) Improve fundamental understanding of the development of combustion instabilities with HCCI operation through modeling and experiments; (2) Develop low-order model and feedback combustion metrics which are well suited to real-time predictive controls; and (3) Construct multi-cylinder engine system with advanced Delphi technologies and charac-terize HCCI behavior to better understand limitations and opportunities for expanded high-efficiency operation.« less

Flame Acceleration and Transition to Detonation in High Speed Turbulent Combustion

DTIC Science & Technology

2016-12-21

gas mixtures and sprays is dif- ficult to overestimate, as it is the main process in all internal-combustion engines used for propulsion and energy...generation. These include piston engines, gas turbines, various types of jet engines, and some rocket engines . On the other hand , preventing high...speed combustion is critical for the safety of any human activities that involve handling of po- t entially explosive gases or volatile liquids . Thus

Final Report - Low Temperature Combustion Chemistry And Fuel Component Interactions

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

Wooldridge, Margaret

Recent research into combustion chemistry has shown that reactions at “low temperatures” (700 – 1100 K) have a dramatic influence on ignition and combustion of fuels in virtually every practical combustion system. A powerful class of laboratory-scale experimental facilities that can focus on fuel chemistry in this temperature range is the rapid compression facility (RCF), which has proven to be a versatile tool to examine the details of fuel chemistry in this important regime. An RCF was used in this project to advance our understanding of low temperature chemistry of important fuel compounds. We show how factors including fuel molecularmore » structure, the presence of unsaturated C=C bonds, and the presence of alkyl ester groups influence fuel auto-ignition and produce variable amounts of negative temperature coefficient behavior of fuel ignition. We report new discoveries of synergistic ignition interactions between alkane and alcohol fuels, with both experimental and kinetic modeling studies of these complex interactions. The results of this project quantify the effects of molecular structure on combustion chemistry including carbon bond saturation, through low temperature experimental studies of esters, alkanes, alkenes, and alcohols.« less

Preliminary assessment of combustion modes for internal combustion wave rotors

NASA Technical Reports Server (NTRS)

Nalim, M. Razi

1995-01-01

Combustion within the channels of a wave rotor is examined as a means of obtaining pressure gain during heat addition in a gas turbine engine. Several modes of combustion are considered and the factors that determine the applicability of three modes are evaluated in detail; premixed autoignition/detonation, premixed deflagration, and non-premixed compression ignition. The last two will require strong turbulence for completion of combustion in a reasonable time in the wave rotor. The compression/autoignition modes will require inlet temperatures in excess of 1500 R for reliable ignition with most hydrocarbon fuels; otherwise, a supplementary ignition method must be provided. Examples of combustion mode selection are presented for two core engine applications that had been previously designed with equivalent 4-port wave rotor topping cycles using external combustion.

Combustion of a polymer (PMMA) sphere in microgravity

NASA Technical Reports Server (NTRS)

Yang, Jiann C.; Hamins, Anthony

1995-01-01

Polymer combustion is a highly complicated process where chemical reactions may occur not only in the gas phase, but also in the condensed phase as well as at the solid-gas interphase. The chemistry depends strongly on the coupling between the condensed phase and gas phase phenomena. For some polymers, additional complications arise due to the formation of char layers. For others, the behavior of the condensed phase involves swelling, bubbling, melting, sputtering, and multi-stage combustion. Some of these features bear resemblance to the phenomena observed in coal particle combustion. In addition to its relevance to spacecraft fire safety, the combustion of polymeric materials is related to many applications including solid and hybrid rocket propulsion, and of recent interest, waste incineration . The burning rate is one of the most important parameters used to characterize the combustion of polymers. It has been used to rank the polymer flammability under the same experimental conditions and to evaluate various modes of inhibiting polymer flammability. The main objective of this work is to measure the burning rates of a polymeric material in low gravity. Because of inherent logistical difficulties involved in microgravity experiments, it is impossible to examine a wide spectrum of polymeric materials. It is desirable to investigate a polymer whose combustion is less complicated, and yet will lead to a better understanding of the burning characteristics of other more complicated materials. Therefore, a typical non-charring polymer is selected for use in this experimental study. PMMA (polymethylmethacrylate) has been chosen because its thermo-physical properties are well characterized. Although the combustion of PMMA has been extensively studied in 1G experiments, only a limited amount of work has been conducted in low gravity. A spherical sample geometry is chosen in this study because it is the simplest configuration in terms of the microgravity hardware design

Low-Temperature Combustion of High Octane Fuels in a Gasoline Compression Ignition Engine

DOE PAGES

Cung, Khanh Duc; Ciatti, Stephen Anthony; Tanov, Slavey; ...

2017-12-21

Gasoline Compression Ignition (GCI) has been shown as one of the advanced combustion concepts that could potentially provide a pathway to achieve cleaner and more efficient combustion engines. Fuel and air in GCI are not fully premixed as compared to homogeneous charge compression ignition (HCCI) which is a completely kinetic-controlled combustion system. Therefore, the combustion phasing can be controlled by the time of injection, usually post injection in a multiple-injection scheme, to mitigate combustion noise. Gasoline fuels ignite more difficult than Diesel. The autoignition quality of gasoline can be indicated by research octane number (RON). Fuels with high octane tendmore » to have more resistance to auto-ignition, hence more time for fuel-air mixing. In this study, three fuels, namely, Aromatic, Alkylate, and E30, with similar RON value of 98 but different hydrocarbon compositions were tested in a multi-cylinder engine under GCI combustion mode. Considerations of EGR, start of injection (SOI), and boost were investigated to study the sensitivity of dilution, local stratification, and reactivity of the charge, respectively, for each fuel. Combustion phasing was kept constant during the experiments to the changes in ignition and combustion process before and after 50% of the fuel mass is burned. Emission characteristics at different levels of EGR and lambda were revealed for all fuels with E30 having the lowest filter smoke number (FSN) and was also most sensitive to the change in dilution. Reasonably low combustion noise (< 90 dB) and stable combustion (COVIMEP < 3%) were maintained during the experiments. The second part of this paper contains visualization of the combustion process obtained from endoscope imaging for each fuel at selected conditions. Soot radiation signal from GCI combustion were strong during late injection, and also more intense at low EGR conditions. Furthermore, soot/temperature profiles indicated only the high

Low-Temperature Combustion of High Octane Fuels in a Gasoline Compression Ignition Engine

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

Cung, Khanh Duc; Ciatti, Stephen Anthony; Tanov, Slavey

Gasoline Compression Ignition (GCI) has been shown as one of the advanced combustion concepts that could potentially provide a pathway to achieve cleaner and more efficient combustion engines. Fuel and air in GCI are not fully premixed as compared to homogeneous charge compression ignition (HCCI) which is a completely kinetic-controlled combustion system. Therefore, the combustion phasing can be controlled by the time of injection, usually post injection in a multiple-injection scheme, to mitigate combustion noise. Gasoline fuels ignite more difficult than Diesel. The autoignition quality of gasoline can be indicated by research octane number (RON). Fuels with high octane tendmore » to have more resistance to auto-ignition, hence more time for fuel-air mixing. In this study, three fuels, namely, Aromatic, Alkylate, and E30, with similar RON value of 98 but different hydrocarbon compositions were tested in a multi-cylinder engine under GCI combustion mode. Considerations of EGR, start of injection (SOI), and boost were investigated to study the sensitivity of dilution, local stratification, and reactivity of the charge, respectively, for each fuel. Combustion phasing was kept constant during the experiments to the changes in ignition and combustion process before and after 50% of the fuel mass is burned. Emission characteristics at different levels of EGR and lambda were revealed for all fuels with E30 having the lowest filter smoke number (FSN) and was also most sensitive to the change in dilution. Reasonably low combustion noise (< 90 dB) and stable combustion (COVIMEP < 3%) were maintained during the experiments. The second part of this paper contains visualization of the combustion process obtained from endoscope imaging for each fuel at selected conditions. Soot radiation signal from GCI combustion were strong during late injection, and also more intense at low EGR conditions. Furthermore, soot/temperature profiles indicated only the high

Research on EHN additive on the diesel engine combustion characteristics in plateau environment

NASA Astrophysics Data System (ADS)

Sun, Zhixin; Li, Ruoting; Wang, Xiancheng; Hu, Chuan

2017-03-01

Aiming at the combustion deterioration problem of diesel engine in plateau environment, a bench test was carried out for the effects of EHN additive on combustion characteristics of the diesel engine with intake pressure of 0.68 kPa. Test results showed that with the full load working condition of 1 400 r/min: Cylinder pressure and pressure uprising rate decreased with EHN additive added in, mechanical load on the engine could be relieved; peak value of the heat release rate decreased and its occurrence advanced, ignition delay and combustion duration were shortened; cylinder temperature and exhaust gas temperature declined, thermal load on the engine could be relieved, output torque increased while specific oil consumption decreased, and effective thermal efficiency of diesel engine increased.

Meta-control of combustion performance with a data mining approach

NASA Astrophysics Data System (ADS)

Song, Zhe

Large scale combustion process is complex and proposes challenges of optimizing its performance. Traditional approaches based on thermal dynamics have limitations on finding optimal operational regions due to time-shift nature of the process. Recent advances in information technology enable people collect large volumes of process data easily and continuously. The collected process data contains rich information about the process and, to some extent, represents a digital copy of the process over time. Although large volumes of data exist in industrial combustion processes, they are not fully utilized to the level where the process can be optimized. Data mining is an emerging science which finds patterns or models from large data sets. It has found many successful applications in business marketing, medical and manufacturing domains The focus of this dissertation is on applying data mining to industrial combustion processes, and ultimately optimizing the combustion performance. However the philosophy, methods and frameworks discussed in this research can also be applied to other industrial processes. Optimizing an industrial combustion process has two major challenges. One is the underlying process model changes over time and obtaining an accurate process model is nontrivial. The other is that a process model with high fidelity is usually highly nonlinear, solving the optimization problem needs efficient heuristics. This dissertation is set to solve these two major challenges. The major contribution of this 4-year research is the data-driven solution to optimize the combustion process, where process model or knowledge is identified based on the process data, then optimization is executed by evolutionary algorithms to search for optimal operating regions.

Boiler using combustible fluid

DOEpatents

Baumgartner, H.; Meier, J.G.

1974-07-03

A fluid fuel boiler is described comprising a combustion chamber, a cover on the combustion chamber having an opening for introducing a combustion-supporting gaseous fluid through said openings, means to impart rotation to the gaseous fluid about an axis of the combustion chamber, a burner for introducing a fluid fuel into the chamber mixed with the gaseous fluid for combustion thereof, the cover having a generally frustro-conical configuration diverging from the opening toward the interior of the chamber at an angle of between 15/sup 0/ and 55/sup 0/; means defining said combustion chamber having means defining a plurality of axial hot gas flow paths from a downstream portion of the combustion chamber to flow hot gases into an upstream portion of the combustion chamber, and means for diverting some of the hot gas flow along paths in a direction circumferentially of the combustion chamber, with the latter paths being immersed in the water flow path thereby to improve heat transfer and terminating in a gas outlet, the combustion chamber comprising at least one modular element, joined axially to the frustro-conical cover and coaxial therewith. The modular element comprises an inner ring and means of defining the circumferential, radial, and spiral flow paths of the hot gases.

FEANICS: A Multi-User Facility For Conducting Solid Fuel Combustion Experiments On ISS

NASA Technical Reports Server (NTRS)

Frate, David T.; Tofil, Todd A.

2001-01-01

The Destiny Module on the International Space Station (ISS) will soon be home for the Fluids and Combustion Facility's (FCF) Combustion Integrated Rack (CIR), which is being developed at the NASA Glenn Research Center in Cleveland, Ohio. The CIR will be the platform for future microgravity combustion experiments. A multi-user mini-facility called FEANICS (Flow Enclosure Accommodating Novel Investigations in Combustion of Solids) will also be built at NASA Glenn. This mini-facility will be the primary means for conducting solid fuel combustion experiments in the CIR on ISS. The main focus of many of these solid combustion experiments will be to conduct basic and applied scientific investigations in fire-safety to support NASA's Bioastronautics Initiative. The FEANICS project team will work in conjunction with the CIR project team to develop upgradeable and reusable hardware to meet the science requirements of current and future investigators. Currently, there are six experiments that are candidates to use the FEANICS mini-facility. This paper will describe the capabilities of this mini-facility and the type of solid combustion testing and diagnostics that can be performed.

Reaction Mechanisms on Multiwell Potential Energy Surfaces in Combustion (and Atmospheric) Chemistry

DOE PAGES

Osborn, David L.

2017-03-15

Chemical reactions occurring on a potential energy surface with multiple wells are ubiquitous in low temperature combustion and the oxidation of volatile organic compounds in earth’s atmosphere. The rich variety of structural isomerizations that compete with collisional stabilization make characterizing such complex-forming reactions challenging. This review describes recent experimental and theoretical advances that deliver increasingly complete views of their reaction mechanisms. New methods for creating reactive intermediates coupled with multiplexed measurements provide many experimental observables simultaneously. Automated methods to explore potential energy surfaces can uncover hidden reactive pathways, while master equation methods enable a holistic treatment of both sequential andmore » well-skipping pathways. Our ability to probe and understand nonequilibrium effects and reaction sequences is increasing. These advances provide the fundamental science base for predictive models of combustion and the atmosphere that are crucial to address global challenges.« less

Reaction Mechanisms on Multiwell Potential Energy Surfaces in Combustion (and Atmospheric) Chemistry

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

Osborn, David L.

Chemical reactions occurring on a potential energy surface with multiple wells are ubiquitous in low temperature combustion and the oxidation of volatile organic compounds in earth’s atmosphere. The rich variety of structural isomerizations that compete with collisional stabilization make characterizing such complex-forming reactions challenging. This review describes recent experimental and theoretical advances that deliver increasingly complete views of their reaction mechanisms. New methods for creating reactive intermediates coupled with multiplexed measurements provide many experimental observables simultaneously. Automated methods to explore potential energy surfaces can uncover hidden reactive pathways, while master equation methods enable a holistic treatment of both sequential andmore » well-skipping pathways. Our ability to probe and understand nonequilibrium effects and reaction sequences is increasing. These advances provide the fundamental science base for predictive models of combustion and the atmosphere that are crucial to address global challenges.« less

Emission characteristics of kerosene-air spray combustion with plasma assistance

NASA Astrophysics Data System (ADS)

Liu, Xingjian; He, Liming; Zeng, Hao; Jin, Tao; Chen, Yi; Zhang, Yihan; Liu, Pengfei

2015-09-01

A plasma assisted combustion system for combustion of kerosene-air mixtures was developed to study emission levels of O2, CO2, CO, and NOx. The emission measurement was conducted by Testo 350-Pro Flue Gas Analyzer. The effect of duty ratio, feedstock gas flow rate and applied voltage on emission performance has been analyzed. The results show that O2 and CO emissions reduce with an increase of applied voltage, while CO2 and NOx emissions increase. Besides, when duty ratio or feedstock gas flow rate decreases, the same emission results would appear. The emission spectrum of the air plasma of plasma assisted combustion actuator was also registered to analyze the kinetic enhancement effect of plasma, and the generation of ozone was believed to be the main factor that plasma makes a difference in our experiment. These results are valuable for the future optimization of kerosene-fueled aircraft engine when using plasma assisted combustion devices to exert emission control.

Space shuttle main engine: Interactive design challenges

NASA Technical Reports Server (NTRS)

Mccarty, J. P.; Wood, B. K.

1985-01-01

The operating requirements established by NASA for the SSME were considerably more demanding than those for earlier rocket engines used in the military launch vehicles or Apollo program. The SSME, in order to achieve the high performance, low weight, long life, reusable objectives, embodied technical demands far in excess of its predecessor rocket engines. The requirements dictated the use of high combustion pressure and the staged combustion cycle which maximizes performance through total use of all propellants in the main combustion process. This approach presented a myriad of technical challenges for maximization of performance within attainable state of the art capabilities for operating pressures, operating temperatures and rotating machinery efficiencies. Controlling uniformity of the high pressure turbomachinery turbine temperature environment was a key challenge for thrust level and life capability demanding innovative engineering. New approaches in the design of the components were necessary to accommodate the multiple use, minimum maintenance objectives. Included were the use of line replaceable units to facilitate field maintenance automatic checkout and internal inspection capabilities.

Possibility of Coal Combustion Product Conditioning

NASA Astrophysics Data System (ADS)

Błaszczyński, Tomasz Z.; Król, Maciej R.

2018-03-01

This paper is focused on properties of materials known as green binders. They can be used to produce aluminium-siliceous concrete and binders known also as geopolymers. Comparing new ecological binders to ordinary cements we can see huge possibility of reducing amount of main greenhouse gas which is emitted to atmosphere by 3 to even 10 times depending of substrate type used to new green material production. Main ecological source of new materials obtaining possibility is to use already available products which are created in coal combustion and steel smelting process. Most of them are already used in many branches of industry. They are mostly civil engineering, chemistry or agriculture. Conducted research was based on less popular in civil engineering fly ash based on lignite combustion. Materials were examine in order to verify possibility of obtaining hardened mortars based of different factors connected with process of geopolymerization, which are temperature, amount of reaction reagent and time of heat treatment. After systematizing the matrices for the basic parameters affecting the strength of the hardened mortars, the influence of the fly ash treatment for increasing the strength was tested.

Specialized data analysis for the Space Shuttle Main Engine and diagnostic evaluation of advanced propulsion system components

NASA Technical Reports Server (NTRS)

1993-01-01

The Marshall Space Flight Center is responsible for the development and management of advanced launch vehicle propulsion systems, including the Space Shuttle Main Engine (SSME), which is presently operational, and the Space Transportation Main Engine (STME) under development. The SSME's provide high performance within stringent constraints on size, weight, and reliability. Based on operational experience, continuous design improvement is in progress to enhance system durability and reliability. Specialized data analysis and interpretation is required in support of SSME and advanced propulsion system diagnostic evaluations. Comprehensive evaluation of the dynamic measurements obtained from test and flight operations is necessary to provide timely assessment of the vibrational characteristics indicating the operational status of turbomachinery and other critical engine components. Efficient performance of this effort is critical due to the significant impact of dynamic evaluation results on ground test and launch schedules, and requires direct familiarity with SSME and derivative systems, test data acquisition, and diagnostic software. Detailed analysis and evaluation of dynamic measurements obtained during SSME and advanced system ground test and flight operations was performed including analytical/statistical assessment of component dynamic behavior, and the development and implementation of analytical/statistical models to efficiently define nominal component dynamic characteristics, detect anomalous behavior, and assess machinery operational condition. In addition, the SSME and J-2 data will be applied to develop vibroacoustic environments for advanced propulsion system components, as required. This study will provide timely assessment of engine component operational status, identify probable causes of malfunction, and indicate feasible engineering solutions. This contract will be performed through accomplishment of negotiated task orders.

Novel Supercritical Carbon Dioxide Power Cycle Utilizing Pressured Oxy-combustion in Conjunction with Cryogenic Compression

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

Brun, Klaus; McClung, Aaron; Davis, John

2014-03-31

The team of Southwest Research Institute® (SwRI) and Thar Energy LLC (Thar) applied technology engineering and economic analysis to evaluate two advanced oxy-combustion power cycles, the Cryogenic Pressurized Oxy-combustion Cycle (CPOC), and the Supercritical Oxy-combustion Cycle. This assessment evaluated the performance and economic cost of the two proposed cycles with carbon capture, and included a technology gap analysis of the proposed technologies to determine the technology readiness level of the cycle and the cycle components. The results of the engineering and economic analysis and the technology gap analysis were used to identify the next steps along the technology development roadmapmore » for the selected cycle. The project objectives, as outlined in the FOA, were 90% CO{sub 2} removal at no more than a 35% increase in cost of electricity (COE) as compared to a Supercritical Pulverized Coal Plant without CO{sub 2} capture. The supercritical oxy-combustion power cycle with 99% carbon capture achieves a COE of $121/MWe. This revised COE represents a 21% reduction in cost as compared to supercritical steam with 90% carbon capture ($137/MWe). However, this represents a 49% increase in the COE over supercritical steam without carbon capture ($80.95/MWe), exceeding the 35% target. The supercritical oxy-combustion cycle with 99% carbon capture achieved a 37.9% HHV plant efficiency (39.3% LHV plant efficiency), when coupling a supercritical oxy-combustion thermal loop to an indirect supercritical CO{sub 2} (sCO{sub 2}) power block. In this configuration, the power block achieved 48% thermal efficiency for turbine inlet conditions of 650°C and 290 atm. Power block efficiencies near 60% are feasible with higher turbine inlet temperatures, however a design tradeoff to limit firing temperature to 650°C was made in order to use austenitic stainless steels for the high temperature pressure vessels and piping and to minimize the need for advanced turbomachinery

The FCF Combustion Integrated Rack: Microgravity Combustion Science Onboard the International Space Station

NASA Technical Reports Server (NTRS)

OMalley, Terence F.; Weiland, Karen J.

2002-01-01

The Combustion Integrated Rack (CIR) is one of three facility payload racks being developed for the International Space Station (ISS) Fluids and Combustion Facility (FCF). Most microgravity combustion experiments will be performed onboard the Space Station in the Combustion Integrated Rack. Experiment-specific equipment will be installed on orbit in the CIR to customize it to perform many different scientific experiments during the ten or more years that it will operate on orbit. This paper provides an overview of the CIR, including a description of its preliminary design and planned accommodations for microgravity combustion science experiments, and descriptions of the combustion science experiments currently planned for the CIR.

Coal combustion system

DOEpatents

Wilkes, Colin; Mongia, Hukam C.; Tramm, Peter C.

1988-01-01

In a coal combustion system suitable for a gas turbine engine, pulverized coal is transported to a rich zone combustor and burned at an equivalence ratio exceeding 1 at a temperature above the slagging temperature of the coal so that combustible hot gas and molten slag issue from the rich zone combustor. A coolant screen of water stretches across a throat of a quench stage and cools the combustible gas and molten slag to below the slagging temperature of the coal so that the slag freezes and shatters into small pellets. The pelletized slag is separated from the combustible gas in a first inertia separator. Residual ash is separated from the combustible gas in a second inertia separator. The combustible gas is mixed with secondary air in a lean zone combustor and burned at an equivalence ratio of less than 1 to produce hot gas motive at temperature above the coal slagging temperature. The motive fluid is cooled in a dilution stage to an acceptable turbine inlet temperature before being transported to the turbine.

Numerical Investigation of Hydrogen and Kerosene Combustion in Supersonic Air Streams

NASA Technical Reports Server (NTRS)

Taha, A. A.; Tiwari, S. N.; Mohieldin, T. O.

1999-01-01

The effect of mixing schemes on the combustion of both gaseous hydrogen and liquid kerosene is investigated. Injecting pilot gaseous hydrogen parallel to the supersonic incoming air tends to maintain the stabilization of the main liquid kerosene, which is normally injected. Also the maximum kerosene equivalence ratio that can maintain stable flame can be increased by increasing the pilot energy level. The wedge flame holding contributes to an increased kerosene combustion efficiency by the generation of shock-jet interaction.

Research on optimization of combustion efficiency of thermal power unit based on genetic algorithm

NASA Astrophysics Data System (ADS)

Zhou, Qiongyang

2018-04-01

In order to improve the economic performance and reduce pollutant emissions of thermal power units, the characteristics of neural network in establishing boiler combustion model are analyzed based on the analysis of the main factors affecting boiler efficiency by using orthogonal method. In addition, on the basis of this model, the genetic algorithm is used to find the best control amount of the furnace combustion in a certain working condition. Through the genetic algorithm based on real number encoding and roulette selection is concluded: the best control quantity at a condition of furnace combustion can be combined with the boiler combustion system model for neural network training. The precision of the neural network model is further improved, and the basic work is laid for the research of the whole boiler combustion optimization system.

Friction Stir Welding of GR-Cop 84 for Combustion Chamber Liners

NASA Technical Reports Server (NTRS)

Russell, Carolyn K.; Carter, Robert; Ellis, David L.; Goudy, Richard

2004-01-01

GRCop-84 is a copper-chromium-niobium alloy developed by the Glenn Research Center for liquid rocket engine combustion chamber liners. GRCop-84 exhibits superior properties over conventional copper-base alloys in a liquid hydrogen-oxygen operating environment. The Next Generation Launch Technology program has funded a program to demonstrate scale-up production capabilities of GR-Cop 84 to levels suitable for main combustion chamber production for the prototype rocket engine. This paper describes a novel method of manufacturing the main combustion chamber liner. The process consists of several steps: extrude the GR-Cop 84 powder into billets, roll the billets into plates, bump form the plates into cylinder halves and friction stir weld the halves into a cylinder. The cylinder is then metal spun formed to near net liner dimensions followed by finish machining to the final configuration. This paper describes the friction stir weld process development including tooling and non-destructive inspection techniques, culminating in the successful production of a liner preform completed through spin forming.

Gaseous emissions from sewage sludge combustion in a moving bed combustor.

PubMed

Batistella, Luciane; Silva, Valdemar; Suzin, Renato C; Virmond, Elaine; Althoff, Chrtistine A; Moreira, Regina F P M; José, Humberto J

2015-12-01

Substantial increase in sewage sludge generation in recent years requires suitable destination for this residue. This study evaluated the gaseous emissions generated during combustion of an aerobic sewage sludge in a pilot scale moving bed reactor. To utilize the heat generated during combustion, the exhaust gas was applied to the raw sludge drying process. The gaseous emissions were analyzed both after the combustion and drying steps. The results of the sewage sludge characterization showed the energy potential of this residue (LHV equal to 14.5 MJ kg(-1), db) and low concentration of metals, polycyclic aromatic hydrocarbons (PAH), polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF). The concentration of CO, NOx, BTEX (benzene, toluene, ethylbenzene and xylenes) emitted from the sludge combustion process were lower than the legal limits. The overall sludge combustion and drying process showed low emissions of PCDD/PCDF (0.42 ng I-TEQ N m(-3)). BTEX and PAH emissions were not detected. Even with the high nitrogen concentration in the raw feed (5.88% db), the sludge combustion process presented NOx emissions below the legal limit, which results from the combination of appropriate feed rate (A/F ratio), excess air, and mainly the low temperature kept inside the combustion chamber. It was found that the level of CO emissions from the overall sludge process depends on the dryer operating conditions, such as the oxygen content and the drying temperature, which have to be controlled throughout the process in order to achieve low CO levels. The aerobic sewage sludge combustion process generated high SO2 concentration due to the high sulfur content (0.67 wt%, db) and low calcium concentration (22.99 g kg(-1)) found in the sludge. The high concentration of SO2 in the flue gas (4776.77 mg N m(-3)) is the main factor inhibiting PCDD/PCDF formation. Further changes are needed in the pilot plant scheme to reduce SO2 and particulate matter emissions

Combustion characteristics and air pollutant formation during oxy-fuel co-combustion of microalgae and lignite.

PubMed

Gao, Yuan; Tahmasebi, Arash; Dou, Jinxiao; Yu, Jianglong

2016-05-01

Oxy-fuel combustion of solid fuels is seen as one of the key technologies for carbon capture to reduce greenhouse gas emissions. The combustion characteristics of lignite coal, Chlorella vulgaris microalgae, and their blends under O2/N2 and O2/CO2 conditions were studied using a Thermogravimetric Analyzer-Mass Spectroscopy (TG-MS). During co-combustion of blends, three distinct peaks were observed and were attributed to C. vulgaris volatiles combustion, combustion of lignite, and combustion of microalgae char. Activation energy during combustion was calculated using iso-conventional method. Increasing the microalgae content in the blend resulted in an increase in activation energy for the blends combustion. The emissions of S- and N-species during blend fuel combustion were also investigated. The addition of microalgae to lignite during air combustion resulted in lower CO2, CO, and NO2 yields but enhanced NO, COS, and SO2 formation. During oxy-fuel co-combustion, the addition of microalgae to lignite enhanced the formation of gaseous species. Copyright © 2016 Elsevier Ltd. All rights reserved.

TOPICAL REVIEW: Plasma assisted ignition and combustion

NASA Astrophysics Data System (ADS)

Starikovskaia, S. M.

2006-08-01

In recent decades particular interest in applications of nonequilibrium plasma for the problems of plasma-assisted ignition and plasma-assisted combustion has been observed. A great amount of experimental data has been accumulated during this period which provided the grounds for using low temperature plasma of nonequilibrium gas discharges for a number of applications at conditions of high speed flows and also at conditions similar to automotive engines. The paper is aimed at reviewing the data obtained and discusses their treatment. Basic possibilities of low temperature plasma to ignite gas mixtures are evaluated and historical references highlighting pioneering works in the area are presented. The first part of the review discusses plasmas applied to plasma-assisted ignition and combustion. The paper pays special attention to experimental and theoretical analysis of some plasma parameters, such as reduced electric field, electron density and energy branching for different gas discharges. Streamers, pulsed nanosecond discharges, dielectric barrier discharges, radio frequency discharges and atmospheric pressure glow discharges are considered. The second part depicts applications of discharges to reduce the ignition delay time of combustible mixtures, to ignite transonic and supersonic flows, to intensify ignition and to sustain combustion of lean mixtures. The results obtained by different authors are cited, and ways of numerical modelling are discussed. Finally, the paper draws some conclusions on the main achievements and prospects of future investigations in the field.

Advanced Boost System Developing for High EGR Applications

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

Sun, Harold

2012-09-30

To support industry efforts of clean and efficient internal combustion engine development for passenger and commercial applications • This program focuses on turbocharger improvement for medium and light duty diesel applications, from complete system optimization percepective to enable commercialization of advanced diesel combustion technologies, such as HCCI/LTC. • Improve combined turbocharger efficiency up to 10% or fuel economy by 3% on FTP cycle at Tier II Bin 5 emission level.

Radiation/Catalytic Augmented Combustion.

DTIC Science & Technology

1984-05-01

interest to compare the experimental results for the solid bluff body with a thuoretical result. Using simple argtinieiiLs from fluid mechanics " one...responsibility through completion. Dr. A. E. Cerkanowlcz assisted in writing this final report. Experimental studies on catalytic augmented combustion...as well as with other combustion species, lead to ignition and sustained combustion via chain reactions. Simple combustion enhancement without

Coal combustion products

USGS Publications Warehouse

Kalyoncu, R.S.; Olson, D.W.

2001-01-01

Coal-burning powerplants, which supply more than half of U.S. electricity, also generate coal combustion products, which can be both a resource and a disposal problem. The U.S. Geological Survey collaborates with the American Coal Ash Association in preparing its annual report on coal combustion products. This Fact Sheet answers questions about present and potential uses of coal combustion products.

Sensitivity Analysis to Turbulent Combustion Models for Combustor-Turbine Interactions

NASA Astrophysics Data System (ADS)

Miki, Kenji; Moder, Jeff; Liou, Meng-Sing

2017-11-01

The recently-updated Open National CombustionCode (Open NCC) equipped with alarge-eddy simulation (LES) is applied to model the flow field inside the Energy Efficient Engine (EEE) in conjunction with sensitivity analysis to turbulent combustion models. In this study, we consider three different turbulence-combustion interaction models, the Eddy-Breakup model (EBU), the Linear-Eddy Model (LEM) and the Probability Density Function (PDF)model as well as the laminar chemistry model. Acomprehensive comparison of the flow field and the flame structure will be provided. One of our main interests isto understand how a different model predicts thermal variation on the surface of the first stage vane. Considering that these models are often used in combustor/turbine communities, this study should provide some guidelines on numerical modeling of combustor-turbine interactions.

Advanced general aviation engine/airframe integration study

NASA Technical Reports Server (NTRS)

Zmroczek, L. A.

1982-01-01

A comparison of the in-airframe performance and efficiency of the advanced engine concepts is presented. The results indicate that the proposed advanced engines can significantly improve the performance and economy of general aviation airplanes. The engine found to be most promising is the highly advanced version of a rotary combustion (Wankel) engine. The low weight and fuel consumption of this engine, as well as its small size, make it suited for aircraft use.

Characterizing dilute combustion instabilities in a multi-cylinder spark-ignited engine using symbolic analysis

DOE PAGES

Daw, C. Stuart; Finney, Charles E. A.; Kaul, Brian C.; ...

2014-12-29

Spark-ignited internal combustion engines have evolved considerably in recent years in response to increasingly stringent regulations for emissions and fuel-economy. One new advanced engine strategy utilizes high levels of exhaust gas recirculation (EGR) to reduce combustion temperatures, thereby increasing thermodynamic efficiency and reducing nitrogen oxide emissions. While this strategy can be highly effective, it also poses major control and design challenges due to the large combustion oscillations that develop at sufficiently high EGR levels. Previous research has documented that combustion instabilities can propagate between successive engine cycles in individual cylinders via self-generated feedback of reactive species and thermal energy inmore » the retained residual exhaust gases. In this work, we use symbolic analysis to characterize multi-cylinder combustion oscillations in an experimental engine operating with external EGR. At low levels of EGR, intra-cylinder oscillations are clearly visible and appear to be associated with brief, intermittent coupling among cylinders. As EGR is increased further, a point is reached where all four cylinders lock almost completely in phase and alternate simultaneously between two distinct bi-stable combustion states. From a practical perspective, it is important to understand the causes of this phenomenon and develop diagnostics that might be applied to ameliorate its effects. We demonstrate here that two approaches for symbolizing the engine combustion measurements can provide useful probes for characterizing these instabilities.« less

Fundamentals of Gas Turbine combustion

NASA Technical Reports Server (NTRS)

Gerstein, M.

1979-01-01

Combustion problems and research recommendations are discussed in the areas of atomization and vaporization, combustion chemistry, combustion dynamics, and combustion modelling. The recommendations considered of highest priority in these areas are presented.

Combustion kinetics and emission characteristics of polycyclic aromatic hydrocarbons from polylactic acid combustion.

PubMed

Chien, Yi-Chi; Liang, Chenju; Liu, Shou-Heng; Yang, Shu-Hua

2010-07-01

This study investigates the combustion kinetics and emission factors of 16 U.S. Environmental Protection Agency priority polycyclic aromatic hydrocarbons (PAHs) in polylactic acid (PLA) combustion. Experimentally, two reactions are involved in the PLA combustion process that potentially result in the release of lactide, acetaldehyde, and n-hexaldehyde. The products may continuously be oxidized to form carbon dioxide (CO2) and some PAHs produced because of incomplete combustion. The analytical results indicate that the emission factors for PAHs are in the range of not detectable to 98.04 microg/g. The emission factors are much lower than those of poly(ethylene terephalate) (PET) and other combustion of plastics. Results from this work suggest that combustion is a good choice for waste PLA disposal.

Development and test of combustion chamber for Stirling engine heated by natural gas

NASA Astrophysics Data System (ADS)

Li, Tie; Song, Xiange; Gui, Xiaohong; Tang, Dawei; Li, Zhigang; Cao, Wenyu

2014-04-01

The combustion chamber is an important component for the Stirling engine heated by natural gas. In the paper, we develop a combustion chamber for the Stirling engine which aims to generate 3˜5 kWe electric power. The combustion chamber includes three main components: combustion module, heat exchange cavity and thermal head. Its feature is that the structure can divide "combustion" process and "heat transfer" process into two apparent individual steps and make them happen one by one. Since natural gas can mix with air fully before burning, the combustion process can be easily completed without the second wind. The flame can avoid contacting the thermal head of Stirling engine, and the temperature fields can be easily controlled. The designed combustion chamber is manufactured and its performance is tested by an experiment which includes two steps. The experimental result of the first step proves that the mixture of air and natural gas can be easily ignited and the flame burns stably. In the second step of experiment, the combustion heat flux can reach 20 kW, and the energy utilization efficiency of thermal head has exceeded 0.5. These test results show that the thermal performance of combustion chamber has reached the design goal. The designed combustion chamber can be applied to a real Stirling engine heated by natural gas which is to generate 3˜5 kWe electric power.

Radial inflow gas turbine engine with advanced transition duct

DOEpatents

Wiebe, David J

2015-03-17

A gas turbine engine (10), including: a turbine having radial inflow impellor blades (38); and an array of advanced transition combustor assemblies arranged circumferentially about the radial inflow impellor blades (38) and having inner surfaces (34) that are adjacent to combustion gases (40). The inner surfaces (34) of the array are configured to accelerate and orient, for delivery directly onto the radial inflow impellor blades (38), a plurality of discrete flows of the combustion gases (40). The array inner surfaces (34) define respective combustion gas flow axes (20). Each combustion gas flow axis (20) is straight from a point of ignition until no longer bound by the array inner surfaces (34), and each combustion gas flow axis (20) intersects a unique location on a circumference defined by a sweep of the radial inflow impellor blades (38).

Combuster. [low nitrogen oxide formation

NASA Technical Reports Server (NTRS)

Mckay, R. A. (Inventor)

1978-01-01

A combuster is provided for utilizing a combustible mixture containing fuel and air, to heat a load fluid such as water or air, in a manner that minimizes the formation of nitrogen oxide. The combustible mixture passes through a small diameter tube where the mixture is heated to its combustion temperature, while the load fluid flows past the outside of the tube to receive heat. The tube is of a diameter small enough that the combustible mixture cannot form a flame, and yet is not subject to wall quench, so that combustion occurs, but at a temperature less than under free flame conditions. Most of the heat required for heating the combustible mixture to its combustion temperature, is obtained from heat flow through the walls of the pipe to the mixture.

Induced effects of advanced oxidation processes

PubMed Central

Liu, Peng; Li, Chaolin; Zhao, Zhuanjun; Lu, Gang; Cui, Haibo; Zhang, Wenfang

2014-01-01

Hazardous organic wastes from industrial, military, and commercial activities represent one of the greatest challenges to human beings. Advanced oxidation processes (AOPs) are alternatives to the degradation of those organic wastes. However, the knowledge about the exact mechanisms of AOPs is still incomplete. Here we report a phenomenon in the AOPs: induced effects, which is a common property of combustion reaction. Through analysis EDTA oxidation processes by Fenton and UV-Fenton system, the results indicate that, just like combustion, AOPs are typical induction reactions. One most compelling example is that pre-feeding easily oxidizable organic matter can promote the oxidation of refractory organic compound when it was treated by AOPs. Connecting AOPs to combustion, it is possible to achieve some helpful enlightenment from combustion to analyze, predict and understand AOPs. In addition, we assume that maybe other oxidation reactions also have induced effects, such as corrosion, aging and passivation. Muchmore research is necessary to reveal the possibilities of induced effects in those fields. PMID:24503715

Induced effects of advanced oxidation processes.

PubMed

Liu, Peng; Li, Chaolin; Zhao, Zhuanjun; Lu, Gang; Cui, Haibo; Zhang, Wenfang

2014-02-07

Hazardous organic wastes from industrial, military, and commercial activities represent one of the greatest challenges to human beings. Advanced oxidation processes (AOPs) are alternatives to the degradation of those organic wastes. However, the knowledge about the exact mechanisms of AOPs is still incomplete. Here we report a phenomenon in the AOPs: induced effects, which is a common property of combustion reaction. Through analysis EDTA oxidation processes by Fenton and UV-Fenton system, the results indicate that, just like combustion, AOPs are typical induction reactions. One most compelling example is that pre-feeding easily oxidizable organic matter can promote the oxidation of refractory organic compound when it was treated by AOPs. Connecting AOPs to combustion, it is possible to achieve some helpful enlightenment from combustion to analyze, predict and understand AOPs. In addition, we assume that maybe other oxidation reactions also have induced effects, such as corrosion, aging and passivation. Muchmore research is necessary to reveal the possibilities of induced effects in those fields.

Status on the Verification of Combustion Stability for the J-2X Engine Thrust Chamber Assembly

NASA Technical Reports Server (NTRS)

Casiano, Matthew; Hinerman, Tim; Kenny, R. Jeremy; Hulka, Jim; Barnett, Greg; Dodd, Fred; Martin, Tom

2013-01-01

Development is underway of the J -2X engine, a liquid oxygen/liquid hydrogen rocket engine for use on the Space Launch System. The Engine E10001 began hot fire testing in June 2011 and testing will continue with subsequent engines. The J -2X engine main combustion chamber contains both acoustic cavities and baffles. These stability aids are intended to dampen the acoustics in the main combustion chamber. Verification of the engine thrust chamber stability is determined primarily by examining experimental data using a dynamic stability rating technique; however, additional requirements were included to guard against any spontaneous instability or rough combustion. Startup and shutdown chug oscillations are also characterized for this engine. This paper details the stability requirements and verification including low and high frequency dynamics, a discussion on sensor selection and sensor port dynamics, and the process developed to assess combustion stability. A status on the stability results is also provided and discussed.

Jet plume injection and combustion system for internal combustion engines

DOEpatents

Oppenheim, A.K.; Maxson, J.A.; Hensinger, D.M.

1993-12-21

An improved combustion system for an internal combustion engine is disclosed wherein a rich air/fuel mixture is furnished at high pressure to one or more jet plume generator cavities adjacent to a cylinder and then injected through one or more orifices from the cavities into the head space of the cylinder to form one or more turbulent jet plumes in the head space of the cylinder prior to ignition of the rich air/fuel mixture in the cavity of the jet plume generator. The portion of the rich air/fuel mixture remaining in the cavity of the generator is then ignited to provide a secondary jet, comprising incomplete combustion products which are injected into the cylinder to initiate combustion in the already formed turbulent jet plume. Formation of the turbulent jet plume in the head space of the cylinder prior to ignition has been found to yield a higher maximum combustion pressure in the cylinder, as well as shortening the time period to attain such a maximum pressure. 24 figures.

Jet plume injection and combustion system for internal combustion engines

DOEpatents

Oppenheim, Antoni K.; Maxson, James A.; Hensinger, David M.

1993-01-01

An improved combustion system for an internal combustion engine is disclosed wherein a rich air/fuel mixture is furnished at high pressure to one or more jet plume generator cavities adjacent to a cylinder and then injected through one or more orifices from the cavities into the head space of the cylinder to form one or more turbulent jet plumes in the head space of the cylinder prior to ignition of the rich air/fuel mixture in the cavity of the jet plume generator. The portion of the rich air/fuel mixture remaining in the cavity of the generator is then ignited to provide a secondary jet, comprising incomplete combustion products which are injected into the cylinder to initiate combustion in the already formed turbulent jet plume. Formation of the turbulent jet plume in the head space of the cylinder prior to ignition has been found to yield a higher maximum combustion pressure in the cylinder, as well as shortening the time period to attain such a maximum pressure.

Overview of Low Emission Combustion Research At NASA Glenn

NASA Technical Reports Server (NTRS)

Reddy, D. R.

2016-01-01

An overview of research efforts at NASA Glenn Research Center (GRC) in low-emission combustion technology that have made a significant impact on the nitrogen oxides (NOx) emission reduction in aircraft propulsion is presented. The technology advancements and their impact on aircraft emissions are discussed in the context of NASA's Aeronautics Research Mission Directorate (ARMD) high-level goals in fuel burn, noise and emission reductions. The highlights of the research presented here show how the past and current efforts laid the foundation for the engines that are flying today as well as how the continued technology advancements will significantly influence the next generation of aviation propulsion system designs.

Path planning during combustion mode switch

DOEpatents

Jiang, Li; Ravi, Nikhil

2015-12-29

Systems and methods are provided for transitioning between a first combustion mode and a second combustion mode in an internal combustion engine. A current operating point of the engine is identified and a target operating point for the internal combustion engine in the second combustion mode is also determined. A predefined optimized transition operating point is selected from memory. While operating in the first combustion mode, one or more engine actuator settings are adjusted to cause the operating point of the internal combustion engine to approach the selected optimized transition operating point. When the engine is operating at the selected optimized transition operating point, the combustion mode is switched from the first combustion mode to the second combustion mode. While operating in the second combustion mode, one or more engine actuator settings are adjusted to cause the operating point of the internal combustion to approach the target operating point.

Helicopter far-field acoustic levels as a function of reduced main-rotor advancing blade-tip Mach number

NASA Technical Reports Server (NTRS)

Mueller, Arnold W.; Smith, Charles D.; Lemasurier, Philip

1990-01-01

During the design of a helicopter, the weight, engine, rotor speed, and rotor geometry are given significant attention when considering the specific operations for which the helicopter will be used. However, the noise radiated from the helicopter and its relationship to the design variables is currently not well modeled with only a limited set of full-scale field test data to study. In general, limited field data have shown that reduced main-rotor advancing blade-tip Mach numbers result in reduced far-field noise levels. The status of a recent helicopter noise research project is reviewed. It is designed to provide flight experimental data which may be used to further understand helicopter main-rotor advancing blade-tip Mach number effects on far-field acoustic levels. Preliminary results are presented relative to tests conducted with a Sikorsky S-76A helicopter operating with both the rotor speed and the flight speed as the control variable. The rotor speed was operated within the range of 107 to 90 percent NR at nominal forward speeds of 35, 100, and 155 knots.

Staged, High-Pressure Oxy-Combustion Technology: Development and Scale-Up

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

Axelbaum, Richard; Kumfer, Benjamin; Gopan, Akshay

The immediate need for a high efficiency, low cost carbon capture process has prompted the recent development of pressurized oxy-combustion. With a greater combustion pressure the dew point of the flue gas is increased, allowing for effective integration of the latent heat of flue gas moisture into the Rankine cycle. This increases the net plant efficiency and reduces costs. A novel, transformational process, named Staged, Pressurized Oxy-Combustion (SPOC), achieves additional step changes in efficiency and cost reduction by significantly reducing the recycle of flue gas. The research and development activities conducted under Phases I and II of this project (FE0009702)more » include: SPOC power plant cost and performance modeling, CFD-assisted design of pressurized SPOC boilers, theoretical analysis of radiant heat transfer and ash deposition, boiler materials corrosion testing, construction of a 100 kWth POC test facility, and experimental testing. The results of this project have advanced the technology readiness level (TRL) of the SPOC technology from 1 to 5.« less

Study on the valorization routes of ashes from thermoelectric power plants working under mono-and co-combustion regimes

NASA Astrophysics Data System (ADS)

Barbosa, Rui Pedro Fernandes

The main objective of this thesis was to study new valorization routes of ashes produced in combustion and co-combustion processes. Three main valorization pathways were analyzed: (i)production of cement mortars, (ii) production of concretes, and (iii) use as chemical agents to remove contaminants from wastewaters. Firstly, the ashes produced during the mono-combustion of coal, co-combustion of coal and meat and bone meal (MBM), and mono-combustion of MBM were characterized. The aim of this study was to understand the ashes properties in extreme levels of substitution of coal by a residue with a high contamination of specific metals. The substitution of coal by MBM produced ashes with higher content of heavy metals. Secondly, the ashes coming from an industrial power plant working under mono-combustion(coal) and co-combustion conditions (coal+sewage sludge+MBM) were studied. The use of cofuels did not promote significant changes in the chemical and ecotoxicological properties of ashes. Fly ashes were successfully stabilized/solidified in cement mortar, and bottom and circulating ashes were successfully used as raw materials in concrete. The third step involved the characterization and valorization of biomass ashes resulting from the combustion of forestry residues. The highest concentrations of metals/metalloids were found in the lowest particle size fractions of ashes. Biomass ashes successfully substituted cement and natural aggregates in concretes, without compromising their mechanical, chemical, and ecotoxicological properties. Finally, the biomass ashes were tested as chemical agents to remove contaminants from wastewaters. The removal of P, mainly phosphates, and Pb from wastewaters was assayed. Biomass ashes presented a high capacity to remove phosphates. As fly ashes were more efficient in removing phosphates, they were further used to remove Pb from wastewaters. Again, they presented a high efficiency in Pb removal. New potential valorization routes for

Expanding Robust HCCI Operation with Advanced Valve and Fuel Control Technologies

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

Szybist, J. P.; Confer, K.

2012-09-11

Delphi Automotive Systems and ORNL established this CRADA to advance the commercialization potential of the homogeneous charge compression ignition (HCCI) advanced combustion strategy for gasoline engine platforms. HCCI combustion has been shown by others to produce high diesel-like efficiency on a gasoline engine platform while simultaneously producing low NOX and particulate matter emissions. However, the commercialization barriers that face HCCI combustion are significant, with requirements for a more active engine control system, likely with next-cycle closed-loop feedback control, and with advanced valve train technologies to enable negative valve overlap conditions. In the partnership between Delphi and ORNL, each organization broughtmore » a unique and complementary set of skills to the project. Delphi has made a number of breakthroughs with production-intent valve train technologies and controls in recent years to make a part time production-intent HCCI engine plausible. ORNL has extensive knowledge and expertise with HCCI combustion, and also has a versatile research engine with hydraulic valve actuation (HVA) that is useful for guiding production of a cam-based HCCI system. Partnering these knowledge bases and capabilities was essential towards making progress to better understand HCCI combustion and the commercialization barriers that it faces. ORNL and Delphi maintained strong collaboration throughout the project. Meetings were held regularly, with additional reports, presentations, and meetings as necessary to maintain progress. Delphi provided guidance to ORNL regarding operational strategies to investigate on their single-cylinder research engine with HVA and data from their experimental multi-cylinder engine for modeling. ORNL provided single-cylinder engine data and modeling results.« less

Microgravity Smoldering Combustion Takes Flight

NASA Technical Reports Server (NTRS)

1996-01-01

The Microgravity Smoldering Combustion (MSC) experiment lifted off aboard the Space Shuttle Endeavour in September 1995 on the STS-69 mission. This experiment is part of series of studies focused on the smolder characteristics of porous, combustible materials in a microgravity environment. Smoldering is a nonflaming form of combustion that takes place in the interior of combustible materials. Common examples of smoldering are nonflaming embers, charcoal briquettes, and cigarettes. The objective of the study is to provide a better understanding of the controlling mechanisms of smoldering, both in microgravity and Earth gravity. As with other forms of combustion, gravity affects the availability of air and the transport of heat, and therefore, the rate of combustion. Results of the microgravity experiments will be compared with identical experiments carried out in Earth's gravity. They also will be used to verify present theories of smoldering combustion and will provide new insights into the process of smoldering combustion, enhancing our fundamental understanding of this frequently encountered combustion process and guiding improvement in fire safety practices.

Combustion instability and active control: Alternative fuels, augmentors, and modeling heat release

NASA Astrophysics Data System (ADS)

Park, Sammy Ace

Experimental and analytical studies were conducted to explore thermo-acoustic coupling during the onset of combustion instability in various air-breathing combustor configurations. These include a laboratory-scale 200-kW dump combustor and a 100-kW augmentor featuring a v-gutter flame holder. They were used to simulate main combustion chambers and afterburners in aero engines, respectively. The three primary themes of this work includes: 1) modeling heat release fluctuations for stability analysis, 2) conducting active combustion control with alternative fuels, and 3) demonstrating practical active control for augmentor instability suppression. The phenomenon of combustion instabilities remains an unsolved problem in propulsion engines, mainly because of the difficulty in predicting the fluctuating component of heat release without extensive testing. A hybrid model was developed to describe both the temporal and spatial variations in dynamic heat release, using a separation of variables approach that requires only a limited amount of experimental data. The use of sinusoidal basis functions further reduced the amount of data required. When the mean heat release behavior is known, the only experimental data needed for detailed stability analysis is one instantaneous picture of heat release at the peak pressure phase. This model was successfully tested in the dump combustor experiments, reproducing the correct sign of the overall Rayleigh index as well as the remarkably accurate spatial distribution pattern of fluctuating heat release. Active combustion control was explored for fuel-flexible combustor operation using twelve different jet fuels including bio-synthetic and Fischer-Tropsch types. Analysis done using an actuated spray combustion model revealed that the combustion response times of these fuels were similar. Combined with experimental spray characterizations, this suggested that controller performance should remain effective with various alternative fuels

Lump wood combustion process

NASA Astrophysics Data System (ADS)

Kubesa, Petr; Horák, Jiří; Branc, Michal; Krpec, Kamil; Hopan, František; Koloničný, Jan; Ochodek, Tadeáš; Drastichová, Vendula; Martiník, Lubomír; Malcho, Milan

2014-08-01

The article deals with the combustion process for lump wood in low-power fireplaces (units to dozens of kW). Such a combustion process is cyclical in its nature, and what combustion facility users are most interested in is the frequency, at which fuel needs to be stoked to the fireplace. The paper defines the basic terms such as burnout curve and burning rate curve, which are closely related to the stocking frequency. The fuel burning rate is directly dependent on the immediate thermal power of the fireplace. This is also related to the temperature achieved in the fireplace, magnitude of flue gas losses and the ability to generate conditions favouring the full burnout of the fuel's combustible component, which, at once ensures the minimum production of combustible pollutants. Another part of the paper describes experiments conducted in traditional fireplaces with a grate, at which well-dried lump wood was combusted.

Numerical modeling of spray combustion with an advanced VOF method

NASA Technical Reports Server (NTRS)

Chen, Yen-Sen; Shang, Huan-Min; Shih, Ming-Hsin; Liaw, Paul

1995-01-01

This paper summarizes the technical development and validation of a multiphase computational fluid dynamics (CFD) numerical method using the volume-of-fluid (VOF) model and a Lagrangian tracking model which can be employed to analyze general multiphase flow problems with free surface mechanism. The gas-liquid interface mass, momentum and energy conservation relationships are modeled by continuum surface mechanisms. A new solution method is developed such that the present VOF model can be applied for all-speed flow regimes. The objectives of the present study are to develop and verify the fractional volume-of-fluid cell partitioning approach into a predictor-corrector algorithm and to demonstrate the effectiveness of the present approach by simulating benchmark problems including laminar impinging jets, shear coaxial jet atomization and shear coaxial spray combustion flows.

Advanced expander test bed engine

NASA Technical Reports Server (NTRS)

Mitchell, J. P.

1992-01-01

The Advanced Expander Test Bed (AETB) is a key element in NASA's Space Chemical Engine Technology Program for development and demonstration of expander cycle oxygen/hydrogen engine and advanced component technologies applicable to space engines as well as launch vehicle upper stage engines. The AETB will be used to validate the high pressure expander cycle concept, study system interactions, and conduct studies of advanced mission focused components and new health monitoring techniques in an engine system environment. The split expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust.

Combustion Research aboard the ISS Utilizing the Combustion Integrated Rack and Microgravity Science Glovebox

NASA Astrophysics Data System (ADS)

Sutliff, T. J.; Otero, A. M.; Urban, D. L.

2002-01-01

The Physical Sciences Research Program of NASA has chartered a broad suite of peer-reviewed research investigating both fundamental combustion phenomena and applied combustion research topics. Fundamental research provides insights to develop accurate simulations of complex combustion processes and allows developers to improve the efficiency of combustion devices, to reduce the production of harmful emissions, and to reduce the incidence of accidental uncontrolled combustion (fires, explosions). The applied research benefit humans living and working in space through its fire safety program. The Combustion Science Discipline is implementing a structured flight research program utilizing the International Space Station (ISS) and two of its premier facilities, the Combustion Integrated Rack of the Fluids and Combustion Facility and the Microgravity Science Glovebox to conduct this space-based research. This paper reviews the current vision of Combustion Science research planned for International Space Station implementation from 2003 through 2012. A variety of research efforts in droplets and sprays, solid-fuels combustion, and gaseous combustion have been independently selected and critiqued through a series of peer-review processes. During this period, while both the ISS carrier and its research facilities are under development, the Combustion Science Discipline has synergistically combined research efforts into sub-topical areas. To conduct this research aboard ISS in the most cost effective and resource efficient manner, the sub-topic research areas are implemented via a multi-user hardware approach. This paper also summarizes the multi-user hardware approach and recaps the progress made in developing these research hardware systems. A balanced program content has been developed to maximize the production of fundamental and applied combustion research results within the current budgetary and ISS operational resource constraints. Decisions on utilizing the

The role of primary and secondary air on wood combustion in cookstoves

NASA Astrophysics Data System (ADS)

Kirch, Thomas; Birzer, Cristian H.; Medwell, Paul R.; Holden, Liam

2018-03-01

A two-stage solid fuel research furnace was used to examine the claim that through forced draught greater mixing and more complete combustion could be achieved. By varying the primary air (PA) and secondary air (SA) flow the influence on the combustion process was investigated. In the first part of the combustion, when the release of volatile compounds predominates, the variation of neither PA nor SA had a significant influence. In the second part when mainly char is oxidised an increase in both PA and SA lead to a rising nominal combustion efficiency (?)), with a greater impact observed with SA. Furthermore higher air flows caused the heat transfer, to a pot above the furnace, to decline. Therefore forced draught does lead to greater mixing and mitigation of emissions, but in the presented configuration a trade-off between a higher NCE and a lower heat transfer needs consideration.

Combustion of textile residues in a packed bed

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

Ryu, Changkook; Phan, Anh N.; Sharifi, Vida N.

2007-08-15

Textile is one of the main components in the municipal waste which is to be diverted from landfill for material and energy recovery. As an initial investigation for energy recovery from textile residues, the combustion of cotton fabrics with a minor fraction of polyester was investigated in a packed bed combustor for air flow rates ranging from 117 to 1638 kg/m{sup 2} h (0.027-0.371 m/s). Tests were also carried out in order to evaluate the co-combustion of textile residues with two segregated waste materials: waste wood and cardboard. Textile residues showed different combustion characteristics when compared to typical waste materialsmore » at low air flow rates below 819 kg/m{sup 2} h (0.186 m/s). The ignition front propagated fast along the air channels randomly formed between packed textile particles while leaving a large amount of unignited material above. This resulted in irregular behaviour of the temperature profile, ignition rate and the percentage of weight loss in the ignition propagation stage. A slow smouldering burn-out stage followed the ignition propagation stage. At air flow rates of 1200-1600 kg/m{sup 2} h (0.272-0.363 m/s), the bed had a maximum burning rate of about 240 kg/m{sup 2} h consuming most of the combustibles in the ignition propagation stage. More uniform combustion with an increased burning rate was achieved when textile residues were co-burned with cardboard that had a similar bulk density. (author)« less

Combustion characteristics of the LO2/GCH4 fuel-rich preburners for staged combustion cycle rocket engines

NASA Astrophysics Data System (ADS)

Ono, Fumiei; Tamura, Hiroshi; Sakamoto, Hiroshi; Sasaki, Masaki

1991-09-01

The combustion characteristics of Liquid Oxygen (LO2)/Gaseous Methane (GCH4) fuel rich preburners were experimentally studied using subscale hardware. Three types of preburners with coaxial type propellant injection elements were designed and fabricated, and were used for hot fire testing. LO2 was used as oxidizer, and GCH4 at room temperature was used as fuel. The tests were conducted at chamber pressures ranging from 6.7 to 11.9 M Pa, and oxidizer to fuel ratios ranged from 0.16 to 0.42. The test results, which include combustion gas temperature T(sub c), characteristic velocity C(sup *) and soot adhesion data, are presented. The T(sub c) efficiency and the C(sup *) efficiency were found to be a function of oxidizer to fuel ratio and chamber pressure. These efficiencies are correlated by an empirical correlation parameter which accounts for the effects of oxidizer to fuel ratio and chamber pressure. The exhaust plumes were colorless and transparent under all tests conditions. There was some soot adhesion to the chamber wall, but no soot adhesion was observed on the main injector simulator orifices. Higher temperature igniter gas was required to ignite the main propellants of the preburner compared with that of the LO2/Gaseous Hydrogen (GH2) propellants combination.

Advanced Vacuum Plasma Spray (VPS) for a Robust, Longlife and Safe Space Shuttle Main Engine (SSME)

NASA Technical Reports Server (NTRS)

Holmes, Richard R.; Elam, Sandra K.; McKechnie, Timothy N.; Power, Christopher A.

2010-01-01

In 1984, the Vacuum Plasma Spray Lab was built at NASA/Marshall Space Flight Center for applying durable, protective coatings to turbine blades for the space shuttle main engine (SSME) high pressure fuel turbopump. Existing turbine blades were cracking and breaking off after five hot fire tests while VPS coated turbine blades showed no wear or cracking after 40 hot fire tests. Following that, a major manufacturing problem of copper coatings peeling off the SSME Titanium Main Fuel Valve Housing was corrected with a tenacious VPS copper coating. A patented VPS process utilizing Functional Gradient Material (FGM) application was developed to build ceramic lined metallic cartridges for space furnace experiments, safely containing gallium arsenide at 1260 degrees centigrade. The VPS/FGM process was then translated to build robust, long life, liquid rocket combustion chambers for the space shuttle main engine. A 5K (5,000 Lb. thrust) thruster with the VPS/FGM protective coating experienced 220 hot firing tests in pristine condition with no wear compared to the SSME which showed blanching (surface pulverization) and cooling channel cracks in less than 30 of the same hot firing tests. After 35 of the hot firing tests, the injector face plates disintegrated. The VPS/FGM process was then applied to spraying protective thermal barrier coatings on the face plates which showed 50% cooler operating temperature, with no wear after 50 hot fire tests. Cooling channels were closed out in two weeks, compared to one year for the SSME. Working up the TRL (Technology Readiness Level) to establish the VPS/FGM process as viable technology, a 40K thruster was built and is currently being tested. Proposed is to build a J-2X size liquid rocket engine as the final step in establishing the VPS/FGM process TRL for space flight.

Heat regenerative external combustion engine

NASA Astrophysics Data System (ADS)

Duva, Anthony W.

1993-03-01

It is an object of the invention to provide an external combustion expander-type engine having improved efficiency. It is another object of the invention to provide an external combustion engine in which afterburning in the exhaust channel is substantially prevented. Yet another object of the invention is to provide an external combustion engine which is less noisy than an external combustion engine of conventional design. These and other objects of the invention will become more apparent from the following description. The above objects of the invention are realized by providing a heat regenerative external combustion engine. The heat regenerative external combustion engine of the invention comprises a combustion chamber for combusting a monopropellant fuel in order to form an energized gas. The energized gas is then passed through a rotary valve to a cylinder having a reciprocating piston disposed therein. The gas is spent in moving the piston, thereby driving a drive shaft.

Heat transfer in rocket engine combustion chambers and regeneratively cooled nozzles

NASA Technical Reports Server (NTRS)

1993-01-01

A conjugate heat transfer computational fluid dynamics (CFD) model to describe regenerative cooling in the main combustion chamber and nozzle and in the injector faceplate region for a launch vehicle class liquid rocket engine was developed. An injector model for sprays which treats the fluid as a variable density, single-phase media was formulated, incorporated into a version of the FDNS code, and used to simulate the injector flow typical of that in the Space Shuttle Main Engine (SSME). Various chamber related heat transfer analyses were made to verify the predictive capability of the conjugate heat transfer analysis provided by the FDNS code. The density based version of the FDNS code with the real fluid property models developed was successful in predicting the streamtube combustion of individual injector elements.

Characterizing dilute combustion instabilities in a multi-cylinder spark-ignited engine using symbolic analysis.

PubMed

Daw, C S; Finney, C E A; Kaul, B C; Edwards, K D; Wagner, R M

2015-02-13

Spark-ignited internal combustion engines have evolved considerably in recent years in response to increasingly stringent regulations for emissions and fuel economy. One new advanced engine strategy ustilizes high levels of exhaust gas recirculation (EGR) to reduce combustion temperatures, thereby increasing thermodynamic efficiency and reducing nitrogen oxide emissions. While this strategy can be highly effective, it also poses major control and design challenges due to the large combustion oscillations that develop at sufficiently high EGR levels. Previous research has documented that combustion instabilities can propagate between successive engine cycles in individual cylinders via self-generated feedback of reactive species and thermal energy in the retained residual exhaust gases. In this work, we use symbolic analysis to characterize multi-cylinder combustion oscillations in an experimental engine operating with external EGR. At low levels of EGR, intra-cylinder oscillations are clearly visible and appear to be associated with brief, intermittent coupling among cylinders. As EGR is increased further, a point is reached where all four cylinders lock almost completely in phase and alternate simultaneously between two distinct bi-stable combustion states. From a practical perspective, it is important to understand the causes of this phenomenon and develop diagnostics that might be applied to ameliorate its effects. We demonstrate here that two approaches for symbolizing the engine combustion measurements can provide useful probes for characterizing these instabilities. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

A robust framework to predict mercury speciation in combustion flue gases.

PubMed

Ticknor, Jonathan L; Hsu-Kim, Heileen; Deshusses, Marc A

2014-01-15

Mercury emissions from coal combustion have become a global concern as growing energy demands have increased the consumption of coal. The effective implementation of treatment technologies requires knowledge of mercury speciation in the flue gas, namely concentrations of elemental, oxidized and particulate mercury at the exit of the boiler. A model that can accurately predict mercury species in flue gas would be very useful in that context. Here, a Bayesian regularized artificial neural network (BRANN) that uses five coal properties and combustion temperature was developed to predict mercury speciation in flue gases before treatment technology implementation. The results of the model show that up to 97 percent of the variation in mercury species concentration is captured through the use of BRANNs. The BRANN model was used to conduct a parametric sensitivity which revealed that the coal chlorine content and coal calorific value were the most sensitive parameters, followed by the combustion temperature. The coal sulfur content was the least important parameter. The results demonstrate the applicability of BRANNs for predicting mercury concentration and speciation in combustion flue gas and provide a more efficient and effective technique when compared to other advanced non-mechanistic modeling strategies. Copyright © 2013 Elsevier B.V. All rights reserved.

Method and apparatus for active control of combustion rate through modulation of heat transfer from the combustion chamber wall

DOEpatents

Roberts, Jr., Charles E.; Chadwell, Christopher J.

2004-09-21

The flame propagation rate resulting from a combustion event in the combustion chamber of an internal combustion engine is controlled by modulation of the heat transfer from the combustion flame to the combustion chamber walls. In one embodiment, heat transfer from the combustion flame to the combustion chamber walls is mechanically modulated by a movable member that is inserted into, or withdrawn from, the combustion chamber thereby changing the shape of the combustion chamber and the combustion chamber wall surface area. In another embodiment, heat transfer from the combustion flame to the combustion chamber walls is modulated by cooling the surface of a portion of the combustion chamber wall that is in close proximity to the area of the combustion chamber where flame speed control is desired.

Reversed flow fluidized-bed combustion apparatus

DOEpatents

Shang, Jer-Yu; Mei, Joseph S.; Wilson, John S.

1984-01-01

The present invention is directed to a fluidized-bed combustion apparatus provided with a U-shaped combustion zone. A cyclone is disposed in the combustion zone for recycling solid particulate material. The combustion zone configuration and the recycling feature provide relatively long residence times and low freeboard heights to maximize combustion of combustible material, reduce nitrogen oxides, and enhance sulfur oxide reduction.

Advanced research and technology program for advanced high pressure oxygen-hydrogen rocket propulsion

NASA Technical Reports Server (NTRS)

Marsik, S. J.; Morea, S. F.

1985-01-01

A research and technology program for advanced high pressure, oxygen-hydrogen rocket propulsion technology is presently being pursued by the National Aeronautics and Space Administration (NASA) to establish the basic discipline technologies, develop the analytical tools, and establish the data base necessary for an orderly evolution of the staged combustion reusable rocket engine. The need for the program is based on the premise that the USA will depend on the Shuttle and its derivative versions as its principal Earth-to-orbit transportation system for the next 20 to 30 yr. The program is focused in three principal areas of enhancement: (1) life extension, (2) performance, and (3) operations and diagnosis. Within the technological disciplines the efforts include: rotordynamics, structural dynamics, fluid and gas dynamics, materials fatigue/fracture/life, turbomachinery fluid mechanics, ignition/combustion processes, manufacturing/producibility/nondestructive evaluation methods and materials development/evaluation. An overview of the Advanced High Pressure Oxygen-Hydrogen Rocket Propulsion Technology Program Structure and Working Groups objectives are presented with highlights of several significant achievements.

Advanced research and technology programs for advanced high-pressure oxygen-hydrogen rocket propulsion

NASA Technical Reports Server (NTRS)

Marsik, S. J.; Morea, S. F.

1985-01-01

A research and technology program for advanced high pressure, oxygen-hydrogen rocket propulsion technology is presently being pursued by the National Aeronautics and Space Administration (NASA) to establish the basic discipline technologies, develop the analytical tools, and establish the data base necessary for an orderly evolution of the staged combustion reusable rocket engine. The need for the program is based on the premise that the USA will depend on the Shuttle and its derivative versions as its principal Earth-to-orbit transportation system for the next 20 to 30 yr. The program is focused in three principal areas of enhancement: (1) life extension, (2) performance, and (3) operations and diagnosis. Within the technological disciplines the efforts include: rotordynamics, structural dynamics, fluid and gas dynamics, materials fatigue/fracture/life, turbomachinery fluid mechanics, ignition/combustion processes, manufacturing/producibility/nondestructive evaluation methods and materials development/evaluation. An overview of the Advanced High Pressure Oxygen-Hydrogen Rocket Propulsion Technology Program Structure and Working Groups objectives are presented with highlights of several significant achievements.

Advanced research and technology programs for advanced high-pressure oxygen-hydrogen rocket propulsion

NASA Astrophysics Data System (ADS)

Marsik, S. J.; Morea, S. F.

1985-03-01

A research and technology program for advanced high pressure, oxygen-hydrogen rocket propulsion technology is presently being pursued by the National Aeronautics and Space Administration (NASA) to establish the basic discipline technologies, develop the analytical tools, and establish the data base necessary for an orderly evolution of the staged combustion reusable rocket engine. The need for the program is based on the premise that the USA will depend on the Shuttle and its derivative versions as its principal Earth-to-orbit transportation system for the next 20 to 30 yr. The program is focused in three principal areas of enhancement: (1) life extension, (2) performance, and (3) operations and diagnosis. Within the technological disciplines the efforts include: rotordynamics, structural dynamics, fluid and gas dynamics, materials fatigue/fracture/life, turbomachinery fluid mechanics, ignition/combustion processes, manufacturing/producibility/nondestructive evaluation methods and materials development/evaluation. An overview of the Advanced High Pressure Oxygen-Hydrogen Rocket Propulsion Technology Program Structure and Working Groups objectives are presented with highlights of several significant achievements.

Flammability of Heterogeneously Combusting Metals

NASA Technical Reports Server (NTRS)

Jones, Peter D.

1998-01-01

Most engineering materials, including some metals, most notably aluminum, burn in homogeneous combustion. 'Homogeneous' refers to both the fuel and the oxidizer being in the same phase, which is usually gaseous. The fuel and oxidizer are well mixed in the combustion reaction zone, and heat is released according to some relation like q(sub c) = delta H(sub c)c[((rho/rho(sub 0))]exp a)(exp -E(sub c)/RT), Eq. (1) where the pressure exponent a is usually close to unity. As long as there is enough heat released, combustion is sustained. It is useful to conceive of a threshold pressure beyond which there is sufficient heat to keep the temperature high enough to sustain combustion, and beneath which the heat is so low that temperature drains away and the combustion is extinguished. Some materials burn in heterogeneous combustion, in which the fuel and oxidizer are in different phases. These include iron and nickel based alloys, which burn in the liquid phase with gaseous oxygen. Heterogeneous combustion takes place on the surface of the material (fuel). Products of combustion may appear as a solid slag (oxide) which progressively covers the fuel. Propagation of the combustion melts and exposes fresh fuel. Heterogeneous combustion heat release also follows the general form of Eq.(1), except that the pressure exponent a tends to be much less than 1. Therefore, the increase in heat release with increasing pressure is not as dramatic as it is in homogeneous combustion. Although the concept of a threshold pressure still holds in heterogeneous combustion, the threshold is more difficult to identify experimentally, and pressure itself becomes less important relative to the heat transfer paths extant in any specific application. However, the constants C, a, and E(sub c) may still be identified by suitable data reduction from heterogeneous combustion experiments, and may be applied in a heat transfer model to judge the flammability of a material in any particular actual

Spectral modeling of radiation in combustion systems

NASA Astrophysics Data System (ADS)

Pal, Gopalendu

involves interactions between the local particle and energy emitted by all other particles and, hence, cannot be obtained from particle ensembles directly. To close the nonlinear coupling between turbulence and absorption, i.e., "absorption TRI", an optically thin fluctuation approximation can be applied to virtually all combustion problems and obtain acceptable accuracy. In the present study a composition-PDF method is applied, in which only the temperature and the species concentrations are treated as random variables. A closely coupled hybrid finite-volume/Monte Carlo scheme is adopted, in which the Monte Carlo method is used to solve the composition-PDF for chemical reactions and the finite volume method is used to solve for the flow field and radiation. Spherical harmonics method-based finite volume solvers (P-1 and P-3) are developed using the data structures of the high fidelity open-source code flow software OpenFOAM. Spectral radiative properties of the participating medium are modeled using full-spectrum k-distribution methods. Advancements of basic k-distribution methods are performed for nongray nonhomogeneous gas- and particulate-phase (soot, fuel droplets, ash, etc.) participating media using multi-scale and multi-group based approaches. These methods achieve close-to benchmark line-by-line (LBL) accuracy in strongly inhomogeneous media at a tiny fraction of LBL's computational cost. A portable spectral module is developed, which includes all the basic to advanced k-distribution methods along with the precompiled accurate and compact k-distribution databases. The P-1 /P-3 RTE solver coupled with the spectral module is used in conjunction with the combined Reynolds-averaged Navier-Stokes (RANS) and composition-PDF-based turbulence-chemistry solver to investigate TRI in multiphase turbulent combustion systems. The combustion solvers developed in this study is employed to simulate several turbulent jet flames, such as Sandia Flame D, and artificial nonsooting

Bulkhead insert for an internal combustion engine

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

Maki, Clifford E.; Chottiner, Jeffrey Eliot; Williams, Rick L.

An engine includes a cylinder block defining at least one main bearing bulkhead adjacent to a cylinder, and a crankshaft rotatably housed within the block by a main bearing. A bulkhead insert has a cap portion, and an insert portion provided within the bulkhead. The insert portion has having first and second end regions connected by first and second straps. Each strap having a flanged beam cross section. The first and second ends of the insert portion are configured to connect a main bearing cap column to a cylinder head column. Each of the first and second end regions definemore » at least one protrusion having a surface substantially normal to engine combustion and reactive loads. The cap portion is configured to mate with the first end region at the main bearing cap column and support the main bearing.« less

LES Modeling of Supersonic Combustion at SCRAMJET Conditions

NASA Astrophysics Data System (ADS)

Vane, Zachary; Lacaze, Guilhem; Oefelein, Joseph

2016-11-01

Results from a series of large-eddy simulations (LES) of the Hypersonic International Flight Research Experiment (HIFiRE) are examined with emphasis placed on the coupled performance of the wall and combustion models. The test case of interest corresponds to the geometry and conditions found in the ground based experiments performed in the HIFiRE Direct Connect Rig (HDCR) in dual-mode operation. In these calculations, the turbulence and mixing characteristics of the high Reynolds number turbulent boundary layer with multi-species fuel injection are analyzed using a simplified chemical model and combustion closure to predict the heat release measured experimentally. These simulations are then used to identify different flame regimes in the combustor section. Concurrently, the performance of an equilibrium wall-model is evaluated in the vicinity of the fuel injectors and in the flame-holding cavity where regions of boundary layer and thermochemical non-equilibrium are present. Support for this research was provided by the Defense Advanced Research Projects Agency (DARPA).

Combustion Of Interacting Droplet Arrays In Microgravity

NASA Technical Reports Server (NTRS)

Dietrich, D. L.; Struk, P. M.; Ikegami, M.; Xu, G.

2003-01-01

Theory and experiments involving single droplet combustion date back to 1953, with the first microgravity work appearing in 1956. The problem of a spherical droplet burning in an infinite, quiescent microgravity environment is a classical problem in combustion research with the classical solution appearing in nearly every textbook on combustion. The microgravity environment offered by ground-based facilities such as drop towers and space-based facilities is ideal for studying the problem experimentally. A recent review by Choi and Dryer shows significant advances in droplet combustion have been made by studying the problem experimentally in microgravity and comparing the results to one dimensional theoretical and numerical treatments of the problem. Studying small numbers of interacting droplets in a well-controlled geometry represents a logical step in extending single droplet investigations to more practical spray configurations. Studies of droplet interactions date back to Rex and co-workers, and were recently summarized by Annamalai and Ryan. All previous studies determined the change in the burning rate constant, k, or the flame characteristics as a result of interactions. There exists almost no information on how droplet interactions a effect extinction limits, and if the extinction limits change if the array is in the diffusive or the radiative extinction regime. Thus, this study examined experimentally the effect that droplet interactions have on the extinction process by investigating the simplest array configuration, a binary droplet array. The studies were both in normal gravity, reduced pressure ambients and microgravity facilities. The microgravity facilities were the 2.2 and 5.2 second drop towers at the NASA Glenn Research Center and the 10 second drop tower at the Japan Microgravity Center. The experimental apparatus and the data analysis techniques are discussed in detail elsewhere.

A Feasibility Study for Advanced Technology Integration for General Aviation.

DTIC Science & Technology

1980-05-01

154 4.5.9.4 Stratified Charge Reciprocating Engine ..... .. 155 4.5.9.5 Advanced Diesel Engine . ... 158 4.5.9.6 Liquid Cooling ... ........ 159... diesel , rotary combustion engine, advanced reciprocating engine concepts. (7) Powerplant control - integrated controls, microprocessor- based controls...Research Center Topics. (1) GATE (2) Positive displacement engines (a) Advanced reciprocating engines. (b) Alternative engine systems Diesel engines

Equipment concept design and development plans for microgravity science and applications research on space station: Combustion tunnel, laser diagnostic system, advanced modular furnace, integrated electronics laboratory

NASA Technical Reports Server (NTRS)

Uhran, M. L.; Youngblood, W. W.; Georgekutty, T.; Fiske, M. R.; Wear, W. O.

1986-01-01

Taking advantage of the microgravity environment of space NASA has initiated the preliminary design of a permanently manned space station that will support technological advances in process science and stimulate the development of new and improved materials having applications across the commercial spectrum. Previous studies have been performed to define from the researcher's perspective, the requirements for laboratory equipment to accommodate microgravity experiments on the space station. Functional requirements for the identified experimental apparatus and support equipment were determined. From these hardware requirements, several items were selected for concept designs and subsequent formulation of development plans. This report documents the concept designs and development plans for two items of experiment apparatus - the Combustion Tunnel and the Advanced Modular Furnace, and two items of support equipment the Laser Diagnostic System and the Integrated Electronics Laboratory. For each concept design, key technology developments were identified that are required to enable or enhance the development of the respective hardware.

Subgrid Combustion Modeling for the Next Generation National Combustion Code

NASA Technical Reports Server (NTRS)

Menon, Suresh; Sankaran, Vaidyanathan; Stone, Christopher

2003-01-01

In the first year of this research, a subgrid turbulent mixing and combustion methodology developed earlier at Georgia Tech has been provided to researchers at NASA/GRC for incorporation into the next generation National Combustion Code (called NCCLES hereafter). A key feature of this approach is that scalar mixing and combustion processes are simulated within the LES grid using a stochastic 1D model. The subgrid simulation approach recovers locally molecular diffusion and reaction kinetics exactly without requiring closure and thus, provides an attractive feature to simulate complex, highly turbulent reacting flows of interest. Data acquisition algorithms and statistical analysis strategies and routines to analyze NCCLES results have also been provided to NASA/GRC. The overall goal of this research is to systematically develop and implement LES capability into the current NCC. For this purpose, issues regarding initialization and running LES are also addressed in the collaborative effort. In parallel to this technology transfer effort (that is continuously on going), research has also been underway at Georgia Tech to enhance the LES capability to tackle more complex flows. In particular, subgrid scalar mixing and combustion method has been evaluated in three distinctly different flow field in order to demonstrate its generality: (a) Flame-Turbulence Interactions using premixed combustion, (b) Spatially evolving supersonic mixing layers, and (c) Temporal single and two-phase mixing layers. The configurations chosen are such that they can be implemented in NCCLES and used to evaluate the ability of the new code. Future development and validation will be in spray combustion in gas turbine engine and supersonic scalar mixing.

Computation of H2/air reacting flowfields in drag-reduction external combustion

NASA Technical Reports Server (NTRS)

Lai, H. T.

1992-01-01

Numerical simulation and analysis of the solution are presented for a laminar reacting flowfield of air and hydrogen in the case of external combustion employed to reduce base drag in hypersonic vehicles operating at transonic speeds. The flowfield consists of a transonic air stream at a Mach number of 1.26 and a sonic transverse hydrogen injection along a row of 26 orifices. Self-sustained combustion is computed over an expansion ramp downstream of the injection and a flameholder, using the recently developed RPLUS code. Measured data is available only for surface pressure distributions and is used for validation of the code in practical 3D reacting flowfields. Pressure comparison shows generally good agreements, and the main effects of combustion are also qualitatively consistent with experiment.

Thermogravimetric investigation of the co-combustion between the pyrolysis oil distillation residue and lignite.

PubMed

Li, Hao; Xia, Shuqian; Ma, Peisheng

2016-10-01

Co-combustion of lignite with distillation residue derived from rice straw pyrolysis oil was investigated by non-isothermal thermogravimetric analysis (TGA). The addition of distillation residue improved the reactivity and combustion efficiency of lignite, such as increasing the weight loss rate at peak temperature and decreasing the burnout temperature and the total burnout. With increasing distillation residue content in the blended fuels, the synergistic interactions between distillation residue and lignite firstly increased and then decreased during co-combustion stage. Results of XRF, FTIR, (13)C NMR and SEM analysis indicated that chemical structure, mineral components and morphology of samples have great influence on the synergistic interactions. The combustion mechanisms and kinetic parameters were calculated by the Coats Redfern model, suggesting that the lowest apparent activation energy (120.19kJ/mol) for the blended fuels was obtained by blending 60wt.% distillation residue during main co-combustion stage. Copyright © 2016 Elsevier Ltd. All rights reserved.

Advanced nozzle and engine components test facility

NASA Technical Reports Server (NTRS)

Beltran, Luis R.; Delroso, Richard L.; Delrosario, Ruben

1992-01-01

A test facility for conducting scaled advanced nozzle and engine component research is described. The CE-22 test facility, located in the Engine Research Building of the NASA Lewis Research Center, contains many systems for the economical testing of advanced scale-model nozzles and engine components. The combustion air and altitude exhaust systems are described. Combustion air can be supplied to a model up to 40 psig for primary air flow, and 40, 125, and 450 psig for secondary air flow. Altitude exhaust can be simulated up to 48,000 ft, or the exhaust can be atmospheric. Descriptions of the multiaxis thrust stand, a color schlieren flow visualization system used for qualitative flow analysis, a labyrinth flow measurement system, a data acquisition system, and auxiliary systems are discussed. Model recommended design information and temperature and pressure instrumentation recommendations are included.

Research Needs and Impacts in Predictive Simulation for Internal Combustion Engines (PreSICE)

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

Eckerle, Wayne; Rutland, Chris; Rohlfing, Eric

This report is based on a SC/EERE Workshop to Identify Research Needs and Impacts in Predictive Simulation for Internal Combustion Engines (PreSICE), held March 3, 2011, to determine strategic focus areas that will accelerate innovation in engine design to meet national goals in transportation efficiency. The U.S. has reached a pivotal moment when pressures of energy security, climate change, and economic competitiveness converge. Oil prices remain volatile and have exceeded $100 per barrel twice in five years. At these prices, the U.S. spends $1 billion per day on imported oil to meet our energy demands. Because the transportation sector accountsmore » for two-thirds of our petroleum use, energy security is deeply entangled with our transportation needs. At the same time, transportation produces one-quarter of the nation’s carbon dioxide output. Increasing the efficiency of internal combustion engines is a technologically proven and cost-effective approach to dramatically improving the fuel economy of the nation’s fleet of vehicles in the near- to mid-term, with the corresponding benefits of reducing our dependence on foreign oil and reducing carbon emissions. Because of their relatively low cost, high performance, and ability to utilize renewable fuels, internal combustion engines—including those in hybrid vehicles—will continue to be critical to our transportation infrastructure for decades. Achievable advances in engine technology can improve the fuel economy of automobiles by over 50% and trucks by over 30%. Achieving these goals will require the transportation sector to compress its product development cycle for cleaner, more efficient engine technologies by 50% while simultaneously exploring innovative design space. Concurrently, fuels will also be evolving, adding another layer of complexity and further highlighting the need for efficient product development cycles. Current design processes, using “build and test” prototype engineering, will

An Overview of Low-Emission Combustion Research at NASA Glenn

NASA Technical Reports Server (NTRS)

Reddy, Dhanireddy R.; Lee, Chi-Ming

2016-01-01

An overview of research efforts at NASA Glenn Research Center (GRC) in low-emission combustion technology that have made a significant impact on the nitrogen oxides (NOx) emission reduction in aircraft propulsion is presented. The technology advancements and their impact on aircraft emissions are discussed in the context of NASA's Aeronautics Research Mission Directorate (ARMD) high-level goals in fuel burn, noise and emission reductions. The highlights of the research presented here show how the past and current efforts laid the foundation for the engines that are flying today as well as how the continued technology advancements will significantly influence the next generation of aviation propulsion system designs.

Periodic equivalence ratio modulation method and apparatus for controlling combustion instability

DOEpatents

Richards, George A.; Janus, Michael C.; Griffith, Richard A.

2000-01-01

The periodic equivalence ratio modulation (PERM) method and apparatus significantly reduces and/or eliminates unstable conditions within a combustion chamber. The method involves modulating the equivalence ratio for the combustion device, such that the combustion device periodically operates outside of an identified unstable oscillation region. The equivalence ratio is modulated between preselected reference points, according to the shape of the oscillation region and operating parameters of the system. Preferably, the equivalence ratio is modulated from a first stable condition to a second stable condition, and, alternatively, the equivalence ratio is modulated from a stable condition to an unstable condition. The method is further applicable to multi-nozzle combustor designs, whereby individual nozzles are alternately modulated from stable to unstable conditions. Periodic equivalence ratio modulation (PERM) is accomplished by active control involving periodic, low frequency fuel modulation, whereby low frequency fuel pulses are injected into the main fuel delivery. Importantly, the fuel pulses are injected at a rate so as not to affect the desired time-average equivalence ratio for the combustion device.

Transient flow combustion

NASA Technical Reports Server (NTRS)

Tacina, R. R.

1984-01-01

Non-steady combustion problems can result from engine sources such as accelerations, decelerations, nozzle adjustments, augmentor ignition, and air perturbations into and out of the compressor. Also non-steady combustion can be generated internally from combustion instability or self-induced oscillations. A premixed-prevaporized combustor would be particularly sensitive to flow transients because of its susceptability to flashback-autoignition and blowout. An experimental program, the Transient Flow Combustion Study is in progress to study the effects of air and fuel flow transients on a premixed-prevaporized combustor. Preliminary tests performed at an inlet air temperature of 600 K, a reference velocity of 30 m/s, and a pressure of 700 kPa. The airflow was reduced to 1/3 of its original value in a 40 ms ramp before flashback occurred. Ramping the airflow up has shown that blowout is more sensitive than flashback to flow transients. Blowout occurred with a 25 percent increase in airflow (at a constant fuel-air ratio) in a 20 ms ramp. Combustion resonance was found at some conditions and may be important in determining the effects of flow transients.

Droplet evaporation and combustion in a liquid-gas multiphase system

NASA Astrophysics Data System (ADS)

Muradoglu, Metin; Irfan, Muhammad

2017-11-01

Droplet evaporation and combustion in a liquid-gas multiphase system are studied computationally using a front-tracking method. One field formulation is used to solve the flow, energy and species equations with suitable jump conditions. Both phases are assumed to be incompressible; however, the divergence-free velocity field condition is modified to account for the phase change at the interface. Both temperature and species gradient driven phase change processes are simulated. Extensive validation studies are performed using the benchmark cases: The Stefan and the sucking interface problems, d2 law and wet bulb temperature comparison with the psychrometric chart values. The phase change solver is then extended to incorporate the burning process following the evaporation as a first step towards the development of a computational framework for spray combustion. We used detailed chemistry, variable transport properties and ideal gas behaviour for a n-heptane droplet combustion; the chemical kinetics being handled by the CHEMKIN. An operator-splitting approach is used to advance temperature and species mass fraction in time. The numerical results of the droplet burning rate, flame temperature and flame standoff ratio show good agreement with the experimental and previous numeric.

Experimental investigation of wood combustion in a fixed bed with hot air

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

Markovic, Miladin, E-mail: m.markovic@utwente.nl; Bramer, Eddy A.; Brem, Gerrit

Highlights: • Upward combustion is a new combustion concept with ignition by hot primary air. • Upward combustion has three stages: short drying, rapid devolatilization and char combustion. • Variation of fuel moisture and inert content have little influence on the combustion. • Experimental comparison between conventional and upward combustion is presented. - Abstract: Waste combustion on a grate with energy recovery is an important pillar of municipal solid waste (MSW) management in the Netherlands. In MSW incinerators fresh waste stacked on a grate enters the combustion chamber, heats up by radiation from the flame above the layer and ignitionmore » occurs. Typically, the reaction zone starts at the top of the waste layer and propagates downwards, producing heat for drying and devolatilization of the fresh waste below it until the ignition front reaches the grate. The control of this process is mainly based on empiricism. MSW is a highly inhomogeneous fuel with continuous fluctuating moisture content, heating value and chemical composition. The resulting process fluctuations may cause process control difficulties, fouling and corrosion issues, extra maintenance, and unplanned stops. In the new concept the fuel layer is ignited by means of preheated air (T > 220 °C) from below without any external ignition source. As a result a combustion front will be formed close to the grate and will propagate upwards. That is why this approach is denoted by upward combustion. Experimental research has been carried out in a batch reactor with height of 4.55 m, an inner diameter of 200 mm and a fuel layer height up to 1 m. Due to a high quality two-layer insulation adiabatic conditions can be assumed. The primary air can be preheated up to 350 °C, and the secondary air is distributed via nozzles above the waste layer. During the experiments, temperatures along the height of the reactor, gas composition and total weight decrease are continuously monitored. The

Investigation of the combustion kinetics and polycyclic aromatic hydrocarbon emissions from polycaprolactone combustion.

PubMed

Chien, Y C; Yang, S H

2013-01-01

Polycaprolactone (PCL) is one of the most attractive biodegradable plastics that has been widely used in medicine and agriculture fields. Because of the large increase in biodegradable plastics usage, the production of waste biodegradable plastics will be increasing dramatically, producing a growing environmental problem. Generally, waste PCL is collected along with municipal solid wastes and then incinerated. This study investigates the combustion kinetics and emission factors of 16 US Environmental Protection Agency (EPA) priority polycyclic aromatic hydrocarbons (PAHs) in the PCL combustion. Experimentally, two reactions are involved in the PCL combustion process, possibly resulting in the emission of carbon dioxide, propanal, protonated caprolactone and very small amounts of PAH produced by incomplete combustion. The intermediate products may continuously be oxidized to form CO2. The emission factors for 16 US EPA priority PAHs are n.d. -2.95 microg/g, which are much lower than those of poly lactic acid and other plastics combustion. The conversion of PCL is 100%. Results from this work suggest that combustion is a good choice for the waste PCL disposal.

Combustion research for gas turbine engines

NASA Technical Reports Server (NTRS)

Mularz, E. J.; Claus, R. W.

1985-01-01

Research on combustion is being conducted at Lewis Research Center to provide improved analytical models of the complex flow and chemical reaction processes which occur in the combustor of gas turbine engines and other aeropropulsion systems. The objective of the research is to obtain a better understanding of the various physical processes that occur in the gas turbine combustor in order to develop models and numerical codes which can accurately describe these processes. Activities include in-house research projects, university grants, and industry contracts and are classified under the subject areas of advanced numerics, fuel sprays, fluid mixing, and radiation-chemistry. Results are high-lighted from several projects.

NASA Microgravity Combustion Science Program

NASA Technical Reports Server (NTRS)

King, Merrill K.

1997-01-01

Combustion is a key element of many critical technologies used by contemporary society. For example, electric power production, home heating, surface and air transportation, space propulsion, and materials synthesis all utilize combustion as a source of energy. Yet, although combustion technology is vital to our standard of living, it poses great challenges to maintaining a habitable environment. For example, pollutants, atmospheric change and global warming, unwanted fires and explosions, and the incineration of hazardous wastes are major problem areas which would benefit from improved understanding of combustion. Effects of gravitational forces impede combustion studies more than most other areas of science since combustion involves production of high-temperature gases whose low density results in buoyant motion, vastly complicating the execution and interpretation of experiments. Effects of buoyancy are so ubiquitous that their enormous negative impact on the rational development of combustion science is generally not recognized. Buoyant motion also triggers the onset of turbulence, yielding complicating unsteady effects. Finally, gravity forces cause particles and drops to settle, inhibiting deconvoluted studies of heterogeneous flames important to furnace, incineration and power generation technologies. Thus, effects of buoyancy have seriously limited our capabilities to carry out 'clean' experiments needed for fundamental understanding of flame phenomena. Combustion scientists can use microgravity to simplify the study of many combustion processes, allowing fresh insights into important problems via a deeper understanding of elemental phenomena also found in Earth-based combustion processes and to additionally provide valuable information concerning how fires behave in microgravity and how fire safety on spacecraft can be enhanced.

Characterization of Combustion and Emission of Several Kinds of Herbaceous Biomass Pellets in a Circulating Fluidized Bed Combustor

NASA Astrophysics Data System (ADS)

Li, S. Y.; Teng, H. P.; Jiao, W. H.; Shang, L. L.; Lu, Q. G.

Characterizations of combustion and emission of four kinds of herbaceous biomass pellets were investigated in a 0.15 MWt circulating fluidized bed. Corn stalk, wheat stalk, cotton stalk and king grass, which are typical herbaceous biomass in China, were chosen for this study. Temperature profile, emission in flue gas and agglomeration were studied by changing the combustion temperature between 750°C and 880°C. The combustion efficiencies are in the range from 97.4% to 99.4%, which are relatively high due to the homogeneous temperature profiles and good circulating fluidization of bed material. Suitable combustion temperatures for the different herbaceous biomass are mainly depended on the emission and bed agglomeration. SO2 and HCl concentrations in flue gas are in direct proportion to the sulfur and chlorine contents of the herbaceous biomass. Agglomeration at the cyclone leg and the loop seal is the main reason for defluidization in the CFB combustor.

The Multi-User Droplet Combustion Apparatus: the Development and Integration Concept for Droplet Combustion Payloads in the Fluids and Combustion Facility Combustion Integrated Rack

NASA Astrophysics Data System (ADS)

Myhre, C. A.

2002-01-01

The Multi-user Droplet Combustion Apparatus (MDCA) is a multi-user facility designed to accommodate four different droplet combustion science experiments. The MDCA will conduct experiments using the Combustion Integrated Rack (CIR) of the NASA Glenn Research Center's Fluids and Combustion Facility (FCF). The payload is planned for the International Space Station. The MDCA, in conjunction with the CIR, will allow for cost effective extended access to the microgravity environment, not possible on previous space flights. It is currently in the Engineering Model build phase with a planned flight launch with CIR in 2004. This paper provides an overview of the capabilities and development status of the MDCA. The MDCA contains the hardware and software required to conduct unique droplet combustion experiments in space. It consists of a Chamber Insert Assembly, an Avionics Package, and a multiple array of diagnostics. Its modular approach permits on-orbit changes for accommodating different fuels, fuel flow rates, soot sampling mechanisms, and varying droplet support and translation mechanisms to accommodate multiple investigations. Unique diagnostic measurement capabilities for each investigation are also provided. Additional hardware provided by the CIR facility includes the structural support, a combustion chamber, utilities for the avionics and diagnostic packages, and the fuel mixing capability for PI specific combustion chamber environments. Common diagnostics provided by the CIR will also be utilized by the MDCA. Single combustible fuel droplets of varying sizes, freely deployed or supported by a tether are planned for study using the MDCA. Such research supports how liquid-fuel-droplets ignite, spread, and extinguish under quiescent microgravity conditions. This understanding will help us develop more efficient energy production and propulsion systems on Earth and in space, deal better with combustion generated pollution, and address fire hazards associated with

Study on atomization and combustion characteristics of LOX/methane pintle injectors

NASA Astrophysics Data System (ADS)

Fang, Xin-xin; Shen, Chi-bing

2017-07-01

Influences of main structural parameters of the LOX/methane pintle injectors on atomization cone angles and combustion performances were studied by experiments and numerical simulation respectively. In addition, improvement was brought up to the structure of the pintle injectors and combustion flow fields of two different pintle engines were obtained. The results indicate that, with increase of the gas-liquid mass flow ratio, the atomization cone angle decreases. In the condition of the same gas-liquid mass flow ratio, as the thickness of the LOX-injection gap grows bigger, the atomization cone angle becomes smaller. In the opposite, when the half cone angle of the LOX-injection gap grows bigger, the atomization cone angle becomes bigger. Moreover, owing to the viscous effects of the pintle tip, with increase of the 'skip distance', the atomization cone angle gets larger. Two big recirculation zones in the combustor lead to combustion stability of the pintle engines. When the value of the non-dimensional 'skip distance' is near 1, the combustion efficiency of the pintle engines is the highest. Additionally, pintle engines with LOX injected in quadrangular slots can acquire better mixing efficiency of the propellants and higher combustion efficiency as the gas methane can pass through the adjacent slots. However, the annular-channel type of pintle injectors has an 'enclosed' area near the pintle tip which has a great negative influence on the combustion efficiency.

Small-scale, self-propagating combustion realized with on-chip porous silicon.

PubMed

Piekiel, Nicholas W; Morris, Christopher J

2015-05-13

For small-scale energy applications, energetic materials represent a high energy density source that, in certain cases, can be accessed with a very small amount of energy input. Recent advances in microprocessing techniques allow for the implementation of a porous silicon energetic material onto a crystalline silicon wafer at the microscale; however, combustion at a small length scale remains to be fully investigated, particularly with regards to the limitations of increased relative heat loss during combustion. The present study explores the critical dimensions of an on-chip porous silicon energetic material (porous silicon + sodium perchlorate (NaClO4)) required to propagate combustion. We etched ∼97 μm wide and ∼45 μm deep porous silicon channels that burned at a steady rate of 4.6 m/s, remaining steady across 90° changes in direction. In an effort to minimize the potential on-chip footprint for energetic porous silicon, we also explored the minimum spacing between porous silicon channels. We demonstrated independent burning of porous silicon channels at a spacing of <40 μm. Using this spacing, it was possible to have a flame path length of >0.5 m on a chip surface area of 1.65 cm(2). Smaller porous silicon channels of ∼28 μm wide and ∼14 μm deep were also utilized. These samples propagated combustion, but at times, did so unsteadily. This result may suggest that we are approaching a critical length scale for self-propagating combustion in a porous silicon energetic material.

Environmental aspects of fossil fuels combustion in Poland

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

Sekula, R.

Combustion of fossil fuels is the main source of energy in Poland. Coal will probably remain the basic fuel for energy generation for many years. The principal problems connected with fuel utilization in Poland are presented in this study. The major pollutants and ways to reduce air pollution are also described. Data are based on the report of the Polish Academy of Sciences.

Combustible and incombustible speciation of Cl and S in various components of municipal solid waste.

PubMed

Watanabe, Nobuhisa; Yamamoto, Osamu; Sakai, Mamoru; Fukuyama, Johji

2004-01-01

Chlorine (Cl) and sulfur (S) in municipal solid waste (MSW) are important reactive elements during combustion. They generate the acidic pollutants HCl and SOx, and, furthermore, produce and suppress organic chlorinated compounds. Nevertheless, few practical reports about Cl and S content in MSW have been published. In combustion and recycling processes, both combustible Cl and S, and incombustible Cl and S species are equally important. This paper presents the results of a comprehensive study about combustible and incombustible Cl and S in MSW components, including kitchen garbage, paper, textiles, wood and leaves, plastics and small chips. By integrating this collected data with data about MSW composition, not only the overall content of Cl and S in MSW, but also the origins of both combustible and incombustible Cl and S were estimated. The average Cl content in bulk MSW was 3.7 g/kg of raw MSW, of which 2.7 and 1.0 g/kg were combustible and incombustible, respectively. The Cl contribution from plastics was 76% and 27% with respect to combustible and incombustible states. The average S content in bulk MSW was 0.81 g/kg of raw MSW, of which 0.46 g/kg was combustible and 0.35 g/kg was incombustible. Combustible S was mainly due to synthetic textiles, while incombustible S was primarily from paper.

Comparing the greenhouse gas emissions from three alternative waste combustion concepts

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

Vainikka, Pasi, E-mail: pasi.vainikka@vtt.fi; Tsupari, Eemeli; Sipilae, Kai

2012-03-15

Highlights: Black-Right-Pointing-Pointer Significant GHG reductions are possible by efficient WtE technologies. Black-Right-Pointing-Pointer CHP and high power-to-heat ratio provide significant GHG savings. Black-Right-Pointing-Pointer N{sub 2}O and coal mine type are important in LCA GHG emissions of FBC co-combustion. Black-Right-Pointing-Pointer Substituting coal and fuel oil by waste is beneficial in electricity and heat production. Black-Right-Pointing-Pointer Substituting natural gas by waste may not be reasonable in CHP generation. - Abstract: Three alternative condensing mode power and combined heat and power (CHP) waste-to-energy concepts were compared in terms of their impacts on the greenhouse gas (GHG) emissions from a heat and power generation system.more » The concepts included (i) grate, (ii) bubbling fluidised bed (BFB) and (iii) circulating fluidised bed (CFB) combustion of waste. The BFB and CFB take advantage of advanced combustion technology which enabled them to reach electric efficiency up to 35% and 41% in condensing mode, respectively, whereas 28% (based on the lower heating value) was applied for the grate fired unit. A simple energy system model was applied in calculating the GHG emissions in different scenarios where coal or natural gas was substituted in power generation and mix of fuel oil and natural gas in heat generation by waste combustion. Landfilling and waste transportation were not considered in the model. GHG emissions were reduced significantly in all of the considered scenarios where the waste combustion concepts substituted coal based power generation. With the exception of condensing mode grate incinerator the different waste combustion scenarios resulted approximately in 1 Mton of fossil CO{sub 2}-eq. emission reduction per 1 Mton of municipal solid waste (MSW) incinerated. When natural gas based power generation was substituted by electricity from the waste combustion significant GHG emission reductions were not

Impacts of Combustion Conditions and Photochemical Processing on the Light Absorption of Biomass Combustion Aerosol.

PubMed

Martinsson, J; Eriksson, A C; Nielsen, I Elbæk; Malmborg, V Berg; Ahlberg, E; Andersen, C; Lindgren, R; Nyström, R; Nordin, E Z; Brune, W H; Svenningsson, B; Swietlicki, E; Boman, C; Pagels, J H

2015-12-15

The aim was to identify relationships between combustion conditions, particle characteristics, and optical properties of fresh and photochemically processed emissions from biomass combustion. The combustion conditions included nominal and high burn rate operation and individual combustion phases from a conventional wood stove. Low temperature pyrolysis upon fuel addition resulted in "tar-ball" type particles dominated by organic aerosol with an absorption Ångström exponent (AAE) of 2.5-2.7 and estimated Brown Carbon contributions of 50-70% to absorption at the climate relevant aethalometer-wavelength (520 nm). High temperature combustion during the intermediate (flaming) phase was dominated by soot agglomerates with AAE 1.0-1.2 and 85-100% of absorption at 520 nm attributed to Black Carbon. Intense photochemical processing of high burn rate flaming combustion emissions in an oxidation flow reactor led to strong formation of Secondary Organic Aerosol, with no or weak absorption. PM1 mass emission factors (mg/kg) of fresh emissions were about an order of magnitude higher for low temperature pyrolysis compared to high temperature combustion. However, emission factors describing the absorption cross section emitted per kg of fuel consumed (m(2)/kg) were of similar magnitude at 520 nm for the diverse combustion conditions investigated in this study. These results provide a link between biomass combustion conditions, emitted particle types, and their optical properties in fresh and processed plumes which can be of value for source apportionment and balanced mitigation of biomass combustion emissions from a climate and health perspective.

Combustion in microgravity: The French contribution

NASA Astrophysics Data System (ADS)

Prud'homme, Roger; Legros, Guillaume; Torero, José L.

2017-01-01

Microgravity (drop towers, parabolic flights, sounding rockets and space stations) are particularly relevant to combustion problems given that they show high-density gradients and in many cases weak forced convection. For some configurations where buoyancy forces result in complex flow fields, microgravity leads to ideal conditions that correspond closely to canonical problems, e.g., combustion of a spherical droplet in a far-field still atmosphere, Emmons' problem for flame spreading over a solid flat plate, deflagration waves, etc. A comprehensive chronological review on the many combustion studies in microgravity was written first by Law and Faeth (1994) and then by F.A. Williams (1995). Later on, new recommendations for research directions have been delivered. In France, research has been managed and supported by CNES and CNRS since the creation of the microgravity research group in 1992. At this time, microgravity research and future activities contemplated the following: Droplets: the "D2 law" has been well verified and high-pressure behavior of droplet combustion has been assessed. The studies must be extended in two main directions: vaporization in mixtures near the critical line and collective effects in dense sprays. Flame spread: experiments observed blue flames governed by diffusion that are in accordance with Emmons' theory. Convection-dominated flames showed significant departures from the theory. Some theoretical assumptions appeared controversial and it was noted that radiation effects must be considered, especially when regarding the role of soot production in quenching. Heterogeneous flames: two studies are in progress, one in Poitiers and the other in Marseilles, about flame/suspension interactions. Premixed and triple flames: the knowledge still needs to be complemented. Triple flames must continue to be studied and understanding of "flame balls" still needs to be addressed.

Reducing mode circulating fluid bed combustion

DOEpatents

Lin, Yung-Yi; Sadhukhan, Pasupati; Fraley, Lowell D.; Hsiao, Keh-Hsien

1986-01-01

A method for combustion of sulfur-containing fuel in a circulating fluid bed combustion system wherein the fuel is burned in a primary combustion zone under reducing conditions and sulfur captured as alkaline sulfide. The reducing gas formed is oxidized to combustion gas which is then separated from solids containing alkaline sulfide. The separated solids are then oxidized and recycled to the primary combustion zone.

Analytical investigation of thermal barrier coatings for advanced power generation combustion turbines

NASA Technical Reports Server (NTRS)

Amos, D. J.

1977-01-01

An analytical evaluation was conducted to determine quantitatively the improvement potential in cycle efficiency and cost of electricity made possible by the introduction of thermal barrier coatings to power generation combustion turbine systems. The thermal barrier system, a metallic bond coat and yttria stabilized zirconia outer layer applied by plasma spray techniques, acts as a heat insulator to provide substantial metal temperature reductions below that of the exposed thermal barrier surface. The study results show the thermal barrier to be a potentially attractive means for improving performance and reducing cost of electricity for the simple, recuperated, and combined cycles evaluated.

Bioaccumulation and effects of metals and trace elements from aquatic disposal of coal combustion residues: recent advances and recommendations for further study.

PubMed

Rowe, Christopher L

2014-07-01

Advances have been made recently in assessing accumulation and effects of coal combustion residues (CCR). I provide a brief review of recent advancements, provide a tabulated summary of results of recent work, and put forth recommendations for future studies. One advancement is that mercury accumulation has begun to receive (limited) attention, whereas it had rarely been considered in the past. Additionally, some constituents of CCR have been shown to be accumulated by adults and transferred to offspring, sometimes compromising offspring health. Studies have demonstrated that amphibians, possessing complex life cycles, may accumulate and transfer some contaminants to terrestrial systems. Some study has been given to molecular and cellular effects of CCR exposure, although these studies have been limited to invertebrates. Population models have also been applied to CCR affected systems and have shown that CCR may affect animal populations under some conditions. In light of these advancements, there are several topics that require further assessment. First, more attention to Hg and its dynamics in CCR affected systems is warranted. Hg can be highly accumulative and toxic under some conditions and may interact with other components of CCR (notably Se), perhaps altering accumulation and effects of the contaminant mixtures. Second, further investigation of maternal transfer and effects of CCR contaminants need to be conducted. These studies could benefit from incorporation of quantitative models to project impacts on populations. Finally, more attention to the organic constituents of CCR (PAHs) is required, as a focus on inorganic compounds only may restrict our knowledge of contaminant dynamics and effects as a whole. While further studies will shed light on some chemical and biological nuances of exposure and effect, information available to date from numerous study sites implicates CCR as a bulk effluent that presents risks of bioaccumulation and effects on organisms

Combustion Mechanisms of Solids

DTIC Science & Technology

1992-02-24

ELEMENT NO. NO NO ACCESSION NO Arlington, VA 22217-5000 11 TITLE (include Security Classification) COMBUSTION MECHANISMS OF SOLIDS 12. PERSONAL AUTHOR(S...FIELD GROUP I SUB-GROUP COMBUSTION , SOLID PROPELLANT 19 ABSTRACT (Continue on reverse if necessary and identify by block number) This report...ingredients tested (AP, AN, PBAN, NMMO and BAMO-THF). Ingredient combustion behavior was studied by the edge burning sandwich method using sandwiches

Combustion Processes Indoors: a Source of High OH Radical Concentrations Through the Photolysis of Hono

NASA Astrophysics Data System (ADS)

Bartolomei, V.; Gomez Alvarez, E.; Glor, M.; Gligorovski, S.; Temime-Roussel, B.; Quivet, E.; Strekowski, R.; Zetzsch, C.; Held, A. B.; Wortham, H.

2013-12-01

and span (wavelength distribution) indoors have been performed, which had been identified as a clear flaw in our knowledge restricting the advancement of indoor air quality models. OH concentration levels have been determined using d9-butanol as tracer, using the OH clock determination procedure by PTR-MS-TOF. The OH radical concentration was investigated using different light intensities representative from indoor conditions, both natural and artificial and also different levels of RH. The PSS model has been performed in order to evaluate the contribution of different sources to the OH radical concentrations indoors under these conditions. The obtained results from the PSS model clearly indicate that the main source of OH radical indoors under combustion conditions is the photolysis of HONO under typical indoor irradiation conditions. REFERENCES Gómez Alvarez E, Wortham H, Strekowski R, Zetzsch C, Gligorovski S (2012) Atmospheric photo-sensitized heterogeneous and multiphase reactions: From outdoors to indoors, Environ. Sci. Technol. 46, 1955-1963. Gómez Alvarez, E.; Amedro, D.; Afif, C. ; Gligorovski, S.; Schoemacker , C.; Fittschen, C. ; Doussin, J. F.; Wortham, H. (2013) Unexpectedly high indoor hydroxyl radical concentrations associated with nitrous acid. Proc. Natl. Acad. Sci. USA Accepted.

The effect of low ceiling on the external combustion of the cabin fire

NASA Astrophysics Data System (ADS)

Su, Shichuan; Chen, Changyun; Wang, Liang; Wei, Chengyin; Cui, Haibing; Guo, Chengyu

2018-06-01

External combustion is a phenomenon where the flame flares out of the window and burns outside. Because of the particularity of the ship's cabin structure, there is a great danger in the external combustion. In this paper, the numerical calculation and analysis of three kinds of low ceiling ship cabin fire are analyzed based on the large eddy numerical simulation technique. Through the analysis of temperature, flue gas velocity, heat flux density and so on, the external combustion phenomenon of fire development is calculated. The results show that when external combustion occurs, the amount of fuel escaping decreases with the roof height. The temperature above the window increases with the height of the ceiling. The heat flux density in the external combustion flame is mainly provided by radiation, and convection is only a small part; In the plume area there is a time period, in this time period, the convective heat flux density is greater than the radiation heat flux, this time with the ceiling height increases. No matter which ceiling height, the external combustion will seriously damage the structure of the ship after a certain period of time. The velocity distribution of the three roof is similar, but with the height of the ceiling, the area size is also increasing.

A Study on the Effect of Stratified Mixture Formation on Combustion Characteristics in a Constant Volume Combustion Chamber

NASA Astrophysics Data System (ADS)

Lee, Kihyung; Lee, Changhee; Jeoung, Haeyoung

It is well known that a lean burn engine caused by stratified mixture formation has many kinds of advantages to combustion characteristics, such as higher thermal efficiency and lower CO, NOx levels than conventional homogeneous mixture combustion. Although this combustion can achieve low fuel consumption, it produces much unburned hydrocarbon and soot because of inhomogeneity of the charge mixture in the combustion chamber. Therefore, it is necessary to investigate the effect of mixture formation on combustion characteristics in order to obtain the stable lean combustion. In this paper, fundamental studies for stratified combustion were carried out using a constant volume combustion chamber. The effect of mixture formation on the combustion characteristics in the chamber was examined experimentally. In addition, the effect of turbulence on stratified charge combustion process was observed by schlieren photography. From this study, as the swirl intensity increases, (Sv)max is rapidly enhanced and the period of combustion is shortened. We also find that the stratification degree can be quantified by using burning velocity and it was controlled by induced air pressure and turbulent intensity.

Combustion of liquid-fuel droplets in supercritical conditions

NASA Technical Reports Server (NTRS)

Shuen, J. S.; Yang, Vigor; Hsaio, C. C.

1992-01-01

A comprehensive analysis of liquid-fuel droplet combustion in both subcritical and supercritical environments has been conducted. The formulation is based on the complete conservation equations for both gas and liquid phases, and accommodates variable thermophysical properties, finite-rate chemical kinetics, and a full treatment of liquid-vapor phase equilibrium at the drop surface. The governing equations and associated interfacial boundary conditions are solved numerically using a fully coupled, implicit scheme with the dual time-stepping integration technique. The model is capable of treating the entire droplet history, including the transition from the subcritical to supercritical state. As a specific example, the combustion of n-pentane fuel droplets in air is studied for pressures in the range of 5-140 atm. Results indicate that the ambient gas pressure exerts significant control of droplet gasification and burning processes through its influence on fluid transport, gas-liquid interfacial thermodynamics, and chemical reactions. The droplet gasification rate increases progressively with pressure. However, the data for the overall burnout time exhibit a considerable change in the combustion mechanism at the critical pressure, mainly as a result of reduced mass diffusivity and latent heat of vaporization with increased pressure.

Tabulated Combustion Model Development For Non-Premixed Flames

NASA Astrophysics Data System (ADS)

Kundu, Prithwish

Turbulent non-premixed flames play a very important role in the field of engineering ranging from power generation to propulsion. The coupling of fluid mechanics and complicated combustion chemistry of fuels pose a challenge for the numerical modeling of these type of problems. Combustion modeling in Computational Fluid Dynamics (CFD) is one of the most important tools used for predictive modeling of complex systems and to understand the basic fundamentals of combustion. Traditional combustion models solve a transport equation of each species with a source term. In order to resolve the complex chemistry accurately it is important to include a large number of species. However, the computational cost is generally proportional to the cube of number of species. The presence of a large number of species in a flame makes the use of CFD computationally expensive and beyond reach for some applications or inaccurate when solved with simplified chemistry. For highly turbulent flows, it also becomes important to incorporate the effects of turbulence chemistry interaction (TCI). The aim of this work is to develop high fidelity combustion models based on the flamelet concept and to significantly advance the existing capabilities. A thorough investigation of existing models (Finite-rate chemistry and Representative Interactive Flamelet (RIF)) and comparative study of combustion models was done initially on a constant volume combustion chamber with diesel fuel injection. The CFD modeling was validated with experimental results and was also successfully applied to a single cylinder diesel engine. The effect of number of flamelets on the RIF model and flamelet initialization strategies were studied. The RIF model with multiple flamelets is computationally expensive and a model was proposed on the frame work of RIF. The new model was based on tabulated chemistry and incorporated TCI effects. A multidimensional tabulated chemistry database generation code was developed based on the 1

Combustion of horse manure for heat production.

PubMed

Lundgren, J; Pettersson, E

2009-06-01

The main objectives of this paper have been to evaluate the use of horse manure and wood-shavings as a fuel for heat production and to provide sets of data on the chemical composition, ash characteristics and ash forming elements of the fuel. Another objective has been to investigate the possibility to use the ash as fertiliser by analysing the heavy metal and nutrient contents. The results showed that the fuel is well suited for combustion for heat production causing low emissions of products of incomplete combustion. The emissions of NO(x) were however high due to the high content of fuel bound nitrogen. Emissions of CO and NO(x) were typically in the range of 30-150 mg/Nm(3) and 280-350 mg/Nm(3) at 10 vol% O(2), respectively. The analysis of the ash showed on sufficiently low concentration of heavy metals to allow recycling.

The Effect of Gravity on the Combustion Synthesis of Porous Ceramics and Metal Matrix Composites

NASA Technical Reports Server (NTRS)

Moore, J. J.; Woodger, T. C.; Wolanski, T.; Yi, H. C.; Guigne, J. Y.

1997-01-01

Combustion synthesis (self propagating, high temperature synthesis-SHS) is a novel technique that is capable of producing many advanced materials. The ignition temperature (Tig) of such combustion synthesis reactions is often coincident with that of the lowest melting point reactant. The resultant liquid metal wets and spreads around the other solid reactant particles of higher melting points, thereby improving the reactant contact and kinetics, followed by formation of the required compounds. This ignition initiates a combustion propagating wave whose narrow reaction front rapidly travels through the reactants. Since this process is highly exothermic, the heat released by combustion often melts the reactant particles ahead of the combustion front and ignites the adjacent reactant layer, resulting in a self-sustaining reaction. Whenever a fluid phase (liquid or gas) is generated by the reaction system, gravity-driven phenomena can occur. Such phenomena include convective flows of fluid by conventional or unstable convection and settling of the higher density phases. A combustion process is often associated with various kinds of fluid flow. For instance, if the SHS reaction is carried out under inert or reactive gas atmospheres, or a volatile, e.g., B2O3, is deliberately introduced as a reactant, convective flows of the gas will occur due to a temperature gradient existing in the atmosphere when a combustion wave is initiated. The increased gas flow will produce a porous (or expanded) SHS product. Owing to the highly exothermic nature of many SHS reactions, liquid phase(s) can also form before, at, or after the combustion front. The huge temperature gradient at the combustion front can induce convective flows (conventional or unstable) of the liquid phase. Each of these types of convective fluid flow can change the combustion behavior of the synthesizing reaction, and, therefore, the resultant product microstructure. In addition, when two or more phases of different

New perspectives for advanced automobile diesel engines

NASA Technical Reports Server (NTRS)

Tozzi, L.; Sekar, R.; Kamo, R.; Wood, J. C.

1983-01-01

Computer simulation results are presented for advanced automobile diesel engine performance. Four critical factors for performance enhancement were identified: (1) part load preheating and exhaust gas energy recovery, (2) fast heat release combustion process, (3) reduction in friction, and (4) air handling system efficiency. Four different technology levels were considered in the analysis. Simulation results are compared in terms of brake specific fuel consumption and vehicle fuel economy in km/liter (miles per gallon). Major critical performance sensitivity areas are: (1) combustion process, (2) expander and compressor efficiency, and (3) part load preheating and compound system. When compared to the state of the art direct injection, cooled, automobile diesel engine, the advanced adiabatic compound engine concept showed the unique potential of doubling the fuel economy. Other important performance criteria such as acceleration, emissions, reliability, durability and multifuel capability are comparable to or better than current passenger car diesel engines.

Fluids and Combustion Facility: Combustion Integrated Rack Modal Model Correlation

NASA Technical Reports Server (NTRS)

McNelis, Mark E.; Suarez, Vicente J.; Sullivan, Timothy L.; Otten, Kim D.; Akers, James C.

2005-01-01

The Fluids and Combustion Facility (FCF) is a modular, multi-user, two-rack facility dedicated to combustion and fluids science in the US Laboratory Destiny on the International Space Station. FCF is a permanent facility that is capable of accommodating up to ten combustion and fluid science investigations per year. FCF research in combustion and fluid science supports NASA's Exploration of Space Initiative for on-orbit fire suppression, fire safety, and space system fluids management. The Combustion Integrated Rack (CIR) is one of two racks in the FCF. The CIR major structural elements include the International Standard Payload Rack (ISPR), Experiment Assembly (optics bench and combustion chamber), Air Thermal Control Unit (ATCU), Rack Door, and Lower Structure Assembly (Input/Output Processor and Electrical Power Control Unit). The load path through the rack structure is outlined. The CIR modal survey was conducted to validate the load path predicted by the CIR finite element model (FEM). The modal survey is done by experimentally measuring the CIR frequencies and mode shapes. The CIR model was test correlated by updating the model to represent the test mode shapes. The correlated CIR model delivery is required by NASA JSC at Launch-10.5 months. The test correlated CIR flight FEM is analytically integrated into the Shuttle for a coupled loads analysis of the launch configuration. The analysis frequency range of interest is 0-50 Hz. A coupled loads analysis is the analytical integration of the Shuttle with its cargo element, the Mini Payload Logistics Module (MPLM), in the Shuttle cargo bay. For each Shuttle launch configuration, a verification coupled loads analysis is performed to determine the loads in the cargo bay as part of the structural certification process.

Multi-stage combustion using nitrogen-enriched air

DOEpatents

Fischer, Larry E.; Anderson, Brian L.

2004-09-14

Multi-stage combustion technology combined with nitrogen-enriched air technology for controlling the combustion temperature and products to extend the maintenance and lifetime cycles of materials in contact with combustion products and to reduce pollutants while maintaining relatively high combustion and thermal cycle efficiencies. The first stage of combustion operates fuel rich where most of the heat of combustion is released by burning it with nitrogen-enriched air. Part of the energy in the combustion gases is used to perform work or to provide heat. The cooled combustion gases are reheated by additional stages of combustion until the last stage is at or near stoichiometric conditions. Additional energy is extracted from each stage to result in relatively high thermal cycle efficiency. The air is enriched with nitrogen using air separation technologies such as diffusion, permeable membrane, absorption, and cryogenics. The combustion method is applicable to many types of combustion equipment, including: boilers, burners, turbines, internal combustion engines, and many types of fuel including hydrogen and carbon-based fuels including methane and coal.

Advanced expander test bed program

NASA Technical Reports Server (NTRS)

Masters, A. I.; Mitchell, J. C.

1991-01-01

The Advanced Expander Test Bed (AETB) is a key element in NASA's Chemical Transfer Propulsion Program for development and demonstration of expander cycle oxygen/hydrogen engine technology component technology for the next space engine. The AETB will be used to validate the high-pressure expander cycle concept, investigate system interactions, and conduct investigations of advanced missions focused components and new health monitoring techniques. The split-expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust.

NASA Microgravity Combustion Science Program

NASA Technical Reports Server (NTRS)

King, Merrill K.

1999-01-01

Combustion has been a subject of increasingly vigorous scientific research for over a century, not surprising considering that combustion accounts for approximately 85% of the world's energy production and is a key element of many critical technologies used by contemporary society. Although combustion technology is vital to our standard of living, it also poses great challenges to maintaining a habitable environment. A major goal of combustion research is production of fundamental (foundational) knowledge that can be used in developing accurate simulations of complex combustion processes, replacing current "cut-and-try" approaches and allowing developers to improve the efficiency of combustion devices, to reduce the production of harmful emissions, and to reduce the incidence of accidental uncontrolled combustion. With full understanding of the physics and chemistry involved in a given combustion process, including details of the unit processes and their interactions, physically accurate models which can then be used for parametric exploration of new combustion domains via computer simulation can be developed, with possible resultant definition of radically different approaches to accomplishment of various combustion goals. Effects of gravitational forces on earth impede combustion studies more than they impede most other areas of science. The effects of buoyancy are so ubiquitous that we often do not appreciate the enormous negative impact that they have had on the rational development of combustion science. Microgravity offers potential for major gains in combustion science understanding in that it offers unique capability to establish the flow environment rather than having it dominated by uncontrollable (under normal gravity) buoyancy effects and, through this control, to extend the range of test conditions that can be studied. It cannot be emphasized too strongly that our program is dedicated to taking advantage of microgravity to untangle complications caused

Advanced Health Management System for the Space Shuttle Main Engine

NASA Technical Reports Server (NTRS)

Davidson, Matt; Stephens, John; Rodela, Chris

2006-01-01

Pratt & Whitney Rocketdyne, Inc., in cooperation with NASA-Marshall Space Flight Center (MSFC), has developed a new Advanced Health Management System (AHMS) controller for the Space Shuttle Main Engine (SSME) that will increase the probability of successfully placing the shuttle into the intended orbit and increase the safety of the Space Transportation System (STS) launches. The AHMS is an upgrade o the current Block II engine controller whose primary component is an improved vibration monitoring system called the Real-Time Vibration Monitoring System (RTVMS) that can effectively and reliably monitor the state of the high pressure turbomachinery and provide engine protection through a new synchronous vibration redline which enables engine shutdown if the vibration exceeds predetermined thresholds. The introduction of this system required improvements and modification to the Block II controller such as redesigning the Digital Computer Unit (DCU) memory and the Flight Accelerometer Safety Cut-Off System (FASCOS) circuitry, eliminating the existing memory retention batteries, installation of the Digital Signal Processor (DSP) technology, and installation of a High Speed Serial Interface (HSSI) with accompanying outside world connectors. Test stand hot-fire testing along with lab testing have verified successful implementation and is expected to reduce the probability of catastrophic engine failures during the shuttle ascent phase and improve safely by about 23% according to the Quantitative Risk Assessment System (QRAS), leading to a safer and more reliable SSME.

Space Station Freedom combustion research

NASA Technical Reports Server (NTRS)

Faeth, G. M.

1992-01-01

Extended operations in microgravity, on board spacecraft like Space Station Freedom, provide both unusual opportunities and unusual challenges for combustion science. On the one hand, eliminating the intrusion of buoyancy provides a valuable new perspective for fundamental studies of combustion phenomena. On the other hand, however, the absence of buoyancy creates new hazards of fires and explosions that must be understood to assure safe manned space activities. These considerations - and the relevance of combustion science to problems of pollutants, energy utilization, waste incineration, power and propulsion systems, and fire and explosion hazards, among others - provide strong motivation for microgravity combustion research. The intrusion of buoyancy is a greater impediment to fundamental combustion studies than to most other areas of science. Combustion intrinsically heats gases with the resulting buoyant motion at normal gravity either preventing or vastly complicating measurements. Perversely, this limitation is most evident for fundamental laboratory experiments; few practical combustion phenomena are significantly affected by buoyancy. Thus, we have never observed the most fundamental combustion phenomena - laminar premixed and diffusion flames, heterogeneous flames of particles and surfaces, low-speed turbulent flames, etc. - without substantial buoyant disturbances. This precludes rational merging of theory, where buoyancy is of little interest, and experiments, that always are contaminated by buoyancy, which is the traditional path for developing most areas of science. The current microgravity combustion program seeks to rectify this deficiency using both ground-based and space-based facilities, with experiments involving space-based facilities including: laminar premixed flames, soot processes in laminar jet diffusion flames, structure of laminar and turbulent jet diffusion flames, solid surface combustion, one-dimensional smoldering, ignition and flame

Mutagenicity assessment of aerosols in emissions from domestic combustion processes.

PubMed

Canha, Nuno; Lopes, Isabel; Vicente, Estela Domingos; Vicente, Ana M; Bandowe, Benjamin A Musa; Almeida, Susana Marta; Alves, Célia A

2016-06-01

Domestic biofuel combustion is one of the major sources of regional and local air pollution, mainly regarding particulate matter and organic compounds, during winter periods. Mutagenic and carcinogenic activity potentials of the ambient particulate matter have been associated with the fraction of polycyclic aromatic hydrocarbons (PAH) and their oxygenated (OPAH) and nitrogenated (NPAH) derivatives. This study aimed at assessing the mutagenicity potential of the fraction of this polycyclic aromatic compound in particles (PM10) from domestic combustion by using the Ames assays with Salmonella typhimurium TA98 and TA100. Seven biofuels, including four types of pellets and three agro-fuels (olive pit, almond shell and shell of pine nuts), were tested in an automatic pellet stove, and two types of wood (Pinus pinaster, maritime pine, and Eucalyptus globulus, eucalypt) were burned in a traditional wood stove. For this latter appliance, two combustion phases-devolatilisation and flaming/smouldering-were characterised separately. A direct-acting mutagenic effect for the devolatilisation phase of pine combustion and for both phases of eucalypt combustion was found. Almond shell revealed a weak direct-acting mutagenic effect, while one type of pellets, made of recycled wastes, and pine (devolatilisation) presented a cytotoxic effect towards strain TA100. Compared to the manually fired appliance, the automatic pellet stove promoted lower polyaromatic mutagenic emissions. For this device, only two of the studied biofuels presented a weak mutagenic or cytotoxic potential.

HSR combustion analytical research

NASA Technical Reports Server (NTRS)

Nguyen, H. Lee

1992-01-01

Increasing the pressure and temperature of the engines of a new generation of supersonic airliners increases the emissions of nitrogen oxides (NO(x)) to a level that would have an adverse impact on the Earth's protective ozone layer. In the process of evolving and implementing low emissions combustor technologies, NASA LeRC has pursued a combustion analysis code program to guide combustor design processes, to identify potential concepts of the greatest promise, and to optimize them at low cost, with short turnaround time. The computational analyses are evaluated at actual engine operating conditions. The approach is to upgrade and apply advanced computer programs for gas turbine applications. Efforts were made in further improving the code capabilities for modeling the physics and the numerical methods of solution. Then test cases and measurements from experiments are used for code validation.

Simultaneous identification of multi-combustion-intermediates of alkanol-air flames by femtosecond filament excitation for combustion sensing

PubMed Central

Li, Helong; Chu, Wei; Xu, Huailiang; Cheng, Ya; Chin, See-Leang; Yamanouchi, Kaoru; Sun, Hong-Bo

2016-01-01

Laser filamentation produced by the propagation of intense laser pulses in flames is opening up new possibility in application to combustion diagnostics that can provide useful information on understanding combustion processes, enhancing combustion efficiency and reducing pollutant products. Here we present simultaneous identification of multiple combustion intermediates by femtosecond filament excitation for five alkanol-air flames fueled by methanol, ethanol, n-propanol, n-butanol, and n-pentanol. We experimentally demonstrate that the intensities of filament-induced photoemission signals from the combustion intermediates C, C2, CH, CN increase with the increasing number of carbons in the fuel molecules, and the signal ratios between the intermediates (CH/C, CH/C2, CN/C, CH/C2, CN/CH) are different for different alkanol combustion flames. Our observation provides a way for sensing multiple combustion components by femtosecond filament excitation in various combustion conditions that strongly depend on the fuel species. PMID:27250021

Simultaneous identification of multi-combustion-intermediates of alkanol-air flames by femtosecond filament excitation for combustion sensing.

PubMed

Li, Helong; Chu, Wei; Xu, Huailiang; Cheng, Ya; Chin, See-Leang; Yamanouchi, Kaoru; Sun, Hong-Bo

2016-06-02

Laser filamentation produced by the propagation of intense laser pulses in flames is opening up new possibility in application to combustion diagnostics that can provide useful information on understanding combustion processes, enhancing combustion efficiency and reducing pollutant products. Here we present simultaneous identification of multiple combustion intermediates by femtosecond filament excitation for five alkanol-air flames fueled by methanol, ethanol, n-propanol, n-butanol, and n-pentanol. We experimentally demonstrate that the intensities of filament-induced photoemission signals from the combustion intermediates C, C2, CH, CN increase with the increasing number of carbons in the fuel molecules, and the signal ratios between the intermediates (CH/C, CH/C2, CN/C, CH/C2, CN/CH) are different for different alkanol combustion flames. Our observation provides a way for sensing multiple combustion components by femtosecond filament excitation in various combustion conditions that strongly depend on the fuel species.

Evaluation of advanced combustion concepts for dry NO sub x suppression with coal-derived, gaseous fuels

NASA Technical Reports Server (NTRS)

Beebe, K. W.; Symonds, R. A.; Notardonato, J. J.

1982-01-01

The emissions performance of a rich lean combustor (developed for liquid fuels) was determined for combustion of simulated coal gases ranging in heating value from 167 to 244 Btu/scf (7.0 to 10.3 MJ/NCM). The 244 Btu/scf gas is typical of the product gas from an oxygen blown gasifier, while the 167 Btu/scf gas is similar to that from an air blown gasifier. NOx performance of the rich lean combustor did not meet program goals with the 244 Btu/scf gas because of high thermal NOx, similar to levels expected from conventional lean burning combustors. The NOx emissions are attributed to inadequate fuel air mixing in the rich stage resulting from the design of the large central fuel nozzle delivering 71% of the total gas flow. NOx yield from ammonia injected into the fuel gas decreased rapidly with increasing ammonia level, and is projected to be less than 10% at NH3 levels of 0.5% or higher. NOx generation from NH3 is significant at ammonia concentrations significantly less than 0.5%. These levels may occur depending on fuel gas cleanup system design. CO emissions, combustion efficiency, smoke and other operational performance parameters were satisfactory. A test was completed with a catalytic combustor concept with petroleum distillate fuel. Reactor stage NOx emissions were low (1.4g NOx/kg fuel). CO emissions and combustion efficiency were satisfactory. Airflow split instabilities occurred which eventually led to test termination.

Chemical composition and speciation of particulate organic matter from modern residential small-scale wood combustion appliances.

PubMed

Czech, Hendryk; Miersch, Toni; Orasche, Jürgen; Abbaszade, Gülcin; Sippula, Olli; Tissari, Jarkko; Michalke, Bernhard; Schnelle-Kreis, Jürgen; Streibel, Thorsten; Jokiniemi, Jorma; Zimmermann, Ralf

2018-01-15

Combustion technologies of small-scale wood combustion appliances are continuously developed decrease emissions of various pollutants and increase energy conversion. One strategy to reduce emissions is the implementation of air staging technology in secondary air supply, which became an established technique for modern wood combustion appliances. On that account, emissions from a modern masonry heater fuelled with three types of common logwood (beech, birch and spruce) and a modern pellet boiler fuelled with commercial softwood pellets were investigated, which refer to representative combustion appliances in northern Europe In particular, emphasis was put on the organic constituents of PM2.5, including polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs (OPAHs) and phenolic species, by targeted and non-targeted mass spectrometric analysis techniques. Compared to conventional wood stoves and pellet boilers, organic emissions from the modern appliances were reduced by at least one order of magnitude, but to a different extent for single species. Hence, characteristic ratios of emission constituents and emission profiles for wood combustion identification and speciation do not hold for this type of advanced combustion technology. Additionally, an overall substantial reduction of typical wood combustion markers, such as phenolic species and anhydrous sugars, were observed. Finally, it was found that slow ignition of log woods changes the distribution of characteristic resin acids and phytosterols as well as their thermal alteration products, which are used as markers for specific wood types. Our results should be considered for wood combustion identification in positive matrix factorisation or chemical mass balance in northern Europe. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of Alcohol on Diesel Engine Combustion Operating with Biodiesel-Diesel Blend at Idling Conditions

NASA Astrophysics Data System (ADS)

Mahmudul, H. M.; Hagos, Ftwi. Y.; A, M. Mukhtar N.; Mamat, Rizalman; Abdullah, A. Adam

2018-03-01

Biodiesel is a promising alternative fuel to run the automotive engine. However, its blends have not been properly investigated during idling as it is the main problem to run the vehicles in a big city. The purpose of this study is to evaluate the impact of alcohol additives such as butanol and ethanol on combustion parameters under idling conditions when a single cylinder diesel engine operates with diesel, diesel-biodiesel blends, and diesel biodiesel-alcohol blends. The engine combustion parameters such as peak pressure, heat release rate and ignition delay were computed. This investigation has revealed that alcohol blends with diesel and biodiesel, BU20 blend yield higher maximum peak cylinder pressure than diesel. B5 blend was found with the lowest energy release among all. B20 was slightly lower than diesel. BU20 blend was seen with the highest peak energy release where E20 blend was found advance than diesel. Among all, the blends alcohol component revealed shorter ignition delay. B5 and B20 blends were influenced by biodiesel interference and the burning fraction were found slightly slower than conventional diesel where BU20 and E20 blends was found slightly faster than diesel So, based on the result, it can be said that among the alcohol blends butanol and ethanol can be promising alternative at idling conditions and can be used without any engine modifications.

Method for in situ combustion

DOEpatents

Pasini, III, Joseph; Shuck, Lowell Z.; Overbey, Jr., William K.

1977-01-01

This invention relates to an improved in situ combustion method for the recovery of hydrocarbons from subterranean earth formations containing carbonaceous material. The method is practiced by penetrating the subterranean earth formation with a borehole projecting into the coal bed along a horizontal plane and extending along a plane disposed perpendicular to the plane of maximum permeability. The subterranean earth formation is also penetrated with a plurality of spaced-apart vertical boreholes disposed along a plane spaced from and generally parallel to that of the horizontal borehole. Fractures are then induced at each of the vertical boreholes which project from the vertical boreholes along the plane of maximum permeability and intersect the horizontal borehole. The combustion is initiated at the horizontal borehole and the products of combustion and fluids displaced from the earth formation by the combustion are removed from the subterranean earth formation via the vertical boreholes. Each of the vertical boreholes are, in turn, provided with suitable flow controls for regulating the flow of fluid from the combustion zone and the earth formation so as to control the configuration and rate of propagation of the combustion zone. The fractures provide a positive communication with the combustion zone so as to facilitate the removal of the products resulting from the combustion of the carbonaceous material.

Combustion Integration Rack (CIR) Testing

NASA Image and Video Library

2015-02-18

Fluids and Combustion Facility (FCF), Combustion Integration Rack (CIR) during testing in the Structural Dynamics Laboratory (SDL). The Fluids and Combustion Facility (FCF) is a set of two International Space Station (ISS) research facilities designed to support physical and biological experiments in support of technology development and validation in space. The FCF consists of two modular, reconfigurable racks called the Combustion Integration Rack (CIR) and the Fluids Integration Rack (FIR). The CIR and FIR were developed at NASAʼs Glenn Research Center.

Flow Distribution Around the SSME Main Injector Assembly Using Porosity Formulation

NASA Technical Reports Server (NTRS)

Cheng, Gary C.; Chen, Yen-Sen; Wang, Ten-See

1995-01-01

Hot gas turbulent flow distribution around the main injector assembly of the Space Shuttle Main Engine (SSME) and Liquid Oxidizer (LOX) flow distribution through the LOX posts have a great effect on the combustion phenomena inside the main combustion chamber. In order to design a CFD model to be an effective engineering analysis tool with good computational turn- around time (especially for 3-D flow problems) and still maintain good accuracy in describing the flow features, the concept of porosity was employed to describe the effects of blockage and drag force due to the presence of the LOX posts in the turbulent flow field around the main injector assembly of the SSME. 2-D numerical studies were conducted to identify the drag coefficients of the flows both through tube banks and around the shielded posts over a wide range of Reynolds numbers. Empirical, analytical expressions of the drag coefficient as a function of local flow Reynolds number were then deduced. The porosity model was applied to the turbulent flow around the main injector assembly of the SSME, and analyses were performed. The 3-D CFD analysis was divided into three parts, LOX dome, hot gas injector assembly, and hydrogen cavity. The numerical results indicate that the mixture ratio at the downstream of injector face was close to stoichiometric around baffle elements.

Flow Distribution Around the SSME Main Injector Assembly Using Porosity Formulation

NASA Technical Reports Server (NTRS)

Cheng, Gary C.; Chen, Yen-Sen; Wang, Ten-See

1995-01-01

Hot gas turbulent flow distribution around the main injector assembly of the Space Shuttle Main Engine (SSME) and Liquid Oxidizer (LOX) flow distribution through the LOX posts have a great effect on the combustion phenomena inside the main combustion chamber. In order to design a CFD model to be an effective engineering analysis tool with good computational turn-around time (especially for 3-D flow problems) and still maintain good accuracy in describing the flow features, the concept of porosity was employed to describe the effects of blockage and drag force due to the presence of the LOX posts in the turbulent flow field around the main injector assembly of the SSME. 2-D numerical studies were conducted to identify the drag coefficients of the flows both through tube banks and around the shielded posts over a wide range of Reynolds numbers. Empirical, analytical expressions of the drag coefficient as a function of local flow Reynolds number were then deduced. The porosity model was applied to the turbulent flow around the main injector assembly of the SSME, and analyses were performed. The 3-D CFD analysis was divided into three parts, LOX dome, hot gas injector assembly, and hydrogen cavity. The numerical results indicate that the mixture ratio at the downstream of injector face was close to stoichiometric around baffle elements.

Plasma-assisted combustion technology for NOx reduction in industrial burners.

PubMed

Lee, Dae Hoon; Kim, Kwan-Tae; Kang, Hee Seok; Song, Young-Hoon; Park, Jae Eon

2013-10-01

Stronger regulations on nitrogen oxide (NOx) production have recently promoted the creation of a diverse array of technologies for NOx reduction, particularly within the combustion process, where reduction is least expensive. In this paper, we discuss a new combustion technology that can reduce NOx emissions within industrial burners to single-digit parts per million levels without employing exhaust gas recirculation or other NOx reduction mechanisms. This new technology uses a simple modification of commercial burners, such that they are able to perform plasma-assisted staged combustion without altering the outer configuration of the commercial reference burner. We embedded the first-stage combustor within the head of the commercial reference burner, where it operated as a reformer that could host a partial oxidation process, producing hydrogen-rich reformate or synthesis gas product. The resulting hydrogen-rich flow then ignited and stabilized the combustion flame apart from the burner rim. Ultimately, the enhanced mixing and removal of hot spots with a widened flame area acted as the main mechanisms of NOx reduction. Because this plasma burner acted as a low NOx burner and was able to reduce NOx by more than half compared to the commercial reference burner, this methodology offers important cost-effective possibilities for NOx reduction in industrial applications.

Experimental and theoretical study of iron and mild steel combustion in oxygen flows

NASA Astrophysics Data System (ADS)

El-Rabii, Hazem; Kazakov, Kirill A.; Muller, Maryse

2017-03-01

The effects of oxygen flow speed and pressure on the iron and mild steel combustion are investigated experimentally and theoretically. The studied specimens are vertical cylindrical rods subjected to an axial oxygen flow and ignited at the upper end by laser irradiation. Three main stages of the combustion process have been identified experimentally: (1) induction period, during which the rod is heated until an intensive metal oxidation begins at its upper end; (2) static combustion, during which a laminar liquid "cap'' slowly grows on the upper rod end, and, after the liquid cap detachment from the sample; (3) dynamic combustion, which is characterized by a rapid metal consumption and turbulent liquid motions. An analytical description of these stages is given. In particular, a model of the dynamic combustion is constructed based on the turbulent oxygen transport through the liquid metal-oxide flow. This model yields a simple expression for the fraction of metal burned in the process and allows one to calculate the normal propagation speed of the solid metal-liquid interface as a function of the oxygen flow speed and pressure. A comparison of the theory with the experimental results is made, and its potential application is mentioned.

Co-Optima Project E2.2.2: Accelerate Development of ACI/LTC Fuel Effects on RCCI Combustion.

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

Musculus, Mark P.

Many advanced combustion approaches have demonstrated potential for achieving diesel-like thermal efficiency but with much lower pollutant emissions of particulate matter (PM) and nitrogen oxides (NOx). RCCI is one advanced combustion concept, which makes use of in-cylinder blending of two fuels with differing reactivity for improved control of the combustion phasing and rate (Reitz et al., 2015). Previous research and development at ORNL has demonstrated successful implementation of RCCI on a light-duty multi-cylinder engine over a wide range of operating conditions (Curran et al., 2015). Several challenges were encountered when extending the research to practical applications, including limits to themore » operating range, both for high and low loads. Co-optimizing the engine and fuel aspects of the RCCI approach might allow these operating limits to be overcome. The in-cylinder mechanisms by which fuel properties interact with engine operating condition variables is not well understood, however, in part because RCCI is a new combustion concept that is still being developed, and limited data have been acquired to date, especially using in-cylinder optical/imaging diagnostics. The objective of this work is to use in-cylinder diagnostics in a heavy-duty single-cylinder optical engine at SNL to understand the interplay between fuel properties and engine hardware and operating conditions for RCCI in general, and in particular for the light-duty multi-cylinder all-metal RCCI engine experiments at ORNL.« less

The 17th JANNAF Combustion Meeting, Volume 1

NASA Technical Reports Server (NTRS)

Eggleston, D. S. (Editor)

1980-01-01

The combustion of solid rocket propellants and combustion in ramjets is addressed. Subjects discussed include metal burning, steady-state combustion of composite propellants, velocity coupling and nonlinear instability, vortex shedding and flow effects on combustion instability, combustion instability in solid rocket motors, combustion diagnostics, subsonic and supersonic ramjet combustion, characterization of ramburner flowfields, and injection and combustion of ramjet fuels.

Advanced catalytic combustors for low pollutant emissions, phase 1

NASA Technical Reports Server (NTRS)

Dodds, W. J.

1979-01-01

The feasibility of employing the known attractive and distinguishing features of catalytic combustion technology to reduce nitric oxide emissions from gas turbine engines during subsonic, stratospheric cruise operation was investigated. Six conceptual combustor designs employing catalytic combustion were defined and evaluated for their potential to meet specific emissions and performance goals. Based on these evaluations, two parallel-staged, fixed-geometry designs were identified as the most promising concepts. Additional design studies were conducted to produce detailed preliminary designs of these two combustors. Results indicate that cruise nitric oxide emissions can be reduced by an order of magnitude relative to current technology levels by the use of catalytic combustion. Also, these combustors have the potential for operating over the EPA landing-takeoff cycle and at cruise with a low pressure drop, high combustion efficiency and with a very low overall level of emission pollutants. The use of catalytic combustion, however, requires advanced technology generation in order to obtain the time-temperature catalytic reactor performance and durability required for practical aircraft engine combustors.

Combustion Science

NASA Image and Video Library

2003-04-01

This photograph depicts one of over thirty tests conducted on the Vortex Combustion Chamber Engine at Marshall Space Flight Center's (MSFC) test stand 115, a joint effort between NASA's MSFC and the U.S. Army AMCOM of Redstone Arsenal. The engine tests were conducted to evaluate an irnovative, "self-cooled", vortex combustion chamber, which relies on tangentially injected propellants from the chamber wall producing centrifugal forces that keep the relatively cold liquid propellants near the wall.

Design and Fabrication of Oxygen/RP-2 Multi-Element Oxidizer-Rich Staged Combustion Thrust Chamber Injectors

NASA Technical Reports Server (NTRS)

Garcia, C. P.; Medina, C. R.; Protz, C. S.; Kenny, R. J.; Kelly, G. W.; Casiano, M. J.; Hulka, J. R.; Richardson, B. R.

2016-01-01

As part of the Combustion Stability Tool Development project funded by the Air Force Space and Missile Systems Center, the NASA Marshall Space Flight Center was contracted to assemble and hot-fire test a multi-element integrated test article demonstrating combustion characteristics of an oxygen/hydrocarbon propellant oxidizer-rich staged-combustion engine thrust chamber. Such a test article simulates flow through the main injectors of oxygen/kerosene oxidizer-rich staged combustion engines such as the Russian RD-180 or NK-33 engines, or future U.S.-built engine systems such as the Aerojet-Rocketdyne AR-1 engine or the Hydrocarbon Boost program demonstration engine. On the current project, several configurations of new main injectors were considered for the thrust chamber assembly of the integrated test article. All the injector elements were of the gas-centered swirl coaxial type, similar to those used on the Russian oxidizer-rich staged-combustion rocket engines. In such elements, oxidizer-rich combustion products from the preburner/turbine exhaust flow through a straight tube, and fuel exiting from the combustion chamber and nozzle regenerative cooling circuits is injected near the exit of the oxidizer tube through tangentially oriented orifices that impart a swirl motion such that the fuel flows along the wall of the oxidizer tube in a thin film. In some elements there is an orifice at the inlet to the oxidizer tube, and in some elements there is a sleeve or "shield" inside the oxidizer tube where the fuel enters. In the current project, several variations of element geometries were created, including element size (i.e., number of elements or pattern density), the distance from the exit of the sleeve to the injector face, the width of the gap between the oxidizer tube inner wall and the outer wall of the sleeve, and excluding the sleeve entirely. This paper discusses the design rationale for each of these element variations, including hydraulic, structural

2011 Laser Diagnostics in Combustion Gordon Research Conference, (August 14-19, 2011, Waterville Valley Resort, Waterville Valley, NH)

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

Thomas Settersten

2011-08-19

The vast majority of the world's energy needs are met by combustion of fossil fuels. Optimum utilization of limited resources and control of emissions of pollutants and greenhouse gases demand sustained improvement of combustion technology. This task can be satisfied only by detailed knowledge of the underlying physical and chemical processes. Non-intrusive laser diagnostics continuously contribute to our growing understanding of these complex and coupled multi-scale processes. The GRC on Laser Diagnostics in Combustion focuses on the most recent scientific advances and brings together scientists and engineers working at the leading edge of combustion research. Major tasks of the communitymore » are developing and applying methods for precise and accurate measurements of fluid motion and temperatures; chemical compositions; multi-phase phenomena appearing near walls, in spray and sooting combustion; improving sensitivities, precision, spatial resolution and tracking transients in their spatio-temporal development. The properties and behaviour of novel laser sources, detectors, optical systems that lead to new diagnostic capabilities are also part of the conference program.« less

Advanced Earth-to-Orbit Propulsion Technology 1986, volume 2

NASA Technical Reports Server (NTRS)

Richmond, R. J.; Wu, S. T.

1986-01-01

Technology issues related to oxygen/hydrogen and oxygen/hydrocarbon propulsion are addressed. Specific topics addressed include: rotor dynamics; fatigue/fracture and life; bearings; combustion and cooling processes; and hydrogen environment embrittlement in advanced propulsion systems.

Mission Success for Combustion Science

NASA Technical Reports Server (NTRS)

Weiland, Karen J.

2004-01-01

This presentation describes how mission success for combustion experiments has been obtained in previous spaceflight experiments and how it will be obtained for future International Space Station (ISS) experiments. The fluids and combustion facility is a payload planned for the ISS. It is composed of two racks: the fluids Integrated rack and the Combustion INtegrated Rack (CIR). Requirements for the CIR were obtained from a set of combustion basis experiments that served as surrogates for later experiments. The process for experiments that fly on the ISS includes proposal selection, requirements and success criteria definition, science and engineering reviews, mission operations, and postflight operations. By following this process, the microgravity combustion science program has attained success in 41 out of 42 experiments.

Microgravity combustion of dust clouds: Quenching distance measurements

NASA Technical Reports Server (NTRS)

Goroshin, S.; Kleine, H.; Lee, J. H. S.; Frost, D.

1995-01-01

The current level of physical understanding of dust combustion phenomena is still in a rudimentary state compared with the understanding of gas combustion processes. The reason for such a lack of fundamental understanding is partially based on the complexity of multiphase combustion and the enormous diversity of chemical-physical properties of heterogeneous combustible mixtures but is largely due to difficulties in the experimental investigation of dust combustion. The influence of gravity on a dust suspension is the main reason. First of all, when particulates (either solid particles or liquid droplets) with a characteristic size of the order of tens of microns are suspended, they rapidly settle in the gravitational field. To maintain a particulate suspension for a time duration adequate to carry out combustion experiments invariably requires continuous convection of particulates at or in excess of the gravitational settling velocity. Of necessity, this makes the experiments turbulent in character and makes it impossible to study laminar dust flames. For particle sizes of the order of microns a stable laminar dust flow can be maintained only for relatively small dust concentrations (e.g., for low fuel equivalence ratios) at normal gravity conditions. High dust loading leads to gravitational instability of the dust cloud and to the formation of recirculation cells in a dust suspension in a confined volume, or to the rapid sedimentation of the dense dust cloud as a whole in an unconfined volume. In addition, many important solid fuels such as low volatile coal, carbon, and boron have low laminar flame speeds (of the order of several centimeters per second). Gravitational convection that occurs in combustion products due to the buoyancy forces disrupts low speed dust flames and, therefore, makes observation of such flames at normal gravity impossible. The only way to carry out 'clean' fundamental experiments in dust combustion over a wide range of dust cloud

Heavy-Duty Low-Temperature and Diesel Combustion & Heavy-Duty Combustion Modeling

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

Musculus, Mark P.

Regulatory drivers and market demands for lower pollutant emissions, lower carbon dioxide emissions, and lower fuel consumption motivate the development of clean and fuel-efficient engine operating strategies. Most current production engines use a combination of both in-cylinder and exhaust emissions-control strategies to achieve these goals. The emissions and efficiency performance of in-cylinder strategies depend strongly on flow and mixing processes associated with fuel injection. Various diesel engine manufacturers have adopted close-coupled post-injection combustion strategies to both reduce pollutant emissions and to increase engine efficiency for heavy-duty applications, as well as for light- and medium-duty applications. Close-coupled post-injections are typically shortmore » injections that follow a larger main injection in the same cycle after a short dwell, such that the energy conversion efficiency of the post-injection is typical of diesel combustion. Of the various post-injection schedules that have been reported in the literature, effects on exhaust soot vary by roughly an order of magnitude in either direction of increasing or decreasing emissions relative to single injections (O’Connor et al., 2015). While several hypotheses have been offered in the literature to help explain these observations, no clear consensus has been established. For new engines to take full advantage of the benefits that post-injections can offer, the in-cylinder mechanisms that affect emissions and efficiency must be identified and described to provide guidance for engine design.« less

Thermal Model of the Promoted Combustion Test

NASA Technical Reports Server (NTRS)

Jones, Peter D.

1996-01-01

Flammability of metals in high pressure, pure oxygen environments, such as rocket engine turbopumps, is commonly evaluated using the Promoted Combustion Test (PCT). The PCT emphasizes the ability of an ignited material to sustain combustion, as opposed to evaluating the sample's propensity to ignite in the first place. A common arrangement is a rod of the sample material hanging in a chamber in which a high pressure, pure oxygen environment is maintained. An igniter of some energetically combusting material is fixed to the bottom of the rod and fired. This initiates combustion, and the sample burns and melts at its bottom tip. A ball of molten material forms, and this ball detaches when it grows too large to be supported by surface tension with the rod. In materials which do not sustain combustion, the combustion then extinguishes. In materials which do sustain combustion, combustion re-initiates from molten residue left on the bottom of the rod, and the melt ball burns and grows until it detaches again. The purpose of this work is development of a PCT thermal simulation model, detailing phase change, melt detachment, and the several heat transfer modes. Combustion is modeled by a summary rate equation, whose parameters are identified by comparison to PCT results. The sensitivity of PCT results to various physical and geometrical parameters is evaluated. The identified combustion parameters may be used in design of new PCT arrangements, as might be used for flammability assessment in flow-dominated environments. The Haynes 214 nickel-based superalloy, whose PCT results are applied here, burns heterogeneously (fuel and oxidizer are of different phases; combustion takes place on the fuel surface). Heterogeneous combustion is not well understood. (In homogeneous combustion, the metal vaporizes, and combustion takes place in an analytically treatable cloud above the surface). Thermal modeling in heterogeneous combustion settings provides a means for linking test

Development of a Premixed Combustion Capability for Scramjet Combustion Experiments

NASA Technical Reports Server (NTRS)

Rockwell, Robert D.; Goyne, Christopher P.; Rice, Brian E.; Chelliah, Harsha; McDaniel, James C.; Edwards, Jack R.; Cantu, Luca M. L.; Gallo, Emanuela C. A.; Cutler, Andrew D.; Danehy, Paul M.

2015-01-01

Hypersonic air-breathing engines rely on scramjet combustion processes, which involve high speed, compressible, and highly turbulent flows. The combustion environment and the turbulent flames at the heart of these engines are difficult to simulate and study in the laboratory under well controlled conditions. Typically, wind-tunnel testing is performed that more closely approximates engine testing rather than a careful investigation of the underlying physics that drives the combustion process. The experiments described in this paper, along with companion data sets being developed separately, aim to isolate the chemical kinetic effects from the fuel-air mixing process in a dual-mode scramjet combustion environment. A unique fuel injection approach is taken that produces a nearly uniform fuel-air mixture at the entrance to the combustor. This approach relies on the precombustion shock train upstream of the dual-mode scramjet combustor. A stable ethylene flame anchored on a cavity flameholder with a uniformly mixed combustor inflow has been achieved in these experiments allowing numerous companion studies involving coherent anti-Stokes Raman scattering (CARS), particle image velocimetry (PIV), and planar laser induced fluorescence (PLIF) to be performed.

A combustion model of vegetation burning in "Tiger" fire propagation tool

NASA Astrophysics Data System (ADS)

Giannino, F.; Ascoli, D.; Sirignano, M.; Mazzoleni, S.; Russo, L.; Rego, F.

2017-11-01

In this paper, we propose a semi-physical model for the burning of vegetation in a wildland fire. The main physical-chemical processes involved in fire spreading are modelled through a set of ordinary differential equations, which describe the combustion process as linearly related to the consumption of fuel. The water evaporation process from leaves and wood is also considered. Mass and energy balance equations are written for fuel (leaves and wood) assuming that combustion process is homogeneous in space. The model is developed with the final aim of simulating large-scale wildland fires which spread on heterogeneous landscape while keeping the computation cost very low.

Spherical combustion clouds in explosions

NASA Astrophysics Data System (ADS)

Kuhl, A. L.; Bell, J. B.; Beckner, V. E.; Balakrishnan, K.; Aspden, A. J.

2013-05-01

This study explores the properties of spherical combustion clouds in explosions. Two cases are investigated: (1) detonation of a TNT charge and combustion of its detonation products with air, and (2) shock dispersion of aluminum powder and its combustion with air. The evolution of the blast wave and ensuing combustion cloud dynamics are studied via numerical simulations with our adaptive mesh refinement combustion code. The code solves the multi-phase conservation laws for a dilute heterogeneous continuum as formulated by Nigmatulin. Single-phase combustion (e.g., TNT with air) is modeled in the fast-chemistry limit. Two-phase combustion (e.g., Al powder with air) uses an induction time model based on Arrhenius fits to Boiko's shock tube data, along with an ignition temperature criterion based on fits to Gurevich's data, and an ignition probability model that accounts for multi-particle effects on cloud ignition. Equations of state are based on polynomial fits to thermodynamic calculations with the Cheetah code, assuming frozen reactants and equilibrium products. Adaptive mesh refinement is used to resolve thin reaction zones and capture the energy-bearing scales of turbulence on the computational mesh (ILES approach). Taking advantage of the symmetry of the problem, azimuthal averaging was used to extract the mean and rms fluctuations from the numerical solution, including: thermodynamic profiles, kinematic profiles, and reaction-zone profiles across the combustion cloud. Fuel consumption was limited to ˜ 60-70 %, due to the limited amount of air a spherical combustion cloud can entrain before the turbulent velocity field decays away. Turbulent kinetic energy spectra of the solution were found to have both rotational and dilatational components, due to compressibility effects. The dilatational component was typically about 1 % of the rotational component; both seemed to preserve their spectra as they decayed. Kinetic energy of the blast wave decayed due to the

A CFD model for biomass combustion in a packed bed furnace

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

Karim, Md. Rezwanul; Department of Mechanical & Chemical Engineering, Islamic University of Technology, Gazipur 1704; Ovi, Ifat Rabbil Qudrat

Climate change has now become an important issue which is affecting environment and people around the world. Global warming is the main reason of climate change which is increasing day by day due to the growing demand of energy in developed countries. Use of renewable energy is now an established technique to decrease the adverse effect of global warming. Biomass is a widely accessible renewable energy source which reduces CO{sub 2} emissions for producing thermal energy or electricity. But the combustion of biomass is complex due its large variations and physical structures. Packed bed or fixed bed combustion is themore » most common method for the energy conversion of biomass. Experimental investigation of packed bed biomass combustion is difficult as the data collection inside the bed is challenging. CFD simulation of these combustion systems can be helpful to investigate different operational conditions and to evaluate the local values inside the investigation area. Available CFD codes can model the gas phase combustion but it can’t model the solid phase of biomass conversion. In this work, a complete three-dimensional CFD model is presented for numerical investigation of packed bed biomass combustion. The model describes the solid phase along with the interface between solid and gas phase. It also includes the bed shrinkage due to the continuous movement of the bed during solid fuel combustion. Several variables are employed to represent different parameters of solid mass. Packed bed is considered as a porous bed and User Defined Functions (UDFs) platform is used to introduce solid phase user defined variables in the CFD. Modified standard discrete transfer radiation method (DTRM) is applied to model the radiation heat transfer. Preliminary results of gas phase velocity and pressure drop over packed bed have been shown. The model can be useful for investigation of movement of the packed bed during solid fuel combustion.« less

Effect of the Ethanol Injection Moment During Compression Stroke on the Combustion of Ethanol - Diesel Dual Direct Injection Engine

NASA Astrophysics Data System (ADS)

Liang, Yu; Zhou, Liying; Huang, Haomin; Xu, Mingfei; Guo, Mei; Chen, Xin

2018-01-01

A set of GDI system is installed on a F188 single-cylinder, air-cooled and direct injection diesel engine, which is used for ethanol injection, with the injection time controlled by the crank angle signal collected by AVL angle encoder. The injection of ethanol amounts to half of the thermal equivalent of an original diesel fuel. A 3D combustion model is established for the ethanol - diesel dual direct injection engine. Diesel was injected from the original fuel injection system, with a fuel supply advance angle of 20°CA. The ethanol was injected into the cylinder during compression process. Diesel injection began after the completion of ethanol injection. Ethanol injection starting point of 240°CA, 260°CA, 280°CA, 300°CA and 319.4°CA were simulated and analyzed. Due to the different timing of ethanol injection, the ignition of the ethanol mixture when diesel fires, results in non-uniform ignition distribution and flame propagation rate, since the distribution and concentration gradients of the ethanol mixture in the cylinder are different, thus affecting the combustion process. The results show that, when ethanol is injected at 319.4°CA, the combustion heat release rate and the pressure rise rate during the initial stage are the highest. Also, the maximum combustion pressure, with a relatively advance phase, is the highest. In case of later initial ethanol injection, the average temperature in the cylinder during the initial combustion period will have a faster rise. In case of initial injection at 319.4°CA, the average temperature in the cylinder is the highest, followed by 240°CA ethanol injection. In the post-combustion stage, the earlier ethanol injection will result in higher average temperature in the cylinder and more complete fuel combustion. The injection of ethanol at 319.4°CA produces earlier and highest NOX emissions.

Combustion

NASA Technical Reports Server (NTRS)

Bulzan, Dan

2007-01-01

An overview of the emissions related research being conducted as part of the Fundamental Aeronautics Subsonics Fixed Wing Project is presented. The overview includes project metrics, milestones, and descriptions of major research areas. The overview also includes information on some of the emissions research being conducted under NASA Research Announcements. Objective: Development of comprehensive detailed and reduced kinetic mechanisms of jet fuels for chemically-reacting flow modeling. Scientific Challenges: 1) Developing experimental facilities capable of handling higher hydrocarbons and providing benchmark combustion data. 2) Determining and understanding ignition and combustion characteristics, such as laminar flame speeds, extinction stretch rates, and autoignition delays, of jet fuels and hydrocarbons relevant to jet surrogates. 3) Developing comprehensive kinetic models for jet fuels.

Combustion Integrated Rack (CIR)

NASA Image and Video Library

2016-06-22

NASA Glenn engineer Chris Mroczka installs a gas-jet burner in a chamber within the center’s Combustion Integrated Rack. This chamber is where scientists conduct gaseous combustion experiments in a zero gravity environment.

Review of modern low emissions combustion technologies for aero gas turbine engines

NASA Astrophysics Data System (ADS)

Liu, Yize; Sun, Xiaoxiao; Sethi, Vishal; Nalianda, Devaiah; Li, Yi-Guang; Wang, Lu

2017-10-01

Pollutant emissions from aircraft in the vicinity of airports and at altitude are of great public concern due to their impact on environment and human health. The legislations aimed at limiting aircraft emissions have become more stringent over the past few decades. This has resulted in an urgent need to develop low emissions combustors in order to meet legislative requirements and reduce the impact of civil aviation on the environment. This article provides a comprehensive review of low emissions combustion technologies for modern aero gas turbines. The review considers current high Technologies Readiness Level (TRL) technologies including Rich-Burn Quick-quench Lean-burn (RQL), Double Annular Combustor (DAC), Twin Annular Premixing Swirler combustors (TAPS), Lean Direct Injection (LDI). It further reviews some of the advanced technologies at lower TRL. These include NASA multi-point LDI, Lean Premixed Prevaporised (LPP), Axially Staged Combustors (ASC) and Variable Geometry Combustors (VGC). The focus of the review is placed on working principles, a review of the key technologies (includes the key technology features, methods of realising the technology, associated technology advantages and design challenges, progress in development), technology application and emissions mitigation potential. The article concludes the technology review by providing a technology evaluation matrix based on a number of combustion performance criteria including altitude relight auto-ignition flashback, combustion stability, combustion efficiency, pressure loss, size and weight, liner life and exit temperature distribution.

Advanced Seal Development for Large Industrial Gas Turbines

NASA Technical Reports Server (NTRS)

Chupp, Raymond E.

2006-01-01

Efforts are in progress to develop advanced sealing for large utility industrial gas turbine engines (combustion turbines). Such seals have been under developed for some time for aero gas turbines. It is desired to transition this technology to combustion turbines. Brush seals, film riding face and circumferential seals, and other dynamic and static sealing approaches are being incorporated into gas turbines for aero applications by several engine manufacturers. These seals replace labyrinth or other seals with significantly reduced leakage rates. For utility industrial gas turbines, leakage reduction with advanced sealing can be even greater with the enormous size of the components. Challenges to transitioning technology include: extremely long operating times between overhauls; infrequent but large radial and axial excursions; difficulty in coating larger components; and maintenance, installation, and durability requirements. Advanced sealing is part of the Advanced Turbine Systems (ATS) engine development being done under a cooperative agreement between Westinghouse and the US Department of Energy, Office of Fossil Energy. Seal development focuses on various types of seals in the 501ATS engine both at dynamic and static locations. Each development includes rig testing of candidate designs and subsequent engine validation testing of prototype seals. This presentation gives an update of the ongoing ATS sealing efforts with special emphasis on brush seals.

Modeling Combustion in Supersonic Flows

NASA Technical Reports Server (NTRS)

Drummond, J. Philip; Danehy, Paul M.; Bivolaru, Daniel; Gaffney, Richard L.; Tedder, Sarah A.; Cutler, Andrew D.

2007-01-01

This paper discusses the progress of work to model high-speed supersonic reacting flow. The purpose of the work is to improve the state of the art of CFD capabilities for predicting the flow in high-speed propulsion systems, particularly combustor flow-paths. The program has several components including the development of advanced algorithms and models for simulating engine flowpaths as well as a fundamental experimental and diagnostic development effort to support the formulation and validation of the mathematical models. The paper will provide details of current work on experiments that will provide data for the modeling efforts along with with the associated nonintrusive diagnostics used to collect the data from the experimental flowfield. Simulation of a recent experiment to partially validate the accuracy of a combustion code is also described.

Supersonic Combustion Research at NASA

NASA Technical Reports Server (NTRS)

Drummond, J. P.; Danehy, Paul M.; Gaffney, Richard L., Jr.; Tedder, Sarah A.; Cutler, Andrew D.; Bivolaru, Daniel

2007-01-01

This paper discusses the progress of work to model high-speed supersonic reacting flow. The purpose of the work is to improve the state of the art of CFD capabilities for predicting the flow in high-speed propulsion systems, particularly combustor flowpaths. The program has several components including the development of advanced algorithms and models for simulating engine flowpaths as well as a fundamental experimental and diagnostic development effort to support the formulation and validation of the mathematical models. The paper will provide details of current work on experiments that will provide data for the modeling efforts along with the associated nonintrusive diagnostics used to collect the data from the experimental flowfield. Simulation of a recent experiment to partially validate the accuracy of a combustion code is also described.

Combustion and NOx emissions in deep-air-staging combustion of char in a circulating fluidized bed

NASA Astrophysics Data System (ADS)

Gong, Zhiqiang; Wang, Zhentong; Wang, Lei; Du, Aixun

2017-10-01

Combustion and NOx emissions in deep-air-staging (with higher level secondary air (SA) injection) combustion of char have been investigated in a CFB test rig. A good fluidized condition and uniform temperature distribution can be achieved with injection of higher level SA. NOx emission decreases with injection of higher level SA and the reduction effect is more obvious at higher temperature. NOx emission decreases with combustion temperature increasing for char combustion.

Contribution of developing advanced engineering methods in interdisciplinary studying the piston rings from 1.6 spark ignited Ford engine at Technical University of Cluj-Napoca

NASA Astrophysics Data System (ADS)

-Aurel Cherecheş, Ioan; -Ioana Borzan, Adela; -Laurean Băldean, Doru

2017-10-01

Study of construction and wearing process in the case of piston-rings and other significant components from internal combustion engines leads at any time to creative and useful optimizing ideas, both in designing and manufacturing phases. Main objective of the present paper is to realize an interdisciplinary research using advanced methods in piston-rings evaluation of a common vehicle on the streets which is Ford Focus FYDD. Specific objectives are a theoretical study of the idea for advanced analysis method in piston-rings evaluation and an applied research developed in at Technical University from Cluj-Napoca with the motor vehicle caught in the repairing process.

Development of High Efficiency Clean Combustion Engine Designs for Spark-Ignition and Compression-Ignition Internal Combustion Engines

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

Marriott, Craig; Gonzalez, Manual; Russell, Durrett

2011-06-30

This report summarizes activities related to the revised STATEMENT OF PROJECT OBJECTIVES (SOPO) dated June 2010 for the Development of High-Efficiency Clean Combustion engine Designs for Spark-Ignition and Compression-Ignition Internal Combustion Engines (COOPERATIVE AGREEMENT NUMBER DE-FC26-05NT42415) project. In both the spark- (SI) and compression-ignition (CI) development activities covered in this program, the goal was to develop potential production-viable internal combustion engine system technologies that both reduce fuel consumption and simultaneously met exhaust emission targets. To be production-viable, engine technologies were also evaluated to determine if they would meet customer expectations of refinement in terms of noise, vibration, performance, driveability, etc.more » in addition to having an attractive business case and value. Prior to this activity, only proprietary theoretical / laboratory knowledge existed on the combustion technologies explored The research reported here expands and develops this knowledge to determine series-production viability. Significant SI and CI engine development occurred during this program within General Motors, LLC over more than five years. In the SI program, several engines were designed and developed that used both a relatively simple multi-lift valve train system and a Fully Flexible Valve Actuation (FFVA) system to enable a Homogeneous Charge Compression Ignition (HCCI) combustion process. Many technical challenges, which were unknown at the start of this program, were identified and systematically resolved through analysis, test and development. This report documents the challenges and solutions for each SOPO deliverable. As a result of the project activities, the production viability of the developed clean combustion technologies has been determined. At this time, HCCI combustion for SI engines is not considered production-viable for several reasons. HCCI combustion is excessively sensitive to control

Large Eddy Simulations of Colorless Distributed Combustion Systems

NASA Astrophysics Data System (ADS)

Abdulrahman, Husam F.; Jaberi, Farhad; Gupta, Ashwani

2014-11-01

Development of efficient and low-emission colorless distributed combustion (CDC) systems for gas turbine applications require careful examination of the role of various flow and combustion parameters. Numerical simulations of CDC in a laboratory-scale combustor have been conducted to carefully examine the effects of these parameters on the CDC. The computational model is based on a hybrid modeling approach combining large eddy simulation (LES) with the filtered mass density function (FMDF) equations, solved with high order numerical methods and complex chemical kinetics. The simulated combustor operates based on the principle of high temperature air combustion (HiTAC) and has shown to significantly reduce the NOx, and CO emissions while improving the reaction pattern factor and stability without using any flame stabilizer and with low pressure drop and noise. The focus of the current work is to investigate the mixing of air and hydrocarbon fuels and the non-premixed and premixed reactions within the combustor by the LES/FMDF with the reduced chemical kinetic mechanisms for the same flow conditions and configurations investigated experimentally. The main goal is to develop better CDC with higher mixing and efficiency, ultra-low emission levels and optimum residence time. The computational results establish the consistency and the reliability of LES/FMDF and its Lagrangian-Eulerian numerical methodology.

Compound specific radiocarbon analyses to apportion sources of combustion products in sedimentary pyrogenic carbon deposits

NASA Astrophysics Data System (ADS)

Hanke, Ulrich M.; Schmidt, Michael W. I.; McIntyre, Cameron P.; Reddy, Christopher M.; Wacker, Lukas; Eglinton, Timothy I.

2016-04-01

Pyrogenic carbon (PyC) is a collective term for carbon-rich residues comprised of a continuum of products generated during biomass burning and fossil fuel combustion. PyC is a key component of the global carbon cycle due to its slow intrinsic decomposition rate and its ubiquity in the environment. It can originate from natural or anthropogenic vegetation fires, coal mining, energy production, industry and transport. Subsequently, PyC can be transported over long distances by wind and water and can eventually be buried in sediments. Information about the origin of PyC (biomass burning vs. fossil fuel combustion) deposited in estuarine sediments is scarce. We studied the highly anoxic estuarine sediments of the Pettaquamscutt River (Rhode Island, U.S.) in high temporal resolution over 250 years and found different combustion proxies reflect local and regional sources of PyC (Hanke et al. in review; Lima et al. 2003). The polycyclic aromatic hydrocarbons (PAH) originate from long-range atmospheric transport, whereas bulk PyC, detected as benzene polycarboxylic acids (BPCA), mainly stems from local catchment run-off. However, to unambiguously apportion PyC sources, we need additional information, such as compound specific radiocarbon (14C) measurements. We report 14C data for individual BPCA including error analysis and for combustion-related PAH. First results indicate that biomass burning is the main source of PyC deposits, with additional minor contributions from fossil fuel combustion. References Hanke U.M., T.I. Eglinton, A.L.L. Braun, C. Reddy, D.B. Wiedemeier, M.W.I. Schmidt. Decoupled sedimentary records of combustion: causes and implications. In review. Lima, A. L.; Eglinton, T. I.; Reddy, C. M., High-resolution record of pyrogenic polycyclic aromatic hydrocarbon deposition during the 20th century. ES&T, 2003, 37 (1), 53-61.

The effect of biomass on pollutant emission and burnout in co-combustion with coal

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

Kruczek, H.; Raczka, P.; Tatarek, A.

This paper presents experimental and numerical results on the co-combustion of different types of biomass with hard and brown coal. The main aim of this work was to assess the impact of the cocombustion of biomass in brown and hard coal-fired systems on the combustion process itself and on the level of pollutant formation and its dependence on combustion temperature stoichiometry. The experimental results obtained have shown that in general biomass addition leads to decreased NO and SO{sub 2} emissions, except with the hard coal Bogdanka. In addition, the biomass has a beneficial effect on the burnout of the coal/biomassmore » mixture. To help to account for this effect, the behaviour of coal and biomass, the coal/biomass mixture and of fuel-N was studied by thermal analysis, in nitrogen and in air. The results obtained have shown that gas phase interactions are dominant in the combustion of biomass/coal mixtures.« less

Fuel Vaporization and Its Effect on Combustion in a High-Speed Compression-Ignition Engine

NASA Technical Reports Server (NTRS)

Rothrock, A M; Waldron, C D

1933-01-01

The tests discussed in this report were conducted to determine whether or not there is appreciable vaporization of the fuel injected into a high-speed compression-ignition engine during the time available for injection and combustion. The effects of injection advance angle and fuel boiling temperature were investigated. The results show that an appreciable amount of the fuel is vaporized during injection even though the temperature and pressure conditions in the engine are not sufficient to cause ignition either during or after injection, and that when the conditions are such as to cause ignition the vaporization process affects the combustion. The results are compared with those of several other investigators in the same field.

Rotating Detonation Combustion: A Computational Study for Stationary Power Generation

NASA Astrophysics Data System (ADS)

Escobar, Sergio

The increased availability of gaseous fossil fuels in The US has led to the substantial growth of stationary Gas Turbine (GT) usage for electrical power generation. In fact, from 2013 to 2104, out of the 11 Tera Watts-hour per day produced from fossil fuels, approximately 27% was generated through the combustion of natural gas in stationary GT. The thermodynamic efficiency for simple-cycle GT has increased from 20% to 40% during the last six decades, mainly due to research and development in the fields of combustion science, material science and machine design. However, additional improvements have become more costly and more difficult to obtain as technology is further refined. An alternative to improve GT thermal efficiency is the implementation of a combustion regime leading to pressure-gain; rather than pressure loss across the combustor. One concept being considered for such purpose is Rotating Detonation Combustion (RDC). RDC refers to a combustion regime in which a detonation wave propagates continuously in the azimuthal direction of a cylindrical annular chamber. In RDC, the fuel and oxidizer, injected from separated streams, are mixed near the injection plane and are then consumed by the detonation front traveling inside the annular gap of the combustion chamber. The detonation products then expand in the azimuthal and axial direction away from the detonation front and exit through the combustion chamber outlet. In the present study Computational Fluid Dynamics (CFD) is used to predict the performance of Rotating Detonation Combustion (RDC) at operating conditions relevant to GT applications. As part of this study, a modeling strategy for RDC simulations was developed. The validation of the model was performed using benchmark cases with different levels of complexity. First, 2D simulations of non-reactive shock tube and detonation tubes were performed. The numerical predictions that were obtained using different modeling parameters were compared with

Combustion Research Aboard the ISS Utilizing the Combustion Integrated Rack and Microgravity Science Glovebox

NASA Technical Reports Server (NTRS)

Sutliff, Thomas J.; Otero, Angel M.; Urban, David L.

2002-01-01

The Physical Sciences Research Program of NASA sponsors a broad suite of peer-reviewed research investigating fundamental combustion phenomena and applied combustion research topics. This research is performed through both ground-based and on-orbit research capabilities. The International Space Station (ISS) and two facilities, the Combustion Integrated Rack and the Microgravity Science Glovebox, are key elements in the execution of microgravity combustion flight research planned for the foreseeable future. This paper reviews the Microgravity Combustion Science research planned for the International Space Station implemented from 2003 through 2012. Examples of selected research topics, expected outcomes, and potential benefits will be provided. This paper also summarizes a multi-user hardware development approach, recapping the progress made in preparing these research hardware systems. Within the description of this approach, an operational strategy is presented that illustrates how utilization of constrained ISS resources may be maximized dynamically to increase science through design decisions made during hardware development.

Numerical simulation and validation of SI-CAI hybrid combustion in a CAI/HCCI gasoline engine

NASA Astrophysics Data System (ADS)

Wang, Xinyan; Xie, Hui; Xie, Liyan; Zhang, Lianfang; Li, Le; Chen, Tao; Zhao, Hua

2013-02-01

SI-CAI hybrid combustion, also known as spark-assisted compression ignition (SACI), is a promising concept to extend the operating range of CAI (Controlled Auto-Ignition) and achieve the smooth transition between spark ignition (SI) and CAI in the gasoline engine. In this study, a SI-CAI hybrid combustion model (HCM) has been constructed on the basis of the 3-Zones Extended Coherent Flame Model (ECFM3Z). An ignition model is included to initiate the ECFM3Z calculation and induce the flame propagation. In order to precisely depict the subsequent auto-ignition process of the unburned fuel and air mixture independently after the initiation of flame propagation, the tabulated chemistry concept is adopted to describe the auto-ignition chemistry. The methodology for extracting tabulated parameters from the chemical kinetics calculations is developed so that both cool flame reactions and main auto-ignition combustion can be well captured under a wider range of thermodynamic conditions. The SI-CAI hybrid combustion model (HCM) is then applied in the three-dimensional computational fluid dynamics (3-D CFD) engine simulation. The simulation results are compared with the experimental data obtained from a single cylinder VVA engine. The detailed analysis of the simulations demonstrates that the SI-CAI hybrid combustion process is characterised with the early flame propagation and subsequent multi-site auto-ignition around the main flame front, which is consistent with the optical results reported by other researchers. Besides, the systematic study of the in-cylinder condition reveals the influence mechanism of the early flame propagation on the subsequent auto-ignition.

Studies on Decomposition and Combustion Mechanism of Solid Fuel Rich Propellants

DTIC Science & Technology

2010-08-30

thrust to cruise at supersonic speed. This was followed by the test of large diameter ramjet called burner test vehicle (BTV). Advanced low volume...propellant surface. Vernekar et al (43) found that in pressed AP-Al pellets , maximum burn rate is obtained at intermediate metal content. Jain et al...conjunction with high pressure window strand burner . They found that the propellant combustion was irregular and regression rate varied from 0.3 to 3

Combustion and Performance Analyses of Coaxial Element Injectors with Liquid Oxygen/Liquid Methane Propellants

NASA Technical Reports Server (NTRS)

Hulka, J. R.; Jones, G. W.

2010-01-01

Liquid rocket engines using oxygen and methane propellants are being considered by the National Aeronautics and Space Administration (NASA) for in-space vehicles. This propellant combination has not been previously used in a flight-qualified engine system, so limited test data and analysis results are available at this stage of early development. NASA has funded several hardware-oriented activities with oxygen and methane propellants over the past several years with the Propulsion and Cryogenic Advanced Development (PCAD) project, under the Exploration Technology Development Program. As part of this effort, the NASA Marshall Space Flight Center has conducted combustion, performance, and combustion stability analyses of several of the configurations. This paper summarizes the analyses of combustion and performance as a follow-up to a paper published in the 2008 JANNAF/LPS meeting. Combustion stability analyses are presented in a separate paper. The current paper includes test and analysis results of coaxial element injectors using liquid oxygen and liquid methane or gaseous methane propellants. Several thrust chamber configurations have been modeled, including thrust chambers with multi-element swirl coax element injectors tested at the NASA MSFC, and a uni-element chamber with shear and swirl coax injectors tested at The Pennsylvania State University. Configurations were modeled with two one-dimensional liquid rocket combustion analysis codes, the Rocket Combustor Interaction Design and Analysis (ROCCID), and the Coaxial Injector Combustion Model (CICM). Significant effort was applied to show how these codes can be used to model combustion and performance with oxygen/methane propellants a priori, and what anchoring or calibrating features need to be applied or developed in the future. This paper describes the test hardware configurations, presents the results of all the analyses, and compares the results from the two analytical methods

Research Data Acquired in World-Class, 60-atm Subsonic Combustion Rig

NASA Technical Reports Server (NTRS)

Lee, Chi-Ming; Wey, Changlie

1999-01-01

NASA Lewis Research Center's new, world-class, 60-atmosphere (atm) combustor research facility, the Advanced Subsonic Combustion Rig (ASCR), is in operation and producing highly unique research data. Specifically, data were acquired at high pressures and temperatures representative of future subsonic engines from a fundamental flametube configuration with an advanced fuel injector. The data acquired include exhaust emissions as well as pressure and temperature distributions. Results to date represent an improved understanding of nitrous oxide (NOx) formation at high pressures and temperatures and include an NOx emissions reduction greater than 70 percent with an advanced fuel injector at operating pressures to 800 pounds per square inch absolute (psia). ASCR research is an integral part of the Advanced Subsonic Technology (AST) Propulsion Program. This program is developing critical low-emission combustion technology that will result in the next generation of gas turbine engines producing 50 to 70 percent less NOx emissions in comparison to 1996 International Civil Aviation Organization (ICAO) limits. The results to date indicate that the AST low-emission combustor goals of reducing NOx emissions by 50 to 70 percent are feasible. U.S. gas turbine manufacturers have started testing the low-emissions combustors at the ASCR. This collaborative testing will enable the industry to develop low-emission combustors at the high pressure and temperature conditions of future subsonic engines. The first stage of the flametube testing has been implemented. Four GE Aircraft Engines low-emissions fuel injector concepts, three Pratt & Whitney concepts, and two Allison concepts have been tested at Lewis ASCR facility. Subsequently, the flametube was removed from the test stand, and the sector combustor was installed. The testing of low emissions sector has begun. Low-emission combustors developed as a result of ASCR research will enable U.S. engine manufacturers to compete on a

Combustion of diesel fuel from a toxicological perspective. I. Origin of incomplete combustion products.

PubMed

Scheepers, P T; Bos, R P

1992-01-01

Since the use of diesel engines is still increasing, the contribution of their incomplete combustion products to air pollution is becoming ever more important. The presence of irritating and genotoxic substances in both the gas phase and the particulate phase constituents is considered to have significant health implications. The quantity of soot particles and the particle-associated organics emitted from the tail pipe of a diesel-powered vehicle depend primarily on the engine type and combustion conditions but also on fuel properties. The quantity of soot particles in the emissions is determined by the balance between the rate of formation and subsequent oxidation. Organics are absorbed onto carbon cores in the cylinder, in the exhaust system, in the atmosphere and even on the filter during sample collection. Diesel fuel contains polycyclic aromatic hydrocarbons (PAHs) and some alkyl derivatives. Both groups of compounds may survive the combustion process. PAHs are formed by the combustion of crankcase oil or may be resuspended from engine and/or exhaust deposits. The conversion of parent PAHs to oxygenated and nitrated PAHs in the combustion chamber or in the exhaust system is related to the vast amount of excess combustion air that is supplied to the engine and the high combustion temperature. Whether the occurrence of these derivatives is characteristic for the composition of diesel engine exhaust remains to be ascertained. After the emission of the particles, their properties may change because of atmospheric processes such as aging and resuspension. The particle-associated organics may also be subject to (photo)chemical conversions or the components may change during sampling and analysis. Measurement of emissions of incomplete combustion products as determined on a chassis dynamometer provides knowledge of the chemical composition of the particle-associated organics. This knowledge is useful as a basis for a toxicological evaluation of the health hazards of

One-step solution combustion synthesis of pure Ni nanopowders with enhanced coercivity: The fuel effect

NASA Astrophysics Data System (ADS)

Khort, Alexander; Podbolotov, Kirill; Serrano-García, Raquel; Gun'ko, Yurii K.

2017-09-01

In this paper, we report a new modified one-step combustion synthesis technique for production of Ni metal nanoparticles. The main unique feature of our approach is the use of microwave assisted foam preparation. Also, the effect of different types of fuels (urea, citric acid, glycine and hexamethylenetetramine) on the combustion process and characteristics of resultant solid products were investigated. It is observed that the combination of microwave assisted foam preparation and using of hexamethylenetetramine as a fuel allows producing pure ferromagnetic Ni metal nanoparticles with enhanced coercivity (78 Oe) and high value of saturation magnetization (52 emu/g) by one-step solution combustion synthesis under normal air atmosphere without any post-reduction processing.

The Combination of Internal-Combustion Engine and Gas Turbine

NASA Technical Reports Server (NTRS)

Zinner, K.

1947-01-01

While the gas turbine by itself has been applied in particular cases for power generation and is in a state of promising development in this field, it has already met with considerable success in two cases when used as an exhaust turbine in connection with a centrifugal compressor, namely, in the supercharging of combustion engines and in the Velox process, which is of particular application for furnaces. In the present paper the most important possibilities of combining a combustion engine with a gas turbine are considered. These "combination engines " are compared with the simple gas turbine on whose state of development a brief review will first be given. The critical evaluation of the possibilities of development and fields of application of the various combustion engine systems, wherever it is not clearly expressed in the publications referred to, represents the opinion of the author. The state of development of the internal-combustion engine is in its main features generally known. It is used predominantly at the present time for the propulsion of aircraft and road vehicles and, except for certain restrictions due to war conditions, has been used to an increasing extent in ships and rail cars and in some fields applied as stationary power generators. In the Diesel engine a most economical heat engine with a useful efficiency of about 40 percent exists and in the Otto aircraft engine a heat engine of greatest power per unit weight of about 0.5 kilogram per horsepower.

Advanced bridge safety initiative : live load testing and load rating of the Evans Brook Bridge (#5506) and the Hastings Bridge (#5507) in Batchelders Grant, Maine.

DOT National Transportation Integrated Search

2014-01-01

The Advanced Structures and Composites Center at the University of Maine (UMaine) performed live load testing : and rating factor analysis for two bridges (No. 5506 and No. 5507) in Batchelders Grant, Maine. The bridge load : rating performed by cons...

Performance of a flameless combustion furnace using biogas and natural gas.

PubMed

Colorado, A F; Herrera, B A; Amell, A A

2010-04-01

Flameless combustion technology has proved to be flexible regarding the utilization of conventional fuels. This flexibility is associated with the main characteristic of the combustion regime, which is the mixing of the reactants above the autoignition temperature of the fuel. Flameless combustion advantages when using conventional fuels are a proven fact. However, it is necessary to assess thermal equipments performance when utilizing bio-fuels, which usually are obtained from biomass gasification and the excreta of animals in bio-digesters. The effect of using biogas on the performance of an experimental furnace equipped with a self-regenerative Flameless burner is reported in this paper. All the results were compared to the performance of the system fueled with natural gas. Results showed that temperature field and uniformity are similar for both fuels; although biogas temperatures were slightly lower due to the larger amount of inert gases (CO(2)) in its composition that cool down the reactions. Species patterns and pollutant emissions showed similar trends and values for both fuels, and the energy balance for biogas showed a minor reduction of the efficiency of the furnace; this confirms that Flameless combustion is highly flexible to burn conventional and diluted fuels. Important modifications on the burner were not necessary to run the system using biogas. Additionally, in order to highlight the advantages of the Flameless combustion regime, some comparisons of the burner performance working in Flameless mode and working in conventional mode are presented. Copyright 2009 Elsevier Ltd. All rights reserved.

Combustion distribution control using the extremum seeking algorithm

NASA Astrophysics Data System (ADS)

Marjanovic, A.; Krstic, M.; Djurovic, Z.; Kvascev, G.; Papic, V.

2014-12-01

Quality regulation of the combustion process inside the furnace is the basis of high demands for increasing robustness, safety and efficiency of thermal power plants. The paper considers the possibility of spatial temperature distribution control inside the boiler, based on the correction of distribution of coal over the mills. Such control system ensures the maintenance of the flame focus away from the walls of the boiler, and thus preserves the equipment and reduces the possibility of ash slugging. At the same time, uniform heat dissipation over mills enhances the energy efficiency of the boiler, while reducing the pollution of the system. A constrained multivariable extremum seeking algorithm is proposed as a tool for combustion process optimization with the main objective of centralizing the flame in the furnace. Simulations are conducted on a model corresponding to the 350MW boiler of the Nikola Tesla Power Plant, in Obrenovac, Serbia.

Energy Conversion and Combustion Sciences

DTIC Science & Technology

2012-03-08

Rotational /Continuous Detonation • Only Single Initiation needed (Circumvent Initiation/DDT difficulty/loss in PDE ) • 10-100x cycle rate increase • Near...new fuels: 1. Rotational or Continuous Detonation (intense/concentrated combustion); 2. Flameless combustion (distributed combustion process...Steady Exit Flow *CFD Courtesy of NRL Rotational Detonation : (PI: Schauer, AFRL/RZ, working with NRL) Rotational Approach Allows Continuous

One Step Combustion Synthesis Of YAG:Ce Phosphor For Solid State Lighting

NASA Astrophysics Data System (ADS)

Yadav, Pooja; Gupta, K. Vijay Kumar; Muley, Aarti; Joshi, C. P.; Moharil, S. V.

2011-10-01

YAG:Ce is an important phosphor having applications in various fields ranging from solid state lighting to scintillation detectors. YAG phosphors doped with activators are mainly synthesized by solid state reaction techniques that require high sintering temperatures (above 1500°C) to eliminate YAM and YAP phases. Though several soft chemical routes have been explored for synthesis of YAG, most of these methods are complex and phase pure materials are not obtained in one step, but prolonged annealing at temperatures around 1000 C or above becomes necessary. One step combustion synthesis of YAG:Ce3+ and related phosphors carried out at 500 C furnace temperature is reported here. Activation with Ce3+ could be achieved during the synthesis without taking recourse to any post-combustion thermal treatment. LEDs prepared from the combustion synthesized YAG:Ce3+, exhibited properties comparable to those produced from the commercial phosphor.

Cavity Coupled Aeroramp Injector Combustion Study

DTIC Science & Technology

2009-08-01

Lin 5 Taitech Inc., Beavercreek, OH, 45430 The difficulties with fueling of supersonic combustion ramjet engines with hydrocarbon based fuels...combustor to not force the pre- combustion shock train out of the isolator and, in a full engine with inlet, cause an inlet unstart and likely...metric used to quantify engine performance is the combustion efficiency. Figure 9 shows the comparison of the combustion efficiency as a function of

Partitioning factor of mercury during coal combustion in low capacity domestic heating units.

PubMed

Hlawiczka, Stanislaw; Kubica, Krystyna; Zielonka, Urszula

2003-08-01

Data from an experiment concerning Hg emission from coal combustion in a furnace of 5.6 kW capacity are presented. The goal of the experiment was to define how much of the mercury in coal combusted in the stove was emitted to the atmosphere in gaseous form because vapors contribute mainly to human intake of the metal from ambient air. The partitioning factor kappa, defined as the ratio of gaseous mercury mass emitted to the air and mercury mass contained in the unit coal mass before combustion was evaluated. The mean value of the kappa factors determined in the study was 0.52 indicating that on average only 52% of the mercury was emitted to the air in gaseous form during coal combustion in an apparatus similar to a domestic furnace. The kappa value determined seems relatively low indicating that besides mercury emitted to the atmosphere in gaseous form, a large portion of the mercury is present in particulate matter trapped in the chimney duct and emitted to the air.

Hypergolic Combustion Demonstration in a Reciprocating Internal Combustion Engine

DTIC Science & Technology

1984-05-01

deposit problem encountered with Pearl Kerosene. Specifications and properties data for JP-7 fuel are in Table 5-2. 5.5.3. Methanol. Methanol ( CH OH...methylphenol, 0./1,000 bbls. 8.4 max. 8.4 PWA536, PPM 200-250 225 27 ’, •X TABLE 5-3. Typical Properties for Methanol(8) Formula CH 0,i Molecular weight 32.&2...46_ LIST OF REFERENCES (1) Hopple, L. 0. "Pyrophoric Combustion in Internal Combustion Engines," Eaton Technical Report No. 7845 , 1978. (2) Hoppie

Selection of technology for the low calorific synthetic gas combustion in the gas turbine combustion chamber

NASA Astrophysics Data System (ADS)

Filippov, Prokopy; Levin, Evgeny; Ryzhkov, Alexander

2017-10-01

The leading gas turbines manufacturers are developing the technologies of the environmental friendly combustion of industrial and synthetic gases of low calorific values. In this case they are faced with critical problems concerning combustion stability assurance and the necessity of the gas turbines significant modernization due to the differences between the low calorific and natural gases. The numerical simulation results of the low calorific value synthetic gas combustion in the combustion chamber by means of different technologies are considered in the paper.

Transient combustion in hybrid rockets

NASA Astrophysics Data System (ADS)

Karabeyoglu, Mustafa Arif

1998-09-01

Hybrid rockets regained interest recently as an alternative chemical propulsion system due to their advantages over the solid and liquid systems that are currently in use. Development efforts on hybrids revealed two important problem areas: (1) low frequency instabilities and (2) slow transient response. Both of these are closely related to the transient behavior which is a poorly understood aspect of hybrid operation. This thesis is mainly involved with a theoretical study of transient combustion in hybrid rockets. We follow the methodology of identifying and modeling the subsystems of the motor such as the thermal lags in the solid, boundary layer combustion and chamber gasdynamics from a dynamic point of view. We begin with the thermal lag in the solid which yield the regression rate for any given wall heat flux variation. Interesting phenomena such as overshooting during throttling and the amplification and phase lead regions in the frequency domain are discovered. Later we develop a quasi-steady transient hybrid combustion model supported with time delays for the boundary layer processes. This is integrated with the thermal lag system to obtain the thermal combustion (TC) coupled response. The TC coupled system with positive delays generated low frequency instabilities. The scaling of the instabilities are in good agreement with actual motor test data. Finally, we formulate a gasdynamic model for the hybrid chamber which successfully resolves the filling/emptying and longitudinal acoustic behavior of the motor. The TC coupled system is later integrated to the gasdynamic model to obtain the overall response (TCG coupled system) of gaseous oxidizer motors with stiff feed systems. Low frequency instabilities were also encountered for the TCG coupled system. Apart from the transient investigations, the regression rate behavior of liquefying hybrid propellants such as solid cryogenic materials are also studied. The theory is based on the possibility of enhancement

Organic coal-water fuel: Problems and advances (Review)

NASA Astrophysics Data System (ADS)

Glushkov, D. O.; Strizhak, P. A.; Chernetskii, M. Yu.

2016-10-01

The study results of ignition of organic coal-water fuel (OCWF) compositions were considered. The main problems associated with investigation of these processes were identified. Historical perspectives of the development of coal-water composite fuel technologies in Russia and worldwide are presented. The advantages of the OCWF use as a power-plant fuel in comparison with the common coal-water fuels (CWF) were emphasized. The factors (component ratio, grinding degree of solid (coal) component, limiting temperature of oxidizer, properties of liquid and solid components, procedure and time of suspension preparation, etc.) affecting inertia and stability of the ignition processes of suspensions based on the products of coaland oil processing (coals of various types and metamorphism degree, filter cakes, waste motor, transformer, and turbine oils, water-oil emulsions, fuel-oil, etc.) were analyzed. The promising directions for the development of modern notions on the OCWF ignition processes were determined. The main reasons limiting active application of the OCWF in power generation were identified. Characteristics of ignition and combustion of coal-water and organic coal-water slurry fuels were compared. The effect of water in the composite coal fuels on the energy characteristics of their ignition and combustion, as well as ecological features of these processes, were elucidated. The current problems associated with pulverization of composite coal fuels in power plants, as well as the effect of characteristics of the pulverization process on the combustion parameters of fuel, were considered. The problems hindering the development of models of ignition and combustion of OCWF were analyzed. It was established that the main one was the lack of reliable experimental data on the processes of heating, evaporation, ignition, and combustion of OCWF droplets. It was concluded that the use of high-speed video recording systems and low-inertia sensors of temperature and gas

Smoldering Combustion Experiments in Microgravity

NASA Technical Reports Server (NTRS)

Walther, David C.; Fernandez-Pello, A. Carlos; Urban, David L.

1997-01-01

The Microgravity Smoldering Combustion (MSC) experiment is part of a study of the smolder characteristics of porous combustible materials in a microgravity environment. Smoldering is a non-flaming form of combustion that takes place in the interior of porous materials and takes place in a number of processes ranging from smoldering of porous insulation materials to high temperature synthesis of metals. The objective of the study is to provide a better understanding of the controlling mechanisms of smolder, both in microgravity and normal-gravity. As with many forms of combustion, gravity affects the availability of oxidizer and transport of heat, and therefore the rate of combustion. Microgravity smolder experiments, in both a quiescent oxidizing environment, and in a forced oxidizing flow have been conducted aboard the NASA Space Shuttle (STS-69 and STS-77 missions) to determine the effect of the ambient oxygen concentration and oxidizer forced flow velocity on smolder combustion in microgravity. The experimental apparatus is contained within the NASA Get Away Special Canister (GAS-CAN) Payload. These two sets of experiments investigate the propagation of smolder along the polyurethane foam sample under both diffusion driven and forced flow driven smoldering. The results of the microgravity experiments are compared with identical ones carried out in normal gravity, and are used to verify present theories of smolder combustion. The results of this study will provide new insights into the smoldering combustion process. Thermocouple histories show that the microgravity smolder reaction temperatures (Ts) and propagation velocities (Us) lie between those of identical normal-gravity upward and downward tests. These observations indicate the effect of buoyancy on the transport of oxidizer to the reaction front.

36th International Symposium on Combustion (ISOC2016)

DTIC Science & Technology

2016-12-01

GREENHOUSE GASES / IC ENGINE COMBUSTION I GAS TURBINE COMBUSTION I NOVEL COMBUSTION CONCEPTS, TECHNOLOGIES AND SYSTEMS 15. SUBJECT TERMS Reaction...pollutants and greenhouse gases; IC engine combustion; Gas turbine combustion; Novel combustion concepts, technologies and systems 16. SECURITY...PLENARY LECTURE TRANSFER (15 min) am Turbulent Flames IC Engines Laminar Flames Reaction Kinetics Gas Turbines Soot Solid Fuels/Pollutants

AIR EMISSIONS FROM SCRAP TIRE COMBUSTION

EPA Science Inventory

The report discusses air emissions from two types of scrap tire combustion: uncontrolled and controlled. Uncontrolled sources are open tire fires, which produce many unhealthful products of incomplete combustion and release them directly into the atmosphere. Controlled combustion...

Closeup View of the Space Shuttle Main Engine (SSME) 2044 ...

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

Close-up View of the Space Shuttle Main Engine (SSME) 2044 mounted in a SSME Engine Handler in the SSME processing Facility at Kennedy Space Center. This view shows SSME 2044 with its expansion nozzle removed and an Engine Leak-Test Plug is set in the throat of the Main Combustion Chamber in the approximate center of the image, the insulated, High-Pressure Fuel Turbopump sits below that and the Low Pressure Oxidizer Turbopump Discharge Duct sits towards the top of the engine assembly in this view. - Space Transportation System, Space Shuttle Main Engine, Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Design and fabrication of advanced materials from Illinois coal wastes. Quarterly report, 1 March 1995--31 May 1995

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

Malhotra, V.M.; Wright, M.A.

1995-12-31

The main goal of this project is to develop a bench-scale procedure to design and fabricate advanced brake and structural composite materials from Illinois coal combustion residues. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), differential thermal analysis (DTA), and transmission-Fourier transform infrared (FTIR) were conducted on PCC fly ash (Baldwin), FBC fly ash (ADM unit1-6), FBC fly ash (S.I. coal), FBC spent bed ash (ADM unit1-6), bottom ash, and scrubber sludge (CWLP) residues to characterize their geometrical shapes, mineral phases, and thermal stability. Our spectroscopic results indicate that the scrubber sludge is mainly composed of a gypsum-like phase whosemore » lattice structure is different from the lattice structure of conventional gypsum, and sludge does not contain hannebachite (CaSO{sub 3}0.5H{sub 2}O) phase. In the second and third quarters the focus of research has been on developing protocols for the formation of advanced brake composites and structural composites. Our attempts to fabricate brake frictional shoes, in the form of 1.25 inch disks, from PCC fly ash, FBC spent bed ash, scrubber sludge, coal char, iron particles, and coal tar were successful. Based on the experience gained and microscopic analyses, we have now upscaled our procedures to fabricate 2.5 inch diameter disks from coal combustion residues. The SEM and Young`s modulus analyses of brake composites fabricated at 400 psi < Pressure < 2200 psi suggest pressure has a strong influence on the particle packing and the filling of interstices in our composites.« less

The effect of azeotropism on combustion characteristics of blended fuel pool fire.

PubMed

Ding, Yanming; Wang, Changjian; Lu, Shouxiang

2014-04-30

The effect of azeotropism on combustion characteristics of blended fuel pool fire was experimentally studied in an open fire test space of State Key Laboratory of Fire Science. A 30 cm × 30 cm square pool filled with n-heptane and ethanol blended fuel was employed. Flame images, burning rate and temperature distribution were collected and recorded in the whole combustion process. Results show that azeotropism obviously dominates the combustion behavior of n-heptane/ethanol blended fuel pool fire. The combustion process after ignition exhibits four typical stages: initial development, azeotropic burning, single-component burning and decay stage. Azeotropism appears when temperature of fuel surface reaches azeotropic point and blended fuel burns at azeotropic ratio. Compared with individual pure fuel, the effect of azeotropism on main fire parameters, such as flame height, burning rate, flame puffing frequency and centerline temperature were analyzed. Burning rate and centerline temperature of blended fuel are higher than that of individual pure fuel respectively at azeotropic burning stage, and flame puffing frequency follows the empirical formula between Strouhal and Froude number for pure fuel. Copyright © 2014 Elsevier B.V. All rights reserved.

Co-combustion of E+E waste plastics in the TAMARA test plant

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

Vehlow, J.; Wanke, T.; Bergfeldt, B.

1997-12-01

The co-combustion of different amounts of various plastic fractions of electrical and electronic (E+E) waste together with municipal solid waste has been tested in the Karlsruhe test incinerator TAMARA. The tests revealed no negative influences upon the combustion process. In general the increased heating value of the fuel causes an improved burnout in all residue streams. The halogens Cl and Br added with the plastics are mainly transferred as HCl or HBr into the flue gas. An influence upon the formation of chlorinated dioxins and furans could not be observed. With increasing Br feed bromine containing homologues were detected inmore » the raw gas. The furans formed easier than the dioxins and those homologues carrying one Br atom were by far prevailing. Even at high Br input the total amount of mixed halogenated species was limited to approximately 30% of the total load of such compounds which did not leave the typical operation window for PCDD/PCDF in TAMARA. The co-combustion tests demonstrated that MSW combustion is an ecologically acceptable and economically sound disposal route for limited amounts of specific E+E waste.« less

Three Dimensional Transient Turbulent Simulations of Scramjet Fuel Injection and Combustion

NASA Astrophysics Data System (ADS)

Bahbaz, Marwane

2011-11-01

Scramjet is a propulsion system that is more effective for hypersonic flights (M >5). The main objective of the simulation is to understand both the mixing and combustion process of air flow using hydrogen fuel in high speed environment s. The understanding of this phenomenon is used to determine the number of fuel injectors required to increase combustion efficiency and energy transfer. Due to the complexity of this simulation, multiple software tools are used to achieve this objective. First, Solid works is used to draw a scramjet combustor with accurate measurements. Second software tool used is Gambit; It is used to make several types of meshes for the scramjet combustor. Finally, Open Foam and CFD++ are software used to process and post process the scramjet combustor. At this stage, the simulation is divided into two categories. The cold flow category is a series of simulations that include subsonic and supersonic turbulent air flow across the combustor channel with fuel interaction from one or more injectors'. The second category is the combustion simulations which involve fluid flow and fuel mixing with ignition. The simulation and modeling of scramjet combustor will assist to investigate and understand the combustion process and energy transfer in hypersonic environment.

Combustion products generating and metering device

NASA Technical Reports Server (NTRS)

Wiberg, R. E.; Klisch, J. A. (Inventor)

1971-01-01

An apparatus for generating combustion products at a predetermined fixed rate, mixing the combustion products with air to achieve a given concentration, and distributing the resultant mixture to an area or device to be tested is described. The apparatus is comprised of blowers, a holder for the combustion product generating materials (which burn at a predictable and controlled rate), a mixing plenum chamber, and a means for distributing the air combustion product mixture.

A combustion driven shock tunnel to complement the free piston shock tunnel T5 at GALCIT

NASA Technical Reports Server (NTRS)

Belanger, Jacques; Hornung, Hans G.

1992-01-01

A combustion driven shock tunnel was designed and built at GALCIT to supply the hypersonic facility T5 with 'hot' hydrogen for mixing and combustion experiments. This system was chosen over other options for better flexibility and for safety reasons. The shock tunnel is described and the overall efficiency of the system is discussed. The biggest challenge in the design was to synchronize the combustion driven shock tunnel with T5. To do so, the main diaphragm of the combustion driven shock tunnel is locally melted by an electrical discharge. This local melting is rapidly followed by the complete collapse of the diaphragm in a very repeatable way. A first set of experiments on supersonic hydrogen transverse jets over a flat plate have just been completed with the system and some of the preliminary results are presented.

Combustion and Magnetohydrodynamic Processes in Advanced Pulse Detonation Rocket Engines

NASA Astrophysics Data System (ADS)

Cole, Lord Kahil

A number of promising alternative rocket propulsion concepts have been developed over the past two decades that take advantage of unsteady combustion waves in order to produce thrust. These concepts include the Pulse Detonation Rocket Engine (PDRE), in which repetitive ignition, propagation, and reflection of detonations and shocks can create a high pressure chamber from which gases may be exhausted in a controlled manner. The Pulse Detonation Rocket Induced Magnetohydrodynamic Ejector (PDRIME) is a modification of the basic PDRE concept, developed by Cambier (1998), which has the potential for performance improvements based on magnetohydrodynamic (MHD) thrust augmentation. The PDRIME has the advantage of both low combustion chamber seeding pressure, per the PDRE concept, and efficient energy distribution in the system, per the rocket-induced MHD ejector (RIME) concept of Cole, et al. (1995). In the initial part of this thesis, we explore flow and performance characteristics of different configurations of the PDRIME, assuming quasi-one-dimensional transient flow and global representations of the effects of MHD phenomena on the gas dynamics. By utilizing high-order accurate solvers, we thus are able to investigate the fundamental physical processes associated with the PDRIME and PDRE concepts and identify potentially promising operating regimes. In the second part of this investigation, the detailed coupling of detonations and electric and magnetic fields are explored. First, a one-dimensional spark-ignited detonation with complex reaction kinetics is fully evaluated and the mechanisms for the different instabilities are analyzed. It is found that complex kinetics in addition to sufficient spatial resolution are required to be able to quantify high frequency as well as low frequency detonation instability modes. Armed with this quantitative understanding, we then examine the interaction of a propagating detonation and the applied MHD, both in one-dimensional and two

Detection and analysis of emitted radiation for advanced monitoring and control of combustors

NASA Astrophysics Data System (ADS)

Ballester, J.; Sanz, A.; Hernandez, R.; Smolarz, A.

2005-09-01

The permanent optimization of combustion equipment could provide very important benefits in terms of efficiency, reliability and reduced pollution. However, current capabilities for monitoring and control of industrial flames are very limited; the lack of reliable diagnostic techniques is, most probably, the main obstacle to achieve those goals. Novel instrumentation systems based on the processing of the radiation emitted by the flames could help greatly to fill this gap, as radiation signals are known to contain very rich information about flame properties Optical sensors offer the benefit of being selective, rapid and able to gather data from extremely hostile environments. Passive optical sensors offer the further advantages of simplicity and low cost. With the rapidly growing capability of sensor hardware, there is an increased interest and need to develop data interpretation strategies that will allow optical flame emission data to be converted into meaningful combustor state information. The present work describes new results achieved on the use of optical sensors for the development of advanced monitoring systems of lean-premixed flames representative of gas turbine combustors. Different complementary signals have been analyzed: broad band emission using a Si photodiode, a narrow band around 310 nm measured with a photomultiplier and measurement of UV+VIS emission spectra. The signals have been processed using both conventional and advanced methods. The results obtained demonstrate that optical sensors can yield useful, instantaneous information on the actual flame properties, not available with the sensors currently used in practical combustion systems.

Simulation of low temperature combustion mechanism of different combustion-supporting agents in close-coupled DOC and DPF system.

PubMed

Jiao, Penghao; Li, Zhijun; Li, Qiang; Zhang, Wen; He, Li; Wu, Yue

2018-07-01

In the coupled Diesel Oxidation Catalyst (DOC) and Diesel Particular Filter (DPF) system, soot cannot be completely removed by only using the passive regeneration. And DPF active regeneration is necessary. The research method in this paper is to spray different kinds of combustion-supporting agents to the DOC in the front of the DPF. Therefore, the low temperature combustion mechanism of different kinds of combustion-supporting agents in DOC was studied, in order to grasp the law of combustion in DOC, and the influence of follow-up emission on DPF removal of soot. During the study, CH 4 H 2 mixture and diesel (n-heptane + toluene) were used as combustion-supporting agents respectively. The simplified mechanisms of two kinds of gas mixtures used as the combustion-supporting agents in DPF have been constructed and testified in the paper. In this paper, the combustion and emission conditions of the two combustion-supporting agents were analyzed so as to meet the practical requirements of different working conditions. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.