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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5

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NASA NTRS1981

Development of a high-temperature durable catalyst for use in catalytic combustors for advanced automotive gas turbine engines

Durable catalytic reactors for advanced gas turbine engines were developed. Objectives were: to evaluate furnace aging as a cost effective catalytic reactor screening test, measure reactor degradation as a function of furnace aging, demonstrate 1,000 hours of combustion durability, and define a catalytic reactor system with a high probability of successful integration into an automotive gas turbine engine. Fourteen different catalytic reactor concepts were evaluated, leading to the selection of one for a durability combustion test with diesel fuel for combustion conditions. Eight additional catalytic reactors were evaluated and one of these was successfully combustion tested on propane fuel. This durability reactor used graded cell honeycombs and a combination of noble metal and metal oxide catalysts. The reactor was catalytically active and structurally sound at the end of the durability test.

Tong, H.↗

NASA NTRS1981

Ceramics for the AGT101 automotive gas turbine

An advanced gas turbine powertrain for automotive application is being developed. Objectives of the program include a fuel consumption of 42.8 mpg on No. 2 diesel fuel in a 3000 pound car, same overall vehicle performance as obtained with a conventional spark ignition internal combustion engine, low emission, multiple fuel capacity, reliability, and competitive cost. The AGT101 powertrain consists of a power section, gearbox and transmission, and the design and analysis conducted thus far support the initial engine concept, as no significant design changes have been required. The ceramic rotor design approach and component materials are discussed, and it is projected that the AGT powertrain will be competitive with any other alternative powertrain in meeting the design objectives.

Kreiner, D. M.↗

NASA NTRS1944

Researches on the Piston Ring

In internal combustion engines, steam engines, air compressors, and so forth, the piston ring plays an important role. Especially, the recent development of Diesel engines which require a high compression pressure for their working, makes, nowadays, the packing action of the piston ring far more important than ever. Though a number of papers have been published in regard to researches on the problem of the piston ring, none has yet dealt with an exact measurement of pressure exerted on the cylinder wall at any given point of the ring. The only paper that can be traced on this subject so far is Mr. Nakagawa's report on the determination of the relative distribution of pressure on the cylinder wall, but the measuring method adopted therein appears to need further consideration. No exact idea has yet been obtained as to how the obturation of gas between the piston and cylinder, the frictional resistance of the piston, and the wear of the cylinder wall are affected by the intensity and the distribution of the radial pressure of the piston ring. Consequently, the author has endeavored, by employing an apparatus of his own invention, to get an exact determination of the pressure distribution of the piston ring. By means of a newly devised ring tester, to which piezoelectricity of quartz was applied, the distribution of the radial pressure of many sample rings on the market was accurately determined. Since many famous piston rings show very irregular pressure distribution, the author investigated and achieved a manufacturing process of the piston ring which will exert uniform pressure on the cylinder wall. Temperature effects on the configuration and on the mean spring power have also been studied. Further, the tests were performed to ascertain how the gas tightness of the piston ring may be affected by the number or spring power. The researches as to the frictional resistance between the piston ring and the cylinder wall were carried out, too. The procedure of study, and experiments conducted by the author, on this subject will be fully described in the following paragraphs.

Ehihara, Keikiti↗

NASA NTRS1938

Auto-Ignition and Combustion of Diesel Fuel in a Constant-Volume Bomb

Report presents the results of a study of variations in ignition lag and combustion associated with changes in air temperature and density for a diesel fuel in a constant-volume bomb. The test results have been discussed in terms of engine performance wherever comparisons could be drawn. The most important conclusions drawn from this investigation are: the ignition lag was essentially independent of the injected fuel quantity. Extrapolation of the curves for the fuel used shows that the lag could not be greatly decreased by exceeding the compression-ignition engines. In order to obtain the best combustion and thermal efficiency, it was desirable to use the longest ignition lag consistent with a permissible rate of pressure rise.

Selden, Robert F↗

NASA NTRS1936

Automatic stabilization

This report concerns the study of automatic stabilizers and extends it to include the control of the three-control system of the airplane instead of just altitude control. Some of the topics discussed include lateral disturbed motion, static stability, the mathematical theory of lateral motion, and large angles of incidence. Various mechanisms and stabilizers are also discussed. The feeding of Diesel engines by injection pumps actuated by engine compression, achieves the required high speeds of injection readily and permits rigorous control of the combustible charge introduced into each cylinder and of the peak pressure in the resultant cycle.

Haus, FR↗

NASA NTRSDate not supplied

Liquid Jet Response to Detonation Waves in a Linear Detonation Combustor

The impact of periodic detonation wave impact on a liquid fuel jet is investigated in a linear detonation combustor. The linear detonation combustor operated with gaseous natural gas and oxygen generates sustained, self-excited detonation waves that propagate along its length at approximately 8 kHz, representing a wave propagation frequency in typical rocket rotating detonation engines. The effect of the detonation wave on the dynamic injection and break-up of a single diesel jet injected into the combustion chamber at varying injection pressures is evaluated with chemiluminescence, fuel planar laser induced fluorescence and Mie scattering measurements at 100 kHz. The detonation wave significantly impacts the liquid jet trajectory with its deflection in both windward and leeward direction as the adverse pressure gradient across it changes between wave passages. The maximum recovery height of the liquid jet is observed to be consistent across all operating conditions, and dependent on the detonation wave strength in the chamber.

propulsion↗

NASA NTRS1977

Durability testing at one atmosphere of advanced catalysts and catalyst supports for automotive gas turbine engine combustors, part 1

The durability of catalysts and catalyst supports in a combustion environment was experimentally demonstrated. A test of 1000 hours duration was completed with two catalysts, using diesel fuel and operating at catalytically supported thermal combustion conditions. The performance of the catalysts was determined by monitoring emissions throughout the test, and by examining the physical condition of the catalyst core at the conclusion of the test. The test catalysts proved to be capable of low emissions operation after 1000 hours diesel aging, with no apparent physical degradation of the catalyst support.

Heck, R. M.↗

NASA NTRS1979

Durability testing of advanced catalysts and catalyst supports for gas turbine engine combustors

The paper presents new information on the durability of a CATCOM catalyst operating at low-emission combustion temperatures (about 1527 K) with a liquid fuel, No. 2 diesel. Information on the activity of No. 2 diesel after 1000 hr of aging is given. In addition, a unique in situ activity test developed for monitoring the subtle changes in the catalyst activity of the CATCOM catalyst is also detailed. The study demonstrated the feasibility of using a CATCOM catalyst in catalytically supported thermal combustion for extended operating periods

Heck, R. M.↗

NASA NTRS1985

A computer simulation of the turbocharged turbo compounded diesel engine system: A description of the thermodynamic and heat transfer models

A computer simulation of the turbocharged turbocompounded direct-injection diesel engine system was developed in order to study the performance characteristics of the total system as major design parameters and materials are varied. Quasi-steady flow models of the compressor, turbines, manifolds, intercooler, and ducting are coupled with a multicylinder reciprocator diesel model, where each cylinder undergoes the same thermodynamic cycle. The master cylinder model describes the reciprocator intake, compression, combustion and exhaust processes in sufficient detail to define the mass and energy transfers in each subsystem of the total engine system. Appropriate thermal loading models relate the heat flow through critical system components to material properties and design details. From this information, the simulation predicts the performance gains, and assesses the system design trade-offs which would result from the introduction of selected heat transfer reduction materials in key system components, over a range of operating conditions.

Assanis, D. N.↗

NASA NTRS2020

High Pressure Transcritical Combustion (HPTC Combustion)

Combustion is the predominant source of the energy in the US and worldwide, and an overwhelming majority in the transportation sector, particularly liquid hydrocarbons (i.e., gasoline, diesel and jet fuel). Engine manufacturers move to higher operating pressures, above and beyond the critical pressures of the fuel, in order to optimize performance, maximize efficiency and reduce pollutant formation. The design of the next generation of engines, however, are limited by a lack of fundamental understanding of the thermo-physical properties, fluid behavior and chemical kinetics at these high pressures. Terrestrial laboratory studies are hampered by the ubiquitous buoyant flow that renders fundamental experiments difficult and/or impossible to interpret. Studying high pressure transcritical phenomena in microgravity allows researchers to investigate the fundamental aspects of phase change, chemical kinetics and property evaluation in a simplified geometry without the complicating influence of a buoyancy-induced flow.

Combustion↗

NASA NTRS1979

Tests of NASA ceramic thermal barrier coating for gas-turbine engines

A two-layer thermal barrier coating system with a bond coating of nickel-chromium-aluminum-yttrium and a ceramic coating of yttria-stabilized zirconia was tested for corrosion protection, thermal protection and durability. Full-scale gas-turbine engine tests demonstrated that this coating eliminated burning, melting, and warping of uncoated parts. During cyclic corrosion resistance tests made in marine diesel fuel products of combustion in a burner rig, the ceramic cracked on some specimens. Metallographic examination showed no base metal deterioration.

Liebert, C. H.↗

NASA NTRS1980

Thermal barrier coatings for heat engine components

A comprehensive NASA-Lewis program of coating development for aircraft gas turbine blades and vanes is presented. Improved ceramic layer compositions are investigated, along the MCrAlY bond films and the methods of uniform deposition of the coatings; the thermomechanical and fuel impurity tolerance limits of the coatings are being studied. Materials include the ZrO2-Y2O3/NiCrAlY system; the effects of the bond coat and zirconia composition on coating life and Mach 1 burner rig test results are discussed. It is concluded that Diesel engines can also utilize thermal barrier coatings; they have been used successfully on piston crowns and exhaust valves of shipboard engines to combat lower grade fuel combustion corrosion.

Levine, S. R.↗

NASA NTRS1984

Methods for heat transfer and temperature field analysis of the insulated diesel

Work done during phase 1 of a three-year program aimed at developing a comprehensive heat transfer and thermal analysis methodology oriented specifically to the design requirements of insulated diesel engines is reported. The technology developed in this program makes possible a quantitative analysis of the low heat rejection concept. The program is comprehensive in that it addresses all the heat transfer issues that are critical to the successful development of the low heat rejection diesel engine: (1) in-cylinder convective and radiative heat transfer; (2) cyclic transient heat transfer in thin solid layers at component surfaces adjacent to the combustion chamber; and (3) steady-state heat conduction in the overall engine structure. The Integral Technologies, Inc. (ITI) program is comprised of a set of integrated analytical and experimental tasks. A detailed review of the ITI program approach is provided, including the technical issues which underlie it and a summay of the methods that were developed.

Morel, T.↗

NASA NTRS1987

Design, calibration and error analysis of instrumentation for heat transfer measurements in internal combustion engines

The paper reports the methodology and uncertainty analyses of instrumentation for heat transfer measurements in internal combustion engines. Results are presented for determining the local wall heat flux in an internal combustion engine (using a surface thermocouple-type heat flux gage) and the apparent flame-temperature and soot volume fraction path length product in a diesel engine (using two-color pyrometry). It is shown that a surface thermocouple heat transfer gage suitably constructed and calibrated will have an accuracy of 5 to 10 percent. It is also shown that, when applying two-color pyrometry to measure the apparent flame temperature and soot volume fraction-path length, it is important to choose at least one of the two wavelengths to lie in the range of 1.3 to 2.3 micrometers. Carefully calibrated two-color pyrometer can ensure that random errors in the apparent flame temperature and in the soot volume fraction path length will remain small (within about 1 percent and 10-percent, respectively).

Ferguson, C. R.↗

NASA NTRS1978

General aviation internal combustion engine research programs at NASA-Lewis Research Center

An update is presented of non-turbine general aviation engine programs underway at the NASA-Lewis Research Center in Cleveland, Ohio. The program encompasses conventional, lightweight diesel and rotary engines. Its three major thrusts are: (a) reduced SFC's; (b) improved fuels tolerance; and (c) reducing emissions. Current and planned future programs in such areas as lean operation, improved fuel management, advanced cooling techniques and advanced engine concepts, are described. These are expected to lay the technology base, by the mid to late 1980's, for engines whose life cycle fuel costs are 30 to 50% lower than today's conventional engines.

Willis, E. A.↗

NASA NTRS1981

Performance and emissions characteristics of aqueous alcohol fumes in a DI diesel engine

A single cylinder DI Diesel engine was fumigated with ethanol and methanol in amounts up to 55% of the total fuel energy. The effects of aqueous alcohol fumigation on engine thermal efficiency, combustion intensity and gaseous exhaust emissions were determined. Assessment of changes in the biological activity of raw particulate and its soluble organic fraction were also made using the Salmonella typhimurium test. Alcohol fumigation improved thermal efficiency slightly at moderate and heavy loads, but increased ignition delay at all operating conditions. Carbon monoxide and unburned hydrocarbon emission generally increased with alcohol fumigation and showed no dependence on alcohol type or quality. Oxide of nitrogen emission showed a strong dependence on alcohol quality; relative emission levels decreased with increasing water content of the fumigant. Particulate mass loading rates were lower for ethanol fueled conditions. However, the biological activity of both the raw particulate and its soluble organic fraction was enhanced by ethanol fumigation at most operating conditions.

Heisey, J. B.↗

NASA NTRS1984

An overview of NASA intermittent combustion engine research

This paper overviews the current program, whose objective is to establish the generic technology base for advanced aircraft I.C. engines of the early 1990's and beyond. The major emphasis of this paper is on development of the past two years. Past studies and ongoing confirmatory experimental efforts are reviewed, which show unexpectly high potential when modern aerospace technologies are applied to inherently compact and balanced I.C. engine configurations. Currently, the program is focussed on two engine concepts the stratified-charge, multi-fuel rotary, and the lightweight two-stroke diesel. A review is given of contracted and planned high performance one-rotor and one-cylinder test engine work addressing several levels of technology. Also reviewed are basic supporting efforts, e.g., the development and experimental validation of computerized airflow and combustion process models, being performed in-house at Lewis Research Center and by university grants.

Willis, E. A.↗

NASA NTRS1984

An overview of NASA intermittent combustion engine research

This paper overviews the current program, whose objective is to establish the generic technology base for advanced aircraft I.C. engines of the early 1990's and beyond. The major emphasis of this paper is on development of the past two years. Past studies and ongoing confirmatory experimental efforts are reviewed, which show unexpectedly high potential when modern aerospace technologies are applied to inherently compact and balanced I.C. engine configurations. Currently, the program is focussed on two engine concepts, the stratified-charge, multi-fuel rotary and the lightweight two-stroke diesel. A review is given of contracted and planned high performance one-rotor and one-cylinder test engine work addressing several levels of technology. Also reviewed are basic supporting efforts, e.g., the development and experimental validation of computerized airflow and combustion process models, being performed in-house at Lewis Research Center and by university grants. Previously announced in STAR as N84-24583

Willis, E. A.↗