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Results for “FUEL COMBUSTION”

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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Ground idle performance improvement of a double-annular combustor by using simulated variable combustor geometry

A test program was undertaken to determine if variable combustor geometry could be used to reduce exhaust emissions of a low-pressure-ratio jet engine operating at ground idle conditions. Three techniques for varying combustor geometry were simulated. Other techniques evaluated were radial fuel staging and the use of preheated fuel. When simulated variable combustor geometry was employed with radial fuel staging, combustion efficiency at a fuel-air ratio of 0.01 was increased from 77 to 95 percent, and exhaust emissions of unburned hydrocarbons and carbon monoxide were significantly reduced.

Schultz, D. F.↗
NASA NTRS1992

Kuwait oil fires - Compositions of source smoke

While the Kuwait oil-fire smoke plumes manifested a pronounced impact on solar radiation in the Gulf region (such as visibility and surface temperatures), smoke plume concentrations of combustion-generated pollutants suggest that the overall chemical impact on the atmosphere of the smoke from these fires was probably much less than anticipated. Combustion in the Kuwaiti oil fires was surprisingly efficient, releasing on average more than 93 percent of the combusted hydrocarbon fuels as CO2. Correspondingly, combustion-produced quantities of carbon monoxide (CO) and carbonaceous particles were low, each about 2 percent by weight. The fraction of CH4 produced by the fires was also relatively low (about 0.2 percent), but source emissions of nonmethane hydrocarbons were high (about 2 percent). Processes other than combustion (e.g., volatilization) probably contributed significantly to the measured in-plume hydrocarbon concentrations. Sulfur emissions (particulate and gaseous) measured at the source fires were lower (about 0.5 percent) than predicted based on average sulfur contents in the crude. N2O emissions from the Kuwaiti oil fires were very low and often could not be distinguished from background concentrations.

Cofer, Wesley R., III↗
NASA NTRS1993

Japan's microgravity combustion science program

Most of energy used by us is generated by combustion of fuels. On the other hand, combustion is responsible for contamination of our living earth. Combustion, also, gives us damage to our life as fire or explosive accidents. Therefore, clean and safe combustion is now eagerly required. Knowledge of the combustion process in combustors is needed to achieve proper designs that have stable operation, high efficiency, and low emission levels. However, current understanding on combustion is far from complete. Especially, there is few useful information on practical liquid and solid particle cloud combustion. Studies on combustion process under microgravity condition will provide many informations for basic questions related to combustors.

Sato, Junichi↗
NASA NTRS2015

An Assessment of Combustion Dynamics in a Low-Nox, Second-Generation Swirl-Venturi Lean Direct Injection Combustion Concept

Dynamic pressure measurements were taken during flame-tube emissions testing of three second-generation swirl-venturi lean direct injection (SV-LDI) combustor configurations. These measurements show that combustion dynamics were typically small. However, a small number of points showed high combustion dynamics, with peak-to-peak dynamic pressure fluctuations above 0.5 psi. High combustion dynamics occurred at low inlet temperatures in all three SV-LDI configurations, so combustion dynamics were explored further at low temperature conditions. A point with greater than 1.5 psi peak-to-peak dynamic pressure fluctuations was identified at an inlet temperature of 450!F, a pressure of 100 psia, an air pressure drop of 3%, and an overall equivalence ratio of 0.35. This is an off design condition: the temperature and pressure are typical of 7% power conditions, but the equivalence ratio is high. At this condition, the combustion dynamics depended strongly on the fuel staging. Combustion dynamics could be reduced significantly without changing the overall equivalence ratio by shifting the fuel distribution between stages. Shifting the fuel distribution also decreased NOx emissions.

low emissions combustors↗
NASA NTRS1995

Fuel Injector With Shear Atomizer

Atomizer for injecting liquid fuel into combustion chamber uses impact and swirl to break incoming stream of fuel into small, more combustible droplets. Slanted holes direct flow of liquid fuel to stepped cylindrical wall. Impact on wall atomizes liquid. Air flowing past vanes entrains droplets of liquid in swirling flow. Fuel injected at pressure lower than customarily needed.

Beal, George W.↗
NASA NTRS2004

Quantitative Analysis of Spectral Interference of Spontaneous Raman Scattering in High-Pressure Fuel-Rich H2-Air Combustion

We present a theoretical study of the spectral interferences in the spontaneous Raman scattering spectra of major combustion products in 30-atm fuel-rich hydrogen-air flames. An effective methodology is introduced to choose an appropriate line-shape model for simulating Raman spectra in high-pressure combustion environments. The Voigt profile with the additive approximation assumption was found to provide a reasonable model of the spectral line shape for the present analysis. The rotational/vibrational Raman spectra of H2, N2, and H2O were calculated using an anharmonic-oscillator model using the latest collisional broadening coefficients. The calculated spectra were validated with data obtained in a 10-atm fuel-rich H2-air flame and showed excellent agreement. Our quantitative spectral analysis for equivalence ratios ranging from 1.5 to 5.0 revealed substantial amounts of spectral cross-talk between the rotational H2 lines and the N2 O-/Q-branch; and between the vibrational H2O(0,3) line and the vibrational H2O spectrum. We also address the temperature dependence of the spectral cross-talk and extend our analysis to include a cross-talk compensation technique that removes the nterference arising from the H2 Raman spectra onto the N2, or H2O spectra.

Kojima, Jun↗
NASA NTRS1980

Catalytic combustion of heavy partially-vaporized fuels

An experimental program to demonstrate efficient catalytic combustion of fuel-lean and fuel-rich mixtures of residual fuel and air, and to assess the influence of incomplete fuel vaporization on the performance of a catalytic reactor is being conducted. A 7.5-cm diameter catalytic reactor was designed and will be tested over a matrix of conditions representative of a gas turbine combustor inlet. For each of three test phases, two series of tests with a uniform but poorly vaporized (less than 50 percent) mixture of No. 6 fuel oil and air will be performed. In the first series, the non-vaporized fuel will be contained in a spray of droplets with a Sauter Mean Diameter (SMD) less than 30 microns. In the second series, the non-vaporized fuel will be characterized by a spray SMD approximately equal to 100 microns. The designs of the fuel injection system and the catalytic reactor are described in this paper.

Rosfjord, T. J.↗
NASA NTRS2018

Fuel Sensitivity of Gas Emissions, Lean Blowout and Combustion Dynamics for a 9-Point LDI Combustor

Fuel sensitivity of gaseous emissions, approach to lean blowout and combustion dynamics are evaluated in this study. Experiments were conducted at the NASA Glenn Research Center's CE-5 flame tube test facility with a 9-point Swirl-Venturi Lean Direct Injection (SV-LDI) combustor. A reference jet fuel (A2) and two test fuels (C1 and C3) from were provided by the National Jet Fuels Combustion Program (NJFCP). C1 is essentially a 2-component iso-paraffin test fuel with a low cetane number of 17, and C3 is a high viscosity test fuel. Approach to lean blowout was monitored in terms of the rapid increase in CO emissions index as equivalence ratio decreased, but testing did not proceed all the way to lean blowout (LBO). Burning C1 was found to produce lower NOx emissions, but C1 flame temperatures were about 25 K higher relative to A2 at near LBO points (where CO emissions increased very rapidly). The NOx emissions of C3 were similar to A2. At low power conditions where fuel injector performance is not optimized for this 9-point LDI combustor, C3 had higher CO emissions than A2 and C1, likely due to C3's higher viscosity relative to A2 and C1. No discernable difference in combustion dynamics was observed between the three fuels tested in the 9-point LDI combustor. While a systematic ignition test campaign was not conducted, it was observed that C1 required a higher equivalence ratio and inlet air temperature for test rig ignition compared to A2 and C3.

Lean Direct Injection↗
NASA NTRS1975

Investigation of critical burning of fuel droplets

Steady and unsteady combustion of liquid fuel droplets under rocket engine conditions was analyzed. Emphasis was placed on combustion at elevated pressures and temperatures. The results and their technical application to the design of liquid fueled rocket engines and the determination of combustion instability characteristics of these engines were summarized.

Faeth, G. M.↗
NASA NTRS1982

Electrostatic fuel conditioning of internal combustion engines

Diesel engines were tested to determine if they are influenced by the presence of electrostatic and magnetic fields. Field forces were applied in a variety of configurations including pretreatment of the fuel and air, however, no affect on engine performance was observed.

Gold, P. I.↗
NASA NTRS1980

A perturbation solution for transverse pressure-sensitive combustion instability in an annulus

A method for analysis of combustion instability in rocket motors based on a combination of the Galerkin method and the two-variable (or multiple-scales) perturbation method is developed. The method is illustrated by applying it to the problem of pressure-sensitive combustion instability in a liquid-fuel annular combustion chamber. To the order of approximation inherent in the method it is found that the complete linear stability analysis and most of the nonlinear stability analysis can be carried out in closed form. The results thus obtained are used to clarify several aspects of the interpretation of numerical solutions obtained by previous investigators.

Googerdy, A.↗
NASA NTRS1983

Catalog of selected heavy duty transport energy management models

A catalog of energy management models for heavy duty transport systems powered by diesel engines is presented. The catalog results from a literature survey, supplemented by telephone interviews and mailed questionnaires to discover the major computer models currently used in the transportation industry in the following categories: heavy duty transport systems, which consist of highway (vehicle simulation), marine (ship simulation), rail (locomotive simulation), and pipeline (pumping station simulation); and heavy duty diesel engines, which involve models that match the intake/exhaust system to the engine, fuel efficiency, emissions, combustion chamber shape, fuel injection system, heat transfer, intake/exhaust system, operating performance, and waste heat utilization devices, i.e., turbocharger, bottoming cycle.

Colello, R. G.↗
NASA NTRS1952

Comparison of turbojet-engine altitude performance characteristics and ignition limits with MIL-F-5624A fuel, grades JP-3 and JP-4

The performance of MIL-F-5624A fuels, grades JP-3 and JP-4, was investigated in an axial-flow turbojet engine over a range of altitude conditions of 10,000 to 55,000 feet. Examination of the fuel flow, combustion efficiency, and net thrust specific fuel consumption showed the grade JP-4 fuel to be slightly inferior to the grade JP-3 fuel, although the altitude ignition limits were essentially equal for the two fuels over a range of flight Mach numbers and fuel-inlet temperatures.

FUELS - TURBINE ENGINES, RAM JETS, AND PULSE JETS↗
NASA NTRS1993

Apparatus for testing high pressure injector elements

An apparatus for testing and evaluating the spray pattern of high pressure fuel injector elements for use in supplying fuel to combustion engines is presented. Prior art fuel injector elements were normally tested by use of low pressure apparatuses which did not provide a purge to prevent mist from obscuring the injector element or to prevent frosting of the view windows; could utilize only one fluid during each test; and had their viewing ports positioned one hundred eighty (180 deg) apart, thus preventing optimum use of laser diagnostics. The high pressure fluid injector test apparatus includes an upper hub, an upper weldment or housing, a first clamp and stud/nut assembly for securing the upper hub to the upper weldment, a standoff assembly within the upper weldment, a pair of window housings having view glasses within the upper weldment, an injector block assembly and purge plate within the upper weldment for holding an injector element to be tested and evaluated, a lower weldment or housing, a second clamp and stud/nut assembly for securing the lower weldment to the upper weldment, a lower hub, a third clamp and stud/nut assembly for securing the lower hub to the lower weldment, mechanisms for introducing fluid under high pressure for testing an injector element, and mechanisms for purging the apparatus to prevent frosting of view glasses within the window housings and to permit unobstructed viewing of the injector element.

Myers, William Neill↗
NASA NTRS1995

Apparatus for testing high pressure injector elements

An apparatus for testing and evaluating the spray pattern of high pressure fuel injector elements for use in supplying fuel to combustion engines is presented. Prior art fuel injector elements were normally tested by use of low pressure apparatuses which did not provide a purge to prevent mist from obscuring the injector element or to prevent frosting of the view windows; could utilize only one fluid during each test; and had their viewing ports positioned one hundred eighty (180 deg) apart, thus preventing optimum use of laser diagnostics. The high pressure fluid injector test apparatus includes an upper hub, an upper weldment or housing, a first clamp and stud/nut assembly for securing the upper hub to the upper weldment, a standoff assembly within the upper weldment, a pair of window housings having view glasses within the upper weldment, an injector block assembly and purge plate within the upper weldment for holding an injector element to be tested and evaluated, a lower weldment or housing, a second clamp and stud/nut assembly for securing the lower weldment to the upper hub, a third clamp and stud/nut assembly for securing the lower hub to the lower weldment, mechanisms for introducing fluid under high pressure for testing an injector element, and mechanisms for purging the apparatus to prevent frosting of view glasses within the window housings and to permit unobstructed viewing of the injector element.

Myers, William Neill↗