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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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Performance and durability of improved air-atomizing splash-cone fuel nozzles

An improved design of air-atomizing fuel nozzles was determined from a study of four differently shaped splash-cone fuel nozzles after 56 hr of durability testing in a combustor segment. Test conditions included fuel-air ratios of 0.008 to 0.018, inlet-air total pressures of 41 to 203 N/cm, inlet-air temperatures of 477 to 811 K, and a reference velocity of 21.3 m/sec. Flat-tip fuel nozzles showed the least erosion damage and at a combustor operating condition of 700 K and 101 N/sq cm an oxides-of-nitrogen emission index of 12 and a smoke number of approximately 18 with a fuel-air ratio of 0.018. Emission indices for carbon monoxide and unburned hydrocarbons were 44 and 16, respectively, at simulated idle conditions of 477 K and 41 N/sq cm.

Ingebo, R. D.↗
NASA NTRS1972

Effects of fuel nozzle design on performance of an experimental annular combustor using natural gas fuel

Tests of various fuel nozzles were conducted with natural gas fuel in a full-annulus combustor. The nozzles were designed to provide either axial, angled, or radial fuel injection. Each fuel nozzle was evaluated by measuring combustion efficiency at relatively severe combustor operating conditions. Combustor blowout and altitude ignition tests were also used to evaluate nozzle designs. Results indicate that angled injection gave higher combustion efficiency, less tendency toward combustion instability, and altitude relight characteristics equal to or superior to those of the other fuel nozzles that were tested.

Wear, J. D.↗
NASA NTRS2001

Hydrogen/Air Fuel Nozzle Emissions Experiments

The use of hydrogen combustion for aircraft gas turbine engines provides significant opportunities to reduce harmful exhaust emissions. Hydrogen has many advantages (no CO2 production, high reaction rates, high heating value, and future availability), along with some disadvantages (high current cost of production and storage, high volume per BTU, and an unknown safety profile when in wide use). One of the primary reasons for switching to hydrogen is the elimination of CO2 emissions. Also, with hydrogen, design challenges such as fuel coking in the fuel nozzle and particulate emissions are no longer an issue. However, because it takes place at high temperatures, hydrogen-air combustion can still produce significant levels of NOx emissions. Much of the current research into conventional hydrocarbon-fueled aircraft gas turbine combustors is focused on NOx reduction methods. The Zero CO2 Emission Technology (ZCET) hydrogen combustion project will focus on meeting the Office of Aerospace Technology goal 2 within pillar one for Global Civil Aviation reducing the emissions of future aircraft by a factor of 3 within 10 years and by a factor of 5 within 25 years. Recent advances in hydrocarbon-based gas turbine combustion components have expanded the horizons for fuel nozzle development. Both new fluid designs and manufacturing technologies have led to the development of fuel nozzles that significantly reduce aircraft emissions. The goal of the ZCET program is to mesh the current technology of Lean Direct Injection and rocket injectors to provide quick mixing, low emissions, and high-performance fuel nozzle designs. An experimental program is planned to investigate the fuel nozzle concepts in a flametube test rig. Currently, a hydrogen system is being installed in cell 23 at NASA Glenn Research Center's Research Combustion Laboratory. Testing will be conducted on a variety of fuel nozzle concepts up to combustion pressures of 350 psia and inlet air temperatures of 1200 F. Computational fluid dynamics calculations, with the Glenn developed National Combustor Code, are being performed to optimize the fuel nozzle designs.

Smith, Timothy D.↗
NASA NTRS1955

Transient and steady-state performance of a single turbojet combustor with four different fuel nozzles

Acceleration and steady-state performance of a tubular combustor was evaluated at two simulated altitudes with four different fuel nozzles. Temperature response lag was observed with all the nozzles. Except for rich-limit blowout, the only combustion failures observed during acceleration were with a fuel nozzle that gave an interrupted flow delivery during the acceleration. This same nozzle, because of superior fuel atomization, gave the highest steady-state combustion efficiencies.

Mccafferty, Richard J↗
NASA NTRS1973

Use of an air-assisted fuel nozzle to reduce idle emissions of a jt8d engine combustor

Tests were performed at typical engine idle conditions on a single-can JT8D combustor installed in a 24 centimeter (9.45 in.) housing to evaluate the effect of an air-assist nozzle on reducing exhaust emissions. By injecting high-pressure air through the secondary-flow passage of a standard duplex fuel nozzle, it was possible to reduce hydrocarbon emissions from 840 parts per million to 95 parts per million and carbon monoxide emissions from 873 parts per million to 258 parts per million. NOX emissions increased slightly from 18 parts per million to 22 parts per million. An air-assist differential pressure of only 20.1 newtons per square centimeter (29.1 psi) and an airflow rate of only 0.22 percent of the total combustor airflow was required.

Papathakos, L. C.↗
NASA NTRS1973

High-pressure combustor exhaust emissions with improved air-atomizing and conventional pressure-atomizing fuel nozzles

A high-pressure combustor segment 0.456 meter (18 in.) long with a maximum cross section of 0.153 by 0.305 meter (6 by 12 in.) was tested with specially designed air-atomizing and conventional pressure-atomizing fuel nozzles at inlet-air temperatures of 340 to 755 k (610 deg to 1360 R), reference velocities of 12.4 to 26.1 meters per second (41 to 86 ft/sec), and fuel-air ratios of 0.008 to 0.020. Increasing inlet-air pressure from 4 to 20 atmospheres generally increased smoke number and nitric oxide, but decreased carbon monoxide and unburned hydrocarbon concentrations with air-atomizing and pressure-atomizing nozzles. Emission indexes for carbon monoxide and unburned hydrocarbons were lower at 4, 10, and 20 atmospheres, and nitric oxide emission indexes were lower at 10 and 20 atmospheres with air-atomizing than with pressure-atomizing nozzles.

Ingebo, R. D.↗
NASA NTRS1973

Effect of fuel zoning and fuel nozzle design on pollution emissions at ground idle conditions for a double-annular ram-induction combustor

An exhaust emission survey was conducted on a double-annular ram induction combustor at simulated ground idle conditions. The combustor was designed for a large augmented turbofan engine capable of sustained flight speeds up to Mach 3.0. The emission levels of total hydrocarbon (THC), carbon monoxide, carbon dioxide, and nitric oxide were measured. The effects of fuel zoning, fuel nozzle design, and operating conditions (inlet temperature and reference Mach number) on the level of these emissions were determined. At an overall combustor fuel/air ratio of 0.007, fuel zoning reduced THC emissions by a factor of 5 to 1. The reduction in THC emissions is attributed to the increase in local fuel/air ratio provided by the fuel zoning. An alternative method of increasing fuel/air ratio would be to operate with larger-than-normal compressor overboard bleed; however, analysis on this method indicated an increase in idle fuel consumption of 20 percent. The use of air-atomizing nozzles reduced the THC emissions by 2 to 1.

Clements, T. R.↗
NASA NTRS1936

Details of the Construction and Production of Fuel Pumps and Fuel Nozzles for the Airplane Diesel Engine

This report presents investigations into the design and construction of fuel pumps for diesel engines. The results of the pump tests on the engines showed that, with a good cut-off, accurate injection, assured by the proper adjustment of the pump elements, there is a decrease in the consumption of fuel and hence an increase in the rated power of the engine. Some of the aspects investigated include: cam profile, coefficient of discharge, and characteristics of the injection system.

Lubenetsky, W S↗