Trends in noise control for aircraft gas-turbine power plants
Jet aircraft noise sources and reduction from gas turbine engines including jet exhausts, fans, lift devices, and unducted rotors
Chestnutt, D.↗
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Determination of Primary-zone Smoke Concentrations from Spectral Radiance Measurements in Gas Turbine Combustors
Measurement of smoke concentration in primary zone of gas turbine combustor at high ambient pressures by spectral radiance technique
Norgren, Carl T.↗
Effect of increased fuel temperature on emissions of oxides of nitrogen from a gas turbine combustor burning ASTM jet-A fuel
An annular gas turbine combustor was tested with heated ASTM Jet-A fuel to determine the effect of increased fuel temperature on the formation of oxides of nitrogen. Fuel temperature ranged from ambient to 700 K. The NOx emission index increased at a rate of 6 percent per 100 K increase in fuel temperature.
Marchionna, N. R.↗
Mainshaft seals for small gas turbine engines
An experimental evaluation of mainshaft seals for small gas turbine engines was conducted with shaft speeds to 213 m/s (700 ft/sec), air pressures to 148 Newtons per square centimeter abs. (215 psia), and air temperatures to 412k(282 F). A radial face seal incorporating self-acting geometry for lift augmentation was evaluated. In addition, three conventional carbon seal types (face, circumferential segmented, and rotating ring) were run for comparison. Test results indicated that the conventional seals used in this evaluation may not be satisfactory in future advanced engines because of excessive air leakage. On the other hand, the self-acting face seal was shown to have the potential capability of limiting leakages to one-half that of the conventional face seals and one-fifth that of conventional ring seals. A 150-hour endurance test of the self-acting face seal was conducted.
Ludwig, L. P.↗
Mainshaft seals for small gas turbine engines
An experimental evaluation of mainshaft seals for small gas turbine engines was conducted with shaft speeds to 213 m/sec, air pressures to 215 psia, and air temperatures to 412 K. A radial face seal incorporating self-acting geometry for lift augmentation was evaluated. In addition, three conventional carbon seal types (face, circumferential segmented, and rotating ring) were run for comparison. Test results indicated that the conventional seals used in this evaluation may not be satisfactory in future advanced engines because of excessive air leakage. On the other hand, the self-acting face seal was shown to have the potential capability of limiting leakages to one-half that of the conventional face seals and one-fifth that of conventional ring seals. A 150 hour endurance test of the self-action face seal was conducted at speeds to 145 m/sec, air pressures to 180 psia, and air temperatures to 408 K. The seal wear was not measurable.
Ludwig, L. P.↗
Gas turbine engine with convertible accessories
Drive means for connecting a gas turbine engine to its accessories are so constructed as to allow the accessories to be selectively positioned to any one of several predetermined circumferential positions about the perimeter of the engine. This feature permits convenient mounting of the same engine upon vehicles demanding radically different engine mounting arrangements.
Sargisson, D. F.↗
Integrated gas turbine engine-nacelle
A nacelle for use with a gas turbine engine is presented. An integral webbed structure resembling a spoked wheel for rigidly interconnecting the nacelle and engine, provides lightweight support. The inner surface of the nacelle defines the outer limits of the engine motive fluid flow annulus while the outer surface of the nacelle defines a streamlined envelope for the engine.
Adamson, A. P.↗
Integrated gas turbine engine-nacelle
A nacelle for use with a gas turbine engine is provided with an integral webbed structure resembling a spoked wheel for rigidly interconnecting the nacelle and engine. The nacelle is entirely supported in its spacial relationship with the engine by means of the webbed structure. The inner surface of the nacelle defines the outer limits of the engine motive fluid flow annulus, while the outer surface of the nacelle defines a streamlined envelope for the engine.
Adamson, A. P.↗
Low NO/x/ and fuel flexible gas turbine combustors
The feasibility of various low NO(x) emission gas turbine combustor configurations was evaluated. The configurations selected for fabrication and testing at full pressure and temperature involved rich-lean staged combustion utilizing diffusion flames, rich-lean prevaporized/premix flames, and staged catalytic combustion. The test rig consisted of a rich burner module, a quench module, and a lean combustion module. Test results are obtained for the combustor while burning petroleum distillate fuel, a coal derived liquid, and a petroleum residual fuel. The results indicate that rich-lean diffusion flames with low fuel-bound nitrogen conversion are achievable with very high combustion efficiencies.
Lew, H. G.↗
Advanced Gas Turbine (AGT) powertrain system development for automotive applications
An automotive gas turbine powertrain system which, when installed in a 1985 production vehicle (3000 pounds inertia weight), is being developed with a CFDC fuel economy of 42.8 miles per gallon based on Environmental Protection Agency (EPA) test procedures and diesel No. 2 fuel. The AGT-powered vehicle shall give substantially the same overall vehicle driveability and performance as a comparable 1985 production vehicle powered by a conventional spark ignition powertrain system (baseline system). Gaseous emissions and particulate levels less than: NOx = 0.4 gm/mile, HC = 0.41 gm/mile, and CO = 3.4 gm/mile, and a total particulate of 0.2 gm/mile, using the same fuel as used for fuel economy measurements is expected, along with the ability to use a variety of alternate fuels.
Source record↗
Small Gas Turbine Combustor Primary Zone Study
The combustion research program, small gas turbine combustor primary zone study is summarized. The basic elements of a design methodology program to obtain the maximum performance potential of small reverse-flow annular combustors is described. Three preferred combustion design approaches for internal flame stabilization patterns were selected. Design features are incorporated in the combustors to address the performance limiting problem areas associated with smaller annular combustors. Performance is predicted by using a 3-D aerodynamic/chemical kinetic elliptic flow analysis, initially developed by Garrett Corporation for the USARTL. It is shown that the analytical flow field predictive models provide a useful design tool for understanding the combustion performance of a small reverse flow annular combustor.
Sullivan, R. E.↗
Advanced Gas Turbine (AGT) technology development
A 74.5 kW (100 hp) automotive gas turbine was evaluated. The engine structure, bearings, oil system, and electronics were demonstrated and no shaft dynamics or other vibration problem were encountered. Areas identified during the five tests are the scroll retention features, and transient thermal deflection of turbine backplates. Modifications were designed. Seroll retention is addressed by modifying the seal arrangement in front of the gasifier turbine assembly, which will increase the pressure load on the scroll in the forward direction and thereby increase the retention forces. the backplate thermal deflection is addressed by geometric changes and thermal insulation to reduce heat input. Combustor rig proof testing of two ceramic combustor assemblies was completed. The combustor was modified to incorporate slots and reduce sharp edges, which should reduce thermal stresses. The development work focused on techniques to sinter these barrier materials onto the ceramic rotors with successes for both material systems. Silicon carbide structural parts, including engine configuration gasifier rotors (ECRs), preliminary gasifier scroll parts, and gasifier and power turbine vanes are fabricated.
Source record↗
Low NO(x) potential of gas turbine engines
The purpose is to correlate emission levels of gas turbine engines. The predictions of NO(x) emissions are based on a review of the literature of previous low NO(x) combustor programs and analytical chemical kinetic calculations. Concepts included in the literature review consisted of lean-premixed-prevaporized (LPP), rich burn/quick quench/lean burn (RQL), and direct injection. The NO(x) emissions were found to be an exponential function of adiabatic combustion temperature over a wide range of inlet temperatures, pressures and (lean) fuel-air ratios. A simple correlation of NO(x) formation with time was not found. The LPP and direct injection (using gaseous fuels) concepts have the lowest NO(x) emissions of the three concepts. The RQL data has higher values of NO(x) than the LPP concept, probably due to the stoichiometric temperatures and NO(x) production that occur during the quench step. Improvements in the quick quench step could reduce the NO(x) emissions to the LPP levels. The low NO(x) potential of LPP is offset by the operational disadvantages of its narrow stability limits and its susceptibility to autoignition/flashback. The Rich-Burn/Quick-Quench/Lean-Burn (RQL) and the direct injection concepts have the advantage of wider stability limits comparable to conventional combustors.
Tacina, Robert R.↗
Feasibility of magnetic bearings for advanced gas turbine engines
The application of active magnetic bearings to advanced gas turbine engines will provide a product with major improvements compared to current oil lubricated bearing designs. A rethinking of the engine rotating and static structure design is necessary and will provide the designer with significantly more freedom to meet the demanding goals of improved performance, increased durability, higher reliability, and increased thrust to weight ratio via engine weight reduction. The product specific technology necessary for this high speed, high temperature, dynamically complex application has been defined. The resulting benefits from this approach to aircraft engine rotor support and the complementary engine changes and improvements have been assessed.
Hibner, David↗
Turbofan gas turbine engine with variable fan outlet guide vanes
A turbofan gas turbine engine includes a forward fan section with a row of fan rotor blades, a core engine, and a fan bypass duct downstream of the forward fan section and radially outwardly of the core engine. The forward fan section has only a single stage of variable fan guide vanes which are variable fan outlet guide vanes downstream of the forward fan rotor blades. An exemplary embodiment of the engine includes an afterburner downstream of the fan bypass duct between the core engine and an exhaust nozzle. The variable fan outlet guide vanes are operable to pivot from a nominal OGV position at take-off to an open OGV position at a high flight Mach Number which may be in a range of between about 2.5-4+. Struts extend radially across a radially inwardly curved portion of a flowpath of the engine between the forward fan section and the core engine.
Wood, Peter John↗
NASA PS304 Lubricant Tested in World's First Commercial Oil-Free Gas Turbine
In a marriage of research and commercial technology, a 30-kW Oil-Free Capstone microturbine electrical generator unit has been installed and is serving as a test bed for long-term life-cycle testing of NASA-developed PS304 shaft coatings. The coatings are used to reduce friction and wear of the turbine engine s foil air bearings during startup and shut down when sliding occurs, prior to the formation of a lubricating air film. This testing supports NASA Glenn Research Center s effort to develop Oil-Free gas turbine aircraft propulsion systems, which will employ advanced foil air bearings and NASA s PS304 high temperature solid lubricant to replace the ball bearings and lubricating oil found in conventional engines. Glenn s Oil-Free Turbomachinery team s current project is the demonstration of an Oil-Free business jet engine. In anticipation of future flight certification of Oil-Free aircraft engines, long-term endurance and durability tests are being conducted in a relevant gas turbine environment using the Capstone microturbine engine. By operating the engine now, valuable performance data for PS304 shaft coatings and for industry s foil air bearings are being accumulated.
Weaver, Harold F.↗
Study and program plan for improved heavy duty gas turbine engine ceramic component development
Fuel economy in a commercially viable gas turbine engine was demonstrated through use of ceramic materials. Study results show that increased turbine inlet and generator inlet temperatures, through the use of ceramic materials, contribute the greatest amount to achieving fuel economy goals. Improved component efficiencies show significant additional gains in fuel economy.
Helms, H. E.↗
The impact of emission standards on the design of aircraft gas turbine engine combustors
The advent of environmental standards for controlling aircraft gas turbine engine emissions has led to a reevaluation of combustor design techniques. Effective emission control techniques have been identified and a wide spectrum of potential applications for these techniques to existing and advanced engines are being considered. Results from advanced combustor concept evaluations and from fundamental experiments are presented and discussed and comparisons are made with existing EPA emission standards and recommended levels for high altitude cruise. The impact that the advanced low emission concepts may impose on future aircraft engine combustor designs and related engine components is discussed.
Rudey, R. A.↗