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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 451 records · Page 25

Thermal-structural Design Study of an Airframe-integrated Scramjet

Design concepts for the cooled structures assembly for the Langley Scramjet engine, for engine subsystems, and for the aircraft/engine interface were developed and evaluated. Results show that the objectives for the Scramjet engine can be met. A thermal protection system was defined that makes it possible to attain a life of 100 hours and 1000 cycles, which is the specified goal. With stoichiometric combustion, the fuel provides an adequate heat sink for cooling the engine at Mach numbers up to 9 at the minimum fuel flow condition. The mechanical design is feasible for manufacture using conventional materials. For the cooled structures in a six-module engine, the mass per unit capture area is 1328 kg/sq m (259 lb/sq ft). The total mass of a six-module engine assembly including the fuel system is 1577 kg (3477 lb).

Buchmann, O. A.↗

Methods for the photochemical utilization of solar energy

The paper considers the 'ground rules' which govern the efficiency of photochemical solar energy conversion and then summarizes the most promising approaches in each of three categories: photochemically assisted thermal systems for the heating and/or cooling of structures; photogalvanic systems for the production of electrical power in applications, such as photorechargeable batteries or inexpensive 'solar cells'; and photochemical formation of fuels for combustion and for use as chemical feedstocks or foods. Three concepts for the photochemical utilization of solar energy in space are found to be particularly promising: (1) photochemical trans-cis isomerization of indigold dyes for photoassisted heating or cooling, (2) the redox stabilized photoelectrolysis cell for the production of hydrogen (and/or oxygen or other useful chemicals), and (3) the liquid-junction photovoltaic cell for the production of electrical power.

Schwerzel, R. E.↗

Effects of impurities in coal-derived liquids on accelerated hot corrosion of superalloys

A Mach 0.3 burner rig was used to determine the effects of potential coal derived liquid fuel impurity combustion of products on hot corrosion in IN-100, IN-792, IN_738, U-700, Mar M-509, and 304 stainless steel. The impurities, added as aqueous solutions to the combustor, were salts of sodium, potassium, vanadium, molybdenum, tungsten, phosphorus, and lead. Extent of attack was determined by metal consumption and compared to the effects of sodium alone. Vanadium, molybdenum, tungsten, phosphorous, and lead in combination with sodium all resulted in increased attack as compared with sodium alone at some temperatures, apparently due in large part to the extension of the formation of liquid deposits. Varying the sodium-potassium ratio had little effect for ratios less than 1:3 for which reduced, but measurable, attack was observed.

Deadmore, D. L.↗

Assessment of the potential of hybrid vehicles: Summary

The potential of hybrid vehicles as a replacement of the conventional gasoline or diesel fueled internal combustion engine vehicle within the next 20 to 30 years, was assessed. Hybrid vehicle designs and applications which are technically and economically viable were studied to determine if reductions in petroleum usage were large enough to warrant major expenditures of research and development funds. Critical technical areas where research and development can be most usefully concentrated were identified.

Surber, F. T.↗

Low NO/x/ combustion systems for burning heavy residual fuels and high-fuel-bound nitrogen fuels

Design concepts are presented for lean-lean and staged rich-lean combustors. The combustors are designed for the dry reduction of thermal NO(x), control of NO(x) from fuels containing high levels of organic nitrogen, and control of smoke from low hydrogen content fuels. The combustor concepts are tested with a wide variety of fuels including a middle distillate, a petroleum based heavy residual, a coal derived synthetic, and ratios of blends of these fuels. The configurations of the lean-lean and rich-lean combustion systems are provided along with a description of the test rig and test procedure.

White, D. J.↗

Pollution reduction technology program small jet aircraft engines, phase 3

A series of Model TFE731-2 engine tests were conducted with the Concept 2 variable geometry airblast fuel injector combustion system installed. The engine was tested to: (1) establish the emission levels over the selected points which comprise the Environmental Protection Agency Landing-Takeoff Cycle; (2) determine engine performance with the combustion system; and (3) evaulate the engine acceleration/deceleration characteristics. The hydrocarbon (HC), carbon monoxide (CO), and smoke goals were met. Oxides of nitrogen (NOx) were above the goal for the same configuration that met the other pollutant goals. The engine and combustor performance, as well as acceleration/deceleration characteristics, were acceptable. The Concept 3 staged combustor system was refined from earlier phase development and subjected to further rig refinement testing. The concept met all of the emissions goals.

Bruce, T. W.↗

Pulsed, Hydraulic Coal-Mining Machine

In proposed coal-cutting machine, piston forces water through nozzle, expelling pulsed jet that cuts into coal face. Spring-loaded piston reciprocates at end of travel to refill water chamber. Machine a onecylinder, two-cycle, internal-combustion engine, fueled by gasoline, diesel fuel, or hydrogen. Fuel converted more directly into mechanical energy of water jet.

Collins, Earl R., Jr.↗

Improved Electronic Control for Electrostatic Precipitators

Electrostatic precipitators remove particulate matter from smoke created by burning refuse. Smoke exposed to electrostatic field, and particles become electrically charged and migrate to electrically charged collecting surfaces. New microprocessor-based electronic control maintains precipitator power at maximum particulate-collection level. Control automatically senses changes in smoke composition due to variations in fuel or combustion and adjusts precipitator voltage and current accordingly. Also, sensitive yet stable fault detection provided.

Johnston, D. F.↗

Ignition System for Gaseous Propellants

Installation of spark plug in fuel-injection manifold of coaxial injector promotes more efficient cooling of combustor walls in rocket and turbine engines. After ignition occurs in fuel injector, combustion maintained in cooled main combustor leaving spark-plug tip in cool, clean environment. Eighteen tests have proven this injector design; no ignition failures occurred in 8,000 seconds of operation with gaseous oxygen and hydrogen. System also used with other propellants gaseous in ignition phase.

Pieron, R. A.↗

Convective Evaporation Of Sprayed Liquid

Theoretical model developed to analyze behavior of both dense and dilute clusters of evaporating liquid drops in gas flows. Particularly useful in search for methods of controlling evaporation, ignition, and combustion of fuel sprays.

Bellan, Josette↗

Thin-film sensors for reusable space propulsion systems

Thin-film thermocouples (TFTCs) were developed for aircraft gas turbine engines and are in use for temperature measurement on turbine blades up to 1800 F. Established aircraft engine gas turbine technology is currently being adapted to turbine engine blade materials and the environment encountered in the Space Shuttle Main Engine (SSME)-severe thermal shock from cryogenic fuel to combustion temperatures. Initial results with coupons of MAR M-246 (+Hf) and PWA 1480 were followed by fabrication of TFTC on SSME turbine blades. Current efforts are focused on preparation for testing in the Turbine Blade Tester at NASA Marshall Space Flight Center.

Hepp, Aloysius F.↗

Transatmospheric vehicle research

Research was conducted into the alternatives to the supersonic combustion ramjet (scramjet) engine for hypersonic flight. A new engine concept, the Oblique Detonation Wave Engine (ODWE) was proposed and explored analytically and experimentally. Codes were developed which can couple the fluid dynamics of supersonic flow with strong shock waves, with the finite rate chemistry necessary to model the detonation process. An additional study was conducted which compared the performance of a hypersonic vehicle powered by a scramjet or an ODWE. Engineering models of the overall performances of the two engines are included. This information was fed into a trajectory program which optimized the flight path to orbit. A third code calculated the vehicle size, weight, and aerodynamic characteristics. The experimental work was carried out in the Ames 20MW arc-jet wind tunnel, focusing on mixing and combustion of fuel injected into a supersonic airstream. Several injector designs were evaluated by sampling the stream behind the injectors and analyzing the mixture with an on-line mass spectrometer. In addition, an attempt was made to create a standing oblique detonation wave in the wind tunnel using hydrogen fuel. It appeared that the conditions in the test chamber were marginal for the generation of oblique detonation waves.

Adelman, Henry G.↗

A computational design tool for scramjet combustor film cooling and fuel mixing predictions

A methodology for the analysis of a film cooled combustor of a hydrogen-fueled, supersonic combustion ramjet (scramjet) is presented. The SHIP3D parabolic flow code, based on an extension of the pressure-correction method of Patankar and Spalding for compressible flow is used to compute the flow field in the combustor. The effect of film cooling on the overall vehicle performance is then calculated using the one-dimensional, multistep cycle code, CPIPE. Results are presented for a conceptual combustor at Mach 16 flight conditions. It is seen that film cooling can have a significant effect on the engine performance.

Kamath, Pradeep S.↗

Mathematical Model For Deposition Of Soot

Semiempirical mathematical model predicts deposition of soot in tubular gas generator in which hydrocarbon fuel burned in very-fuel-rich mixture with pure oxygen. Developed in response to concern over deposition of soot in gas generators and turbomachinery of rocket engines. Also of interest in terrestrial applications involving fuel-rich combustion or analogous process; e.g., purposeful deposition of soot to manufacture carbon black pigments.

Makel, Darby B.↗

Thin-film sensors for space propulsion technology: Fabrication and preparation for testing

The goal of this work is to develop and test thin-film thermocouples for Space Shuttle Main Engine (SSME) components. Thin-film thermocouples have been developed for aircraft gas turbine engines and are in use for temperature measurement on turbine blades up to 1800 F. Established aircraft engine gas turbine technology is currently being adapted to turbine engine blade materials and the environment encountered in the SSME, especially severe thermal shock from cryogenic fuel to combustion temperatures. Initial results using coupons of MAR M-246 (+Hf) and PWA 1480 have been followed by fabrication of thin-film thermocouples on SSME turbine blades. Current efforts are focused on preparing for testing in the Turbine Blade Tester at the NASA Marshall Space Flight Center (MSFC). Future work will include testing of thin-film thermocouples on SSME blades of single crystal PWA 1480 at MSFC.

Kim, Walter S.↗

Historical problem areas lessons learned

Historical problem areas in space transportation propulsion technology are identified in viewgraph form. Problem areas discussed include materials compatibility, contamination, pneumatic/feed system flow instabilities, instabilities in rocket engine combustion and fuel sloshing, exhaust plume interference, composite rocket nozzle failure, and freeze/thaw damage.

Sackheim, Bob↗

Environmental durability of ceramics and ceramic composites

An account is given of the current understanding of the environmental durability of both monolithic ceramics and ceramic-matrix composites, with a view to the prospective development of methods for the characterization, prediction, and improvement of ceramics' environmental durability. Attention is given to the environmental degradation behaviors of SiC, Si3N4, Al2O3, and glass-ceramic matrix compositions. The focus of corrosion prevention in Si-based ceramics such as SiC and Si3N4 is on the high and low sulfur fuel combustion-product effects encountered in heat engine applications of these ceramics; sintering additives and raw material impurities are noted to play a decisive role in ceramics' high temperature environmental response.

Fox, Dennis S.↗