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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 865 records · Page 48
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Soot formation in the methane oxygen and methane/oxygen/hydrogen flame

The feasibility of using methane, recovered from carbon dioxide by the Sabatier-Senderens reaction, was investigated as a fuel in a reaction control engine. A problem to be avoided is the emission of soot particles. It is thought that such particles would remain in the environment of the spacecraft and, thereby, adversely affect optical sightings and possibly have an effect upon communications. The initial studies were of a practical nature. The first was the influence of the spatial arrangement of the fuel and oxygen injectors on soot formation. In the second study, inhibition of soot formation was considered. Considering the given situation, it was impractical to use an additive. However, since methanol combustion does not produce soot, and methanol can be produced from methane in situ, the possibility that methanol could act as an inhibitor was studied. In the third study, since these are restartable engines, the effect of shutdown on the rapidity of soot formation was studied.

Dauerman, L.↗
NASA NTRS1975

Preliminary Shuttle payload contamination assessment

The paper discusses the molecular induced atmosphere of the Shuttle Orbiter and a payload carrier (Spacelab) configuration - long module and a 3-m pallet) in the Shuttle Orbiter payload bay and compares it to the ambient atmosphere at various orbital altitudes. The density and flux of the contaminants are expressed as a function of distance out of the payload bay for a line-of-sight perpendicular to the payload bay and payload carrier. Isodensity plots about the Shuttle Orbiter for a side and end view for each major source are presented. The major sources considered are the external surface materials mass loss, pressurized habitation area leakage, attitude control engines, and supplemental flash evaporator venting. The resulting plots provide an insight into the extent and spatial variation of the on-orbit contaminant-induced environment.

Ress, E. B.↗
NASA NTRS1977

Experiment and analysis on the flow process dynamics of the NASA-Langley eight foot transonic pressure tunnel

A dynamic response test performed in a eight foot transonic pressure tunnel is described. The dynamics of the flow process of the wind tunnel at transonic conditions were obtained. Descriptions of the test conditions, instrumentation, presentation of raw data, analysis of data, and finally, based on experimental evidences, an attempt to construct an input output relationship of the flow process from the viewpoints of control engineering are included.

Tcheng, P.↗
NASA NTRS1977

Static and flyover noise measurements of an inverted profile exhaust jet

Tests using a TF30 mixed flow afterburning turbofan engine in an F-111 airplane were conducted to study the noise characteristics of an inverted velocity profile jet. Full-authority digital engine control allowed the inverted profile jet to be compared to a uniform jet of equal thrust statically and in flight. An exhaust velocity survey showed that the ratio of the outer to inner stream velocities was 1.37; therefore, only small noise reductions were expected. At static conditions, the inverted profile jet was approximately 3 decibels quieter than the uniform jet at peak noise angles. During a flyover it was approximately 1 decibel quieter.

Burcham, F. W., Jr.↗
NASA NTRS1978

Flight effects on the aerodynamic and acoustic characteristics of inverted profile coannular nozzles

The effect of forward flight on the jet noise of coannular exhaust nozzles, suitable for Variable Stream Control Engines (VSCE), was investigated in a series of wind tunnel tests. The primary stream properties were maintained constant at 300 mps and 394 K. A total of 230 acoustic data points was obtained. Force measurement tests using an unheated air supply covered the same range of tunnel speeds and nozzle pressure ratios on each of the nozzle configurations. A total of 80 points was taken. The coannular nozzle OASPL and PNL noise reductions observed statically relative to synthesized values were basically retained under simulated flight conditions. The effect of fan to primary stream area ratio on flight effects was minor. At take-off speed, the peak jet noise for a VSCE was estimated to be over 6 PNdB lower than the static noise level. High static thrust coefficients were obtained for the basic coannular nozzles, with a decay of 0.75 percent at take-off speeds.

Kozlowski, H.↗
NASA NTRS1977

Tilt-proprotor perspective

The general tilt-proprotor concept is discussed, and a more detailed look at the XV-15 aircraft is taken. The special features of the two-engine system, engine control system, and flight control system are mentioned. The main objectives of the XV-15 program are to (1) verify rotor/pylon/wing/dynamic stability and aircraft performance over a representative operational envelope, (2) assess the handling qualities and establish a safe operating envelope, and (3) investigate gust sensitivity, effects of downwash, and hover operation. With regard to rotor/pylon stability, one challenge is to be able to predict a parameter's value and then build hardware to match. The analytical program has gained some respect through aeroelastic and full-scale XV-3 demonstrations. Special concern centers around the thrust and power management system when flying at high speed when very small changes in rotor collective pitch represent large changes in thrust and power. Demonstration of the system awaits wind-tunnel and flight testing.

Few, D. D.↗
NASA NTRS1978

Study of aerodynamic technology for VSTOL fighter attack aircraft

Vertical short takeoff aircraft capability, supersonic dash capability, and transonic agility were investigated for the development of Fighter/attack aircraft to be accommodated on ships smaller than present aircraft carriers. Topics covered include: (1) description of viable V/STOL fighter/attack configuration (a high wing, close-coupled canard, twin-engine, control configured aircraft) which meets or exceeds specified levels of vehicle performance; (2) estimates of vehicle aerodynamic characteristics and the methodology utilized to generate them; (3) description of propulsion system characteristics and vehicle mass properties; (4) identification of areas of aerodynamic uncertainty; and (5) a test program to investigate the areas of aerodynamic uncertainty in the conventional flight mode.

Burhans, W., Jr.↗
NASA NTRS1979

Directivity of acoustic radiation from sources

The radiation properties of acoustic monopoles and dipoles are described. The directivity of radiation from these sources in a free field and in the presence of an absorptive surface is described. The kinematic effects on source radiation due to translation and rotation are discussed. Experimental measurements of sound from an acoustic monopole in motion and the characteristics of helicopter rotor and propeller noise are reviewed. An introduction is provided to several essential concepts required by noise control engineers making measurements of noise from moving sources in the proximity of the ground.

Lansing, D. L.↗
NASA NTRS1979

Research on spectroscopic imaging. Volume 1: Technical discussion

The principals of operation and the capabilities of birefringent filters systems are examined. Topics covered include: Lyot, Solc, and partial polarizer filters; transmission profile management; tuning birefringent filters; field of view; bandpass control; engineering considerations; and recommendations. Improvements for field of view effects, and the development of birefringent filters for spaceflight are discussed in appendices.

Title, A.↗
NASA NTRS1979

VSCE technology definition study

Refined design definition of the variable stream control engine (VSCE) concept for advanced supersonic transports is presented. Operating and performance features of the VSCE are discussed, including the engine components, thrust specific fuel consumption, weight, noise, and emission system. A preliminary engine design is presented.

Howlett, R. A.↗
NASA NTRS1979

Directivity of acoustic radiation from sources

The radiation properties of acoustic monopoles and dipoles are described, as well as the directivity of radiation from these sources in a free field and in the presence of an absorptive surface. The kinematic effects on source radiation due to translation and rotation are discussed. Experimental measurements of sound from an acoustic monopole in motion and the characteristics of helicopter rotor and propeller noise are reviewed. Several essential concepts required by noise control engineers making measurements of noise from moving sources in the proximity of the ground are introduced.

Lansing, D. L.↗
NASA NTRS1977

Quiet Clean Short-haul Experimental Engine (QCSEE) Over The Wing (OTW) design report

The design, fabrication, and testing of two experimental high bypass geared turbofan engines and propulsion systems for short haul passenger aircraft are described. The propulsion technology required for future externally blown flap aircraft with engines located both under the wing and over the wing is demonstrated. Composite structures and digital engine controls are among the topics included.

Source record↗
NASA NTRS1976

Quiet Clean Short-haul Experimental Engine (QCSEE) preliminary under the wing flight propulsion system analysis report

The preliminary design and installation of high bypass, geared turbofan engine with a composite nacelle forming the propulsion system for a short haul passenger aircraft are described. The technology required for externally blown flap aircraft with under the wing (UTW) propulsion system installations for introduction into passenger service in the mid 1980's is included. The design, fabrication, and testing of this UTW experimental engine containing the required technology items for low noise, fuel economy, with composite structure for reduced weight and digital engine control are provided.

Howard, D. F.↗
NASA NTRS1977

Quiet Clean Short-haul Experimental Engine (QCSEE). Composite fan frame subsystem test report

The element and subcomponent testing conducted to verify the composite fan frame design of two experimental high bypass geared turbofan engines and propulsion systems for short haul passenger aircraft is described. Emphasis is placed on the propulsion technology required for future externally blown flap aircraft with engines located both under the wing and over the wing, including technology in composite structures and digital engine controls. The element tests confirmed that the processes used in the frame design would produce the predicted mechanical properties. The subcomponent tests verified that the detail structural components of the frame had adequate structural integrity.

Stotler, C. L., Jr.↗
NASA NTRS1977

Quiet Clean Short-Haul Experimental Engine (QCSEE) Under-the-Wing (UTW) Final Design Report

The QCSEE Program provides for the design, fabrication, and testing of two experimental high-bypass geared turbofan engines and propulsion systems for short-haul passenger aircraft. The overall objective of the program is to develop the propulsion technology required for future externally blown flap types of aircraft with engines located both under-the-wing and over-the-wing. This technology includes work in composite structures and digital engine controls.

Source record↗
NASA NTRS1982

A method for determining the flight readiness of the integrated Space Shuttle system

The Space Shuttle Dynamic Integrated Test (DIT) system is described. The DIT is an open-loop system which makes no attempt to simulate Shuttle sensors, and by which the Shuttle redundancy management system is left unmodified. Open-loop operation is shown to inherently require less computing capacity during a test than the closed-loop alternative. DIT tests have generated a high degree of confidence in the Shuttle hardware, allowing the identification of such problems as a sluggish main fuel valve, which caused a countdown hold seconds before the simulated T-zero, and Main Engine Controller software malfunctions. Attention is given to the combination and substitution of sensor data, the modification of nominal flight software, and the preparation of simulation data. It is noted that greater performance would have been achieved if the interface with DIT had been a design requirement from the outset of Space Shuttle development.

Bacon, I.↗
NASA NTRS1982

Effects of flight on noise radiated from convected ring sources in coaxial dual flow. Part 2: The noise from heated jets

The effects of flight on noise from heated jets are discussed. The effects of the additionally, extraneously-generated dipole and simple source terms which arise as a result of the density gradients across the fluid interfaces were incorporated. The coaxial flows with inverted profiles are shown to be quieter than the conventional profiles; however, the benefit of noise reduction at higher outer-to-inner area ratios is totally offset as the inverted profile incurs a significant massloss and thrust-loss. Amongst all the possible coaxial configurations when on of the coaxial streams is heated-conventional profile (CP), inverted profile (IP) and the variable stream control engine (VSCE) cycle-and at constant massflow and thrust, a VSCE-cycle is the most desirable and the best possible engine cycle inasmuch as it provides over more than 18.0 dB reduction in SPL (as compared against noise from a CP-cycle) at all angles, both statically and in flight, for area ratios Sigma 0.25.

Dash, R.↗
NASA NTRS1983

The quiet short-haul research aircraft

The design concepts, performance capabilities, and projected applications of the Quiet Short-Haul Research Aircraft (QSRA) are discussed. The propulsive lift system of the QSRA provides the lift required for short field operations at low community noise levels. This system consists of four high bipass ratio, geared turbofan engines mounted so that the engine exhaust flows across the upper surface of the wing (upper surface blowing). Large specially shaped flaps behind each engine control the direction of the flow for each phase of flight. A 95 passenger short haul transport based on this technology could operate out of a 2500 foot runway with a combined takeoff and landing 90 EPNdB footprint area of 2.7 sq mi.

Cochrane, J. A.↗