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Schaefer, J. W.

Publications and source records attributed to Schaefer, J. W..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

A status report on the Energy Efficient Engine Project

The Energy Efficient Engine (E3) Project is directed at providing, by 1984, the advanced technologies which could be used for a new generation of fuel conservative turbofan engines. This paper summarizes the scope of the entire project and the current status of these efforts. Included is a description of the preliminary designs of the fully developed engines, the potential benefits of these advanced engines, and highlights of some of the component technology efforts conducted to date.

Macioce, L. E.↗
NASA NTRS1980

The energy efficient engine project

The Energy Efficient Engine Project is directed at providing, by 1984, the advanced technologies which could be used for a generation of fuel conservative turbofan engines. The project is conducted through contracts with the General Electric Company and Pratt and Whitney Aircraft. The scope of the entire project and the current status of these efforts are summarized. A description of the preliminary designs of the fully developed engines is included and the potential benefits of these advanced engines, as well as highlights of some of the component technology efforts conducted to date, are discussed.

Macioce, L. E.↗
NASA NTRS1977

Acoustic performance of inlet multiple-pure-tone suppressors installed on NASA Quiet Engine 'C'

The purpose of the experimental program reported herein was to define the length of multiple pure tone (MPT) treatment required to reasonably suppress the MPT's produced by a supersonic tip speed fan and also determine what other suppression, broadband, and blade passing frequency (BPF), might be accomplished. The experimental results are presented in terms of both far-field and duct acoustic data. Front quadrant sound power level reduction in the far field is shown to agree with duct measurements over the range of treatment lengths. Detailed one-third octave and narrow band spectra at the maximum forward noise angle are presented. Some detailed analyses of one-third-octave band amplitudes are shown as a function of far-field angle. An approximate spinning mode duct propagation analysis is then introduced which predicts the acoustic suppression by the treatment on the multiple pure tones.

Bloomer, H. E.↗
NASA NTRS1977

Aero-acoustic performance comparison of core engine noise suppressors on NASA quiet engine C

The relative aero-acoustic effectiveness of two core engine suppressors, a contractor-designed suppressor delivered with the Quiet Engine, and a NASA-designed suppressor was evaluated. The NASA suppressor was tested with and without a splitter making a total of three configurations being reported in addition to the baseline hardwall case. The aerodynamic results are presented in terms of tailpipe pressure loss, corrected net thrust, and corrected specific fuel consumption as functions of engine power setting. The acoustic results are divided into duct and far-field acoustic data. The NASA-designed core suppressor did the better job of suppressing aft end noise, but the splitter associated with it caused a significant engine performance penality. The NASA core suppressor without the spltter suppressed most of the core noise without any engine performance penalty.

Bloomer, H. E.↗
NASA NTRS1977

Aero-acoustic performance comparison of core engine noise suppressors on NASA quiet engine 'C'

The purpose of the experimental program reported herein was to evaluate and compare the relative aero-acoustic effectiveness of two core engine suppressors, a contractor-designed suppressor delivered with the Quiet Engine, and a NASA-designed suppressor, designed and built subsequently. The NASA suppressor was tested with and without a splitter making a total of three configurations being reported in addition to the baseline hardwall case. The aerodynamic results are presented in terms of tailpipe pressure loss, corrected net thrust, and corrected specific fuel consumption as functions of engine power setting. The acoustic results are divided into duct and far-field acoustic data. The NASA-designed core suppressor did the better job of suppressing aft end noise, but the splitter associated with it caused a significant engine performance penalty. The NASA core suppressor without the splitter suppressed most of the core noise without any engine performance penalty.

Bloomer, H. E.↗
NASA NTRS1977

Dynamics of high-bypass-engine thrust reversal using a variable-pitch fan

The test program demonstrated that successful and rapid forward-to reverse-thrust transients can be performed without any significant engine operational limitations for fan blade pitch changes through either feather pitch or flat pitch. For through-feather-pitch operation with a flight inlet, fan stall problems were encountered, and a fan blade overshoot technique was used to establish reverse thrust.

Schaefer, J. W.↗
NASA NTRS1976

Aerodynamic and acoustic performance of a contracting cowl high throat Mach number inlet installed on NASA Quiet Engine 'C'

The purpose of this experimental program was to evaluate the approach and takeoff performance of a contracting cowl variable geometry design inlet installed on a high-bypass-ratio turbofan engine. The design was finalized after consideration of aerodynamic, acoustic, and mechanical factors which would lead to a viable flight-worthy inlet concept. The aerodynamic results are presented in terms of inlet recovery and distortion parameter as functions of throat Mach number, and acoustic results in terms of Perceived Noise Level. The contracting cowl high throat Mach number inlet is shown to be an attractive means to reduce forward radiated noise from a high bypass ratio turbofan engine.

Bloomer, H. E.↗
NASA NTRS1976

Noise generated by quiet engine fans. 3: Fan C

A family of fans designed with low noise features was acoustically evaluated, and noise results are documented for a 1.6-pressure-ratio, 472-m/sec (155-ft/sec) tip speed fan. The fan is described and some aerodynamic operating data are given. Far field noise around the fan was measured over a range of operating conditions for a variety of configurations having different arrangements of sound absorbing material in the flow ducts. Complete results of 1.3 octave band analysis of the data are presented in tabular form. Included also are acoustic power spectra and sideline perceived noise levels. Representative 1/3 octave band data are presented graphically, and sample graphs of continuous narrow band spectra are also provided.

Montegan, F. J.↗
NASA NTRS1976

Aerodynamic and acoustic performance of a contracting cowl high throat Mach number inlet installed on NASA quiet engine C

The approach and takeoff performance was evaluated of a contracting cowl variable geometry design inlet installed on a high-bypass-ratio turbofan engine. The design was finalized after consideration of aerodynamic, acoustic, and mechanical factors which would lead to a viable flight worthy concept. The aerodynamic results are presented in terms of inlet recovery and distortion parameter as functions of throat Mach number, and acoustic results in terms of Perceived Noise Level. The contracting cowl high throat Mach number inlet is shown to be an attractive means to reduce forward radiated noise from a high bypass ratio turbofan engine.

Blommer, H. E.↗
NASA NTRS1976

Reverse-thrust technology for variable-pitch fan propulsion systems

Tests conducted to develop the technology necessary to meet the unique reverse-thrust performance requirements of a variable pitch fan propulsion system are discussed. The losses and distortion associated with the air entering the fan and core compressor from the rear of the engine, the direction of fan blade pitch rotation for best reverse-thrust aeroacoustic performance, and engine response and operating characteristics during forward- to reverse-thrust transients are among the factors studied. The test results of several scale fan models as well as a full-size variable pitch fan engine are summarized. Results show the following: a flared exhaust nozzle makes a good reverse-thrust inlet; acceptable core inlet duct recovery and distortion levels in reverse flow were demonstrated; adequate thrust levels were achieved; forward- to reverse-thrust response time achieved was better than the goal; thrust and noise levels strongly favor reverse through feather pitch; and finally, flight-type inlets make the establishment of reverse flow more difficult.

Sagerser, D. A.↗
NASA NTRS1975

Analytic and experimental evaluation of flowing air test conditions for selected metallics in a shuttle TPS application

A detailed experimental and analytical evaluation was performed to define the response of TD nickel chromium alloy (20 percent chromium) and coated columbium (R512E on CB-752 and VH-109 on WC129Y) to shuttle orbiter reentry heating. Flight conditions important to the response of these thermal protection system (TPS) materials were calculated, and test conditions appropriate to simulation of these flight conditions in flowing air ground test facilities were defined. The response characteristics of these metallics were then evaluated for the flight and representative ground test conditions by analytical techniques employing appropriate thermochemical and thermal response computer codes and by experimental techniques employing an arc heater flowing air test facility and flat face stagnation point and wedge test models. These results were analyzed to define the ground test requirements to obtain valid TPS response characteristics for application to flight. For both material types in the range of conditions appropriate to the shuttle application, the surface thermochemical response resulted in a small rate of change of mass and a negligible energy contribution. The thermal response in terms of surface temperature was controlled by the net heat flux to the surface; this net flux was influenced significantly by the surface catalycity and surface emissivity. The surface catalycity must be accounted for in defining simulation test conditions so that proper heat flux levels to, and therefore surface temperatures of, the test samples are achieved.

Schaefer, J. W.↗
NASA NTRS1974

Noise generated by quiet engine fans. 2: Fan A

A significant effort within the NASA Quiet Engine Program has been devoted to acoustical evaluation at the Lewis Research Center noise test facility of a family of full-scale fans. This report, documents the noise results obtained with fan A - a 1.5-pressure-ratio, 1160-ft/sec-tip-speed fan. The fan is described and some aerodynamic operating data are given. Far-field noise around the fan was measured for a variety of configurations pertaining to acoustical treatment and over a range of operating conditions. Complete results of 1/3-octave band analysis of the data are presented in tabular form. Included also are power spectra and sideline perceived noise levels. Some representative 1/3-octave band data are presented graphically, and sample graphs of continuous narrow-band spectra are also provided.

Montegani, F. J.↗
NASA NTRS1973

Arc jet tests of RSI materials: Screening and comparative evaluation

Cyclic convective heating test results show that all surface insulation materials tested exhibit a wide range of surface emittance and catalytic activity depending on their surface coatings. Coatings have a significant effect on the overall material response depending on boundary layer characteristics.

Schaefer, J. W.↗