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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 NTRS1976

Macroscopic study of time unsteady noise of an aircraft engine during static tests

Static tests of aircraft engines can exhibit greater than 10 db random unsteadiness of tone noise levels because flow disturbances that prevail near test site facilities are ingested. Presumably such changes are related to installation and test site features. Some properties of unsteady noise observed during tests of a Lycoming YF-102 turbofan engine are presented. Time and spatial variations in tone noise obtained from closely spaced far field and inlet duct microphones are displayed. Long to extremely short intermittent tone bursts are observed. Unsteadiness of the tone, its harmonics, and the broadband noise show little similarity. In the far field, identity of tone bursts is retained over a directivity angle of less than 10 deg. In the inlet duct, tone bursts appear to propagate axially but exhibit little circumferential similarity. They show only slight relationship to tone bursts observed in the far field. The results imply an intermittent generation of random mixtures of propagating duct modes.

Clark, B. J.↗
NASA NTRS1976

Macroscopic study of time unsteady noise of an aircraft engine during static tests

Static tests of aircraft engines can exhibit greater than 10 dB random unsteadiness of tone noise levels because flow disturbances that prevail near test site facilities are ingested. Presumably such changes are related to installation and test site features. This paper presents some properties of unsteady noise observed at a NASA-Lewis facility during tests of a Lycoming YF-102 turbofan engine. Time and spatial variations in tone noise obtained from closely spaced far-field and inlet duct microphones are displayed. Long (0.5 sec) to extremely short (0.001 sec) intermittent tone bursts are observed. Unsteadiness of the tone, its harmonics, and the broadband noise show little similarity. In the far-field, identity of tone bursts is retained over a directivity angle of less than 10 deg. In the inlet duct, tone bursts appear to propagate axially but exhibit little circumferential similarity. They show only slight relationship to tone bursts observed in the far field. The results imply an intermittent generation of random mixtures of propagating duct modes.

Clark, B. J.↗
NASA NTRS1974

Track-train dynamic analysis and test program, truck static test

A series of tests were conducted to define the characteristics of an ASF 11 Ride Truck Assembly including joint slop, friction and stiffness. Loading to the truck assembly included vertical load to simulate the car/pool loading combined with lateral or moment loading that resulted in desired truck deflections for the various phases of testing. All seven test conditions were successfully completed with load and deflection data being collected. No attempt is made to reduce the applicable data other than to provide computer plots.

Nemes, A. G.↗
NASA NTRS1976

Track-train dynamic analysis and test program. Barber S-2 static test

The results of a static test of a Barber S-2 freight truck conducted to measure the stiffness and friction parameters of the modes of deformation which are being used in various mathematical models in the railroad industry were presented. Some difficulty was first experienced with the truck hardware since it was in an essentially new condition with many high spots causing interference. No difficulty was experienced once the interference was removed. The characteristics of the Barber S-2 are very similar to the ASF ride control truck. The major difference between the two trucks is the amount of friction between the bolster and side frames in both the vertical and lateral directions. The Barber S-2 has approximately twice the friction the ASF ride control truck has in the fully loaded condition. This does not necessarily imply that all trucks will have this same ratio of friction.

Abbott, P. W.↗
NASA NTRS1985

Modifications to the nozzle test chamber to extend nozzle static-test capability

The nozzle test chamber was modified to provide a high-pressure-ratio nozzle static-test capability. Experiments were conducted to determine the range of the ratio of nozzle total pressure to chamber pressure and to make direct nozzle thrust measurements using a three-component strain-gage force balance. Pressure ratios from 3 to 285 were measured with several axisymmetric nozzles at a nozzle total pressure of 15 to 190 psia. Devices for measuring system mass flow were calibrated using standard axisymmetric convergent choked nozzles. System mass-flow rates up to 10 lbm/sec are measured. The measured thrust results of these nozzles are in good agreement with one-dimensional theoretical predictions for convergent nozzles.

Keyes, J. W.↗
NASA NTRS1987

Propfan test assessment propfan propulsion system static test report

The propfan test assessment (PTA) propulsion system successfully completed over 50 hours of extensive static ground tests, including a 36 hour endurance test. All major systems performed as expected, verifying that the large-scale 2.74 m diameter propfan, engine, gearbox, controls, subsystems, and flight instrumentation will be satisfactory with minor modifications for the upcoming PTA flight tests on the GII aircraft in early 1987. A test envelope was established for static ground operation to maintain propfan blade stresses within limits for propfan rotational speeds up to 105 percent and power levels up to 3880 kW. Transient tests verified stable, predictable response of engine power and propfan speed controls. Installed engine TSFC was better than expected, probably due to the excellent inlet performance coupled with the supercharging effect of the propfan. Near- and far-field noise spectra contained three dominant components, which were dependent on power, tip speed, and direction. The components were propfan blade tones, propfan random noise, and compressor/propfan interaction noise. No significant turbine noise or combustion noise was evident.

Orourke, D. M.↗
NASA NTRS1979

Thrust oscillations of the Space Shuttle solid rocket Booster motor during static tests

Thrust oscillations have occurred during static tests of Space Shuttle Booster solid rocket motors. These oscillations in measured axial thrust occurred primarily near 15 Hz; these oscillations late in the motor burn reach magnitudes up to approximately + or - 3% of motor thrust. The phenomenon has consistently occurred on the four demonstration motors which have been static tested and appears to be associated with small amplitude, 15 Hz pressure oscillations inside the motor. The source of the pressure oscillations is thought to be associated with the fundamental longitudinal acoustic resonance of the motor at 15 Hz. These thrust oscillations potentially can impact the design of the Space Shuttle vehicle structure. The demonstration motors have been instrumented with an array of transducers to aid in understanding the phenomenon. In addition to measuring axial and lateral thrust of the motor, pressure transducers were located to measure chamber pressure oscillations at the forward dome. Accelerometers and extensometers have measured motions of the structure. A modal survey was conducted on a fired motor to identify its structural dynamic characteristics, and these data were used to validate mathematical models of the motor in the static test facility.

Mason, D. R.↗
NASA NTRS2003

Characterization of Space Shuttle Reusable Rocket Motor Static Test Stand Thrust Measurements

Space Shuttle Reusable Solid Rocket Motors (RSRM) are static tested at two ATK Thiokol Propulsion facilities in Utah, T-24 and T-97. The newer T-97 static test facility was recently upgraded to allow thrust measurement capability. All previous static test motor thrust measurements have been taken at T-24; data from these tests were used to characterize thrust parameters and requirement limits for flight motors. Validation of the new T-97 thrust measurement system is required prior to use for official RSRM performance assessments. Since thrust cannot be measured on RSRM flight motors, flight motor measured chamber pressure and a nominal thrust-to-pressure relationship (based on static test motor thrust and pressure measurements) are used to reconstruct flight motor performance. Historical static test and flight motor performance data are used in conjunction with production subscale test data to predict RSRM performance. The predicted motor performance is provided to support Space Shuttle trajectory and system loads analyses. Therefore, an accurate nominal thrust-to-pressure (F/P) relationship is critical for accurate RSRM flight motor performance and Space Shuttle analyses. Flight Support Motors (FSM) 7, 8, and 9 provided thrust data for the validation of the T-97 thrust measurement system. The T-97 thrust data were analyzed and compared to thrust previously measured at T-24 to verify measured thrust data and identify any test-stand bias. The T-97 FIP data were consistent and within the T-24 static test statistical family expectation. The FSMs 7-9 thrust data met all NASA contract requirements, and the test stand is now verified for future thrust measurements.

Mart L. Cook↗
NASA NTRS1977

Effect of inlet disturbances on fan inlet noise during a static test

Measurements of fan rotor inlet noise taken during static test situations are at variance with aircraft engine flight data. In particular, static tests generally yield a significantly higher tone at blade passage frequency than that measured during flight. To explain this discrepancy, the extent of the influence of inlet ground vortices and large-scale inlet turbulence on the forward-radiated fan noise measured at a static test facility was investigated. While such inlet disturbances were generated intentionally in an anechoic test chamber, far-field acoustic measurements and inlet flow-field hot-film mappings of a fan rotor were obtained. Experimental results indicate that the acoustic effect of such disturbances appears to be less severe for supersonic than for subsonic tip speeds. Further, a reverse flow that occurs on the exterior cowl in static test facilities appears to be an additional prime candidate for creating inlet disturbances and causing variance between flight and static acoustic data.

Bekofske, K. L.↗
NASA NTRS2008

HST Super Lightweight Interchangeable Carrier (SLIC) Static Test

The HST Super Light Weight Interchangeable Carrier Static Test program calls for a total of 15 load cases with an average of 9 simultaneous push/pull locations per load case. This testing program represents the most complex static test ever attempted at Goddard Space Flight Center. Many unique multi-pull fixtures were designed to apply the simultaneous loading. Additionally, a total of 600 channels of data required processing for each loadcase. A total of 1100 separate strain gages were installed on SLIC. A team of 15 trained technicians were needed to apply test loads via mechanical hand pumps for several load cases. All 15 load cases were successfully conducted within 15 weeks. The ManTech team successfully tested all SLIC 1200 interface clips to the required testing loads. Several unique designs were needed to address testing challenges as loadline interference, Payload Safety, payload flexibility and opposing load applications.

Chambers, William V.↗
NASA NTRS1980

Studies on proper simulation during static testing of forward speed effects on fan noise

Significant differences exist in the noise generated by engines in flight and engines operating on the test stand. It was observed that these differences can be reduced by the use of an inflow control structure (ICS) in the static test configuration. The results of the third phase of a three phase program are described. The work performed in the first two phases which dealt with the development of a model for atmospheric turbulence, studies of fan noise generated by rotor turbulence interaction, and the development of an inflow control structure design system are summarized. The final phase of the program covers procedures for performing static testing with an ICS projecting the resulting static test data to actual flight test data. Included is a procedures report which covers the design system and techniques for static testing and projecting the static data to flight.

Peracchio, A. A.↗