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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Wind tunnel and ground static investigation of a large scale model of a lift/cruise fan V/STOL aircraft

An investigation was conducted in a 40 foot by 80 foot wind tunnel to determine the aerodynamic/propulsion characteristics of a large scale powered model of a lift/cruise fan V/STOL aircraft. The model was equipped with three 36 inch diameter turbotip X376B fans powered by three T58 gas generators. The lift fan was located forward of the cockpit area and the two lift/cruise fans were located on top of the wing adjacent to the fuselage. The three fans with associated thrust vectoring systems were used to provide vertical, and short, takeoff and landing capability. For conventional cruise mode operation, only the lift/cruise fans were utilized. The data that were obtained include lift, drag, longitudinal and lateral-directional stability characteristics, and control effectiveness. Data were obtained up to speeds of 120 knots at one model height of 20 feet for the conventional aerodynamic lift configuration and at several thrust vector angles for the powered lift configuration.

Source record↗
NASA NTRS1976

Simulation of Flight-Type Engine Fan Noise in the NASA-Lewis 9X15 Anechoic Wind Tunnel

Flight type noise as contrasted to the usual ground static test noise exhibits substantial reductions in the time unsteadiness of tone noise, and in the mean level of tones calculated to be nonpropagating or cut-off. A model fan designed with cuttoff of the fundamental tone was acoustically tested in the anechoic wind tunnel under both static and tunnel flow conditions. The properties that characterize flight type noise were progressively simulated with increasing tunnel flow. The distinctly lobed directivity pattern of propagating rotor/stator interaction modes was also observed. Excess noise attributed to the ingestion of the flow disturbances that prevail near most static test facilities is substantially reduced with tunnel flow.

Heidmann, M. F.↗
NASA NTRS1973

Low speed wind tunnel investigation of a large scale lift fan STOL transport model

The low-speed aerodynamic characteristics of large scale V/STOL transport models with lift fan and lift-cruise fan propulsion systems are discussed. The model of this investigation had two fans mounted side by side in the nose section of the fuselage. This permitted a reasonably deep inlet on the inboard side of each fan while the outboard side had a fairly shallow inlet. Lift-cruise fans were installed on the aft section of the fuselage. Hood-type deflection ducts were used to turn the fan flow from the cruise direction to the lift direction for STOL performance. Fan performance is shown for all four fans both statically and with crossflow. Longitudinal force and moment results are shown for a representative tip speed (forward speed) range through wing supported flight. Lateral-directional characteristics are also presented. The results are presented without analysis.

Atencio, A., Jr.↗
NASA NTRS1987

Experimental Evaluation of Turning Vane Designs for High-speed and Coupled Fan-drive Corners of 0.1-scale Model of NASA Lewis Research Center's Proposed Altitude Wind Tunnel

Two turning vane designs were experimentally evaluated for the fan-drive corner (corner 2) coupled to an upstream diffuser and the high-speed corner (corner 1) of the 0.1 scale model of NASA Lewis Research Center's proposed Altitude Wind Tunnel. For corner 2 both a controlled-diffusion vane design (vane A4) and a circular-arc vane design (vane B) were studied. The corner 2 total pressure loss coefficient was about 0.12 with either vane design. This was about 25 percent less loss than when corner 2 was tested alone. Although the vane A4 design has the advantage of 20 percent fewer vanes than the vane B design, its vane shape is more complex. The effects of simulated inlet flow distortion on the overall losses for corner 1 or 2 were small.

Gelder, Thomas F.↗
NASA NTRSDate not supplied

Source Diagnostic Fan II (22-Inch) Duct Mode Characteristics as Measured by the Rotating Rake Mode Measurement System while Operated in the NASA Glenn 9x15 Low Speed Wind Tunnel

A 22-inch scale model of the Honeywell Quiet High Speed Fan II was tested in the NASA Glenn 9- by 15-foot Low Speed Wind Tunnel at a tunnel Mach number of 0.10. This was an entry to investigate the effect of “stator clocking” on noise. The fan consisted of a moderately aft swept rotor, and an aft swept set of stator vanes. The fan stage consisted of 22 rotor blades, 50 stator vanes, and 10 downstream support struts. A set of stator vanes designed for lower noise was tested as well as a baseline stator vane set. The stator assembly could be rotated several degrees to adjust the clocking angle between the stator vane pack and the strut assembly. All configurations were with a hard wall duct (no acoustic treatment). The NASA Glenn Research Center’s Rotating Rake Mode Measurement System was utilized to obtain a complete map of the acoustic duct modes present in the ducted fan. The system is a radial rake emersed into the duct that continuously rotates about the duct centerline. For the two stator configurations, data were acquired at several different fan speeds which included nominal, approach, cutback, and takeoff conditions. Analysis of the mode power level results at the fan fundamentals showed the improved designed set resulted in lower rotor-stator and rotor-strut interaction acoustic levels for the interaction modes. Varying the angle between the stators and struts was shown to be a viable method to achieve a minimum in rotor-strut interaction mode power level. Multiple-pure-tones generated by the Quiet High Speed Fan II in the inlet were also measured.

Fan Noise↗
NASA NTRS1981

Forward velocity effects on fan noise and the suppression characteristics of advanced inlets as measured in the NASA Ames 40 by 80 foot wind tunnel: Acoustic data report

Forward velocity effects on the forward radiated fan noise and on the suppression characteristics of three advanced inlets relative to a baseline cylindrical inlet were measured in a wind tunnel. A modified JT15D turbofan engine in a quiet nacelle was the source of fan noise; the advanced inlets were a CTOL hybrid inlet, an STOL hybrid inlet, and a treated deflector inlet. Also measured were the static to flight effects on the baseline inlet noise and the effects on the fan noise of canting the baseline inlet 4 deg downward to simulate typical wing mounted turbofan engines. The 1/3 octave band noise data from these tests are given along with selected plots of 1/3 octave band spectra and directivity and full scale PNL directivities. The test facilities and data reduction techniques used are also described.

Moore, M. T.↗
NASA NTRS2012

Acoustic Performance of the GEAE UPS Research Fan in the NASA Glenn 9- by 15-Foot Low-Speed Wind Tunnel

A model advanced turbofan was acoustically tested in the NASA Glenn 9- by 15-Foot Low-Speed Wind Tunnel in 1994. The Universal Propulsion Simulator fan was designed and manufactured by General Electric Aircraft Engines, and included an active core, as well as bypass, flow paths. The fan was tested with several rotors featuring unswept, forward-swept and aft-swept designs of both metal and composite construction. Sideline acoustic data were taken with both hard and acoustically treated walls in the flow passages. The fan was tested within an airflow at a Mach number of 0.20, which is representative of aircraft takeoff/approach conditions. All rotors showed similar aerodynamic performance. However, the composite rotors typically showed higher noise levels than did corresponding metal rotors. Aft and forward rotor sweep showed at most modest reductions of transonic multiple pure tone levels. However, rotor sweep often introduced increased rotor-stator interaction tone levels. Broadband noise was typically higher for the composite rotors and also for the aft-swept metal rotor. Transonic MPT generation was reduced with increasing fan axis angle of attack (AOA); however, higher downstream noise levels did increase with AOA resulting in higher overall Effective Perceived Noise Level.

Woodward, Richard P.↗
NASA NTRS1993

Fabrication of composite propfan blades for a cruise missile wind tunnel model

This report outlines the procedures that were employed in fabricating prototype graphite-epoxy composite prop fan blades. These blades were used in wind tunnel tests that investigated prop fan propulsion system interactions with a missile airframe in order to study the feasibility of an advanced-technology-propfan-propelled missile. Major phases of the blade fabrication presented include machining of the master blade, mold fabrication, ply cutting and assembly, blade curing, and quality assurance. Specifically, four separate designs were fabricated, 18 blades of each geometry, using the same fabrication technique for each design.

Fite, E. Brian↗
NASA NTRS1974

The effects of forward speed on fan inlet turbulence and its relation to tone noise generation

The effect of forward speed on fan inlet turbulence was studied to determine the feasibility of using a wind tunnel to simulate various flight conditions where turbulence of atmospheric origin enters the engine inlet. The investigation was conducted in the Ames 7- by 10-foot Wind Tunnel with a small-scale low pressure-ratio fan. Results indicate that a wind tunnel of this size does produce large turbulence scale appropriate for simulation of atmospheric scale. But the tunnel's low turbulence intensity seems to cause results contrary to existing theories on the effects of fan inlet velocity ratio on turbulence scale. Limited results with artificially increased turbulence intensity removed this contradiction. Acoustic measurements showed the impact of inlet turbulence on fantone noise.

Hodder, B. K.↗
NASA NTRS1999

Low-Noise Potential of Advanced Fan Stage Stator Vane Designs Verified in NASA Lewis Wind Tunnel Test

With the advent of new, more stringent noise regulations in the next century, aircraft engine manufacturers are investigating new technologies to make the current generation of aircraft engines as well as the next generation of advanced engines quieter without sacrificing operating performance. A current NASA initiative called the Advanced Subsonic Technology (AST) Program has set as a goal a 6-EPNdB (effective perceived noise) reduction in aircraft engine noise relative to 1992 technology levels by the year 2000. As part of this noise program, and in cooperation with the Allison Engine Company, an advanced, low-noise, high-bypass-ratio fan stage design and several advanced technology stator vane designs were recently tested in NASA Lewis Research Center's 9- by 15-Foot Low-Speed Wind Tunnel (an anechoic facility). The project was called the NASA/Allison Low Noise Fan.

Hughes, Christopher E.↗
NASA NTRS1977

Instrumentation complex for Langley Research Center's National Transonic Facility

The instrumentation discussed in the present paper was developed to ensure reliable operation for a 2.5-meter cryogenic high-Reynolds-number fan-driven transonic wind tunnel. It will incorporate four CPU's and associated analog and digital input/output equipment, necessary for acquiring research data, controlling the tunnel parameters, and monitoring the process conditions. Connected in a multipoint distributed network, the CPU's will support data base management and processing; research measurement data acquisition and display; process monitoring; and communication control. The design will allow essential processes to continue, in the case of major hardware failures, by switching input/output equipment to alternate CPU's and by eliminating nonessential functions. It will also permit software modularization by CPU activity and thereby reduce complexity and development time.

Russell, C. H.↗
NASA NTRS1990

Analysis of the National Transonic Facility mishap

The nonlinear dynamic finite element code DYnamic Crash Analysis of STructures (DYCAST) was used to model an accident scenario that occurred at the National Transonic Facility (NTF) wind tunnel. A post mishap investigation revealed that a total of five upstream bulkhead fairing plates were missing, three in one location and two in another. These plates were drawn into the wind tunnel's composite fan blades causing extensive damage. A DYCAST model was developed to determine if one-half of a small thermal shield flange clamp, weighing approximately 2.7 lbs., could have spun off the NTF drive shaft and impacted the bulkhead fairing plates with sufficient energy to cause failure of the attachment bolts. The clamp was presumed to have spun off at a tangent from the NTF drive shaft at a velocity of 1624 in/sec (drive shaft rotating at 580 rpm). The DYCAST analytical model predicts that impact of the 2.7 lbs projectile failed all of the bolts in two of the fairing plates allowing them to escape from the bulkhead ring with a low velocity of a few in/sec.

Fasanella, Edwin L.↗
NASA NTRS1972

Static performance of a 13.97 cm (5.5 inch) diameter model VTOL lift fan

A tip-turbine-driven fan of the type currently being used in wind tunnel tests of VTOL lift fan models was tested. Values of thrust, weight flow, exit total and static pressure, exit swirl angle, and turbine temperature drop were measured as a function of fan speed for several inlet and exit configurations. A standard fan performance map was also obtained.

Lowe, W. H.↗
NASA NTRS2005

Fan Noise Source Diagnostic Test: Rotor Alone Aerodynamic Performance Results

The aerodynamic performance of an isolated fan or rotor alone model was measured in the NASA Glenn Research Center 9- by 15- Foot Low Speed Wind Tunnel as part of the Fan Broadband Source Diagnostic Test conducted at NASA Glenn. The Source Diagnostic Test was conducted to identify the noise sources within a wind tunnel scale model of a turbofan engine and quantify their contribution to the overall system noise level. The fan was part of a 1/5th scale model representation of the bypass stage of a current technology turbofan engine. For the rotor alone testing, the fan and nacelle, including the inlet, external cowl, and fixed area fan exit nozzle, were modeled in the test hardware; the internal outlet guide vanes located behind the fan were removed. Without the outlet guide vanes, the velocity at the nozzle exit changes significantly, thereby affecting the fan performance. As part of the investigation, variations in the fan nozzle area were tested in order to match as closely as possible the rotor alone performance with the fan performance obtained with the outlet guide vanes installed. The fan operating performance was determined using fixed pressure/temperature combination rakes and the corrected weight flow. The performance results indicate that a suitable nozzle exit was achieved to be able to closely match the rotor alone and fan/outlet guide vane configuration performance on the sea level operating line. A small shift in the slope of the sea level operating line was measured, which resulted in a slightly higher rotor alone fan pressure ratio at take-off conditions, matched fan performance at cutback conditions, and a slightly lower rotor alone fan pressure ratio at approach conditions. However, the small differences in fan performance at all fan conditions were considered too small to affect the fan acoustic performance.

Hughes, Christopher E.↗
NASA NTRS1971

Large-scale wind-tunnel investigation of a V/STOL transport model with podded lift fans forward and aft of a low mounted wing

A configuration with outboard pod mounted front fans and rear fans located in the wing trailing-edge and fuselage juncture might have superior induced lift and variation of moment with airspeed. A large scale investigation of this type of configuration was conducted in 40- by 80-foot wind tunnel. The model used was a low wing transport representative of currently operating aircraft. Two lift fans were placed in pods forward of and below the wing with the fan centerline near mid semi-span. Two rear fans were mounted at the wing trailing-edge close to the fuselage with the fan rotor in the wing chord plane. Fan performance was measured statically and with forward speed, and longitudinal aerodynamic characteristics were obtained with the fans operating at various tip-speed ratios.

Hall, L. P.↗
NASA NTRS1977

Ground effects and control effectiveness tests of a .095 scale powered model of a modified T-39 lift/cruise fan V/STOL research airplane

Wind tunnel test data are analysed to determine ground effects and the effectiveness of the aerodynamic control surfaces to provide a technology base for a Navy type A V/STOL airplane. Three 14CM (5.5 inch) turbopowered simulators were used to power the model which was tested primarily in the following configurations: (1) VTOL with flaps deployed, gear down, and engines tilted to 80 deg, 90 deg, and 95 deg, (2) STOL with flap and gear down and engines tilted to 50 deg; and (3) Loiter with flaps and gear up and L/C nacelles off. Data acquired during the tests are included as an appendix.

Dawson, C. R.↗
NASA NTRS1978

VSTOL tilt nacelle aerodynamics and its relation to fan blade stresses

A scale model of a VSTOL tilt nacelle with a 0.508 m single stage fan was tested in a low speed wind tunnel to ascertain inlet aerodynamic and fan aeromechanical performance over the low speed flight envelope. Fan blade stress maxima occurred at discrete rotational speeds corresponding to integral engine order vibrations of the first flatwise bending mode. Increased fan blade stress levels coincided with internal boundary layer separation but became severe only when the separation location had progressed to the entry lip region of the inlet.

Shaw, R. J.↗