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  • 1
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    Mixer-ejector nozzle for jet noise suppression (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: An aero/acoustic model test of a mixer-ejector nozzle was conducted at the 9 x 15 foot low-speed acoustic wind tunnel at NASA Lewis Research Center. The objective of the test was to get a preliminary assessment of ejector pumping and noise reduction potential of this device for possible application in the exhaust system of an advanced supersonic civil transport. The results of the test showed that goal levels of pumping were achieved. Exit pressure/temperature traverse data showed that there was good mixing between the primary and secondary streams. Acoustics data were dominated by shock noise; jet mixing noise levels were low because of a facility limit on primary temperature. The mixer-ejector did significantly reduce shock noise relative to the baseline conic nozzle. Because the relative magnitudes of jet mixing noise and shock noise were not in the correct proportion to properly model engine noise, an Effective Perceived Noise Level (EPNL) assessment was precluded.
    Keywords: ACOUSTICS
    Type: AIAA PAPER 90-1909
    Format: text
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    NASA TECHNICAL REPORTS
  • 2
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    Hot-flow tests of a series of 10-percent-scale turbofan forced mixing nozzles (1984)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An approximately 1/10-scale model of a mixed-flow exhaust system was tested in a static facility with fully simulated hot-flow cruise and takeoff conditions. Nine mixer geometries with 12 to 24 lobes were tested. The areas of the core and fan stream were held constant to maintain a bypass ratio of approximately 5. The research results presented in this report were obtained as part of a program directed toward developing an improved mixer design methodology by using a combined analytical and experimental approach. The effects of lobe spacing, lobe penetration, lobe-to-centerbody gap, lobe contour, and scalloping of the radial side walls were investigated. Test measurements included total pressure and temperature surveys, flow angularity surveys, and wall and centerbody surface static pressure measurements. Contour plots at various stations in the mixing region are presented to show the mixing effectiveness for the various lobe geometries.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA-TP-2268 , E-1746 , NAS 1.60:2268
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    Flight velocity effects on jet noise of several variations of a 48-tube suppressor installed on a plug nozzle (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Because of the relatively high takeoff speeds of supersonic transport aircraft, it is important to know if the flight velocity affects the noise level of suppressor nozzles. To investigate this, a modified F-106B aircraft was used to conduct a series of flyover and static tests on a 48-tube suppressor installed on an uncooled plug nozzle. Comparison of flyover and static spectra indicated that flight velocity had little effect on the noise suppression of the 48-tube suppressor configuration. However, flight velocity adversely affected noise suppression of the 48-tube suppressor with an acoustic shroud and plug installed.
    Keywords: PROPULSION SYSTEMS
    Type: NASA-TM-X-2919 , E-7513
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
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    Flight investigation of an underwing nacelle installation of three variable-flap ejector nozzles (1972)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A modified F-106B aircraft with underwing engine nacelles was flight tested to investigate airframe installation effects on ejector nozzles. Nozzle thrust coefficients, boattail drag coefficients, and boundary layer characteristics were obtained for the three nozzles. All the nozzles were geometrically similar and had 15 deg conical boattails with juncture radii of curvature equal to 0.5 maximum nozzle diameter. The effects of boattail location relative to the wing trailing edge and the ejector to primary nozzle exit diameter ratio were investigated. Shortening the length by 0.48 nozzle diameter lowered the transonic boattail drag rise Mach number from 0.97 to 0.95. Decreasing the nozzle exit diameter, which reduced the ejector to primary nozzle exit diameter ratio from 1.30 to 1.18, increased the gross thrust coefficient 4.8 percent.
    Keywords: PROPULSION SYSTEMS
    Type: NASA-TM-X-2478 , E-6564
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
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    Flight investigation of an underwing nacelle installation of an auxiliary-inlet ejector nozzle with a clamshell flow diverter from Mach 0.6 to 1.3 (1972)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A nozzle installation of general interest is a podded engine mounted near the aft lower surface of the wing. The effect of this installation on the performance of an auxiliary-inlet ejector nozzle with a clamshell flow diverter was investigated over a Mach number range of 0.6 to 1.3 by using a modified F-106B aircraft. The clamshell flow diverter was tested in a 17 deg position with double-hinged synchronized floating doors. The ejector nozzle trailing-edge flaps were simulated in the closed position with a rigid structure which provided a boattail angle of 10 deg. Primary nozzle area was varied as exhaust gas temperature was varied between 975 and 1561 K. With the nozzle in a subsonic cruise position, the nozzle gross thrust coefficient was 0.918 at a flight Mach number of 0.9.
    Keywords: PROPULSION SYSTEMS
    Type: NASA-TM-X-2655 , E-7042
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 6
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    Flight investigation of airframe installation effects on a variable flap ejector nozzle of an underwing engine nacelle at Mach numbers from 0.5 to 1.3 (1970)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Airframe installation effects on variable flap ejector nozzle of underwing engine nacelle
    Keywords: AERODYNAMICS
    Type: NASA-TM-X-2010 , E-5467
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 7
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    Flight investigation of installation effects on a plug nozzle with a series of boattailed primary shrouds installed on an underwing nacelle (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Several variations of a boattailed shroud for a 10 deg conical plug nozzle were tested using an F-106B aircraft for Mach 0.6 to 1.3. The data were obtained so that the tradeoff between boattail and plug size could be studied for an underwing nacelle location. The nozzles were tested with J85-GE-13 turbojet engine, and the data were compared to previous flight results of installed plug nozzles. Boattail area varied from 31 to 66 percent of the nacelle area. The effect of increasing projected boattail area was to increase the gross thrust coefficient in the same way as from isolated data for flight Mach numbers below 0.85. The highest gross thrust coefficient (0.958) was obtained at Mach 0.95 with a long circular arc shroud configuration with a very small amount of secondary air flow.
    Keywords: PROPULSION SYSTEMS
    Type: NASA-TM-X-2983 , E-7612
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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