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A parametric experimental investigation of a scramjet nozzle at Mach 6 with Freon and argon or air used for exhaust simulationA parametric experimental investigation of a scramjet nozzle was conducted with a gas mixture used to simulate the scramjet engine exhaust flow at a free-stream Reynolds number of approximately 6.5 x 10(exp 6) per foot. External nozzle surface angles of 16, 20, and 24 deg were tested with a fixed-length ramp and for cowl internal surface angles of 6 and 12 deg. Pressure data on the external nozzle surface were obtained for mixtures of Freon and argon gases with a ratio of specific heats of about 1.23, which matches that of a scramjet exhaust. Forces and moments were determined by integration of the pressure data. Two nozzle configurations were also tested with air used to simulate the exhaust flow. On the external nozzle surface, lift and thrust forces for air exhaust simulation were approximately half of those for Freon-argon exhaust simulation and the pitching moment was approximately a third. These differences were primarily due to the difference in the ratios of specific heats between the two exhaust simulation gases. A 20 deg external surface angle produced the greatest thrust for a 6 deg cowl internal surface angle. A flow fence significantly increased lift and thrust forces over those for the nozzle without a flow fence.
Document ID
19910007677
Acquisition Source
Legacy CDMS
Document Type
Technical Publication (TP)
Authors
Cubbage, James M.
(Vigyan Research Associates, Inc., Hampton VA., United States)
Monta, William J.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 6, 2013
Publication Date
February 1, 1991
Subject Category
Aerodynamics
Report/Patent Number
L-16707
NASA-TP-3048
NAS 1.60:3048
Accession Number
91N16990
Funding Number(s)
PROJECT: RTOP 763-01-31-24
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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