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Analysis of a six-component, flow-through, strain-gage, force balance used for hypersonic wind tunnel models with scramjet exhaust flow simulationThe thermal effects of simulant gas injection and aerodynamic heating at the model's surface on the measurements of a non-watercooled, flow through balance were investigated. A stainless steel model of a hypersonic air breathing propulsion cruise missile concept (HAPCM-50) was used to evaluate this balance. The tests were conducted in the 20-inch Mach 6 wind tunnel at NASA-Langley. The balance thermal effects were evaluated at freestream Reynolds numbers ranging from .5 to 7 x 10(exp 6) ft and angles of attack between -3.5 to 5 deg at Mach 6. The injection gases considered included cold air, hot air, and a mixture of 50 percent Argon and 50 percent Freon-12. The stagnation temperatures of the cold air, hot air, and Ar-Fr(12) reached 111, 214, and 283 F, respectively within the balance. A bakelite sleeve was inserted into the inner tube of the balance to minimize the thermal effects of these injection gases. Throughout the tests, the normal force, side force, yaw moment, roll moment, and pitching moment balance measurements were unaffected by the balance thermal effects of the injection gases and the wind tunnel flow. However, the axial force (AF) measurement was significantly affected by balance heating. The average zero shifts in the AF measurements were 1.9, 3.8, and 5.9 percent for cold air, hot air, and Ar-Fr(12) injection, respectively. The AF measurements decreased throughout these tests which lasted from 70 to 110 seconds. During the cold air injection tests, the AF measurements were accurate up to at least ten seconds after the model was injected into the wind tunnel test section. For the hot air and Ar-Fr(12) tests, the AF measurements were accurate up to at least five seconds after model injection.
Document ID
19900012459
Acquisition Source
Legacy CDMS
Document Type
Thesis/Dissertation
Authors
Kniskern, Marc W. (North Carolina State Univ. Raleigh, NC, United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1990
Subject Category
Research And Support Facilities (Air)
Report/Patent Number
NASA-CR-186585
NAS 1.26:186585
Accession Number
90N21775
Funding Number(s)
CONTRACT_GRANT: NCC1-129
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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