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Hot-film static-pressure probe for surveying flow fieldsA static pressure probe employing hot-film sensors has been developed for the rapid measurement of the static pressure fields surrounding analytic shapes in hypersonic flows. The hot-film probe is a modification of the standard static pressure probe, consisting of a front hot-film sensor operated as a resistance thermometer, a rear sensor operated at an overheat ratio of 1.5 to 1.8 and a small sonic orifice installed inside the tubing of a conventional device. The probe has been calibrated in helium and air over a range of temperatures and pressures in a bell jar apparatus, with a repeatability of the data to within + or - 0.015 mm Hg. Comparative tests of the hot-film and conventional static pressure probes in a hypersonic helium wind tunnel at Mach 20 and various Reynolds numbers have indicated the settling time of the hot-film probe to be on the order of milliseconds, as compared with 30 sec for the conventional probe. The pressures measured by the two probes were found to be within 10% of each other. Although the hot-film probe makes flow-field static pressure surveys more practical in blowdown hypersonic wind tunnels, viscous and flow angle effects still must be assessed under the conditions of use.
Document ID
19810042528
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Ashby, G. C., Jr.
(NASA Langley Research Center Hampton, VA, United States)
Weinstein, L. M.
(NASA Langley Research Center Hampton, Va., United States)
Date Acquired
August 11, 2013
Publication Date
April 1, 1981
Subject Category
Instrumentation And Photography
Meeting Information
Meeting: International Instrumentation Symposium
Location: Indianapolis, IN
Start Date: April 27, 1981
End Date: April 30, 1981
Sponsors: Instrument Society of America
Accession Number
81A26932
Distribution Limits
Public
Copyright
Other

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