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Hot-wire Measurements in Low Reynolds Number Hypersonic Flows

Dewey, C. Forbes, Jr. (1961) Hot-wire Measurements in Low Reynolds Number Hypersonic Flows. Hypersonic Research Project Memorandum, 63. California Institute of Technology , Pasadena, CA. (Unpublished) https://resolver.caltech.edu/CaltechAUTHORS:20151105-153754956

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Abstract

Measurements were made of the heat loss and recovery temperature of a fine hot-wire at a nominal Mach number of 5.8. Data were obtained over an eight-fold range of Reynolds numbers in the transitional regime between continuum and free-molecule flow. At high Reynolds numbers, the heat transfer data agree well with the results of Laufer and McClellan, which were obtained at lower Mach numbers. At lower Reynolds numbers, the results indicate a monotonic transition between continuum and free molecule heat transfer laws. The slope of the heat transfer correlation also appears to vary monotonically, with Nu=√Re at high Reynolds numbers and Nu ~ Re for Re < < 1. Data on the wire recovery temperature (corresponding to zero net heat transfer) were obtained for free-stream Knudsen numbers between 0.4 and 3.0. Comparison with previous data suggests that for Mach numbers greater than about two the normalized variation of recovery temperature in the transitional regime is a unique function of the free-stream Knudsen number. The steady-state hot-wire may be used to obtain two thermodynamic measurements: the rate of heat transfer from the wire and the wire recovery temperature. An illustrative experiment was performed in the wake of a transverse cylinder, using both hot-wire and pressure instruments in a redundant system of measurements. It was shown that good accuracy may be obtained with a hot-wire even when the Reynolds number based on wire diameter is small.


Item Type:Report or Paper (Technical Report)
Additional Information:Army Ordnance Contracts DA-04-495-Ord-1960 and DA-04-495-ORD-3231.
Group:Hypersonic Research Project
Funders:
Funding AgencyGrant Number
U.S. Army Office of OrdnanceDA-04-495-Ord-1960
U. S. Army Office of OrdnanceDA-04-495-ORD-3231
Series Name:Hypersonic Research Project Memorandum
Issue or Number:63
Record Number:CaltechAUTHORS:20151105-153754956
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20151105-153754956
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:61911
Collection:CaltechAUTHORS
Deposited By: Kristin Buxton
Deposited On:05 Nov 2015 23:57
Last Modified:03 Oct 2019 09:13

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