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An Experimental Investigation of the Effect of Ejecting a Coolant Gas at the Nose of a Blunt Body

Warren, C. Hugh E. (1958) An Experimental Investigation of the Effect of Ejecting a Coolant Gas at the Nose of a Blunt Body. Hypersonic Research Project Memorandum, 47. California Institute of Technology , Pasadena, CA. (Unpublished)

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An experimental investigation has been made of the effect of ejecting nitrogen and helium coolant gases at the nose of a blunt body in the GALCIT 5 inch x 5 inch hype r sonic wind tunnel at a nominal Mach number of 5.8. The gases were ejected with "swirl", to encourage them to flow tangentially to the model surface at ejection, and also straight out. Measurements were made of pressure, temperature and heat flux on the surface of the model at incidences of 0, 4, 8 degrees, and for a range of coolant gas flows. It was found that ejection with swirl did not in fact lead to an easement of the heating problem, because the high tangential velocity with which the coolant was injected into the boundary layer so increased the wall shear stress, and hence by the Reynolds analogy, the heat flux, that it predominated over the reduced driving temperature difference associated with the cooled boundary layer. With straight-out ejection it was found that the heat alleviation capabilities of the ejected coolant were reduced considerably if the momentum flow was sufficiently high that the bow shock wave was bulged out. For the size of ejection orifice in the present study it was possible to eject only nitrogen coolant without disturbing the external flow appreciably. The results suggest, however, that straight-out ejection could provide an effective way of reducing the heat flux provided that the external flow is not disturbed, and tests with a larger ejection orifice are indicated. A technique is proposed for making steady-state heat-flux measurements by measuring the temperature difference across a uniformly thin skin of uniform, low thermal conductivity.

Item Type:Report or Paper (Technical Report)
Additional Information:Hypersonic Research Report Memorandum No. 47. Army Ordnance Contract No. DA-04-495-Ord-19. Army Project 5B0306004 Ordnance Project No. TB3-0118 OOR Project No. 1600-PE.
Group:Hypersonic Research Project
Funding AgencyGrant Number
U.S. Army Office of OrdnanceDA-04-495-Ord-19
Series Name:Hypersonic Research Project Memorandum
Issue or Number:47
Record Number:CaltechAUTHORS:20151029-112313837
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:61712
Deposited On:29 Oct 2015 18:53
Last Modified:03 Oct 2019 09:10

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