Film cooling at hypersonic Mach numbers using forward facing array of micro-jets

Sriram, R and Jagadeesh, G (2009) Film cooling at hypersonic Mach numbers using forward facing array of micro-jets. In: International journal of heat and mass transfer, 52 (15-16). pp. 3654-3664.

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Abstract

Experimental investigations are carried out in the IISc hypersonic shock tunnel on film cooling effectiveness of a single jet (diameter 2 mm and 0.9 mm), and an array forward facing of micro-jets (diameter 300 mu m each) of same effective area (corresponding to the respective single jet). The single jet and the corresponding micro-jets are injected from the stagnation zone of a blunt cone model (58, apex angle and nose radius of 35 mm). Nitrogen and Helium are injected as coolant gases. Experiments are performed at freestream Mach number 5.9, at 0 degrees angle of attack, with a stagnation enthalpy of 1.84 MJ/kg, with and without injections. The ratios of the jet stagnation pressure to the freestream pitot pressure used in the present study are 1.2 and 1.45. Up to 50% reduction in surface heat transfer rate was observed with the array of micro-jets, compared to that of the respective single jet with nitrogen as the coolant, while the corresponding eduction was up to 37% for helium injection, with the schlieren flow visualizations showing no major change in the shock standoff distance, and thus no major changes in other aerodynamic aspects such as drag.

Item Type:	Journal Article
Publication:	International journal of heat and mass transfer
Publisher:	Elsevier science
Additional Information:	Copyright for this article belongs to Elsevier science.
Keywords:	Hypersonic flow; Film cooling; Forward facing jet/micro jets
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited:	21 Jul 2009 10:54
Last Modified:	19 Sep 2010 05:37
URI:	http://eprints.iisc.ac.in/id/eprint/21473

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