Experimental Studies on the Effects of Thermal Bumps in the Flow-Field around a Flat Plate using a Hypersonic Wind Tunnel
Final rept. 1 Oct 2008-31 Jan 2012
MANCHESTER UNIV (UNITED KINGDOM) SCHOOL OF MECHANICAL AEROSPACE AND CIVIL ENGINEERING
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This report presents investigations performed on the hypersonic flow-field over a flat plate with and without thermal induced bump in the University of Manchester hypersonic blowdown wind tunnel HSST at Mach no. 5.0 and free-stream Reynolds no. 6.2x106 to 11.6x106 per metre. Experiments were conducted with air as the test gas. The report consists of two parts The first part deals with the experiments using a microheater coil of 16mm diameter to simulate the thermal bump. Quantitative heat transfer measurements were performed using IR-thermography. The surface pressure measurements using pressure-sensitive paints are also presented. Since IR-thermography has been widely used to measure surface temperature, a brief description of heat flux calculation based on the surface temperature history is given. The theoretical predictions of heat transfer coefficient over the flat plate are also presented. Emphasis is put on the quantitative heat transfer rate measurements. Tests using pressure-sensitive paints are performed to check the applicability of the technique to capture surface maps at high speeds. The results show that the pressure sensitivity is high enough considering the low free-stream pressure and small pressure changes expected along the flat plate surface. Initial studies have also been conducted on generating thermal bumps using a pair of electrodes. The second part deals with the experiments using laser energy deposition volumetric localized heating to simulate the thermal bump. The laser discharge in quiescent air with and without the plate was examined. The effect of pressure wave was investigated. The influence of the presence of an incoming hypersonic free stream is also presented. Schlieren photography and pressure measurements were employed.
- Test Facilities, Equipment and Methods
- Fluid Mechanics