Computational and experimental investigation of supersonic convection over a laser-heated target

Abstract

The cooling effect of a turbulent supersonic boundary layer over a laser-heated flat plate was investigated experimentally and numerically. Experiments were in the Virginia Polytechnic Institute and State University unheated supersonic wind tunnel at Mach 4. An absorbed laser power between 65 and 120 W was used, leading to a maximum heat flux between 10 and 19 MW/m(2) at the center of the 4-mm-diam Gaussian beam. The surface and backside temperature distributions were measured using a midwave infrared camera and type-K thermocouples. The GASP conjugate heat transfer algorithm coupling the Navier-Stokes and the solid conduction equations was used to simulate the experiments. The main experimental results were as follows: Asymmetry in the surface temperature increases with laser power. Maximum cooling near the beam center varies linearly with laser power, in which the proportionality constant corresponds to the ratio of convective cooling to laser heating. For both the 65 and 81 W cases, cooling is somewhat underpredicted at the surface near the center, but agreement improves with distance and on the backside.

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