Influence of Shock Waves on Supersonic Film Cooling

摘要

Supersonic film cooling with and without induced shock waves was investigated numerically. The computations used a freestream Mach number of 3.13 and tangential-slot injection-cooling-stream Mach numbers of 1.3 and 1.8. Parameters investigated included shock wave intensity and coolant properties (nitrogen, methane, and helium). The results indicate that the adiabatic effectiveness is reduced by the impinging oblique shock wave because the shock wave reduces the local Mach number in the coolant layer, which increases the adiabatic-wall temperature. In addition, the oblique shock wave enhances the mixing of the cooling stream with the freestream, especially for stronger shock waves or lighter-gas coolants, which also increases the adiabatic-wall temperature. For the same injection-cooling-stream Mach number, the effects of the oblique shock wave are stronger in helium; however, helium had a higher adiabatic effectiveness than methane and nitrogen, even though the helium mass flow rate was lower than that of either methane or nitrogen. The adiabatic effectiveness is reduced much more by the 10 deg shock waves than by either the 7 or 4 deg shock waves.