Numerical Study of Discrete Hole Supersonic Film Cooling with Shock Generator

Abstract

The effects of the shock wave and the expansion fan on the flat plate film cooling are numerically studied under the supersonic condition with inclined cylindrical film holes. A triangular-shaped shock generator is applied, with both the shock wave and the expansion fan induced. Numerical investigations are conducted under four shock generator wedge angles ranging from 0° to 10° and six Mach numbers of the coolant injection ranging from 0.6 to 1.6. The flow features induced by both the shock generator and the coolant injection as well as their effects are discussed. The film cooling effectiveness is compared between different coolant injection Mach numbers and shock generator wedge angles. The cooling jet can partially resist the interference of the shock waves. With the increase of the coolant Mach number, the negative effect of the shock impingement becomes smaller; however, the positive effect of the expansion fan is less affected. Consequently, with the increase of the shock generator wedge angle, the film cooling performance tends to decrease under a smaller jet Mach number, but it tends to increases under a larger jet Mach number. With the increase of the shock generator wedge angle, the optimal coolant injection Mach number for the best cooling performance gradually increases from 1.0 to 1.2.