Influence of shock wave impinging region on supersonic film cooling

Shock waves can significantly affect the film cooling for supersonic flow and shock waves may have different influence when impinging in different regions.The present study numerically compared the results of shock wave impinging in three different regions and analyzed the effect of impinging region.The shock wave generators were located at x/s=5,25,45 with 4°,7° and 10° shock wave incidence.The mainstream Mach number was 3.2 and the coolant Mach number was 1.2 or 1.5.The numerical results illustrated that the shock wave impinged in the further upstream region led to a larger high-pressure region and a larger vortex in the boundary layer.Moreover,placing the shock wave generator upstream resulted in the lower mass fraction of coolant in the downstream region.The velocity in the upstream part of the cooling layer was lower than the midstream and downstream part,which resulted in the less ability to resist the shock wave impingement.Therefore,the upstream impingement deteriorated the cooling performance to a greater extent.The study also manifested that the stronger shock wave had a larger effect on supersonic film cooling.Increasing the coolant inlet Mach number can increase the blowing ratio and reduce the mixing,which was of benefit to improve cooling effect.