Experimental and numerical study on the impact of shock wave intensity on film cooling

Abstract

In transonic high-load turbines, interactions between trailing-edge shock waves and suction-side film cooling can severely compromise thermal protection and may even lead to localized cooling failure. To investigate the underlying mechanisms and critical effects associated with shock intensity, combined experimental and numerical studies are conducted at an inlet Mach number of 1.45. Weak to moderate shock interference is found to primarily accelerate the vorticity dissipation of the coolant-jet-induced counter-rotating vortex pair (CRVP). As shock intensity further increases, a normal shock forms above the interaction region and, under strong baroclinic effects, induces a sustained reversal of the CRVP, thereby leading to a rapid deterioration of film cooling effectiveness within the shock wave-film interaction region. To quantitatively characterize the severity of SWFI, a wall-pressure-based shock wave interaction intensity parameter (φ) is introduced. When φ exceeds 0.30, film cooling performance is observed to enter a markedly degraded regime. Entropy generation analysis demonstrates that viscous dissipation is the primary source of the entropy generation rate (EGR). Within the SWFI region, more than 70% of the total EGR originates from the coolant–mainstream shear layer, while direct shock-induced compression contributes negligibly.