关键词: 瞬态热冲击; 缝槽气膜冷却; 实验研究; DES仿真分析

Abstract: In order to identify the heat transfer of film cooling under thermal shock conditions，the performance of a slot film cooling scheme over a flat plat was analyzed using experimental technique and CFD approach. It was assumed that the slot film cooling scheme was tested under the transient thermal shock conditions performed by the mainstream temperature gradient ranging from 60℃/s to 100℃/s，and calculated using DES(Detached eddy simulation) model to estimate the effects of coherent shear vortex created by the mixing layer on the heat transfer. It is found that: (1)When the blowing ratio is under the critical one，the adiabatic effectiveness and convective heat transfer coefficient of the slot film cooling scheme decreases during the thermal shock course. (2)The results of DES show that the locations of shear vortex begins to swing and attach the wall move along while the blowing ratio increases，and which，gradually makes the cooling air performance instead of the shear vortex performance as the dominant factor that influence the heat transfer. (3)The adiabatic effectiveness is found to be highly oscillatory，which is mainly caused by the fluctuation of the unsteady vortex structures in the mixing layer. Compared with RANS method，DES approach performs more efficiently in predicting the adiabatic effectiveness.

Key words: Transient thermal shock；Slot film cooling；Experimental investigation；DES approach