Optimisation of crescent-shaped block upstream of the cylindrical hole to enhance film cooling effectiveness using CFD method and genetic algorithm

This study numerically investigated the optimal geometry of the crescent-shaped upstream block for the typical cylindrical inclined film-cooling hole to improve the cooling performance. The maximum area-averaged cooling effectiveness is pursued using the genetic algorithm combined with the CFD method at two blowing ratios of 0.5 and 1.5. Compared with the reference block, two optimised models obtained under the two blowing ratios increased the area-averaged cooling effectiveness by 127.8% at a blowing ratio of 0.5 and 16.6% at a blowing ratio of 1.5, respectively. The enhancement in the cooling performance mainly results from the improvement in the streamwise coolant coverage and the lateral coolant coverage at blowing ratios of 0.5 and 1.5, respectively.