Film cooling performance for the cratered film-cooling holes with various coolant crossflow orientations

Abstract

The present study investigates the influence of the coolant crossflow orientation on the cooling performance for the cratered film-cooling hole. It is well known that the quiescent coolant plenum is mostly adopted in the laboratory for convenience. In the present article, the coolant crossflow channels with three possible orientations in practice are further considered. The flow fields for the film-cooling are solved with the RANS method with the SST turbulence model at blowing ratios of 0.5, 1.0, and 2.0. The numerical results show that the coolant crossflow orientation significantly alters the coolant flow at the hole exit, further the downstream vortex structure and the cooling effectiveness. The symmetric flow and cooling effectiveness distribution occur for the quiescent plenum case, in-line parallel crossflow case, and the counter parallel crossflow case provide, but the asymmetrical flow and cooling effectiveness distribution for the perpendicular crossflow. The in-line parallel crossflow case gives almost considerable cooling effectiveness as the common quiescent plenum case. On the other hand, the counter-parallel crossflow case provides the worst cooling performance due to the opposite flow direction of the coolant supply relative to the mainstream flow. At the high blowing ratio of 2.0, the cooling performance is higher for the perpendicular crossflow feeding despite its asymmetrical distribution of the cooling effectiveness.