Numerical simulation of film-cooling concave plate as coolant jet passes through two rows of holes with various orientations of coolant flow

摘要

Computations are performed to predict the three-dimensional flow and heat transfer of concave plate that is cooled by two staggered rows of film-cooling jets. This investigation considers two coolant flow orientations: (1) the coolant jets were ejected from a straight-blow supply plenum, so the coolant supply plane is parallel to the entrance plane of the coolant jets; (2) the coolant jets were ejected from the cross-blow supply plenum so the coolant supply plane was normal to the entrance plane of the coolant jets. The effects of numerous film-cooling parameters were investigated, including the mainstream Reynolds number, the angular locations of the two-row injections and the blowing ratio. The mainstream Reynolds number, determined by the diameter of the injection hole as the characteristic length, varied from 3440 to 13,760. The blowing ratio ranged from 0.5 to 2.0 with a fixed density ratio of 1.14. Additionally, two angles of injections, 40° and 42°, from the exit plane of the entrance duct are considered. Results are presented as the surface adiabatic film-cooling effectiveness, the temperature distribution and the velocity vector profile. The formation and trace of counter-rotating vortex pairs that result from the interaction between the mainstream hot gas and the cooling jets was clearly exhibited. The laterally averaged film-cooling effectiveness over the concave surface with a straight-blow plenum is slightly higher than that of a cross-blow plenum at all test blowing ratios. Results of this study demonstrate that the blowing ratio is one of the most significant film-cooling parameters over a concave surface.