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The film cooling performance of a trunk-branch hole is investigated by numerical simulation in this paper.The geometry of the hole is a novel cooling concept,which controls the vortices-pair existing at the trunk hole outlet using the injection of the branch hole.The trunk-branch holes require easily machinable round hole as compared to the shaped holes.The flow cases were considered at the blowing ratios of 0.5,0.75,1.0,1.5 and 2.0.At the low blowing ratio of 0.5,the vortices-pair at the outlet of the trunk hole is reduced and the laterally coverage of the film is improved.At the high blowing ratio of 2.0,the vortices-pair is killed by the vortex which is produced by the injection of the branch hole.The flow rate of the two outlets becomes more significantly different when the blowing ratio increases from 0.75 to 2.0.The discharge coefficients increase 0.15 and the laterally averaged film effectiveness improve 0.2 as compared to the cylindrical holes.The optimal blowing ratios occur at M=1.0 or M=1.5 according to the various locations downstream of the holes.
The film cooling performance of a trunk-branch hole is investigated by numerical simulation in this paper. The geometry of the hole is a novel cooling concept, which controls the vortices-pair existing at the trunk hole outlet using the injection of the branch hole. The trunk-branch holes require easily machinable round holes as compared to the shaped holes. The flow cases were considered at the blowing ratios of 0.5, 0.75, 1.0, 1.5 and 2.0. At the low blowing ratio of 0.5, the vortices-pair at the outlet of the trunk hole is reduced and the laterally covered of the film is improved. At the high blowing ratio of 2.0, the vortices-pair is killed by the vortex which is produced by the injection of the branch hole. The flow rate of the two outlets becomes more significantly different when the blowing ratio increases from 0.75 to 2.0. The discharge coefficients increase 0.15 and the laterally averaged film effectiveness improve 0.2 as compared to the cylindrical holes. The optimal blow ratios occur a t M = 1.0 or M = 1.5 according to the various locations downstream of the holes.