Numerical Investigation On Film Cooling Deterioration Area Between The Film Cooling Holes

Enhancing the temperature of gas turbine's inlet is one of the key technology to improve the efficiency of the gas turbine, and the requirement to the blade bearing high temperature is much higher than before. As a result, investigating on flow and heat transfer performance of blade's film cooling possesses is important to protect the blade effectively and design the gas turbine.Basing on SIMPLE algorithm and discretizing the control equation in finite volume method, Realizable k-εturbulence model was applied to numerical simulate the film cooling efficiency on flat, static turbine stage and the rotation turbine stage. The formation reason of cooling deterioration area was analyzed. The variety rule of cooling deterioration area was given by the different ratio of jet flow, angle of jet flow, the distance between jet flow holes. the flown line analysis on blade head of static blade cascade was given, the changing rule of cooling deterioration area by the ratio of jet flow was given. And the variety rule of cooling deterioration area in blade head of rotation blade cascade was given by the different ratio of jet flow and the spin velocity. The results show that:The formation reason of cooling deterioration area is that the covering area of the lengthways coupled-vortex is small at the beginning and the blade wall between the jet flow holes isn't covered. In the flat film cooling, the big angle of jet flow holes, the big ratio of jet flow and small distance between jet flow holes is help to reduce the cooling deterioration area.The film cooling holes in blade head of static blade cascade is of fine film cooling efficiency to the blade pressure face. The film cooling holes which is across collocated is of fine film cooling efficiency to the blade pressure face, too. The cooling jet flow which flows from film cooling holes in the blade root changes its flow track for the influence of the blade hub, and the film cooling efficiency is low. The big ratio of jet flow will get great film cooling efficiency on the blade head of blade cascade, reduce the cooling deterioration area.In the rotation blade cascade, the cooling jet flow which flow from the jet flow holes in blade head will break away from blade wall after wash the blade head, mix into main flow adequately and have no protection of blade in the influence of the rotation blade stage circumferential speed. In the condition of the same ratio of the jet flow, the high spin velocity will form continuous covering effect on the blade head and get great film cooling effect on blade. In the condition of the same spin velocity, the high ratio of the jet flow will form continuous covering effect on blade head and get great film cooling effect on blade.