Effect of Bleed Hole Extraction on the Flow and Heat Transfer Characteristics in Return-flow Impingement at Turbine Blade Leading Edge
Facing the increasing cooling requirements caused by the continuously rising inlet temperature of turbines,this paper proposed a return-flow impingement cooling structure to suppress the negative im-pact of crossflow accumulation on jet cooling at the leading edge of turbine blades.Through the utilization of CFD numerical calculations,a comparative analysis was conducted on the numerical results of various layouts of bleed holes to explore the effects of the suction action of bleed holes on the flow and heat trans-fer characteristics of the cooling structure based on the return-flow impingement cooling structure.The re-search findings indicate that the introduction of bleed holes reconstructs the impinging jet flow field,ef-fectively restraining the development of wall jets and reducing the heat transfer intensity on the impinge-ment target surface.Compared with the layout with three rows of bleed holes,the layout with two rows of bleed holes has a smaller influence on the heat transfer level on the target surface.Additionally,when the bleed holes and impingement holes are aligned in the same position rather than staggered in the stream-wise direction,the suction effect of the bleed holes exhibits the most pronounced weakening effect on the heat transfer performance.
turbine bladereturn-flow impingement coolingbleed holeflow and heat transfer
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