Unsteady Investigation on Flow and Heat Transfer Characteristics of Turbine Blade Squealer Tip
Unsteady flow and heat transfer characteristics on blade squealer tip of a high-pressure turbine was investigated by numerical simulation.Results indicate that Time Transformation method in TBR model is suitable for unsteady aerothermal analysis of turbine blade tip.The roll-up vortex caused by leakage flow from pressure side forms stripe distribution of high heat transfer coefficient at cavity floor,and boundary layer flow makes suction side squealer rim near leading edge form local high heat transfer coefficient.As cavity depth increases,flow field with low speed inside the cavity expands and the size of roll-up vortex also increases.Meanwhile,heat transfer at cavity floor weakens,the range of striped high heat transfer coefficient narrows down and its position gradually moves away from pressure side showing more discrete distribution characteristics at some instants.At different instants,average heat transfer coefficient at cavity floor of blade tip with 2％cavity depth was increased by 7.1％～13.5％compared to tip with 3％cavity depth and was increased by 9.6％～21.9％compared to tip with 3.5％cavity depth.
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