涡轮叶片综合冷却效率实验的缩尺效应

Downscaling Effect on Overall Cooling Effectiveness Experiment of Turbine Blade

基于简化叶片的传热实验,研究缩尺模化对综合冷却效率的影响,得到缩尺效应随主流雷诺数和流量比的变化情况,以及毕渥数和热障涂层厚度对综合冷效缩尺效应的影响规律。采用一维传热模型,量化分析了缩尺模化对综合冷却效率的影响,并在实验中得到验证。结果表明:缩尺比例为1.5时,缩尺叶片综合冷却效率相对基准叶片增加10%,且增幅随主流雷诺数和流量比增加;基准叶片导热系数由17 W/(m·K)增加至50 W/(m·K),缩尺叶片平均综合冷却效率差异由13.71%降至0.34%;热胀涂层厚度等比例缩尺可减小缩尺效应的影响,使缩尺叶片综合冷却效率差异由13.07%降至2.98%。

Based on the heat transfer experiment of simplified blades,the influence of downscaling effect on overall cooling effectiveness(OCE) of blade was studied.The variation of downscaling effect with the mainstream Reynolds number and flow ratio was obtained.The influence rule of Biot numbers and thicknesses of the thermal barrier coating(TBC) on downscaling effects of the OCE was obtained.One dimensional heat transfer model was used to quantify and analyze the OCE variation due to downscaling influences and get verified in the experiment.Results show that when the scale ratio is 1.5,the OCE of the downscaled blade increases by 10% compared with the reference blade.The augmentation is raised as the Reynolds number and mass ratio increase;the thermal conductivity of the reference blade is increased from 17 W/(m·K) to 50 W/(m·K).The average OCE′s discrepancies of downscaled blade is decreased from 13.71% to 0.34%;reducing the thickness of TBC in equal proportion can decrease the influence of downscaling effects and reduce the OCE′s discrepancies of downscaled blade from 13.07% to 2.98%.