冷却气膜射流对涡轮叶栅气动性能的影响

Impact of Cooling Film Jets on the Aerodynamic Performance of Turbine Guidevanes

本文在平面叶栅风洞上实验测量设计工况下,具有压力面及吸力面单排离散气膜孔射流的导向叶栅下游流场,对比研究不同射流比时叶型损失的变化。实验中主流与射流采用相同的工质。结果表明:压力面射流及吸力面射流时,平均总压损失随射流比的增加均表现出先减小后增大的变化趋势,但是损失增大或减小的数值不同,吸力面射流及压力面射流都会使尾迹区发生改变。高压射流气体的动量和质量对损失数值的影响,在小射流比时可以忽略,但是在大射流比时则必须要考虑,才能准确地反映叶型流动损失。

On a planar cascade wind tunnel, experiment was designed to measure the wake flow downstream of a turbine guide vanes with cooling film jets at the designing incidence. Single row of discrete film holes is located on both suction and pressure surfaces. Blade profile losses were measured to compare the influences of film jets at various jet mass ratios. In experiment, the main and secondary jet flows were chosen the same fluid of air. Results showed that when jet flows are both present along suction and pressure surfaces, averaged profile loss tends to decrease at low jet ratios and increase at high jet ratios. However, decrease or increase differed from their variation slope. Along either suction or pressure sides, jet flow changed the wake structure. Influence of high pressure jet flow on loss magnitude will be dependant on its jet ratio. At low jet ratios, it can be neglected, but at high jet ratios, it has to be taken into account for accurate prediction of profile losses.