涡轮静叶叶型对绝热气膜冷却效率的影响

Influence of Gas Turbine Stator Profile on the Adiabatic Film-cooling Effectiveness

对燃气轮机涡轮叶片气膜孔进行参数化设计,分别在均匀加载和后加载导叶上布置了几何参数相同的全气膜冷却结构。采用数值模拟方法在不同供气压力和膨胀比下研究全气膜冷却特性,分析了叶型、供气压力和叶栅膨胀比等多因素对全气膜冷却效率的影响。结果表明:压力面前缘区域(l_c≤0.4)的绝热气膜冷却效率和吹风比受冷气供气压力影响很大,压力面中下游(l_c>0.4)和吸力面的绝热气膜冷却效率受冷气供气压力影响较小;增大冷气供气压力会诱发强烈通道涡,在吸力面形成低冷却效率三角区;气膜冷却相似设计总体上是可行的,叶型变化引起的复合角性能差异是相似设计冷却效率差异的主要来源;膨胀比的改变对冷却性能影响不大,主要影响射流的吹风比。

Film holes with similar geometric parameters were arranged on both front-loading and aft-loading guide vanes of gas turbines by using the parametric design method.The influence of the following factors on the adiabatic film-cooling effectiveness was studied,such as the airfoil shape,the supplying pressure of cooling air and the cascade expansion ratio,etc.Results show that the film-cooling effectiveness and the blowing ratio in the leading area(l_c≤0.4)on pressure side are obviously affected by the supplying pressure of cooling air.The cooling effectiveness in tail area on pressure side(l_c>0.4)and on suction side is less susceptible to the supplying pressure.Increasing the supplying pressure of cooling air would induce strong passage vortices,and form a low-cooling zone on the suction side.The similarity design method is generally effective,in which the major discrepancy is related to the different performance of film holes with compound angles.The expansion ratio of cascade,which mainly affects the blowing ratio of jet,has limited influence on the cooling performance.