涡轮叶顶冷却布置对叶顶传热冷却性能的影响

本文采用数值模拟的方法,对比分析了1+1/2对转涡轮四种不同的叶顶冷却布置方案对叶顶传热、冷却性能以及气动特性的影响。四种布置方案分别是:靠近压力面垂直叶顶方向、靠近压力面且与叶顶有30°出射角、中弧线位置垂直叶顶方向、中弧线位置有30°出射角。研究表明,气膜孔沿压力面布置与气膜孔沿中弧线布置相比可以降低叶顶传热系数;由于气膜孔倾斜布置气膜射流动量降低,且削弱了肾形涡的影响,气膜的侧向覆盖范围增大。因此气膜孔靠近压力面布置可以提高气膜冷却效率;气膜孔靠近压力面且有30°出射角比垂直布置叶顶热负荷减少2.7%。另外,气膜孔靠近压力面布置可以降低主流的泄漏流量,有利于减小泄漏损失和提高涡轮效率。

Effects of Different Cooling Holes Arrangements on Film Cooling Performance of a Gas Turbine Blade Tip

A numerical study is performed to investigate the film cooling performance of cooling holes on a gas turbine blade tip.Four film-cooling holes arrangements have been used on the blade tip of a counter-rotating turbine.Numerical results reveal that area-averaged heat transfer coefficient of film-cooling holes along pressure edge on blade tip is lower than that along the camber line.The area-averaged film cooling effectiveness obviously increases when the holes along the pressure edge. All in all,film cooling holes along pressure edge on turbine blade tip leads to low heat load of the blade especially that with 30°injection angle.Moreover,the film cooling holes along pressure edge on turbine blade tip can decrease the tip leakage by 4%compared to flat tip with no cooling holes at M=1.0.