扫频式射流对涡轮叶栅间隙泄漏流动影响的数值研究

为控制涡轮叶栅中叶顶间隙泄漏流动和改善涡轮气动性能,将扫频式射流器(SJA)作为一种主动流动控制方法应用在涡轮叶栅的研究中。通过非定常数值计算,分析了SJA对涡轮叶栅叶顶间隙流动的作用过程以及作用机理,并且研究了不同工况下SJA对涡轮叶顶流场改善效果以及不同频率的SJA对叶顶流场的影响。结果表明:通过在涡轮叶栅上端壁增加单个SJA装置,可以有效地延迟上端壁的流动分离,其中最佳方案射流流量仅为进口总流量的0.35%,涡轮叶栅出口截面总压损失系数减少了11.48%。存在着最佳的频率284Hz,使SJA装置对流场的作用效果最佳,有效地改善了涡轮叶栅内的间隙流动。

Numerical Study for Effects of Sweeping Jets on Tip Clearance Flow in a Turbine Cascade

Sweeping jet actuator (SJA) has been employed for leakage flow management and aerodynamic performance improvement as an active flow control method in a linear turbine cascade. The interaction mechanism between SJA and the turbine leakage flow has been analyzed with the help of transient numerical methods. Moreover, the cases under different working conditions of the cascade and different working frequencies of SJA have been also discussed. The results support the following conclusions. The arrangement of single SJA on the endwall delayed the separation on the endwall effectively. The total pressure loss coefficient was reduced by 11.48% with the excitation jet flow rate to be only 0.35% of the turbine cascade under the appropriate parameters. Finally, an optimum excitation frequency of 284 Hz existed under which the leakage flow was well managed.