叶尖自发射流条件下涡轮非定常流动的数值模拟

Numerical Simulation of Unsteady Flow in Turbine Cascade with Spontaneous Tip Injection

为分析自发射流条件下非定常尾迹对叶顶间隙流动、S1流面和S2流面上流场参数、叶尖泄漏比和动叶载荷变化的影响,采用数值模拟方法,以Durham叶栅为原型,将动、静叶栅流场通过滑移网格技术耦合,开展非定常计算。结果表明:在静叶非定常尾迹的影响下,转子区域流场内的流动、叶尖间隙泄漏比及叶片周向载荷均呈现出周期性变化的特征;考虑非定常效应和端壁相对运动效应,相较于无叶尖射流,单孔叶尖自发射流可使泄漏比降低4.57%,比定常计算预测的泄漏比低3.43%,表明要想准确获得叶尖射流条件下的叶栅流动特性和叶尖泄漏抑制效果,其间的非定常效应不可忽略。

To investigate the influence of the non-steady wake on the tip jet wake,the parameters of stream face S1 and S2,the tip leakage ratio and the rotor blade load under the condition of spontaneous tip injection were studied.The rotor and stator model abstracted from Durham cascade were numerically investigated by carrying out non-steady calculation using sliding mesh technique.The results showed that the flow field in the rotor,the tip leakage ratio and the circumferential blade load varies periodically under the influence of the stator non-steady wake.Tip leakage is about 4.57% lower with single hole spontaneous tip injection than without it during the unsteady flow calculations,approximately 3.4% lower than the prediction by the steady simulation.It indicates that to obtain the effect of tip injection on the tip leakage flow accurately,the effect of the flow unsteadiness cannot be excluded.