翼梢小翼对涡轮间隙泄漏流动影响的数值研究

Study of Tip Winglets on Leakage Flow in a Transonic Turbine Stage

转子叶片叶尖增加翼梢小翼是控制涡轮间隙泄漏流减小泄漏损失的有效手段之一,为研究翼梢小翼位置对高压涡轮间隙泄漏流动的影响,利用数值模拟方法求解雷诺平均纳维-斯托克斯方程获得涡轮通道内的三维流场,并详细分析叶片压力边和吸力边增加翼梢小翼对间隙泄漏流及涡轮气动损失的影响。研究发现:压力边翼梢小翼可以降低间隙泄漏流量,但基本不改变间隙泄漏涡结构,对涡轮效率影响较小;吸力边翼梢小翼虽然对降低间隙泄漏流量作用不明显,但可以有效地抑制泄漏涡的生成和发展并削弱叶片吸力面壁面潜流,降低泄漏流动损失。结果表明:在控制间隙泄漏流动减小泄漏损失方面,吸力边翼梢小翼明显优于压力边翼梢小翼。

The tip winglet is one of most effective methods for tip desensitization of an axial turbine. In order to investigate the effects of the winglet's location on the tip clearance leakage flow,Reynolds-averaged Navier-Stokes equation was solved by numerical simulation to obtain three-dimensional flowfield of turbine. And the effects of pressure-side and suction-side tip winglets on the tip clearance leakage flow and aerodynamic performance were studied. Results show that the pressure-side tip winglet could reduce the leakage flow mass,but the structure of the leakage vortex is unaltered,which leads to the tiny change of losses. The suction-side winglet is less helpful to reduce leakage flow mass. However the suction-side winglet weakens the strength of the leakage vortex as well as the underflow on the suction side of the rotor blade, as a result the losses decrease markedly and the efficiency of the turbine stage increases. It is clear that suction-side winglets are more effective on tip desensitization than pressure-side winglets.