上游尾迹与涡轮叶栅通道涡相互作用研究

Upstream wake-passage vortex interaction in turbine cascade

采用三维粘性非定常数值模拟方法研究了上游尾迹与涡轮叶栅通道涡的相互作用,对定常、非定常时均以及瞬时时刻流动机理进行了分析.结果表明:上游尾迹的非定常作用一方面增强了叶栅通道涡的径向涡,使得流动损失增大;另一方面能够一定程度上抑制通道涡中流向涡的发展,对控制损失起到正面作用,端区的综合非定常效应取决于两者之间的平衡.在本文计算条件下,上述两方面综合影响使得通道涡的非定常损失增大.

The internal flow of turbomachinery is intrinsically unsteady, so investigating the unsteady interactions in turbine endwall region is meaningful for improving the performance of low aspect/high loading turbine. In this paper, the upstream wake-passage vortex interactions in turbine cascade were simulated by a 3-D unsteady viscous solver, and the flow mechanisms were analyzed. Numerical results indicate that periodic upstream wakes can enhance the radial vorticity of passage vortex, which increases losses. On the other hand, upstream wakes can suppress the streamwise vorticity development of passage vortex to some extent, which reduces losses. The combined unsteady effect in the endwall region depends on the balance of above two factors. At the calculation conditions of this paper, the unsteady losses finally increased.