机匣沟槽对微型轴流涡轮叶尖泄漏流动的影响

Effects of Casing Groove on Tip Leakage Flow of Micro Axial Turbine

关键词:  涡轮转子  机匣沟槽  叶尖泄漏流  效率  微型涡轮发动机

Key words:  Turbine rotor  Casing groove  Tip-leakage flow  Efficiency  Micro turbo engine

摘要:

为了揭示机匣沟槽对微型涡轮叶尖泄漏流动的作用机制，本文通过对某微型涡喷发动机的单级轴流式涡轮进行机匣设计，研究了4%间隙比时不同机匣沟槽结构对其叶尖泄漏流动的影响。计算结果说明：当全机匣沟槽结构的沟槽深度大于叶尖间隙时，封严效果较好；相较于全机匣沟槽结构，后开式机匣沟槽结构的封严效果更好，且随着沟槽前缘间隙的增大，封严效果减弱。当台阶与叶片前缘的距离等于叶尖间隙时，封严效果最佳，即泄漏流明显减弱，同时效率减小量较小。

Abstract:

In order to reveal the mechanism of the casing groove on tip leakage flow of micro turbine， the effects of different casing structures on tip leakage flow of a single stage axial turbine with 4% clearance ratio are studied by casing design for a mini turbojet engine. The calculation results show that when the groove depth of the full casing groove structure is greater than the leaf tip clearance ， the sealing effect is better. Compared with the groove of the full casing， the groove of the rear open casing has better sealing effect. With the increase of the gap at the leading edge of the groove， the sealing effect weakens. When the distance between the step and the blade leading edge is equal to the leaf tip clearance， the sealing effect is best，that is， the leakage flow is obviously weakened， and the reduction of efficiency is small.