Abstract: The boundary layer of low pressure turbine blade (LPT) suction side is in a serious separation state at high flight altitude，low Reynolds number state. With the passive flow control strategy，the separation can be suppressed and the aerodynamic efficiency can be increased. The effects of surface roughness passive control strategy on the profile loss and the boundary layer separation of LPT were investigated experimentally to reduce the separation loss on the suction side at low Reynolds number. The boundary layer flow control effect to an ultra-high-lift LPT blade PACKD-A by 9 surface roughness control strategies were measured in a low speed cascade wind tunnel. The experiment suggested that the roughness strip covered 19.5% suction surface length and with a 20.91μm roughness height(Ra) was the optimum deposit position with a free stream turbulence intensity of 2.2% and in the tested Reynolds number range between 5.0×104～1.6×105. The operating range of the LPT blade was expanded and the profile loss was reduced by the optimum flow control strategy to some extent.

Key words: Low pressure turbine；Surface roughness；Separation；Transition

摘要： 高空低雷诺数状态下，低压涡轮吸力面流动分离严重，利用被动控制手段可以有效缓解流动分离，提高叶型效率。为了降低低雷诺数下吸力面的流动分离，实验研究了粗糙度在定常来流条件下对低压涡轮叶型损失及吸力面附面层分离的控制效果。实验依托一台低速叶栅风洞，考察了9种粗糙度控制方案对PACKD-A超高负荷后加载叶型的流动控制效果。实验发现在来流湍流度2.2%，5.0×104～1.6×105的雷诺数测试范围内，覆盖19.5%吸力面弧长范围，粗糙高度(Ra)为20.91μm的粗糙条带是一种最优布置方案。这一优化的流动控制手段可以在一定程度上兼顾降低叶型损失，扩大涡轮叶片正常工作范围的作用。

关键词: 低压涡轮；表面粗糙度；分离；转捩