来流条件对超高负荷低压涡轮附面层非定常特性影响的实验研究

An Experimental Study of Effects of Inflow Condition to Boundary Layer of an Ultra-High-Lift LPT at Unsteady State

关键词:  低压涡轮  尾迹  附面层  分离  转捩

Key words:  Low pressure turbine  Upstream wakes  Boundary layer  Separation  Transition

摘要:

为深入探索尾迹与附面层的相互作用机理及其对叶型损失的影响，对IET-LPTA后加载超高负荷低压涡轮叶型的定常与非定常气动特性进行了实验研究。实验在低速二维叶栅风洞上进行，该风洞通过上游辐条对尾迹进行模拟，采用热线探针与三孔气动探针作为测试手段。实验发现上游尾迹在低Re状态下对吸力面分离具有较强的抑制作用，可以降低叶型损失。同时研究了不同雷诺数(Re)与来流湍流度(FSTI)对上游尾迹与附面层相互作用机理的影响，发现Re对叶型损失的影响是单向有利的，发现FSTI对叶型损失的影响是双向的。

Abstract:

In order to study the interaction mechanism of the wakes and boundary layer and the influence on profile loss due to the wakes，the effects of unsteady wakes on an ultra-high-lift after loaded low pressure turbine blade IET-LPTA have been investigated experimentally. The measurement is performed on a low speed linear cascade wind tunnel. The upstream wakes is simulated by the moving cylindrical bars upstream of the cascade. The three holes aerodynamic probe and hotwire probe are used as the measurement instrument. The separation bubble on the suction side is suppressed efficiently and profile loss is decreased by the upstream wakes at low Reynolds number. The effects of Reynolds number and free stream turbulence intensity(FSTI)on the mechanism of interaction between upstream wakes and boundary layer have also been investigated. The effect of Re is one-way beneficial to the profile loss and FSTI is in both ways.