Studies Revealing Mechanism of 3D Unsteady Flow Effects in Turbomachines upon Aerodynamic Performance and Development of Performance Control Methods

本文介绍了用低压涡轮机叶型模拟单级轴流涡轮机的非定常流动机理的实验研究和数值模拟。本研究的目的是验证来自边缘密封腔的吹扫流对转子通道中的流场的影响，其导致特别是在转子毂区域中的二次流行为的改变。为了观察转子下游的非定常流态，使用倾斜式热线探针进行了详细的三维非定常测量。非定常测量结果观察到了无吹扫流时叶尖区域的二次流和泄漏流，以及用5孔探针进行的定常测量。三维时变数值模拟显示了主流和吹扫流之间的非定常流动相互作用。

This paper presents an experimental study and numerical simulation of the unsteady flow mechanisms in a single stage axial flow turbine which is simulated the LP turbine airfoils. The target of this study is to verify the influence of the purge flow from the Rim-seal cavity on the flow field in the rotor passage, which leads to changes of the secondary flow behavior especially in the rotor hub region. To observe the unsteady flow pattern at rotor downstream, detailed 3-D unsteady measurements using a slant-type hot wire probe is performed. The result of unsteady measurement observed the secondary flow and the leakage flow in the tip region without the purge flow as well as the steady flow measurement with 5-hole probe. A three-dimensional, time-dependent numerical simulation shows the unsteady flow interactions between the main flow and purge flow.