轮缘封严气流与主流涡系交互作用的非定常数值研究

Unsteady Numerical Investigation on Vortex Interaction Between Rim Seal Flow and Mainstream

为了研究涡轮转静盘腔中轮缘封严气流与主流的非定常涡系交互作用机制,在有无封严气流的工况下,数值模拟了封严气流对主流二次流的影响。结果表明,封严气流对上游静子的堵塞减弱了其轮毂二次流强度,并挤压静子轮毂二次流使得其径向位置降低而区域减小。静子轮毂二次流抑制了封严出流作用以及转子轮毂通道涡的径向扩张,并加剧转子轮毂二次流的总压损失。封严气流诱导形成了腔体诱导涡和剪切诱导涡,其中剪切诱导涡发展成为转子轮毂通道涡的主要组成部分。同时,封严气流通过剪切诱导涡的作用增加了转子轮毂二次流的径向位置和强度。由于转子和静子的相对运动,封严气流与主流的涡系交互作用呈现出明显的非定常变化。

In order to investigate unsteady vortex interaction mechanisms between turbine rotor-stator cavity rim seal flow and mainstream,numerical investigations were conducted for effects of rim seal flow on the secondary flow of mainstream under the condition with and without rim seal flow. The results show that intensity of secondary flow of the stator is weakened due to the blockage effect caused by rim seal flow. In addition,the rim seal flow extrudes secondary flow of the stator and leads to decreasing radial location and area of secondary flow.Besides,the strength of egress flow and radial expansion of rotor hub passage vortex are restrained by hub secondary flow of the stator. The total pressure loss of hub secondary flow of rotor is strengthened by that of the stator.Cavity induced vortex and shear induced vortex are formed due to the induction of rim seal flow. The shear induced vortex is developed into the main part of rotor hub passage vortex. Furthermore,the radial location and intensity of hub secondary flow of the rotor is increased by the shear induced vortex. Due to relative rotation of the stator and rotor,vortex interaction between rim seal flow and mainstream is obviously unsteady.