绊线对大子午扩张涡轮端壁的气动及传热性能影响研究

Effects of Trip Wire on Aerodynamic and Heat Transfer Performance of Large Meridional Expansion Turbine Endwall

关键词:  大子午扩张涡轮  绊线  马蹄涡  总压损失  流动传热特性

Key words:  Large meridional expansion turbine  Trip wire  Horseshoe vortex  Total pressure loss  Flow heat transfer characteristic

摘要:

为了探究绊线对大子午扩张涡轮端壁边界层分离和马蹄涡的削弱效果，分析绊线对大子午扩张涡轮端壁传热特性的影响，针对1.5级涡轮应用SST湍流模型对端壁流动进行精细捕捉，并进行了气动和传热的有效性实验验证。结果显示：绊线减弱了叶片前缘驻点高压区，使得上端壁分离点位置提前。绊线增强了来自涡轮动叶的泄漏涡强度，但极大地削弱上通道涡。此外，中间位置绊线使得总压损失降低了2.28%。叶片前缘热负荷增加，Trip（5.3% E）绊线使得叶片表面热通量降低1.66%。大体上讲，绊线的引入减小了大子午扩张涡轮通道涡等二次流的影响，优化了大子午扩张涡轮的流场，降低了叶片表面换热量。

Abstract:

In order to explore the effects of trip wires on the endwall boundary layer separation and the weakening of horseshoe vortex in large meridional expansion turbines， the influence of trip wires on the endwall heat transfer characteristics of large meridional expansion turbines was analyzed.SST turbulence model was used to capture the endwall flow in a 1.5 stage turbine， and the effectiveness of aerodynamic and heat transfer experiments was verified.The results show that the tripping wire weakens the high pressure area at the stagnation point of the leading edge of the blade and makes the separation point of the upper endwall in advance.The trip wire increases the strength of the leakage vortex from the turbine rotor blade， but greatly weakens the upper passage vortex. In addition， the intermediate trip wire reduced the total pressure loss by 2.28%.The thermal load on the leading edge of the blade increased， trip（5.3% E） reduced the heat flux on the blade surface by 1.66%. In general， the introduction of trip wire reduces the influence of secondary flows such as vortices in the passage of large meridional expansion turbine， optimizes the flow field of large meridional expansion turbine， and reduces the heat exchange on the blade surface.