1.5级大子午扩张涡轮非定常流动和传热特性分析

Analysis of Unsteady Flow and Heat Transfer Characteristics of 1.5 Stage Large Meridian Expansion Turbine

关键词:  涡轮  非定常流动  二次流  传热特性  数值计算

Key words:  Turbine  Unsteady flow  Secondary flow  Heat transfer characteristics  Numerical simulation

摘要:

大子午扩张涡轮端壁会产生复杂的二次流动和较强的热负荷。为了探究其二次流与热负荷之间的关系并深入了解非定常流动和传热特性，采用几何约化法，对1.5级大子午扩张涡轮进行数值模拟。计算结果表明：大子午扩张涡轮上通道涡尺度较大且位置发生改变，沿径向向下移动约20%叶高；第一级静叶（S1）尾迹使第一级动叶（R1）产生强非定常性；第一级动叶（R1）出口泄漏涡、通道涡和尾迹是造成第二级静叶（S2）流动和传热非定常性的主要因素。

Abstract:

The large meridional expansion turbine produces complex secondary flows and strong heat load in the blade endwall region. In order to explore the relationship between secondary flow and heat load， and to further understand the unsteady flow and heat transfer characteristics， the Domain Scaling method was used to simulate the 1.5 stage large meridian expansion turbine. The calculation results show that the size of passage vortex on the large meridian expansion turbine is larger and the position changes， and it moves downward by about 20% blade height in the radial direction. The first stator vane S1 wake makes the first rotor blade R1 highly unsteady. The leakage vortex， passage vortex and wake at R1 exit are the main factors causing the unsteady flow and heat transfer of the second stator vane S2.