1.5级大子午扩张涡轮非定常流动和传热特性分析

大子午扩张涡轮端壁二次流与热负荷之间的关系,对于端壁冷却非常重要。本文采用几何约化法,对某1.5级大子午扩张涡轮进行数值模拟,研究了大子午扩张涡轮上端壁非定常流动和传热特性。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；R1出口泄漏涡、通道涡和尾迹是造成S2流动和传热非定常性的主要因素；传热与二次流密切相关,对传热研究必须与流动相结合。研究结果将有助于提高对大子午扩张涡轮端壁非定常流动和传热特性的认识。

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

The relationship between the secondary flow of the large meridional expansion turbine endwall and the heat load is very important for the endwall cooling. In this paper, the Domain Scaling method was used to simulate the 1.5-stage large meridian expansion turbine, and the unsteady flow and heat transfer characteristics of the upper endwall of the large meridian expansion turbine were studied. 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% in the radial direction. The leakage vortex, passage vortex and wake at R1 exit are the main factors causing the unsteady flow and heat transfer of S2. Heat transfer is closely related to the secondary flow, so the study of heat transfer must be combined with the flow. The results will be helpful to understand the unsteady flow and heat transfer characteristics of the endwall of the large meridian expansion turbine.