动叶围带顶部泄漏流动对透平级气动性能影响的数值研究  

EFFECTS OF THE TIP LEAKAGE FLOWS OF THE SHROUDED ROTOR BLADE ON THE AERODYNAMIC PERFORMANCE OF THE TURBINE STAGE

作　　者：吕强[1] 李军[1] 李国君[1] 丰镇平[1] 

机构地区：[1]西安交通大学能源与动力工程学院,陕西西安710049

出　　处：《工程热物理学报》2007年第z1期85-88,共4页Journal of Engineering Thermophysics

基　　金：国家自然科学基金(No.50506023)

摘　　要：采用计算流体动力学软件CFX-TASCflow数值研究了带围带的动叶顶部间隙内泄漏流动对动叶流动效率以及下一级静叶进口气流角的影响特性。数值模拟了装有不同迷宫式汽封齿数时的动叶顶部间隙泄漏流动特性。揭示了泄漏流动不再是跨叶顶的横向流动,而是在叶顶间隙内沿着轴向流动。给出了动叶顶部间隙泄漏流场的结构,泄漏流与主流掺混后的流场对下游静叶性能的影响。研究结果表明泄漏流与动叶通道内的主流在动叶下游掺混后,改变了上半通道气流的流动方向,使这部分气流偏离设计工况,使下游静叶产生攻角损失。动叶顶部间隙泄漏流有较大的径向速度,在与主流掺混并进入动叶下游静叶后,会向着静叶中叶展处发展,改变静叶上半部流场的结构。动叶顶部间隙汽封齿数增多时这种效果就减小,静叶等熵效率的降低就越少,同时讨论了动叶顶部间隙泄漏流动对透平级气动性能的影响。Effects of the tip leakage flow of the shrouded rotor blade on the aerodynamic performance of the turbine stage were numerical investigated using commercial CFD software CFX-TASCflow. Three conditions with different numbers of sealing fins at the shrouded rotor blade were simulated. The structure of the leakage flow and its influence to the next stator blade were presented.The results show that for shrouded rotor blade the leakage flow is from upstream to downstream of the blade when the leakage flow of the unshrouded rotor blade follows a circumferential way.It is also found that the direction of the up-half span of the flow field is affected obviously when the leakage flow mixed with the main flow and lead to incidence losses to the next stator blade.The leakage flow which has high radial velocity tends to the mid-span in the following stator blade and changes the flow field structure of the up-half passage.With more sealing fins,the loss of the isentropic efficiency of the stator blade is reduced.The influence of the leakage flow to the performance of the turbine stage is carefully studied.

关 键 词：迷宫式密封 透平级 泄漏流动 气动性能 数值模拟 

分 类 号：TK262[动力工程及工程热物理—动力机械及工程]