超高负荷涡轮叶栅叶顶间隙流动特征及间隙高度的影响

采用数值模拟方法研究了超高负荷涡轮叶栅叶顶间隙流动特征,详细分析了泄漏涡、叶顶分离涡、上通道涡等的流动细节,在此基础上分析间隙高度对流场特征和叶片负荷的影响.结果表明:超高负荷涡轮叶栅叶顶间隙区域存在多种形式的流动分离,泄漏流非常强烈,不仅直接影响上通道涡的形成与发展,使通道涡整体向叶根移动,而且部分泄漏流进入下通道涡;随着间隙高度增加,叶顶分离涡和泄漏涡均明显增强,叶片负荷尤其是叶顶负荷有所降低.

Tip clearance flow structures in ultra-highly load turbine cascades and effects of clearance height

Numerical simulation was performed to investigate the tip clearance flow structures in ultra-highly load turbine cascades. Flow details of leakage vortex, tip separation vortex and upper passage vortex were analyzed, then on this basis,the effects of clearance height on flow characteristics and blade loads were analyzed. Results show that, there are several forms of flow separation in tip clearance region of ultra-highly load turbine cascades,leakage flow is very strong, which not only affects the formation and development of upper passage vortex directly and makes passage vortexes move to blade root, but also causes some of leakage flow to enter into the lower passage vortex. As clearance height increases, tip separation vortex and leakage vortex get stronger, blade load especially tip load decreases.