叶顶间隙对超微型透平性能影响的数值模拟

Numerical Simulation of the Effect of Tip Leakage Flow on the Micro Radial-Flow Turbine Performance

为了探索叶顶间隙对超微型径流透平性能的影响,对一半径为27mm、设计转速为240000 r/min的超微型径流透平进行了数值研究。在等温壁面条件下,运用CFX对有/无叶顶间隙的超微型透平叶栅通道内的流场进行了数值模拟,分析了顶部间隙流对叶栅通道内流场的影响。结果表明,由于超微径径流透平动叶顶部间隙相对较大,引起了动叶叶栅通道内流场结构的改变,导致透平效率、轴功的明显降低。

To explore the influences of tip leakage flow on the performance of micro turbine, numerical investigations on a micro radial-flow turbine with diameter of 54 mm and designed rotation speed of 240000 r/min were carried out. Three-dimensional numerical simulations with/without the tip clearance were performed by using the CFD software CFX under isothermal condition at solid wall. The results show that the effects of the tip leakage flow on the flow structure in the micro turbine are significant due to the relatively large tip clearance, which results in obvious decrease of turbine efficiency and power output.