关键词: 涡轮;非定常流;雷诺数;效率;间隙流动+;尾迹干涉+;压力脉动;数值仿真;计算气动声学+

Abstract: Based on SST turbulence model coupled with Lantry-Menter transition model,the 3D flow under 3 different Reynolds number(Re) conditions in a turbine stage were computed using steady and unsteady numerical simulations,respectively,in order to give the differences of numerical simulation results between steady and unsteady calculation.The predicted results show that,the difference between the turbine stage efficiency obtained by steady and unsteady calculation is large both at Re=4×104 and Re=5×105,with the maximal efficiency difference to be 0.6% at Re=4×104,while that is quite small at Re=8×104.The unsteady calculation could reasonably simulate the development of leakage vertex,and the roll up vortex leading to large pressure fluctuation on the rotor blade suction surface caused by the interaction of upstream wake and downstream separated boundary layer on rotor blade at low Reynolds number.Additionally,the distribution of unsteady pressure fluctuation at the turbine stage outlet is presented,which provides an elementary work for computational aero-acoustic,based on the method of Lighthill sound analogy.

Key words: Turbine;Unsteady flow;Reynolds number;Efficiency;Leakage flow+;Stator-rotor interaction+;Pressure fluctuation;Numerical simulation;Computational aero-acoustic+