关键词: 叶尖间隙高度+;叶尖间隙泄漏涡+;不稳定性;数值仿真

Abstract: A pressure-correction based 3D Reynolds-averaged Navier-Stokes equations with high Reynolds-Number k-ε turbulence model and wall function CFD code was used to simulate the tip leakage flow filed in a linear turbine cascade.Based on the Rains model of tip clearance vortex and long wave instability theory,regarding the tip leakage flow and its dummy vortex imaged by the casing wall as a couple of vortex,the instablity of tip leakage vortex was analyzed.The most unstable wavelength and its frequency of tip leakage vortexs under five different tip clearance heights are calculated.The results show that the long wave instablity theory can predict the instablity and the most unstable wavelength and its frequency of tip leakage vortex,which can lay a theoretic foundation for synthetic jet to control the tip leakage vortex.

Key words: Tip clearance height+;Tip leakage vortex+;Instability;Numerical simulation