TIP CLEARANCE EFFECTS ON UNSTEADY BEHAVIOR OF THE TIP LEAKAGE VORTEX AND STATOR/ROTOR INTERACTION TONAL NOISE

摘要

In turbomachinery the tip leakage vortex is an obvious periodic phenomenon associated with rotor blade, its interaction with stator wake will affect the tonal noise level and aerodynamic performance. This study assesses the effects of tip leakage vortex on the stator/rotor interaction tonal noise and its unsteady behavior by 3D unsteady numerical simulations and the Triple-Plane Pressure matching strategy. The fluctuation of blade loading distribution and the interaction of wake negative jet with tip clearance flow change the structure and position of tip leakage vortex and scrapping vortex periodically. From the time-average results, the incoming wakes reduced the strength of vortices. The result also shows that the tonal noise level of turbine stage is decreased with the enlargement of tip clearance.