Effects of tip clearance size on tip leakage flow fields in a subsonic compressor rotor

This paper aims at the numerical analysis of the influence of tip clearance size on aerodynamics in a subsonic tip critical compressor rotor. We make use of well known methods of numerical analysis, including NUMECA Fine/Turbo module, to obtain tip clearance flow fields, which are shown in Figs. 3 through 7 in the full paper. We analyze these figures to identify the effects of the tip clearance size on the behavior of tip leakage vortex, which is closely related to the performance characteristic of the rotor. We find that tip leakage vortex breaks down in all investigated cases. The vortex 'breakdown' causes a sudden growth of the casing-wall boundary layer, which has a large blockage effect on incoming flow. Under the same downstream conditions, the vortex breakdown occurs earliest in the case of the largest tip clearance size. This verifies that the strength of leakage vortex is one of the major factors influencing the vortex breakdown.