Investigation of Tip Leakage Flow in a Compressor Rotor Using DDES

The tip leakage flow (TLF) pattern in tips of compressor is well known but its nature is not fully understood. In this paper, the numerical simulation of tip leakage flow based on delayed detached eddy simulation (DDES) method was performed to improve our understanding about the flow structure and its dynamic mechanisms. Three-dimensional streamlines, pressure and streamwise vorticity were fully analyzed to see the structure of tip leakage vortex (TLV) clearly. The position where TLV generates and loses stability moves ahead to the leading edge from near chock to near stall condition. It was found that the unsteady tip leakage flow was distinct from the steady view. The development of the leakage vortex can be divided into three stages according to the differences. From the spectral analysis, the amplitude of the high frequency part increases because of the leakage vortex instability.