Research On Tip Clearance Unsteady Flow Of An Axial Compressor

Axial compressor as one of the main parts of aero-engine,its performance can affect the whole performance of the engine,which is important for the research of compressor.Different blade tip clearance has certain effect on the performance of compressor.This paper aim to research the flow characters of compressor's blade tip clearance in variable conditions and in different clearance.Through the 3D modeling of compressor blade NASA Rotor37,use steady and unsteady calculation procedure enclosed in NUMECA to calculate the compressor clearance's flow characters in three different blade tip clearance and in different boundary conditions.Results show that: the blade tip clearance has remarkable influence on compressor performance.The increase of the clearance could lead to the decrease of pressure ratio and compressor efficiency.The leakage vortex existed in blade tip clearance can greatly affect the static pressure in clearance area.In sample boundary condition,which means the input pressure is in the sinus configuration,the flow characters in blade tip clearance has the periodicity fluctuation.When the boundary condition changes irregularity,the flow intensity become weak but strong frequency.By analysis the flow characters,we can preliminary summary the formation mechanism: the pressure difference can increase the leakage flow,at the same time,the reinforced leakage flow can decrease the pressure difference which exist in the blade sides;when the pressure difference decrease,the leakage also decreases,the diminished pressure would rise again,and so on.Through the research of the flow in clearance,we can provide the performance reference and foundation for the further research in other conditions.