Numerical Study Of The Effect Of The Tip Cells On The Tip Clearance Flow Characteristics In A Compressor Cascade

As one of the three core components of an aero engine,the performance of the compressor will directly affect the performance of the engine,and related studies have shown that the leakage loss of the compressor cascade occupies 20%to 40%of the total loss of the compressor,so the study Gap leakage has always been an important direction in the field of impeller machinery.First,the grid independence test was carried out,and it was found that when the number of grids is about 3.4 million,the total pressure loss coefficient of the outlet section,the Mach number of the outlet section,and the static pressure ratio of the inlet and outlet will not change significantly with the increase of the mesh Therefore,the grid for controlling all the examples is around 3.4 million,and then the numerical simulation of all the examples is performed based on the SST turbulence model built in the commercial software CFX.Then the influence of the number of tip cells on the gap flow characteristics.of the compressor was studied The results show that when the number of tip cells is 50,each scheme has a good effect of reducing damage;after the.introduction of the tip cells structure,the pressure gradient on both sides of the gap is reduced.Small,to a certain extent,reduces the leakage flow of the blade tip,plays a role in suppressing gap leakage and weakening the secondary flow;in addition,because the resident vortex will be generated inside the tip cells,the flow situation at the top of the flow channel becomes more complicated,and The residence vortex generated in the tip cells will eventually merge into the leakage vortex,so the loss due to blending has increased.Then,the influence of the depth of the tip cells on the flow characteristics of the compressor cascade gap was studied.The results show that the introduction of the tip cells can significantly increase the turning capacity of the gas in the flow channel,so that the gas near the wall surface can flow better against the wall.Reduce the width of the wake;in addition,the tip cells will cause the flow field at the root of the blade to be negatively affected.The range of the recirculation zone will expand outward in the direction of leaf spread and leaf height,respectively,and the root area of the suction surface will be separated.increase.Finally,the applicability of the tip cells at different angles of attack is studied.The results show that the range of attack angle is-8° to+2°,the incoming Mach number is 0.7Ma,and the actual acting angle of attack deviates from the design angle of attack.The effect is more significant;under different angles of attack,the introduction of the tip cells structure can reduce the width of the wake;in addition,the tip cells can significantly change the starting position of the suction surface laminar separation bubble,and the three-dimensional separation of the corner area is intensified.