Influence Of Bump On The Aerodynamic Performance Of Transonic Compressor Cascade

As one of the three core components of gas turbine,the performance of compressor has an important impact on the efficiency and reliability of the whole machine.Take the compressor as an example,increasing the thrust-to-weight ratio of the engine requires increasing the single-stage pressure ratio of the compressor and realize a higher stage load can be achieved on a smaller series.The commonly used method to increase the stage load is to increase the rotation speed of the rotor.This will increase the rotor tip tangential velocity.This will make Mach number of the tip of the blade can reach the supersonic velocity.So shock waves can occur in transonic compressors and shock waves intensify the flow loss inside the compressor.So the control of shock wave system is very important。In this paper,the 50%typical section of a rotor is taken as the reseach object.Adding the bump with different parameters on suction surface of blade.CFD software was used to study prototype cascade and bump cascade by analyzing the total pressure loss coefficient,the distribution of static pressure coefficient and Mach number and so on,get the best shock control bump design scheme by comparing the effects of different parameters bump on the shock structure and internal flow characteristics of cascade of transonic compressor.Firestly,the grid independent verification is carried out,the suitable turbulence model is chosen to ensure the accuracy and reliability of the calculation method.Then,the numerical simulation of the cascade flow field is carried out,the results show that with the increase of the Mach number and the flow loss increases.It also creates shock waves that exacerbate flow losses.With the increase of angle the flow loss increases from-1° to 2°.Numerical simulation is carried out for the prototype cascade and the cascades with different parameters bump under the same import conditions.The results indicate that bump can effectively reduce the shock intensity.When the original shock wave incident between the start of the bump and the vertex,the bump height is less than or equal to the height of boundary layer before the shock wave and the distance between the vertex and the bump ending point is about 1.5 times of the distance between the bump start and the vertex.This parameter bump has the best effect of drag reduction.Finally,under different inlet Mach number and inlet flow Angle,the numerical simulation of the cascade with bump is carried out.The results indicate that in 0° Angle when the inlet Mach number is greater than the design Mach number of bump,the cascade with bump flow can reduce losses,in-1°-2° Angle when the inlet Mach number equals the design Mach number of bump,the cascade with bump flow can reduce losses.