Study Of The Aerodynamic Performance Of A Compressor Tandem Cascade

The flow will be separated more easily with the increase of aero-engine compressor load.The introduction of tandem cascade can improve the compressor performance and reduce the pressure loss.In this paper,the compressor tandem cascade model is numerically simulated by a detached eddy simulation method,and the calculated results are compared with the experimental results of J.Eckel et al.to verify the accuracy and reliability of the calculation.In order to study the three-dimensional flow field at different attack angles,three working conditions of different angles of attack were selected,which are named zero attack angle working condition,rated attack angle working condition and post-stall attack angle working condition.In order to clearly show the vortex structure of tandem cascade flow field,the calculation results of one cycle under each working condition are intercepted,the three-dimensional flow field is processed by using the method of Q criterion,the motion of vortex structure and the influence for flow field are analyzed,and the limited streamline and the instantaneous streamline of the flow field at the half-blade height are observed at the same time.The Fourier modal decomposition method is used to analyze the half-blade height velocity field of tandem cascade at different attack angles.Secondly,the flow field of post-stall attack angle condition is decomposed into three dimensional Fourier modes,and the extracted modes corresponding to the main frequency are basically the same with the result of the half-blade height section.Finally,the upstream rotor blade rotation will cause strong pulsation of cascade flow field and dynamic inflow effect,therefore the research of tandem cascade flow field under dynamic inflow has great significance.Three different frequencies were selected to simulate dynamic inflow field in the post-stall attack angle condition,and the inlet Mach number submitted sine curve variety over time by writing a user-defined command,and the dynamic inflow field was compared with the tandem cascade flow field in a constant Mach number inflow.The flow field under dynamic inflow fluctuates more violently than that under constant inflow,and the lower the frequency is,the worse the flow capacity of the flow field is.