Flow Control Using Endwall Vortex Generator Jet In A High-speed Compressor Cascade

The compressor is one of the core components of the aircraft engine,flow control in the cascade can significantly improve the compressor pressure ratio and efficiency,reduce the flow loss,it is important to improve the performance of the aircraft engine.As an active control method in a cascade,the vortex generator jet is widely used because of its simple structure and effectively control effect.This thesis used the commercial software CFX to simulate the flow in the cascade with and without vortex generator jet under different working conditions,to explore the mechanism of the flow control in the cascade and the influencing factors of the flow control effect.The working conditions of the study include different attack angle under design import Mach,different attack angle under off-design import Mach number and different flow boundary layer characteristics when flow control,the flow boundary layer characteristics including the thickness of the flow boundary and the flow turbulence.The results show that: There is the similar law of the control effect when the attack angle changed under design import Mach and off-design import Mach number,The control effect is not obvious when the attack angle is negative,especially when the large negative angle i=-4ounder design of imported Maher number will worsen the flow in the cascade,with the angle of attack increased,the loss decreases significantly,when the attack angle i=0o,i=2oand i=4ounder design imported Maher number the losses were reduced by 7.2%,10.2% and 13% respectively,but when the angle of attack up to i=2othe reduction is reduced,only 5.8%.When the attack angle i=0o,i=2o,i=4oand i=6 o under off-design imported Maher number the losses were reduced by 7.2%,9.2%,11.2% and 5% respectively.The mixing effect of the jet vortex will reduce the loss of the corner separation and increase the loss of the upper wash area,the control effect of the jet is the composite results of the two parts.So there will be a situation,when the negative attack angle of attack is large,the vortex generator jet could make the flow in the cascade more complicated.The thicker the boundary layer is,the greater the flow loss is,but the better control effect of the jet vortex is.When the turbulence intensity increases,there was a great impact on the cascade aerodynamic performance when the flow boundary layer is thinner,but when the flow boundary layer is thick the aerodynamic performance hardly varies with the change of the turbulence intensity,when the boundary layer thickness increased,the control effect of jet vortex in different flow the boundary layer thickness showed different trends,when the flow boundary layer thickness is thin,with the increase of turbulence intensity,the control effect become worse;When the flow boundary layer is thick,the total pressure loss reduction increases with the increase of turbulence intensity,flow control effect is enhanced.