Influence of plasma actuators as a flow separation control device was investigatedexperimentally.Hump model was used to demonstrate the effect of plasma actuators on externalflow separation,while for internal flow separation a set of compressor cascade was adopted.Inorder to investigate the modification of the flow structure by the plasma actuator,the flow fieldwas examined non-intrusively by particle image velocimetry measurements in the hump modelexperiment and by a hot film probe in the compressor cascade experiment.The results showedthat the plasma actuator could be effective in controlling the flow separation both over the humpand in the compressor cascade when the incoming velocity was low.As the incoming velocityincreased,the plasma actuator was less effective.It is urgent to enhance the intensity of theplasma actuator for its better application.Methods to increase the intensity of plasma actuatorwere also studied.
Three dielectric barrier discharge plasma actuators were mounted at the positions of 20%,40%and 60%of chord length on the endwall in a compressor cascade.The downstream flow field of the cascade has been measured with a mini five-hole pressure probe with and without the plasma actuation.The measured results show that the plasma actuation most effectively reduces total pressure loss and flow blockage when the actuators are operated simultaneously.As each of the actuators is operated independently,the actuator at the position of 20%of chord length most effectively reduces flow blockage, and the actuator at the position of 60%of chord length fairly reduces total pressure loss.However, negative pressure loss reduction occurs with the plasma actuator at the position of 40%of chord length.In brief,the plasma actuation placed on the endwall in the cascade apparently influences the endwall secondary flow,and the optimal locations and strength of actuation are critical for the control of endwall secondary flow in a compressor cascade with the plasma actuators.
LI GangXU YanJiLIN BinZHU JunQiangNIE ChaoQunMA HongWeiWANG ZhaoFeng
