Flow Control Mechanism Of Synthetic Jet In A Low-reaction Compressor Cascade

With the development of modern aircraft technology,it is a fact that the compressor performance becomes higher,which means that the load of compressors becomes higher.With the increase of the load,flow conditions become bad in the compressor,and flow seperation can appear under extreme condition which has a bad impact on the performance of compressors.To suppress flow separation,flow control is applied in the compressor.As an advanced flow control technique,synthetic jet has a dominant advantage over other flow control techniques,which provides an effective method in improving compressor performance.Therefore,the research on the mechanism of flow control in the compressor with synthetic jet has a great significance for improving compressor performance.Numerical simulation method is used to investigate the effects of synthetic jet on flow seperation control in 2D and 3D compressor cascades.In a 2D compressor cascade,the effects of excitation parameters of single synthetic jet actuator on flow seperation control are investigated,including excitation frequency,momentum coefficient,location and jet angle.Excitation frequency plays a major role in producing periodic perturbation to influence flow field,transforming seperation flow into periodic flow induced by the interation of synthetic jet and flow in the cascade under proper conditions.Momentum coefficient has relation to magnitude of injected momentum flux of synthetic jet in a 2D cascade.Different jet angles make flow states influenced by synthetic jet different near the wall.Jet angle also has an effect on the magnitude of tangential momentum flux.Excitation location has an effect on the distribution of injected momentum flux in the cascade.The effects of double synthetic jet actuators are also investigated,which has a dominant advantage over single synthetic jet actuator under proper conditions.In a 3D compressor cascade,momentum coefficient of single synthetic jet actuator has an effect on the magnitude of momentum flux injected into the cascade.Excitation location has an effect on the distribution of injected momentum flux up the sunct ion side and in the corner.Different jet angles make flow states influenced by synthetic jet different near the wall.Jet angle also has an effect on the magnitude of tangential momentum flux.Positionings of the actuator(s)are also investigated to suppress flow separation.It is investigated that synthetic jet can suppress flow separation in 2D and 3D compressor cascades.The flow control mechanism of synthetic jet suppressing flow separation is that synthetic jet makes injected momentum flux distributed proper in a place where flow separation can appear by means of fluid transport,shear,mixing to increase the velocity of boundary layer and improve the boundary layer ability to suppress flow separation.Different parameters,positionings or actuator numbers have different effects on flow separation having different injected momentum distribution in the cascade.