Internal Flow Control Mechanism Near Wall Region with Unsteady Plasma Actuation

The computational modeling used for flow control simulation was established to investigate the mechanism of internal flow control near wall region in an axial compressor with unsteady plasma actuation. Unsteady numerical simulation was performed using a scale adaptive hybrid Reynolds-average Navier-Stokes/large eddy (RANS/LES) method based on shear stress transport (SST) turbulence model. The phenomenological model was used to model the body force over the region of the plasma and added to the momentum equations. The results show that the flow separation at the blade suction surface near wall region is responsible for the tip leakage vortex breakdown and compressor instability. The plasma actuator injects momentum into the flow near wall region. The induced vortex is created due to the interaction between the boundary layer and the high-energy flow near wall region. The induced vortex is created and dissipates periodically, prompting the tip leakage vortex to oscillate periodically. The flow near wall region effectively resists the inverse pressure gradient. The tip leakage vortex spillage ahead of the rotor leading edge and the flow separation at the blade suction surface are suppressed. This allows the compressor to operate at lower mass flow rates. Compared with steady plasma actuation, unsteady plasma actuation improves compressor stability more effectively.