Enhancing the performance of a reversible axial fan through various arrangements of dielectric barrier discharge plasma actuators: A 3D CFD study

This study investigates the optimization of dielectric barrier discharge (DBD) plasma actuator arrangement to enhance the performance of a reversible axial flow fan, focusing on the induced force angle and the axial positioning of the actuators. A three-dimensional numerical approach is employed to analyze the flow structure and performance map of the fan. The findings highlight that tip leakage vortex and hub region vortices significantly contribute to instability at low mass flow rates. Consequently, plasma actuators were strategically positioned on the inner casing and hub surface. The effects of actuator force angle in two configurations: axial alignment and alignment with the blade tip angle were evaluated. Additionally, the influence of three axial positions 0.05, 0.07, and 0.09 of the blade axial chord was assessed by integrating a spatially distributed body force into the Navier-Stokes equations. Results demonstrate that implementing plasma actuators enhances flow energization in the tip and hub regions, leading to improved aerodynamic performance by reducing the size of the tip leakage vortex and mitigating flow blockage. Among the proposed configurations, applying the forcing direction axially proved to be the most effective. Specifically, positioning the plasma jet at 0.07 axial chord at the blade tip and upstream enhanced the fan stall margin by approximately 10%. This improvement is primarily attributed to the ability of the plasma jet to strengthen the axial component of the velocity, thereby injecting greater momentum into areas of the flow that exhibit weaker momentum compared to other configurations.