Research on Design Optimization and Aerodynamic Performance of Hub Cap in Axial Flow Fans

This study employs Computational Fluid Dynamics (CFD) methods to analyze the impact of hub cap axial length and profile on the performance of an axial flow fan. It investigates how the hub cap influences airflow paths, flow separation, and vortex distribution. The results show that increasing the axial length of the hub cap can reduce vortex regions within the impeller, lower the pressure difference between the suction and pressure surfaces, and mitigate flow separation at the junction between the hub cap and hub contour. These findings indicate that more uniform blade loading decreases the likelihood of vortex formation and reduces energy dissipation, thereby improving fan pressure and efficiency. There exists an optimal axial length, beyond which further increases in axial length have little impact on the fan's performance. Moreover, when the axial length is fixed, a well-designed curved hub cap surface can further optimize airflow and enhance fan performance. Experimental validation was conducted to evaluate the impact of the presence or absence of a hub cap on fan efficiency. These studies provide valuable guidance for the design of high-efficiency, high-pressure axial flow fans.