Blade Optimization of Multi-Blade Centrifugal Fan: Experimental and simulation study

Abstract

To overcome the technical challenges of the multi-blade centrifugal fan, such as low efficiency and insufficient total pressure, the single-arc blades of the fan were optimized and replaced in this study. The flow field of the multi-blade centrifugal fan with a single-arc blade and an airfoil blade was simulated and compared using Computational Fluid Dynamics (CFD). Under steady-state conditions, the total pressure, velocity field distribution, and aerodynamic performance of a multi-blade centrifugal fan were analyzed. The numerical results show that the presence of vortices, secondary flows, and boundary layer separation in the flow channel of a single-arc multi-blade centrifugal fan. Combined with the lift-to-drag ratio theory of aerodynamic airfoil, four different airfoil blades were selected for the multi-blade centrifugal fan. It can be found that the lift-to-drag ratio of the airfoil was positively correlated with fan efficiency. Furthermore, the airfoil blade can suppress the above phenomena in the flow channel and enhance the flowability of the blade flow channel. Verified experiments on airfoil effects showed a 3%-7% efficiency improvement in the multi-blade centrifugal fan compared to the single-arc blade. Additionally, the airfoil fan exhibited substantial enhancements in total pressure and power. These findings hold significance for guiding optimal fan design.