Numerical Optimization of Volute Outlet Structure for Forward-Curved Centrifugal Fan

A numerical optimum study on three-dimensional unsteady viscous flow in a centrifugal fan with forward-curved blades was performed.The influence of the outlet angle of the volute,the bare length of the impeller and the cutoff clearance on aerodynamic performance and aerodynamic noise of the centrifugal fan was analyzed concerning the whole impeller-volute configuration.The correlations of the fan efficiency and A-weighted sound pressure level with the three parameters were obtained by quadratic polynomial regression with the response surface methodology(RSM).The results show that the bare length of the impeller and the cutoff clearance affect the fan efficiency and A-weighted sound pressure level significantly.Moreover,A-weighted sound pressure level decreases by 9.4dB with the three parameters optimized while in this case the fan efficiency only decreases slightly.The method of reliable CFD technique in combination with RSM can be effectively applied to the improvement and experiment design of centrifugal fans.