Effects of Inclined Volute Tongue Structure on the Internal Complex Flow and Aerodynamic Performance of the Multi-Blade Centrifugal Fan

Numerical simulation was used to investigate the effect of an inclined volute tongue on the complex flow characteristics and the aerodynamic performance of multi-blade centrifugal fans. We focused on the effects of the clearance, the inclination angle and the volute tongue’s on controlling the centrifugal fan’s internal flow characteristics and aerodynamic performance. The results showed that the volute tongue’s reasonable clearance ratio and the inclined volute tongue design were beneficial to improving the flow pattern around the volute tongue and volute outlet of the centrifugal fan, as well as reducing the local flow loss. It is of great significance to increase the centrifugal fan’s static pressure and related efficiency by increasing the radius and inclination angle of the volute tongue. Due to the reduced of vortex, the local flow loss was reduced. Numerical results indicated that model C’s static pressure rose to 12.5Pa, and the related static-pressure efficiency of to 3.8% compared with the reference geometry due to the reduced of flow loss.