Numerical and Experimental Study on the Effects of Curved Volute on the Aerodynamic Noise of Multi-Blade Centrifugal Fans

To address the issues of non-uniform inlet flow and volute tongue gap backflow caused by airflow redirection at the inlet side of multi-blade centrifugal fans and,this study takes the volute of a double-inlet multi-blade centrifugal fan used in integrated stoves as the research object and proposes an optimization method for a curved volute with parameterized design of its flow passage cross-sections. The stacking line of the curved volute is determined based on the original volute profile and the impeller outer diameter. By constructing a three-arc-shaped flow-passage cross-section profile at each circumferential position of the volute, the axially cut portion of the volute is geometrically reconstructed, and the curved volute configuration is completed along the stacking line. Numerical simulations are conducted to investigate the aerodynamic performance and noise characteristics of the optimized multi-blade centrifugal fan, and a prototype is fabricated considering manufacturing requirements for experimental validation.Under the actual operating conditions of integrated stove applications, experimental measurements are performed to verify the improvement effects of the curved volute on the aerodynamic performance and noise level of the multi-blade centrifugal fan at the working flow rate. The results show that, compared to the original fan, the curved volute fan achieves a noise reduction of 6.4 dB and a power reduction of 4.6% at the same working flow rate. Based on numerical analysis of the internal flow field, the curved volute reduces the velocity gradient at the axial airflow interface, suppresses the diffusion of high turbulent kinetic energy regions near the volute outlet and tongue, and weakens the periodic interaction between the outlet airflow and the volute tongue, effectively lowering the aerodynamic noise level of the multi-blade centrifugal fan. This study provides theoretical foundations and practical insights for internal flow control and efficiency-enhancing, noise reducing designs of multi-blade centrifugal fans.