集流器结构对多翼离心风机气动性能的影响

The effects of inlet nozzle structure and its parameters on the aerodynamic performance of multi-blade centrifugal fan were investigated numerically and experimentally. Numerical method was used to simulate the multi-working conditions of the fan, and the flow rate-pressure curve was obtained. By comparing the numerical simulation with the experimental results, the validity of the computational model and numerical method was testified. Then, by changing the outlet diameter of the inlet nozzle d_o and the clearance δ between inlet nozzle and impeller, the optimum structural parameters of the inlet nozzle could be determined to improve the aerodynamic performance of the fan. Analysis on the internal flow fields of the fan before and after optimization shows that the aerodynamic performance of the fan is improved in the whole operating range when the optimized inlet nozzle is used. However, with the increase of the axial gap between the inlet nozzle and the impeller, the change of the aerodynamic performance of the multi-blade centrifugal fan is nonlinear. When d_o=206 mm and δ=6 mm, the maximum flow rate of the fan is obtained. Experimental results also show that the maximum flow rate and static pressure of the multi-blade centrifugal fan are increased by 1.0 m³/min and 25 Pa, respectively. This study may have a certain theoretical significance and practical application value for the performance improvement of multi-blade centrifugal fans.