Vibration Characteristics Analysis and Structural Optimization of a Volute-Less Centrifugal Fan Frame

This paper uses modal analysis and harmonic response analysis to study the vibration characteristics and vibration response of the frame of a volute-less centrifugal fan. The accuracy of the finite element model is verified by comparing the experimental results with the numerical simulation results. Our focus is on the resonance behavior of the fan frame under the maximum operating conditions. Therefore, the structural parameters are taken as design variables, and the maximum axial amplitude at 2600 rpm and its corresponding axial modal frequencies are taken as target parameters for research. A combination of response surface methodology and multi-objective optimization is used to optimize the structure parameters and solve for the Pareto solution set. Three feasible solutions were selected to verify the method’s accuracy. The results show that the optimized fan frame structure enhances the axial modal frequencies to 52.3 Hz, reflecting a 24% improvement over the baseline. Furthermore, we reduce the maximum vibration velocity at resonance to 2.15 mm/s, effectively minimizing vibration responses and preventing excitation and resonance issues at peak speeds.