Structure Borne Noise Reduction And Aerodynamic Performance Optimization Of Small Centrifugal Fan

In the past decade,the economy has developed rapidly in China,and people’s requirements for the quality of life and living environment have also increased.The small centrifugal fan is widely used in various industries.However,the location of the small centrifugal fan is closer to the staff,the space size limit is relatively strict and the noise and vibration are greater,which will directly affect people’s quality of life and equipment life.Therefore,the development of small centrifugal fan with high performance,low vibration and low noise is getting more and more attention.The simulation of the centrifugal fan can effectively understand the internal flow field of the fan,so as to optimize the design and improve the performance and efficiency of the fan.In this paper,using the finite element analysis software to study the strength and vibration characteristics of low speed centrifugal fan.Contrast and analyze the equivalent stress-strain cloud diagram of stainless steel impeller and aluminum alloy impeller.The results show that the strength of the impeller of the two materials meets the requirements of the fan under operating conditions.By comparing the first 20 modal frequencies of two different material impellers,it is found that the modal frequency distribution of the aluminum alloy impeller is better than that of the stainless steel impeller,and the fundamental frequency of the fan system is avoided by structural optimization of the low speed fan casing.Then the structure borned noise of the low speed fan is reduced.The structure borned noise of the fan at 50 Hz is reduced from 111.8d B to 93.1d B,which is lower than the limit of 95 d B.The structural borned noise at 100 Hz has been reduced from 100.4d B to 96.2d B,which is lower than the limit of 97.1d B.On the other hand,the CFD technology is used to perform orthogonal tests on the import installation angle,the outlet installation angle,the blade thickness and the number of blades of the impeller of the high speed centrifugal fan.Then studying the effect of the expansion angle of the volute outlet and the relative axial distance between the impeller and the volute on the performance of the fan.The orthogonal test is carried out on the impeller of the high speed fan,and the optimal scheme with total pressure as the optimization goal is obtained.In addition,it is found that when the expansion angle of the volute outlet is 15° and the axial distance between the impeller and the volute is 10 mm,the performance optimization of the high speed fan is obvious.After optimization,the total pressure of the high speed centrifugal fan is increased by 5.2%,and the efficiency is increased by 2.7%.