油烟机叶轮异音分析与优化

VIBRATION NOISE AND OPTIMIZATION ANALYSIS OF FAN IMPELLER IN RANGE HOOD

针对装配原工艺叶轮的油烟机会产生81.5 d B噪声的问题,通过仿真和测试相结合的方法,以降低油烟机在最大工作档位的噪声值。首先对装配原工艺和新工艺叶轮的油烟机进行噪声测试以及激励源的振动测试,其次分析了两种工艺叶轮加工工艺的不同,并分别进行模态分析,确定了产生异音的原因。研究表明:原工艺叶轮在生产过程中产生了热应力,导致其固有频率的改变。改变后的频率与激励源激频相近是导致异音的原因。新工艺叶轮生产过程中加入了额外工序使得几乎无热应力产生。最后的改进流程是在原工艺的基础上采用加厚叶轮后圈的方法,提高叶轮的固有频率,避开电机激励频率,从而解决了异音问题。

Up to 81.5 d B high noise occurs in the range hood fitted with original process impeller.This paper presents a method of combing experiment and numerical simulation to reduce the noise level of the range hood under the maximum working condition.First,noise and vibration test of range hood and excitation resource are conducted on a range hood fitted with impellers made by original approach and new process,respectively.Then,the differences between the processing technologies in making the two impellers are analyzed.Modal analysis of the above impellers are performed to determine the cause of the vibration noise.Results show that the thermal stress is generated in the production process,which changes the natural frequency of the impeller made by the original process.Moreover,the changed natural frequency is close to the excitation frequency,which leads to the severe vibration noise.However,less thermal stress is produced in the production process of the new impeller by adding one more step in the production.The final modified procedure is to increase the natural frequency of the impeller by thickening the impeller rear lap and use the original production process.Thus the problems caused by severe vibration noise of the impeller gets solved successfully.