锤片式粉碎机空气动力性噪声的研究

Study on the aerodynamic noise of the hammer mill

为了解决锤片式饲料粉碎机在饲料加工中噪声大的问题,文章以课题室研制的新型锤片式粉碎机为研究对象,利用Fluent和Virtual.Lab软件进行联合仿真的方法,通过噪声测量试验,对粉碎机空气动力性噪声的产生机理进行分析研究。运用Fluent软件计算粉碎机内部稳态流场,以稳态解作为初始值,计算瞬态流场并得到锤片表面脉动压力信息,进行风速试验验证了流场分析的准确性;在Virtual Lab软件的Acoustic模块中采用直接边界元法对粉碎机近场气动噪声进行模拟仿真。结果表明,粉碎机气动噪声主要由出料口向外扩散,于166.7 Hz处达到峰值,随着频率增加逐渐降低,最后趋于稳定。使用噪声传感器对粉碎机进行噪声测量,频谱分析表明:粉碎机噪声峰值出现在166.7 Hz处,且由锤片扰动空气产生的旋转噪声引起,仿真与试验结果基本一致。研究为锤片式粉碎机的减振降噪设计提供了理论依据。

In order to solve the noise problem of hammer mill feed grinder during feed processing, this paper takes the new hammer mill made hv research room as research object. By using the united simulation method of software Fluent and Virtual l,ah lo run noise measurement lest. setting the steadyslate solulinn as initial value to calculate the transient flow field to get the fluctuating information on hammer surface. And then verifying the accuracy of low field analysis by conducting wind speed test： Importing the calculation result from Fluent to the Acoustic module of Virtual Lab, adopting the direct boundary element method lo do analog simulation for the hammer mill＇s aerodynamic noise. The result shows that the hammer mill＇s aerodynamic noise is mainly spread out of the discharge hole and reach to the peak at 166.7 Hz. And then il will gradually decrease and become stable with the increasing of frequency. The result of noise measurement by noise transdueer and the spectral analysis shows that hammer mill＇s noise peak at 166.7 Hz resuhs from the air agitation of hammer. At the same lime, the resuh of simulation and test results are basically same. This research provids the theory basis Io make the design of reducing hammer mill＇s vibration and noise.