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针对小型挖掘机动力舱冷却风扇噪声较大的问题,采用计算流体动力学技术联合无限元的方法对其远场噪声进行分析并改进.基于计算流体动力学方法获得动力舱流场特性,通过流场特性分析得到气动声源;运用Lighthill声类比和无限元法,获得无限大空间的动力舱声场结果;在对原始风扇分析的基础上,重新优选一款新的低噪声风扇,进行计算分析,结果表明可降低风扇噪声1.3dB.将原机改进前后计算所得远场噪声频谱与试验结果进行对比,其变化趋势基本一致,且实测结果表明:新型风扇噪声得以改善,降低了1.7dB.
In order to solve the problem of large noise in the cooling fan of engine compartment of small excavator, the far-field noise is analyzed and improved by combining computational fluid dynamics with the finite element method.Fluid flow field characteristics of the power cabin are obtained by computational fluid dynamics The aerodynamic sound source is obtained through the analysis of the field characteristics; the acoustic cabin sound field results with infinite space are obtained by using the Lighthill acoustic analogy and the infinite element method. Based on the analysis of the original fan, a new low noise fan is re-selected for calculation and analysis, The results show that the fan noise can be reduced by 1.3dB, the far-field noise spectrum calculated before and after modification of the original machine is compared with the experimental results, and the trend is basically the same. The measured results show that the noise of the new fan is improved by 1.7dB.