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针对某大型挖掘机在样机开发阶段出现的机外辐射噪声异常问题,对噪声信号进行处理与分析。应用信号处理与频谱分析方法,识别出挖掘机主噪声源头为排气系统的二次再生噪声;采用CFD技术,找到二次再生噪声的关键因素为排气系统产生的湍流。对排气尾管结构进行改进后,排气尾管末端的湍流强度明显减弱,且实测对比结果表明,采用圆弧型排气尾管的机外辐射噪声降低了5.9 d B(A),效果十分显著,验证了噪声识别及CFD分析方法的有效性与正确性。
Aiming at the abnormal radiation noise problem of a large excavator during the prototype development phase, the noise signal is processed and analyzed. Using signal processing and spectrum analysis, the main noise source of excavator is identified as secondary regeneration noise of exhaust system. The key factor of secondary regeneration noise using CFD technology is turbulence generated by exhaust system. The improvement of the exhaust tail pipe structure, the end of the exhaust tail pipe turbulent intensity was significantly weakened, and the measured results show that the use of circular exhaust tail pipe outside the radiated noise decreased 5.9 d B (A), the effect Is very significant, validates the validity and correctness of the noise identification and CFD analysis methods.