发动机边盖辐射噪声仿真预测及实验

Simulation Prediction and Experimental Test of Radiation Noise of Engine's Side Covers

采取仿真预测与实验测量相结合的方法对某款发动机左边盖结构噪声进行分析。用LMS Test.lab测得发动机左边盖振动加速度信号,以此作为激励,导入到Hypermesh中对左边盖进行有限元分析。提取表面振动速度频谱,作为发动机边盖噪声辐射边界条件,运用LMS Virtual.lab对其进行声学仿真,并对噪声辐射仿真结果进行分析。再通过B&K 3560 D型数据前端对左边盖噪声进行测量,用波束成形法对测量结果进行分析,与仿真结果进行对比验证,两者声功率曲线吻合。对左边盖结构进行改进,再对改进后的左边盖进行噪声测量,整体噪声级呈下降趋势,改进效果显著。对边盖结构噪声预测以及整个发动机的降噪有一定参考作用。

A method combining simulation prediction and experimental measurement is used to analyze the side cover’s structural noise of an engine. The vibration acceleration signal of the left shell of the engine is measured with LMS Test. Lab. This signal is input into the Hypermesh code as an excitation to carry out the finite element analysis for the left shell of the engine. The surface vibration-velocity frequency-spectrum is extracted as the boundary conditions for noise radiation analysis of the engine’s left shell. Using the LMS Virtual. Lab, acoustic simulation of the left shell is done, and the result of the noise radiation is analyzed. The front-terminal of B&K 3560 D data is applied to measure the noise of the left side cover. The measurement result is analyzed with beamforming technology and compared with that of the simulation. It is found that the sound power curves of the two results are in good agreement. Then, the left shell structure is improved, its noise after the improvement is measured and the effect of the improvement is found to be good. This work is of greater reference significance to predict side cover structure-borne noise and reduce the noise of the entire engine.