基于声源成像的发动机模型试车噪声源分析

Noise Sources Analysis of the Engine Model on Basis of Acoustical Sources Mapping

目的在发动机试车噪声环境试验中,基于传声器阵列的声源成像测量方法,在近场单点测量之外,提供一种补充测量手段。方法为验证基于传声器阵列的声源成像方法在发动机工作噪声试验研究中的有效性,通过发动机模型试车试验,设计并搭建传声器阵列,对试验噪声环境进行测量,并详细分析发动机试车中喷流噪声源特征。结果通过声源成像分析手段获得了模型噪声源在时域和频域中的特征规律。通过声源成像云图中喷流噪声源在各个时刻的形态,能够直观反映出发动机模型工作各时刻状态。喷流噪声源在低频部分的能量比较高,声源主要分布在远离喷口的喷流下游位置处;在高频部分,声源主要分布在喷口附近。在中心频率为2000 Hz的1/3倍频程频段内,声压级最大的声源位置距离喷口最远。结论通过试验和分析验证了声源成像在发动机模型试车噪声源分析中的可行性。

In the noise environment test of engine test run,the sound source imaging measurement method based on micro-phone array provides a supplementary measurement method in addition to the near-field single point measurement.In this text,in order to validate the effectiveness of acoustic source mapping on the basis of microphone array during the launch vehicle en-gine test.Through the engine model test,the microphone array was designed and built to measure the noise environment,and the noise source characteristics of jet flow in the engine test were analyzed in detail.The characteristics of noise sources in time domain and frequency domain are obtained by means of sound source imaging analysis.The energy of the jet noise source in the low frequency part is relatively high,and the sound source is mainly distributed at the downstream position of the jet away from the nozzle;in the high frequency part,the sound source is mainly distributed near the nozzle.In the 1/3 octave band with a cen-ter frequency of 2000 Hz,the sound pressure level of the largest source location is farthest from the nozzle.The feasibility of sound source imaging in noise source analysis of engine model test vehicles was verified through tests and analysis.