基于静态试验的发动机自由场声压级计算方法

Calculation Methods to Obtain Free-field Sound Pressure Levels of JetEngine from Static Noise Test

分析通过喷气式发动机静态噪声试验数据获得其自由场声压级的数据修正方法。通过对点声源在刚性地面和有限声学阻抗地面上的分析,得到了基于地面试验数据的自由场声压级修正量计算方法。在此基础上,将点声源模型推广到复杂的喷气式发动机分布式声源模型,得到了可以考虑喷气式发动机喷气声源分布模型的自由场声压级修正量的计算方法。最后,采用参考文献中喷气式发动机噪声数据对该方法进行验证。结果表明,在考虑发动机声源特性和地面阻抗特性的情况下,该方法计算结果与参考文献中结果基本一致,可用于喷气式发动机静态噪声试验中自由场声压级的计算。

The calculation methods to obtain free-field sound pressure levels from static noise test over ground surfaces of jet-engine were studied. Based on the analysis of theoretical basis of ground reflection effects of point source model, the basic methods were deduced. Then the theoretical basis were applied to jet-engines static test data to obtain the correction of free-field sound pressure levels. The methods were applicable to complicated sound source distribution of jet-engine. At last, the calculation methods were validated by noise data from literature. In consideration of the jet-engine sound source characteristics and ground surface impedance characteristics, present results were basically consistent with the results in literature. The method can be used to calculate free-field sound pressure levels of the jet-engine based on static noise tests.