航空发动机噪声地面反射效应计算方法

为了获得准确性更好、适用范围更广的航空发动机噪声地面反射效应计算方法,文章对不同地面声阻抗模型以及噪声干涉效应模型下的地面反射效应进行频率响应特征分析。与公开的试验数据进行对比,结果表明地面声阻抗模型是影响噪声地面反射效应的关键因素。当地面有效声阻抗的不确定性较大时,选择变量个数较少的地面声阻抗特征方程,可以获得准确性更高的噪声地面反射效应的预测结果。根据对比结果,文章提出了一种航空发动机噪声地面反射效应计算方法,为发动机噪声适航性预测程序的升级提供了优化思路。

Prediction method of ground reflection effect of aircraft engine noise

In order to predict the free-field aircraft engine noise accurately in static engine experiments, the ground reflection effect is analyzed with different ground acoustic impedance models and sound coherence models. Comparison between the experiment data and the prediction results shows that the ground acoustic impedance model is the important factor affecting the ground reflection effect of the noise. The characteristic equation of ground acoustic impedance with fewer factors can be selected to get more accurate prediction results of ground reflection, when there is some uncertainty of the effective ground acoustic impedance. According to the comparison results, a calculation method of ground reflection effect of aircraft engine noise is proposed in this paper, which provides an optimization idea for upgrading engine noise airworthiness prediction program.