穿孔管式消声单元气流再生噪声总功率模型

Total power model of flow noise generation in perforated duct muffler element

采用正交试验设计方法确定了穿孔管式消声单元试验样件的具体结构参数,在自行研制的试验台上进行了气流再生噪声测量。根据量纲分析建立了气流再生噪声总功率与结构参数及气流速度的关系模型,利用超静定最小二乘法求解了模型参数,并检验了模型的显著性,利用该模型对气流再生噪声的影响因素进行探讨。结果表明,在显著性水平0.01下,所建模型是高度显著的;穿孔直径和穿孔部分长度的减小均有利于气流再生噪声的降低,而穿孔率和腔体直径对气流再生噪声的影响较小。频谱分析发现,随气流速度增大,气流再生噪声突出峰值频率有向中高频移动的趋势,强度也有所增大,在斯德鲁哈尔数为0.2～0.35的范围内,存在一突出峰值频率,该处的声能量约占总能量的60%以上。

Using orthogonal experimental design method, detailed structure parameters of work piece fbr pertbrated tube muffler element were determined. Flow noise regeneration was measured on the self developing test bench. The model describing the relationship of the total sound power of flow regenerated noise to the structure parameters and Jlow velocit~ was established by utilizing dimensional analysis. Model parameters were solved, making use of hyper static least squar~： method. Significance test of the model was performed, and the law of total sound power level of muMer element tlo~ regenerated noise changing with the parameters was discussed. The results show that the established models are all highl~ significant under 0.0k level. The reducing of the perforated diameter and the perfbrated part length is in f＇avor of the reduction of flow regenerated noise in perforated tube muffler element, and the perforated ratio and expansion chamb~：, diameter have less effect on flow regenerated noise. After analyzing spectral structure of flow regenerated noise, il is indicated that with the increase of flow velocity, the projected peak value frequency has the trend of＇ moving to middle and high frequency bands, and its strength also becomes bigger. When the range of Strouhal number is from 0.2 to 0.35~ there is a peak value frequency component with the sound energy accounting for about 60% of the total energy.