穿孔管消声器声学长度修正的理论公式

The formula for acoustic length correction of perforated tube muffler

推导出穿孔管消声器声学长度修正以及共振频率的理论公式.证明了在均匀分布情况下,多小孔向膨胀腔声辐射与单个小孔向膨胀腔声辐射的声学长度修正系数是一致的.对于小孔向主管道的声辐射,根据理论公式研究了穿孔率、周向均布数以及亥姆赫兹数对声学长度修正的影响,有限元计算得出在直径比小于0.4的情况下声学长度修正系数理论公式与仿真计算结果吻合良好。并利用理论公式的性质以及仿真结果获得了实用的拟合公式,提升了穿孔管消声器在高频时共振频率的计算精度。

The formulas of acoustic length correction and resonance frequency of perforated tube muffler are derived.It is proved that in the case of uniform distribution,the acoustic length correction coefficient of the acoustic radiation from multiple holes to cavity is consistent with that from a single hole to cavity.For the acoustic radiation from the lioles to the main pipe,the effects of perforation porosity,circumferential uniform number and Helmholtz number on the acoustic length correction are studied according to the formula.Results show that the theoretical formula of acoustic length correction coefficient is in good agreement with the simulation results when the diameter radio is less than 0.4.A practical fitting formula is obtained by using the properties of the theoretical formula and the simulation results.The calculation accuracy of resonance frequency of perforated tube muffler at high frequency is improved.