摘要:
针对非对称阻抗插入管消声器三维理论建模与求解问题,提出了一种半解析变分建模和求解方法,试验及有限元结果验证了理论模型和求解结果的正确性,开展了模态频率、声压响应及传递损失等声场特性的预测分析。首先构建插入管消声器内部子声场拉格朗日泛函,基于声压与质点振速连续性条件,得到插入管消声器三维理论模型。随后,将子声场声压展开为切比雪夫-傅里叶级数组合形式,按里兹法求得消声器三维声场模态信息。搭建了消声器传递损失试验平台,进行了刚性壁面和阻抗壁面消声器传递损失测试试验,对理论模型和计算结果进行了验证。通过算例分析了壁面阻抗的大小、阻抗面积和分布形式以及插入管偏置对消声器消声性能的影响。结果表明,提出的变分建模求解方法是有效的,对消声器壁面阻抗位置和形式的合理设置可有效降低输出声压。
Abstract:
A semi-analytical modeling and solving method is proposed for the three-dimensional inserted-pipe muffler with asymmetric impedance boundary conditions and offset inserted-pipes.The experimental curves and finite element analysis results verify the correctness of the theoretical model and corresponding results.The nature frequencies,sound pressure responses and transmission losses are predicted.First of all,the Lagrangian functional of each acoustic subspace in the inserted-pipe muffler is constructed.According to the continuity condition of pressure and particle velocity between acoustic subspaces,the theoretical model of the three-dimensional inserted-pipe muffler is constructed.Then,the sound pressure is expanded into a combined form of Chebyshev-Fourier series and the eigen pairs of the muffler are obtained by using Ritz method.A test rig is set up and the transmission loss tests on mufflers separately with rigid wall or impedance wall are carried out.The effects of several parameters on the performance of muffler are analyzed,including the value of the wall impedance,the area and distribution of the impedance,and the offset of the inserted-pipe.The results show that the proposed method is valid and the reasonable setting of wall impedance in the muffler can effectively reduce the output sound pressure.
百度学术
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