片式消声器内吸声材料及传递损失仿真方法研究

发布时间：2018-03-08 05:01

本文选题：片式消声器　切入点：吸声材料　出处：《青岛大学》2017年硕士论文　论文类型：学位论文

【摘要】：片式消声器是阻性消声器的一种,广泛应用于工业中各类大流量的风机、空压机、空调、冷却塔等设备的消声。片式消声器一般具有较大的进出口横截面积,进出口处平面波的截止频率低,激发的高阶模态数量多,这使得片式消声器传递损失的准确预测变得较为复杂。为了能提高片式消声器声学性能分析计算的效率和预测的精度,本文以片式消声器为研究对象,对其内部吸声材料的声学特性及消声器传递损失的仿真方法进行了研究。首先对片式消声器内部的玻璃棉及护面结构进行了研究,给出玻璃棉和穿孔板垂直入射吸声系数的计算方法,分析了穿孔板作护面板对多孔材料吸声效果的影响,并通过仿真和阻抗管实验测量的方法验证了分析结果及所用模型的正确性。提出利用LMS Virtual.lab有限元模块中的管道声模态边界条件和AML属性来仿真计算片式消声器的传递损失。与传统仿真方法相比,在阻性消声器进出口处为平面波时,两者结果一致;当进出口处出现高阶模态波时传统仿真方式失效,可以采用管道声模态法计算消声器的传递损失。进而利用管道声模态法对课题中所研究的片式消声器进行了传递损失仿真计算,并分析了消声器内多孔材料流阻率和消声器长度对其传递损失的影响。在中国科学院声学研究所北海研究站管道消声实验室内测量了所研究片式消声器的插入损失,在假设其传递损失与插入损失差别不大的前提下,将实验室测量的插入损失与仿真得到的传递损失进行了对比。实验测量结果和本文中仿真结果总体吻合良好,证明了可以利用管道声模态法快速、准确的预测片式消声器的传递损失。
[Abstract]:Chip muffler is a kind of resistive muffler, which is widely used in all kinds of large flow fans, air compressors, air conditioners, cooling towers and other equipment in industry. The low cut-off frequency of the plane wave at the inlet and outlet and the large number of high order modes excited make the accurate prediction of the transmission loss of the muffler more complicated. In order to improve the efficiency of the acoustic performance analysis and the accuracy of the prediction of the muffler, In this paper, the acoustic characteristics of the internal sound absorbing material and the simulation method of the transmission loss of the muffler are studied. Firstly, the structure of the glass wool and the cover inside the muffler is studied. The method of calculating the sound absorption coefficient of glass cotton and perforated plate at vertical incidence is given. The influence of perforated plate as protective panel on the sound absorption effect of porous material is analyzed. The correctness of the analysis results and the models used are verified by simulation and impedance tube experimental measurement. The acoustic modal boundary condition and AML attribute of the finite element module of LMS Virtual.lab are used to simulate and calculate the sound mode of the muffler. Transfer loss. Compared with traditional simulation methods, When the inlet and outlet of the resistive muffler are plane waves, the two results are consistent, and the traditional simulation methods fail when the higher-order mode waves appear at the inlet and outlet. The transmission loss of muffler can be calculated by using the pipe sound mode method, and then the transmission loss of the muffler studied in the subject is simulated by using the pipeline sound mode method. The influence of the flow resistance rate of porous material and the length of muffler on the transmission loss was analyzed. The insertion loss of the studied muffler was measured in the pipe silencing laboratory of Beihai Research Station, Institute of Acoustics, Chinese Academy of Sciences. On the assumption that there is little difference between the transmission loss and the insertion loss, the insertion loss measured in the laboratory is compared with the simulated transfer loss. The experimental results are in good agreement with the simulation results in this paper. It is proved that the transmission loss of the muffler can be predicted quickly and accurately by using the pipe sound mode method.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB535.2

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