【作者】 朱廉洁；

【导师】 季振林；

【作者基本信息】 哈尔滨工程大学 ， 动力机械及工程， 2007， 硕士

【摘要】 进气噪声是发动机主要噪声源之一。本文介绍了发动机进气噪声的研究现状和方法，阐述了进气噪声源特性、产生机理以及控制方法。由于空气滤清器可以作为一个有效的进气消声器，论文对空气滤清器的声学特性进行了详细研究。考虑到滤纸是一种有效的吸声材料，它对空气滤清器消声特性的影响应加以考虑。论文通过实验测量结果和软件计算结果的对比，验证了使用声学软件SYSNOISE计算吸声材料声学特性的正确性，并且研究了吸声材料对空气滤清器消声性能的影响。研究无流状态下空气滤清器和吸声材料声学特性的测量原理。为了验证阻抗管系统进行两载荷法测量消声器传递损失的正确性，设计了简单圆形膨胀腔消声器。结合自编MATLAB程序，以长纤维玻璃丝棉作为吸声材料实验样品，验证了阻抗管进行两载荷法测量吸声材料声学特性方法的正确性，并测量出滤纸的声学特性参数——复波数和复阻抗。以某型捷达车空气滤清器为研究对象，建立其有限元模型，将测得滤纸的声学特性参数导入声学软件SYSNOISE中作为滤纸的材料属性，通过声学仿真计算出空气滤清器的传递损失，与实验测量结果比较表明，对空滤器模型的处理是合理的。对于简化的空滤器模型，研究了固定滤纸在空滤器中的位置和厚度，固定进气内插管长度，改变出口内插管长度对空滤器声学特性的影响。计算结果表明，可以通过调整内插管的长度来改善空气滤清器的消声性能。更多还原

【Abstract】 Induction noise is one of the major automotive noise sources. This paper introduced the situation and methods of intake system noise study, explained the source characteristics and generation mechanisms as well as the control method of intake noise. In view of the fact that the air cleaner may act as an effective intake silencer, the present paper investigated the acoustic attenuation characteristics of air cleaner in detail.Filter paper is a good absorbing material, and its effect on the acoustic attenuation characteristics of air cleaner should be considered. The acoustic characteristics of absorptive materials calculated by SYSNOISE were validated by comparing the experimental results with the calculated results. The effect caused by utilizing absorptive material on muffler had also been studied.The methods of measuring the acoustic characteristic parameters of air cleaner and absorbing material had been studied for the case without mean flow. According to the principle of Two-Load method, the simple expansion chamber was used to verify the methods of measuring the transmission loss of muffler carried out by impedance tube, and the fiber glass was used to verify the methods of measuring the acoustic characteristic parameters of absorptive material combined with the subroutine coded by MATLAB. The characteristic impedance and complex wavenumber of filter paper had also been measured.The finite element models of air cleaner were created based on the physical model of Jetta car and the acoustic characteristic parameters of filter paper were imported to software SYSNOISE for modedling the property of filter paper. The transmission loss of air cleaner had been calculated and compared with the measured results. The results indicated that the model created for air cleaner was reasonable. A simplified model based on the physical model of air cleaner was also created; the acoustic attenuation characteristics of the air cleaner had been studied with the position and thickness of filter paper fixed, the extended length of inlet pipe invariable, the extended length of outlet pipe variable. The results indicated that the desired acoustic attenuation performance of air cleaner can be obtained by accommodating the length of extended pipes.更多还原