多元混合气体中非线性声衰减的数值模拟  

Numerical simulation of nonlinear acoustic attenuation of multi-component gas mixture

作　　者：鄢舒[1] 王殊[1] 

机构地区：[1]华中科技大学电子与信息工程系,武汉430074

出　　处：《声学学报》2008年第6期481-490,共10页Acta Acustica

基　　金：国家自然科学基金资助项目(60472015)

摘　　要：采用直接模拟蒙特卡罗方法(DSMC)对多元混合气体中的非线性声衰减进行数值模拟,提出了一种不依赖于经验参数的声衰减的理论预测模型。通过DSMC数值模拟方法获得了包括氮气、氧气、二氧化碳、甲烷和水蒸气在内的多种多元混合气体的声衰减谱,研究的声波频率范围从8MHz到232MHz。与弛豫衰减的DL模型和经典衰减的Stokes-Kirchhoff公式的结果比较表明,该模型的声衰减预测结果与之相符,其预测精度取决于对产生声衰减的分子碰撞过程的正确认识。另外数值模拟结果还表明,不同频率声波的声衰减对包含不同气体成分的混合气体特征不同,这将使得开发能够定量的检测不同环境和过程中的气体成分的智能声气体传感器成为可能。The direct simulation Monte Carlo （DSMC） method was introduced to model the acoustic propagation in multi-component gas mixture. And a theoretical predictive model of acoustic attenuation was developed, which is independent of experiential parameters. The acoustic attenuation spectra of various multi-component gas mixtures, consisting of nitrogen, oxygen, carbon dioxide, methane and water, were estimated by the DSMC method. The sound frequency range of interest is from 8 MHz to 232 MHz. Compared with the result of the relaxation attenuation based on the DL model plus that of the classical attenuation calculated by the Stokes-Kirchhoff formula, the estimations of acoustic attenuation of our model agreed with them. The precision of the model depends upon the knowledge of the physical mechanism of molecule collision from which the attenuation arises. In addition, the result of our model shows that the characters of the frequency-dependent acoustic attenuation rely on the composition of the gas mixtures. And this could lead to the development of smart acoustic gas sensors capable of quantitatively determining gas composition in various environments and processes.

关 键 词：数值模拟方法 混合气体 声衰减 非线性 Kirchhoff公式 直接模拟蒙特卡罗方法 预测模型 气体成分 

分 类 号：O422[理学—声学]