多原子分子气体中声波弛豫衰减谱的重建算法

Reconstruction algorithm of relaxation attenuation spectrum in polyatomic gas

提出了一种宽频率范围的弛豫衰减谱重建算法,并采用基于SSH理论的方法和基于实验数据的方法估计气体的有效弛豫时间.通过该算法得到了包括氮气、甲烷、氧气、二氧化碳和水蒸气在内的多种多原子分子混合气体的声衰减谱,研究的声波频率范围从1Hz到10GHz.与预测弛豫衰减的DL模型的结果比较表明,该算法获得的弛豫衰减谱结果与之相符,其预测精度取决于对分子弛豫过程的正确认识.另外该算法还被用于几种混合气体中水蒸气和二氧化碳含量的分析,其结果表明弛豫衰减谱可被用于定量分析多原子分子气体的成分组成,这使得实现高灵敏度地检测气体成分的智能声气体传感技术成为可能.

A reconstruction algorithm that synthesizes the relaxation attenuation spectrum in a wide frequency range is presented. And the effective relaxation time of gas can be estimated by two approaches, which are base on SSH theory and experimental data, respectively. The acoustic attenuation spectra of various polyatomic gas mixtures, consisting of nitrogen, methane, oxygen, carbon dioxide and water, were estimated by the reconstruction algorithm. The sound frequency rang of interest is from 1 Hz to 10 GHz. Comparing with the results of the relaxation attenuation based on the DL model, the estimations of relaxation attenuation of the reconstruction algorithm agreed with the latter. The precision of the reconstruction algorithm depends upon the knowledge of the physical mechanism of molecular relaxation processes. In addition, the reconstruction algorithm was applied to quantitatively determining the concentrations of water and carbon dioxide in some polyatomic gas mixtures. The results show that the relaxation attenuation can be used as a quantitative probe of the composition of polyatomic gas mixtures. And this could lead to the development of smart acoustic gas sensors capable of determining the precise compositions of gas mixtures.