文献类型：期刊文献

中文题名：可激发气体振动弛豫时间的两频点声测量重建算法

英文题名：Algorithm for reconstructing vibrational relaxation times in excitable gases by two-frequency acoustic measurements

作者：张克声 朱明 唐文勇 欧卫华 蒋学勤

第一作者：张克声

通信作者：Zhu, M[1]

机构：[1]贵州理工学院信息工程学院;[2]华中科技大学电子信息与通信学院;[3]贵州师范大学大数据与计算机科学学院

第一机构：贵州理工学院电气与信息工程学院

通信机构：corresponding author), Huazhong Univ Sci & Technol, Sch Elect Informat & Commun, Wuhan 430074, Peoples R China.

年份：2016

卷号：0

期号：13

起止页码：172-180

中文期刊名：物理学报

外文期刊名：Acta Physica Sinica

收录：CSTPCD;;EI(收录号：20162902623734);Scopus(收录号：2-s2.0-84978438280);WOS:【SCI-EXPANDED(收录号:WOS:000380364800021)】；北大核心:【北大核心2014】；CSCD:【CSCD2015_2016】；

基金：Project supported by the National Natural Science Foundation of China (Grant Nos. 61461008, 61371139 61571201, 61402122), the Natural Science Foundation of Guizhou Province, China (Grant Nos. [2015]2065, [2014]7361), and the Recruitment Program of Guizhou Institute of Technology (Grant No. XJGC20140601).

语种：中文

中文关键词：弛豫时间;声弛豫吸收;弛豫过程;弛豫频率

外文关键词：relaxation time; sound relaxational absorption; relaxation process; relaxation frequency;

摘要：振动弛豫时间是可激发气体分子内外自由度能量转移速率的宏观体现,它决定了声吸收谱峰值点对应的弛豫频率.本文给出了等温、绝热定压和绝热定容三种不同热力学过程下振动弛豫时间的相互关系;基于Petculescu和Lueptow[2005 Phys.Rev.Lett.94 238301]的弛豫过程合成算法,推导了单一压强下两频点声测量值的弛豫时间重建算法.该算法可应用于等温、绝热定压、绝热定容弛豫时间和弛豫频率的重建测量,并避免了弛豫时间传统声测量方法需要不断改变气体腔体压强的问题.仿真结果表明,对于室温下CO_2,CH_4,Cl_2,N_2和O_2组成的多种气体,重建的弛豫时间和弛豫频率与实验数据相符.
Vibrational relaxation time is a parameter describing the macroscopic behavior of vibrational energy transition rate between molecular internal degrees of freedom（DOF） and external DOF in excitable gas, which determines the relaxation frequency of the maximum point in acoustic absorption spectrum. To measure the vibrational relaxation time, the traditional methods are used to obtain the acoustic absorption spectra by changing the ambient pressure at several operating frequencies. However, these traditional methods are not suitable for real-time measurement due to the complexity of equipment implementation and the non-ideality of test gas under high pressure. In order to solve those problems, we have developed an algorithm [2013 Meas. Sci. Technol. 24 055002] to capture the primary vibrational relaxation processes only based on the measurements of sound absorption and sound speed at two operating frequencies and a single pressure. But the algorithm only can reconstruct the absorption maximum and it cannot capture the relaxation time with high precision. To measure the frequency dependence of the complex effective specific heat of the relaxing gas, an algorithm synthesizing relaxation processes is given by Petculescu and Lueptow [2005 Phys. Rev. Lett.94 238301]. In its derivation process, relaxational angular frequency was set to be the inverse ratio to relaxation time.However, the relaxational angular frequency was measured in the adiabatic process of transmission thermodynamic,while the relaxation time was obtained in the thermodynamic isothermal process, the derivation confused the two thermodynamic processes, making the algorithm unable to capture the relaxation frequency with high precision. In order to estimate the relaxation time with higher accuracy, in this paper we first obtain the theoretical relationship among the relaxation times under the three types of thermodynamics conditions, i.e., isothermal, adiabatic constant pressure and adiabatic constant volume. Then we correct the relaxation time derivation and propose our corrected algorithm to reconstruct the relaxation frequencies and relaxation times under the conditions of isothermal, adiabatic constant pressure and adiabatic constant volume. In experiments and simulations, the relaxation times and relaxation frequencies reconstructed by our corrected algorithm for various gas compositions including carbon dioxide, methane,chlorine, nitrogen, and oxygen around room temperature are consistent with the experimental data.