An algorithm for carbon monoxide concentration detection based on molecular multi-relaxation model

Abstract

In this paper, we focus on the relaxation process of acoustic waves in polyatomic gases, and build up a multi-relaxation algorithmic model of a gas mixture of nitrogen, oxygen, water vapor and carbon monoxide. The model is basing on the complicated transfer mechanism of vibrational-translational, vibrational-vibrational degrees of freedom. By computing acoustic velocity and relaxation attenuation, which is depend on the composition of the gas mixture, acoustic frequency, temperature, and pressure, we notice that changes in carbon monoxide concentration have great influence on these acoustic characteristics of the mixture. Thus it proves the feasibility of detecting carbon monoxide by means of molecular acoustic method. Finally, we describe a detailed model to measure proportion of carbon monoxide. This novel approach not only determines the concentration of carbon monoxide, but also reflects other gases' proportional fluctuations of the mixture, such as water vapor.