Developed Acoustic Multi-relaxation Algorithm for Humidity Measurement in Gas Mixtures

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 and water vapor. The algorithmic is basing on the complicated transfer mechanism of vibrational-translational, vibrational-vibrational degrees of freedom. By computing acoustic velocity and relaxation attenuation, we notice that changes in water vapor concentration have great influence on the relaxation frequency of the mixture, thus proving the feasibility of detecting humidity by means of relaxation method. Finally, we describe a detailed algorithm to measure proportion of water vapor. This novel approach not only determines the concentration of water vapor, but also reflects the proportional fluctuation of the mixture.