Numerical study of double-diffusive mixed convection of heavy gas in ventilation room

¹ School of Building Services Science and Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, PR China
² Department of Applied Physics and Electronics, Umeå University, SE-90187 Umeå, Sweden

^* Corresponding author: zhangying@xauat.edu.cn

Abstract

More than 90% of the toxic gas in the industrial production process is heavy gas. However, under non-isothermal conditions, due to the uncertainty of the direction of buoyancy, the traditional ventilation method cannot be used to discharge heat and pollutants. In this study, we adopted the method of numerical simulation. The model used in this study is a two-dimensional double-diffusion model. The typical heavy-specific gravity gas sulphur hexafluoride (SF6) is used for the pollutants. When the buoyancy ratio is -1, the diffusion law of heavy gas pollutants under non-isothermal conditions is discussed. The results show that the temperature distribution and the pollutant distribution are mainly affected by the size of the vortex on the surface of the pollution source and the heat source. The temperature ventilation efficiency and the average Nu trend are similar, and put forward the optimal ventilation intensity relational formula in the square cavity.