Temperature effect on the diffusion-convection of the radon gas in a room: Numerical simulation

Radon, radioactive natural gas resulting from the disintegration of Uranium and Thorium, is present in subsoil water as well as the air and building materials. Though it is present at weak concentrations, its inhalation increases to the exposure of the man to the radiation. The radon concentration varies with space, climatic conditions, etc... This paper focuses on modelling effect of the temperature on the diffusion and the advection of the radon gas in a habitat during different times of the day. The model is based on Navier-Stokes, energy and concentration equations. The results show that: 1) Temperature accelerate the radon transfer especially when a vertical thermal gradient is applied to the opposite walls, 2) Recirculation zones appear against the wall. These zones should be removed to eliminate the stagnant ones and 3) Varying the dose of the source in time doesn't affect the diffusion-convection behaviour of radon but eliminates the recirculation zones