Vapour Condensation in Presence of Air in the TOSQAN Facility: A Computational Analysis

The present work is focused on the transient computational analysis of a test performed in the French facility TOSQAN. The aim of the study is to contribute to the understanding of the heat and mass transfer mechanisms involved in the problem and to check the possibility of employing a multipurpose commercial CFD code to predict a containment transient and the mass transfer phenomena of interest in the nuclear field. In particular, the effect of the condensation rate at walls through the liquid-gas interface was simulated by appropriate source terms, introduced directly into the mass, species and energy balance equations, evaluated on the basis of the vapour concentration gradient near the vessel walls. To make feasible the numerical solution of the problem by the FLUENT code, the assumption of an extremely thin water film was utilized. In the present paper the calculated time-dependent average temperature and pressure of the atmosphere inside the TOSQAN vessel are compared, together with the steady state temperature profiles, with the available experimental data