A Fluid Film CFD Model for Steam Condensation in Presence of Air

In a nuclear containment, the mixture of steam and air leads to a significant reduction in wall condensation during Loss of Coolant Accident (LOCA). Detailed studies need to be carried out as the film condensation on the wall is closely rated to the safety of containment. In the present work, a three-dimensional Fluid Film steam condensation calculation method is applied and discussed. The current using steam diffusive based Fluid Film condensation model is introduced particularly and the differences from other condensation models are explained. The validation of Fluid Film model is made by comparing condensation heat transfer coefficient with empirical correlations derived by Uchida et al. (1965). Also, three-dimensional simulations of Su experiments (Su et al. 2013) on steam condensation in presence of air are performed with commercial computational fluid dynamics software which has built in Fluid Film Model. Calculated results of steam temperature and heat transfer coefficient are compared to experimental results (Su, Sun & Zhang 2014) and discussed. The comparison shows that the calculated heat transfer coefficient curve fits well with Uchida empirical correlation and the correlation derived from Su experiment. The deviation from Uchida correlation is within 20% and a maximum deviation of 15% from Su experiment. Detailed field profiles are drawn from three dimensional simulation cases and discussed. It is concluded that the condensation of steam-air mixture gases could be successfully calculated using Fluid Film Model.