Numerical simulation on the effect of thermal radiation in the atmosphere mixing inside the CIGMA containment vessel

Hamdani, A.  

During a postulated accident, the containment thermal-hydraulics phenomena will necessarily include radiation heat transfer since it has a significant role in the buoyancy-driven flow for large facilities. In this study, a numerical computational fluid dynamic (CFD) simulation was carried out with a radiation model and different parameters on the component of three gases, i.e., helium, air, and steam. The numerical simulation was performed using open source CFD code OpenFOAM. A fvDOM radiation model was implemented in the present simulation. At first, to achieve a significant temperature difference, very low humidity must be initiated in the initial condition. In this case, the steam content was set to 0.1 percent, and helium stratification was initiated with a molar fraction of 5 percent. The initial temperature and pressure were set to 30C and 1 atm. A transient simulation was started by injecting pure helium through a nozzle from the top vessel with a mass flow rate 5.6 g/s. The numerical results with the radiation model showed reasonable agreement with the experiment data. The preliminary results indicate that thermal radiation should be considered even though the steam content inside the containment vessel is low.