The homogeneous and Lagrangian tracking approaches of the spray simulation in the containment

The spray system is an emergency containment cooling strategy to depressurize and remove heat in the steam or hydrogen generation scenarios. Different kinds of phenomena including gas-droplets mixing, water vaporization, and steam condensation, are coupled into the complicated flow. The thermal-hydraulic simulation code GASFLOW is widely used and verified in series of containment experiments. Also, a homogeneous spray model which treats the droplets as one species in the gas mixture is incorporated in this code. This paper developed the Lagrangian tracking way for the spray simulation which viewed the droplets as dispersed phase. And in this approach, the interactions for gas-droplets and wall-droplets were considered in all aspects of mass, momentum and energy. The priorities of Lagrangian tracking way over homogeneous way were showed by the TOSQAN 101 and 113 spray benchmarks tests. Detailed comparisons between the two models were concentrated on the condensation-evaporation procedure and gas mixing. All these revealed that the Lagrangian way could predict the phase transition and momentum exchange correctly.