Two-Phase Flow Simulation of Gas Entrainment Phenomena in Large-Scale Experimental Model of Sodium-Cooled Fast Reactor

The authors have been developed a high-precision and high-performance numerical simulation algorithm for gas-liquid two-phase flows to simulate the gas entrainment (GE) phenomena in a large-sized sodium-cooled fast reactor in Japan (JSFR). In the simulation algorithm, the piecewise linear interface reconstruction (PLIC) algorithm is employed for the interface-tracking and physics-basis simulation methods are introduced to enhance the numerical reproducibility of interfacial flows. As a result of validation tests, it was confirmed that the developed simulation algorithm could reproduce interfacial flows, including the GE phenomena in simple experiments. In this paper, the developed simulation algorithm is applied to the GE phenomena in a large-scale water experiment which models the complicated geometrical configurations of the structural components in JSFR. For the numerical simulation, an unstructured mesh with about one million cells are generated and optimized to simulate the interfacial deformations near the structural components which cause vortical flows behind them to induce the GE phenomena. As a result of the unsteady simulation, a typical interfacial dynamic behavior, i.e. the development of a gas core (interfacial dent), is well simulated. Therefore, it is confirmed that the developed simulation algorithm is suitable to evaluate numerically the GE phenomena in JSFR.