Multiphase flow modeling of molten material-vapor-liquid mixtures in thermal nonequilibrium

Abstract

This paper presents a numerical model of multi phase flow of the mixtures of molten materialliquid-vapor, particularly in thermal nonequilibrium. It is a two-dimensional, transient, threefluid model in Eulerian coordinates. The equations are solved numerically using the finite difference method that implicitly couples the rates of phase changes, momentum, and energy exchange to determine the pressure, density, and velocity fields. To examine the model's ability to predict an experimental data, calculations have been performed for tests of pouring hot particles and molten material into a water pool. The predictions show good agreement with the experimental data. It appears, however, that the interfacial heat transfer and breakup of molten material need improved models that can be applied to such high temperature, high pressure, multi phase flow conditions.

The impact of thermal non-equilibrium and large-scale 2D/3D effects on debris bed reflooding and coolability

“…However, this model does not take into account the phase change process. On the other hand, three-equation models have been proposed heuristically, for example, in Amarasooriya and Theofanous (1991), Berthoud and Valette (1994), Likhanskii et al (1997), Park et al (2000). As was emphasized by Quintard et al (1997), heuristic approaches lead to intuitive macroscopic models and this may lead to erroneous interpretations since these models are not derived from pore-scale transport equations through some scaling-up theory.…”