A HOMOGENEOUS NON-EQUILIBRIUM TWO-PHASE CRITICAL FLOW MODEL FOR THE ANALYSIS OF SUPERSONIC JET FLOW
During most of a postulated break transient in light water reactors (LWRs') the flow through the break is choked and a jet is formed. In this work a theoretical two-phase critical flow model has been developed. This model is used for providing consistent boundary conditions for a free supersonic two-phase jet model, which employs methods similar to those used in single phase gas jets. The flow is assumed to be quasi-steady, homogeneous, isentropic and one-dimensional. For subcooled liquid stagnation conditions the thermal non-equilibrium phenomena are taken into consideration via a new dimensionless non-equilibrium coefficient, DD which is determined from the conditions that at the choking plane the flow is sonic, M = ; 1. For these values of DD the mass flux at the exit plane is maximized with respect to the exit pressure. The corresponding non-equilibrium coefficient satisfying these two conditions, DD0, is correlated as a function of the stagnation conditions. The model has been validated against the experimental results measured at the Marviken facility.