Unsteady Interfacial coupling of two-phase flow models

The primary coolant circuit in a nuclear power plant contains several distinct components (vessel, core, pipes, ...). To these components correspond one or several codes which have been developed to solve specifc systems of partial differential equations. In order to perform two-phase flow simulations over the whole primary circuit, the coupling of these codes has to be considered. The approach that has been examined within this work consists in coupling the codes by providing information through the coupling interface, taking unsteady effects into account. For that purpose, numerical fluxes calculated at the interface are used. as boundary conditions for each code. The numerical technique relies on the use of an interface model, which is combined with the basic strategy that was introduced by Greenberg and LeRoux in order to compute approximations of steady solutions of nonhomogeneous hyperbolic systems. Three different coupling cases have been examined: the coupling of a one-dimensional Eider system with a two-dimensional Euler system; the coupling of two distinct homogeneous two-phase flow models; the coupling of a four-equation homogeneous model with the standard six-equation two-fluid model.