AN IMPLICIT 2ND-ORDER NUMERICAL-METHOD FOR 3-DIMENSIONAL 2-PHASE FLOWCALCULATIONS

A new numerical method for three-dimensional two-phase flow computatio ns is presented. The method has been implemented within the FLICA-4 co mputer code, which is devoted to three-dimensional thermal-hydraulic a nalysis of nuclear reactor cores. This numerical method is based on a finite volume technique, where convective fluxes at cell interfaces ar e calculated with art approximate Riemann solver A strategy for constr ucting this linearized Riemann solver which extends Roe's scheme, to s olve two-phase flow equations is described. Extension to a second-orde r-accurate method is achieved using a piecewise linear approximation o f the solution and a slope limiter method. For advancing in time, a fu lly implicit integrating step is used Some improvements performed to o btain a linearized implicit solution method that provides fast-running steady-state calculations are also presented. This kind of numerical method, which is widely used for fluid dynamic calculations, is proved to be very efficient for the numerical solution to two-phase flow pro blems.