Fractional step methods for thermohydraulic calculation

Abstract A method of fractional steps is used to extend a semi-implicit finite-difference technique for multidimensional two-phase flow calculations. This extension permits time step size to be chosen independent of convection velocities in one space direction, and still resolves multidimensional coupled sonic and phase exchange effects implicitly by forming a simple Poisson problem for pressure. Because pure time-splitting by physical phenomena was found unsuited to thermal hydraulics problems, a stabilizing corrections method was chosen. An application in nuclear reactor safety analysis is demonstrated.