A coupled phasic exchange algorithm for three-dimensional multi-field analysis of heated flows with mass transfer

A three-dimensional multi-field coupled phasic exchange (CPE) algorithm, for the prediction of general two-phase flows is presented. The algorithm is applicable to an arbitrary number of fields, a four-field construct is adopted here. Ensemble averaged transport equations for mass, momentum, energy and turbulence transport are solved for each field (continuous liquid, continuous vapor, disperse liquid, disperse vapor). This four field structure allows for analysis of adiabatic and boiling systems which contain flow regimes from bubbly through annular. Interfacial mass, momentum, turbulence and heat transfer models provide coupling between fields. The CPE algorithm is a semi-coupled implicit method to solve the set of 25 equations which arise in the formulation. In this paper, the CPE algorithm is summarized, with emphasis on six component numerical strategies employed in the method. These are: (1) incorporation of interfacial momentum force terms in the control volume face flux reconstruction, (2) coupled solution of the discrete linearized system of four constituent field equations for each transport scalar, (3) a consistent pressure-velocity correction scheme which properly accounts for drag and mass transfer, (4) an additive correction strategy for efficient solution of the mixture continuity and coupled field continuity equations, (5) an implicit source term treatment for volume fraction equations which ensures realizability of volume fraction fields during the course of iteration, (6) coupling of the phasic continuity and compatibility equations within the framework of a pressure-volume fraction-velocity correction scheme. The necessity/effectiveness of these strategies is demonstrated in applications to several test cases. The effectiveness and accuracy of the overall method is demonstrated using results of a three-dimensional analysis of boiling SUVA flow in a vertical coolant passage element.