A FIXED-GRID NUMERICAL ALGORITHM FOR TWO-PHASE FLOW AND HEAT TRANSFER IN POROUS MEDIA

Abstract

This study aims at developing a general numerical formalism for efficient simulation of two-phase flow and heat transfer processes in porous media. These problems are characterized by the coexistence of a two-phase zone and single-phase regions with irregular and moving phase interfaces in between. Based on the two-phase mixture model previously developed by the present author and co-workers, a fixed-grid numerical formulation is presented in this article for general problems that may simultaneously include a superheated vapor region, a two-phase zone, and a subcooled liquid region in a single physical domain. The governing equations are solved numerically by two approaches, a pressure-based method and a primitive-variable method. Both methods yield equivalent performance, but the latter appears to offer more convenience and greater flexibility for a wide variety of problems. The present algorithm can be readily implemented into widely available single-phase computational fluid dynamics (CFD) codes. A sample simulation concerning two-phase boiling flow through a porous bed with heating from below is carried out to demonstrate the applicability and efficiency of the proposed formulation. Also, the numerical predictions are compared to available experimental observations with good agreement. The present algorithm provides a powerful, yet routine tool for the numerical modeling of complex two-phase transport processes in porous media.