Applications of the COMMIX code using the porous medium formulation

Abstract A new computational method, the COMMIX Computer Code, has been developed. COMMIX-1 is a three-dimensional, transient, single-phase, component computer code for thermal-hydraulic analysis of both continuum (reactor plenum, ----) and quasi-continuum (rod-bundle, ----) applications. COMMIX-1A is an advanced version of COMMIX-1. The porous medium formulation with volume porosity, surface permeability, distributed resistance and distributed heat source is employed in the COMMIX computer codes. The concept of surface permeability is a new feature added in the present porous medium formulation. It greatly facilitates the modeling of the anisotropic characteristics of a medium containing solid objects such as fuel rods in a reactor fuel assembly. Some pertinent results from the single-phase version of the COMMIX Code are presented. These results demonstrate the capability of the code, as well as its wide range of applicability.