Simultaneous Heat and Mass Transfer Accompanied by Phase Change in Porous Insulation

Abstract

This paper analyzes the accumulation and migration of moisture in an insulation material. The problem is modeled as a two-dimensional, transient, multiphase flow in a porous slab. The local volume-averaging technique is used to arrive at a rigorous and fundamental formulation of the heat and mass transfer process in an insulation system. The controlling parameters and assumptions are presented in detail. The equations are solved by devising a two-phase numerical scheme to obtain the condensation regions and the factors which affect the temperature distribution. The phase change process and its effects on the temperature, vapor density, moisture content, liquid content, and the vapor pressure distributions are discussed in detail. The significant transport mechanisms are identified and a simplified formulation of heat and mass transfer, accompanied by phase change, in an insulation system is presented.