A FULLY NONLINEAR ANALYSIS OF TEMPERATURE, MOISTURE CONTENT, AND PRESSURE IN A CAPILLARY POROUS BODY

Abstract

This article demonstrates, for the first time, a fully nonlinear finite-element solution to Luikov's three-degree-of-freedom system of partial differential equations, which predict the variation of temperature, moisture, and pressure within a capillary porous body. Previously, only an analytical solution in one dimension was feasible but as physical geometries and boundary conditions of engineering problems became more complex, an analytical solution became impractical. Here, we resort to a numerical technique, namely, the finite-element method, to solve Luikov's equations in two dimensions. To solve Luikov's equations numerically, a fully nonlinear model was developed, where all material properties are permitted to vary as the transient solution progresses; previously, only a solution using a partially nonlinear model was possible. The numerical solutions obtained from both numerical models are compared for a two-dimensional container example.