In this paper, transient coupled heat and moisture transfer in the cylinders and cylindrical panels of the porous medium are analyzed with three-dimensional finite element methods. Both Dofour and Soret effects are considered in the formulation, and the FEM-based weak forms of the equations are derived using Galerkin method. In the full cylinder cases, both symmetrical and unsymmetrical boundary conditions for heat and moisture are applied to cover three-dimensional and axisymmetric (two dimensional) analysis cases. The obtained systems of time-dependent differential equations are solved by Runge–Kutta method. The main objective of the present study is the analysis of fully coupled diffusion of heat and moisture in cylindrical coordinates using three-dimensional finite element methods. Also, this study addressed the ability of Runge–Kutta method to solve the coupled sets of differential equations. The results were compared with some analytical solutions in the literature, and a very good agreement was observed. The present formulation can be used for transient analysis of any cylindrical geometry with arbitrary geometrical dimensions and under desired boundary conditions.

在本文中，利用三维有限元方法分析了多孔介质圆柱体和圆柱板中的瞬态耦合传热和水分传递。在公式中考虑了Dofour和Soret效应，并且使用Galerkin方法推导了基于FEM的方程的弱形式。在全圆柱情况下，热和水分的对称和不对称边界条件都适用于覆盖三维和轴对称（二维）分析案例。用Runge-Kutta方法求解所获得的时变微分方程组。本研究的主要目的是使用三维有限元方法分析圆柱坐标中的热量和水分的完全耦合扩散。还，这项研究解决了Runge–Kutta方法求解耦合微分方程组的能力。将结果与文献中的某些分析解决方案进行了比较，并观察到了很好的一致性。本配方可用于在期望的边界条件下对具有任意几何尺寸的任何圆柱几何形状进行瞬态分析。