多孔介质传热传湿过程多层不连续问题的数值分析

Numerical Analysis of Multilayered Discontinuity Problem for Heat and Moisture Transfer in Porous Media

提出了一种基于有限体积法预测非线性边界条件下多层多孔介质内的传热传湿过程的数值分析方法。求解过程中考虑了瞬态边界条件 ,从而避免了通常处理中边界条件设定为常数而给计算带来的误差 ,对于多层多孔介质每一层物性参数的非连续性 ,采用了有效的有限差分逼近处理。利用该方法对典型的三层墙体层与层界面处相对湿度的瞬态值进行了预测 ,计算结果与 Liesen R J等的传递函数求解方法符合很好。

A numerical approach based on finite volume method is proposed to study the procedure of coupled heat and moisture transfer in multilayered porous media under nonlinear boundary conditions. Transient boundary conditions are assumed for both heat and moisture transfers on external surfaces. The error caused by assuming the constant boundary conditions is eliminated by the approach. An efficient finite-difference approximation scheme is used to deal with discontinuity of material properties of the multilayer porous media. Calculations for typical three layers wall are conducted to obtain the transient values of the relative humidity on the interfaces of layer to layer using the method. Results agree well with that obtained by the transfer function method.