非饱和土孔隙气、水、汽、热耦合运动之模拟(英文)

旨在介绍一个描述非饱和土孔隙气、水、汽、热耦合运动的理论模型。该模型假定孔隙气和孔隙水运动分别遵循达西定律 ,而影响水蒸汽运动的两种主要因素分别是分子扩散和孔隙气运动 ,其中受分子扩散影响的孔隙水蒸汽运动可用Fick定律描述。热转移则主要包括了三种形式 ,即传导、对流和汽化潜热。根据有限单元法 ,编制了一个三维的计算机程序用以模拟非饱和土孔隙气、水、汽、热的耦合运动。通过数值分析与干沙试验结果之比较 ,验证了文中之理论模型和计算机程序的可靠性

Modelling fully coupled moisture, air and heat transfer in unsaturated soils

A theoretical model has been proposed to describe fully coupled moisture, air and heat transfer in unsaturated soils. Pore liquid water and pore air transfer were assumed to be governed by Darcy's law and pore water vapour transfer was considered to occur due to two effects, first, under molecular diffusion and, second, as part of the bulk flow of the pore air. The pore water vapour transfer due to the molecular diffusion was described using Fick's law. Heat transfer was formulated to include effects of conduction, convection and latent heat of vapourization. A three dimensional computer program has been developed to incorporate the proposed model for analyzing the transient coupled flow of moisture, air and heat in unsaturated soils. Both the fundamental mathematical formulation and the computer code have been verified by comparing numerical results with test measurements of a drying sand column.