A MODEL OF WATER, VAPOR AND HEAT FLOW IN POROUS MEDIA  

作　　者：Yang Jin-zhong CaI Shu-ying (Wuhan University of Hydraulic and Electric Engineering,Wuhan 430072, P. R. China) 

出　　处：《Journal of Hydrodynamics》1995年第1期1-16,共16页水动力学研究与进展B辑（英文版）

摘　　要：A numerical model physically based on a formulation of water, vapor, and heat transport in saturated- unsaturated soils coupled with a lower atmosphere boundary layer modelling is presented. The inputs required for the computer simulation are weather data, soil thermal and hydraulic properties. The coupled numerical model is tested separately with the experimental result and analytical solution because of the scarcity of suitable analytical solution for the coupled problem. The agreements of the numerical model with the experimental data and the analytiCal solution are excellent. Numerical experiments are performed to analyse the effects of weather conditions, soil water conductivity K, thermal vapor diffusivity DTV, and isothermal vapor conductivity DHV on the evaporation rate from the soil surface. When the soil is wet, the evaporation rate is more sensitive to the input atmospheric conditions. This is the situation for high ground water table and just after rainfall. The accuracy of the measurement of air humidity has stronger effect on evaporation rate than the roughness length. When the soil is dry enough,the soil water conductivity dominates evaporation rate. Neglecting thermal vapor diffusivity and isothermal vapor conductivity introduces an error less than 2. 5% in evaporation rate.A numerical model physically based on a formulation of water, vapor, and heat transport in saturated- unsaturated soils coupled with a lower atmosphere boundary layer modelling is presented. The inputs required for the computer simulation are weather data, soil thermal and hydraulic properties. The coupled numerical model is tested separately with the experimental result and analytical solution because of the scarcity of suitable analytical solution for the coupled problem. The agreements of the numerical model with the experimental data and the analytiCal solution are excellent. Numerical experiments are performed to analyse the effects of weather conditions, soil water conductivity K, thermal vapor diffusivity DTV, and isothermal vapor conductivity DHV on the evaporation rate from the soil surface. When the soil is wet, the evaporation rate is more sensitive to the input atmospheric conditions. This is the situation for high ground water table and just after rainfall. The accuracy of the measurement of air humidity has stronger effect on evaporation rate than the roughness length. When the soil is dry enough,the soil water conductivity dominates evaporation rate. Neglecting thermal vapor diffusivity and isothermal vapor conductivity introduces an error less than 2. 5% in evaporation rate.

关 键 词：coupled model thermodynamic equilibrium saturated-unsaturated soil. 

分 类 号：O357.3[理学—流体力学]