Numerical investigation on the temperature effect on the transport of soil solute

Abstract

In the present paper, a mathematical model called the TE-Model has been built to describe the simultaneous transport of heat, water, gas, and solute in soil, in which the temperature effects on the transports of soil water and soil solute were taken in account. When the temperature effect was neglected, we call it the NTE-Model. Taking NaCl as an example, numerical calculations under constant environmental factors have been carried out to investigate the temperature effect on the transport of soil solute, which showed that the concentrations of NaCl in deep soil layers rose rapidly at the initial stage and then the upward movements slowed down. However, there was a large hysteresis in the concentration variation of soil solute in the shallow layers. After the initial stage, the concentration of NaCl rose almost linearly with time. Furthermore, the concentrations calculated through the TE-Model was larger than those calculated through the NTE-Model. At the conclusion of the 5-year calculating process, relative deviations in soil solute concentration at 10 different depths have been found to reach 61.5%, 59.6%, 54.7%, 49.2%, 44.5%, 40.9%, 37.5%, 34.1%, 29.8%, and 23.0%, respectively.

Validated Leverett Approach for Multiphase Flow in PEFC Diffusion Media

“…15,16 Such a variation in temperature influences the governing transport properties, including permeability, the capillary pressure-saturation relation, fluid viscosity, and the surface energy of the medium, thereby directly affecting the capillary transport characteristics in fuel cell or other porous media. [17][18][19][20][21] Moreover, existing efforts in soil science [22][23][24][25][26][27][28] have revealed that the variation in equilibrium temperature is the dominating factor determining the equilibrium capillary pressure. Thus, understanding the effects of operating temperature on the capillary transport characteristics of a fuel cell DM along with knowledge of the effects of wettability characteristics and compression is of paramount importance for achieving an effective water balance and thermal management strategy in PEFCs.…”