G. Wu et St. Chieng, MODELING MULTICOMPONENT REACTIVE CHEMICAL-TRANSPORT IN NONISOTHERMAL UNSATURATED SATURATED SOILS .1. MATHEMATICAL-MODEL DEVELOPMENT, Transactions of the ASAE, 38(3), 1995, pp. 817-826
A set of coupled equations has been developed to describe the simultan
eous transport of water, heat, and multicomponent reactive chemicals i
n saturated/unsaturated subsurface soils. The water movement equation
takes into account vapor transport in the unsaturated zone, as well as
the fluxes caused by the gradients of temperature and solute concentr
ations. The heat transfer equation includes the components of heat con
duction and latent heat transfer A phase conversion factor is used to
simplify the hear transfer equation, as introduced by Luikov (1966). T
he chemical transport equations are formulated in terms of the total a
nalytic concentrations of all aqueous components. These equations are
identical inform and can be solved one by one to save computer CPU sto
rage. Chemical reactions which can be dealt with in this model include
complexation, acid base reaction, ion exchange, and precipitation-dis
solution.