TY - JOUR
AU1 - Raats, P. A. C.
AB - Balances of mass for the water in n distinct phases and a balance of heat for the medium as a whole are formulated. Following Philip and de Vries, it is assumed that the flux of water in each phase is proportional to the gradient of the pressure in that phase and that the diffusive component of the flux of heat is proportional to the gradient of the temperature. Clapeyron equations are used to express the gradient of the pressure in any phase in terms of the gradient of the pressure in a reference state and of the temperature. The reference state may be the water in one of the phases or the water in some measuring device such as a tensiometer or a psychrometer. Expressions for the total flux of water and for the diffusive flux of heat plus the convective flux of heat associated with the conversion from any phase to the reference state are shown to satisfy the Onsager reciprocal relations. A theorem due to Meixner is used to delineate the class of fluxes and forces that preserves these relations. In particular, it is shown that if the gradients of water content and temperature are used as the driving forces, the Onsager relations are no longer satisfied.
TI - Transformations of fluxes and forces describing the simultaneous transport of water and heat in unsaturated porous media
JF - Water Resources Research
DO - 10.1029/WR011i006p00938
DA - 1975-12-01
UR - https://www.deepdyve.com/lp/wiley/transformations-of-fluxes-and-forces-describing-the-simultaneous-c3dHA53Cl3
SP - 938
EP - 942
VL - 11
IS - 6
DP - DeepDyve
ER -