Transport phenomenain porous media are encounteredin various
disciplines, e. g., civil engineering, chemical engineering, reservoir
engineering, agricul- tural engineering and soil science. In these
disciplines, problems are en- countered in which various extensive
quantities, e. g., mass and heat, are transported through a porous
material domain. Often, the void space of the porous material contains
two or three fluid phases, and the various ex- tensive quantities are
transported simultaneously through the multiphase system. In all these
disciplines, decisions related to a system's development and its
operation have to be made. To do so a tool is needed that will pro- vide
a forecast of the system's response to the implementation of proposed
decisions. This response is expressed in the form of spatial and
temporal distributions of the state variables that describe the system's
behavior. Ex- amples of such state variables are pressure, stress,
strain, density, velocity, solute concentration, temperature, etc., for
each phase in the system, The tool that enables the required predictions
is the model. A model may be defined as a simplified version of the real
porous medium system and the transport phenomena that occur in it.
Because the model is a sim- plified version of the real system, no
unique model exists for a given porous medium system. Different sets of
simplifying assumptions, each suitable for a particular task, will
result in different models.
