A method of control of transfer processes

The effective medium theory for the coupled phenomena of heat conduction an d mass diffusion of solute in heterogeneous media has been derived. The the ory has been applied to a barrier with adaptive conductive and diffusive ch aracteristics to be used for control of heat flow and mass flow of species. The barrier consists of a mixture of small solid particles of ellipsoidal shape which are randomly distributed in a carrier fluid. Volume fraction of the particles is small and Variation in conductive-diffusive properties of the barrier is achieved by changing orientation of the particles. This ana lysis gives an estimate to what a degree the solute flow can be controlled by both bulk concentration and temperature gradient applied to the walls of the barrier. Influence of different parameters like ratios of conductive a nd diffusive properties of particles and the carrier fluid, solubility rati o of the diffusing species in the fluid and in the particle, class of parti cle shapes, particle aspect ratio and volume fraction as well as thickness of the barrier on the species mass how have been studied in detail. (C) 200 0 Elsevier Science Ltd. All rights reserved.