SOME ASPECTS OF HEAT AND MASS TRANSFER IN POROUS MEDIA.

THE TRANSPORT OF HEAT AND SOLUTES BY A FLUID MOVING THROUGH A POROUS MATRIX IS A PHENOMENON OF GREAT INTEREST FROM BOTH APPLICATION AND THEORY POINTS OF VIEW.MASS TRANSFER IN ISOTHERMIC CONDITIONS HAS BEEN STUDIED UNDER THE GENERIC NAME OF 'HYDRODYNAMIC DISPERSION, WITH APPLICATIONS TO PROBLEMS OF MIXING OF FRESH AND SALT WATERS IN AQUIFERS, MISCIBLE DISPLACEMENTS IN OIL RESERVOIRS, SPREADING OF SOLUTES IN FLUIDIZED BEDS AND CRYSTAL WASHERS, SALT LEACHING IN SOILS, ETC.HEAT TRANSFER, IN THE CASE OF A HOMOGENEOUS FLUID, HAS BEEN STUDIED LESS SYSTEMATICALLY, BUT RATHER EXTENSIVELY, WITH RELATION TO DIFFERENT APPLICATIONS, LIKE: DYNAMICS OF HOT UNDERGROUND SPRINGS, TERRESTRIAL HEAT FLOW THROUGH AQUIFER, HOT FLUID AND IGNITION FRONT DISPLACEMENTS IN RESERVOIR ENGINEERING, HEAT EXCHANGE (WITH EVAPORATION AND CONDENSATION) BETWEEN SURFACE SOIL AND ATMOSPHERE, FLOW OF MOISTURE THROUGH POROUS INDUSTRIAL MATERIALS, HEAT EXCHANGES WITH FLUIDIZED BEDS ETC.AT THE HYDRAULICS LABORATORY OF THE TECHNION, THE AUTHOR HAS STUDIED A PROBLEM IN WHICH THE TWO TRANSPORT PHENOMENA ARE COMBINED, NAMELY THE CASE OF THE HOT AND SALTY SPRINGS OF THE SEA OF GALILEE.THE PURPOSE OF THIS PAPER IS TO PRESENT A SYSTEMATICAL DERIVATION OF THE EQUATIONS OF FLOW IN POROUS MEDIA WITH HEAT AND MASS TRANSFER AND OF THE DIFFERENT TYPES OF APPROXIMATIONS USED IN APPLICATIONS.PHYSICAL INTERPRETATION AND ESTIMATES OF ORDER OF MAGNITUDE, RATHER THAN INTRICATE MATHEMATICAL DERIVATIONS, ARE EMPHASIZED.THE CONSIDERATIONS ARE LIMITED TO THE CASES OF AN IMMOBILE AND INERT SOLID MATRIX AND A SLIGHTLY COMPRESSIBLE LIQUID UNDERGOING A SLIGHT DENSITY VARIATION, I.E.HAVING A LOW SOLUTE CONCENTRATION AND A MODERATE TEMPERATURE DROP.THE FLOW IS ASSUMED TO BE IN THE DARCIAN REGIME.THE SCHMIDT NUMBER (VISCOSITY OVER DIFFUSION COEFFICIENTS) IS OF ORDER 10/SUP 3/.(FROM PAPER.).