METHOD FOR DETERMINATION OF SURFACE COEFFICIENTS OF HEAT-MASS EXCHANGE IN WETTED POROUS MATERIALS UNDER CONDITIONS OF MEDIUM VACUUM

摘要

A method for the determination of surface coefficients of heat-mass exchange in wetted porous materials under conditions of medium vacuum includes measurement of temperature of the test sample surface and difference of pressures of air-vapor gas mixture at the ends of vacuum conduit calibrated with capillary. According to theoretically determined expression for flow of water vapor through capillary on basis of data of experimental measurements dynamics of change of molar part of water vapor in vacuum chamber is reproduced, and the surface coefficients of heat-mass exchange are calculated according to known laws of conservation of heat and mass with account of the sources of evaporation in surface layer of wetted porous sample.