Nonequilibrium thermal dynamic modeling of porous medium vacuum drying process

Abstract

Porous medium vacuum drying is a complicated heat and mass transfer process. Based on the theory of heat and mass transfer, a coupled model for the porous medium vacuum drying process is constructed. The model is implemented and solved using COMSOL software. The water evaporation rate is determined using a nonequilibrium method with the rate constant parameter K r. K r values of 1, 10, 1000, and 10000 are simulated. The effects of vapor pressures of 1000, 5000, and 9000Pa; initial moistures of 0.6, 0.5, and 0.4 water saturation; heat temperatures of 323, 333, and 343K; and intrinsic permeability of 10 -13, 10 -14, and 10 -15 m 2 are studied. The results facilitate a better understanding of the porous medium vacuum drying process. © 2012 Zhijun Zhang and Ninghua Kong.