Numerical simulation of conjugate heat and mass transfer process within cylindrical porous media with cylindrical dielectric cores in microwave freeze-drying

This paper presents a numerical model for the process of microwave freeze-drying within a cylindrical porous media with cylindrical dielectric cores. The set of transient governing equations developed are solved numerically with variable time-step finite volume method. Analysis of numerical results may lead to following main conclusions for the new freeze-drying process: (1) Proper usage of cylindrical dielectric cores could dramatically reduce the drying time. (2) The loss factor ε″ of the cylindrical dielectric core is an important parameter influencing the drying behavior. (3) Two sublimation fronts do exist within the porous media due to the existence of inner dielectric cores. (4) The impact of cylindrical dielectric cores on drying could not be ignored even though the initial saturation is low (S0 = 0.2).