Heat and mass transfer in semi-porous channels with application to freeze-drying

Abstract An analytical investigation is made of the heat and momentum transfer of a binary mixture of gases flowing in a parallel plate channel where mass injection occurs at one wall. The walls are at different temperatures and applications to freeze-drying are presented. Integral continuity, momentum, and energy equations are used to establish the velocity, pressure, and temperature distributions. The flow is assumed to be steady, laminar, and incompressible. Closed form solutions are obtained for the velocity and temperature distributions. Applications of the solution to freeze-drying show that under typical conditions 5–40 per cent of the energy transfer to the product surface occurs by convection. Thermal radiation provides the mechanism for the rest of the heat transfer.