A Numerical Implementation of the Soret Effect in Drying Processes

摘要

Drying of porous media is strictly governed by heat and mass transfer. However, contraryto the definition that drying is simultaneous transport mechanisms of heat and mass, most past andcurrent models either account for temperature or concentration gradient effects on drying. Eventhough the complexity of computations of these processes varies with area of application, in mostcases, the Dufour and Soret effects are neglected. This leads to deviations and uncertainties on theassumptions and interpretations of these and other relevant effects on drying. This paper coversthe theoretical methods to derive the coupled transfer effects. In addition, this work proposes andformulates relevant heat and mass transfer equations, as well as the governing equations for dryingprocesses with Dufour and Soret effects. The application of a numerical approach to solve theequations allows for studying of the influence of these effects on the design and operation of dryers.It is shown that the Soret effect can be highly relevant on drying operations with dynamic heatingoperation. While for drying processes where the steady state drying process predominates, the effectis deemed negligible.