A three-dimensional control volume approach to modeling heat and mass transfer in foods materials

A control volume formulation and solution of a set of one way coupled heat and diffusive moisture transfer equations to improve grain-drying simulation of three-dimensional food material is presented. The model assumes that the moisture diffuses to the outer boundaries of the food material in liquid form and that evaporation takes place only at the surface of the food material. The solution procedure developed uses a fully implicit time stepping scheme. Application was made to the drying of barley, soybean, and starch. The model was solved in three-dimensional Cartesian coordinates and was extended to other geometries using an equivalent surface-to-volume ratio index. Among the products tested, the maximum deviation between experimental and simulation results was 3°C in temperature for barley drying and 5% moisture (d.b.) for soybean drying. The overall predictions agreed well with the available experimental data and show a good potential for application in grain and food drying.