Two-dimensional simulation model of steady-state mixed-flow grain drying. Part 1: The model

A model of mixed-flow grain drying is presented in which the two-dimensional nature of the air and grain flow around the inlet and outlet air ducts has been modelled using blocks of concurrent, counter and crossflow beds. The inclusion of cross-flow beds makes the model superior, theoretically, to the models using only parallel-how beds because the more intense heating and drying near the ducts is represented in the cross-flow elements. The model allows the grain that flows near heated air ducts to be modelled separately from that which flows near exhaust ducts, so that the differential in heating, drying and consequent loss in grain viability is calculated. Previously verified simulation models for the heat and mass transfer in each type of bed, and for grain viability loss, were used. Moisture contents and temperatures of grain and air predicted by the model were consistent with observations. Verification of the model is presented in the Part 2 paper. (C) 1998 Silsoe Research Institute.