A review of low temperature drying simulation models

Abstract Literature reporting research into the simulation of low temperature grain drying (air temperature of ambient to ambient plus 5°C) is reviewed with particular regard to their implementation for Operational Research studies. The suitability of each model for use in an overall model of harvesting and drying is examined. The amount of computer time required, robustness for use under a range of management strategies and weather conditions, accuracy and degree of experimental validation are the principal factors considered. Attention is also paid to the data and physical relationships required for simulation. Consideration is given to complex models which describe drying using a set of partial differential equations. These models were principally constructed for studying the physics of drying and modelling high temperature drying (+60°C), but have also been applied to low temperature drying. Equilibrium models which have been developed from partial differential equation models specifically for modelling low temperature drying are examined. Simple empirical logarithmic models are also considered. The applications of simulation models to the study of the management of filling, fan control and the use of supplemental heat and stirring devices are reviewed. Simulation studies have indicated that good management is required to achieve energy efficiencies which are better than those achieved by modern high temperature driers.

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