A model for air flow control in a mixed-flow grain dryer

Mixed-flow dryers are continuous dryers for fluxionary bulk material as grain, granulates from renewable materials etc. These types of dryers are segmented in a number of air inlet and outlet sections which are regularly operated. Principally, the bulk material can not be ventilated homogeneously. Therefore, a non-homogeneous temperature and moisture distribution inside the bulk is developing during ventilation under normal operation. Partially over dried and under dried material is the result. A mathematical model has been developed based on Potential Theory of the Complex Analysis for the air flow distribution through the bulk material. With this model a control strategy can be developed and analyzed to control air inlet flow and air temperature to equalize the temperature distribution inside the dryer.