Design assessment of grain inverters in cross-flow grain dryer via CFD-DEM numerical simulation

Grain inverters are frequently installed in industrial-scale cross-flow grain dryers to provide consistent drying. Wide residence time distributions can result from an unfavourable grain inverter designs in cross-flow grain dryers, leading to uneven drying. In this study, a fluid particles interaction discrete-element method (DEM) coupled with a computational fluid dynamics (CFD) code were used to simulate three different grain inverter designs to examine the impact of design changes on grain drying uniformity. Grain flow, grain temperature, moisture content, and residence time were taken as assessment parameters for three designs of grain inverter. The CFD-DEM model was verified by comparing the predicted moisture reduction curve with the published data from the literature using a geometric design comparable to that published study. Within the grain inverter designs examined, an inverter with a zigzag pattern demonstrated the highest reduction in grain moisture content with the longest residence time, followed by the multiwedge and V-shaped design inverters. The results showed that the CFD-DEM model developed is capable of predicting grain drying and grain volume reduction in a continuous grain dryer. These results are helpful in the design and optimisation of grain inverters to minimise drying non-uniformity.