CFD Modelling of Corn Drying in a Triangular Spouted Bed Dryer

Abstract

Drying is one of the oldest food preservation methods. Mathematical models are increasingly used in drying studies. Starting as a tool to predict drying time, they evolved to become a replacement for a pilot plant study with the application of Computational Fluid Dynamics. But not many studies have been conducted on Spouted Bed Dryer. Furthermore, only handful of those studies modelled the drying and only one has validated the model. While the present study confirmed the merit of CFD modelling, it also discovered that it is unpractical to model a batch drying because of excessive computational time. A CFD model was built for a Triangular Spouted Bed Dryer with Eulerian-Eulerian approach. The model was only usable as a quantitative design guidance. It failed to simulate the onset of dead zone and bridging. Parameter studies on the CFD model showed that air inlet velocity has greater impact on the grain recirculation rate compared to the grain physical properties. The density, porosity and grain diameter affect the grain recirculation rate. A combination of CFD model to provide hydrodynamics parameter and a simple model to predict temperature and moisture content was proposed to simulate batch drying. The solution of Fick’s Law with surface moisture boundary condition was used as the interphase mass transfer model. The model predict the grain moisture content with average relative mean error less than 5% and predict the temperature with the relative mean error of less than 10%.