(743e) Scale up of Heat Transfer for Dry Granular Material in a Bladed Mixer
AIChE Annual Meeting
Thursday, November 14, 2019 - 4:33pm to 4:54pm
In this work, we decouple the problem and focus on studying the heat transfer aspect of agitated drying using dry glass beads. More specifically, we investigate the influence of bed fill height and geometric scaling on heat transfer by studying both the average and standard deviation of the bed temperature. Our approach consists of employing a combination of experiments and discrete element method (DEM) modeling techniques to analyze how heat transfer scales with material fill level and equipment sizing. We carry out a design of experiments and compute heating times as well as heat transfer coefficients for the different conditions. We find that fill height and geometric scaling influence the flow and compressibility of the bed and therefore creates a balance between conduction and granular convection as the dominant mode of heat transfer. We leverage the discrete nature of DEM modeling to evaluate features such as the coordination number and normal overlap between particles. We find that the relationship between fill height, geometric scaling, and heating time is complex and depends on the geometry area available for heat transfer and the particle contacts. Finally, we relate simulation findings to experimental results for validation. This work provides better fundamental insights into how heat transfer scales in a bladed mixer and could greatly aid in the development of drying protocols.