A barrel shape study for a twin-screw conveyor using the Discrete Element Method

Abstract

An effective barrel design is critical for successful material transport in a twin-screw conveyor. However, geometric parameter studies are often overlooked because of their increased complexity over studying scalar parameters due to the cost of manufacturing multiple bespoke components. In recent years, advances in computing power have made simulations an attractive and low-cost method of conducting geometric parameter studies. Here a Discrete Element Method (DEM) study compares the effectiveness of eight barrel geometries in a twin-screw conveyor. The results showed that the industry-accepted figure-of-eight cylinder design was the most effective for particle transport with the greater interaction between the screw and barrel reducing the material throughput time by over 40% compared to other designs. However, alternatives might become attractive if certain specifications were desirable. A design with rounded sides and a flat centre is worse at conveying by 22% compared to the figure-of-eight but there is 15% less net force acting on the particles and similar amounts of mixing. Finally, parameter testing shows that the results will at least be qualitatively consistent across a wide range of the parameter space and should therefore be valid for most materials.