Simulation for Mixing Process in the Solid Conveying Zone of a Twin-screw Extruder

Abstract

Mixing process of polymer pellets in solid conveying zone of a twin-screw extruder (TSE) is numerically investigated by using the discrete element method. It was clarified that the mixing of pellets was mainly performed in the intermeshing part of the TSE from the results of two-dimensional simulations. Moreover, a course of simulation with different conditions was performed to obtain information for improving the mixing performance. The effects of barrel property, tip-clearance, and screw-rotational speed were studied. The results suggested that the shear deformation on particle clusters at the tip-clearance is the most important factor in promoting mixing at the intermeshing part of the TSE. A preliminary result of a three-dimensional simulation with an actual geometry of conveying screws is also shown.