Design parameter to develop secondary flow in twin screw extruder

Abstract

Possibility of generating strong secondary flow in mixing region of twin screw extruder was analyzed numerical FEM simulation using the commercial CFD package Polyflow. Adaptive remeshing - mesh superposition technique was used to generate high density polyethylene velocity profiles in simulation. Clearance between barrel wall and mixing element was increased gradually and observed the changes in flow pattern. Mixing element tip radius was varied by ratio to generate convergence flow in the clearance region and visualize the strength of secondary flow profile. Strong secondary flow at the clearance channel can generates elongation flow and improves the dispersive mixing; helps to decrease the screw length by minimizing kneading disc number in mixing section.