Three-dimensional numerical simulation of liquid in transition segment of the co-rotating twin-screw extruder

To solve the problems of inhomogeneous extrusion velocity and cracking in sections of product in a certain factory, the three-dimensional isothermal flow in transition segment of the co-rotating twin-screw extruder was simulated by using the finite element package POLYFLOW. The distributions of the viscosity and shear stress of material were discussed with the pressures in exit and entrance and rotational speed of screw changed. Effects of the technological parameters on the performance of liquid in transition segment were emphasized. The simulated results show that with the increase of pressure difference in exit and entrance and rotational speed of screw changed, the shear stress increases and the gradient of shear stress of materials in exit decreases, so the ability of dispersive mixture is enhanced and uniformization of materials in transition segment is promoted. With the increasing of the rotational speed of screw, residence time of the polymer melts in transition segment is shortened, which affects the plasticization quality of the polymer melts.