Numerical Investigation of Screw Assemblies Performance in Intermeshing Co-rotating Twin-Screw Extruders(I) Instantaneous Flow Analysis

Three-dimensional isothermal flows of polymer melt in the screw assemblies of a modular intermeshing co-rotating twin-screw extruder ZSK60 were simulated using the polymer flow analysis package POLYFLOW. Based on the velocity and pressure fields calculated, general distribution characteristics of the flow field in screw assemblies (composed of kneading blocks with different disc-widths and stagger angles) were presented; pumping capacity and extrusion stability of the screw assemblies were discussed; and instantaneous mixing capabilities were characterized in terms of average shear rate, average characteristic shear stress and average elongational flow index respectively. The conclusions could offer some methodological guidance for numerical studies of flow in twin-screw extruders, and could also be used as theoretical guidelines for engineering practices in twin-screw extrusion.