Modeling for Starve Fed/Flood Fed Mixing Single-Screw Extruders

Abstract

A composite computer model has been proposed for starve fed/flood fed mixing single screw extruders. The model for starve fed extrusion has been developed by combining a new FEM based melt conveying model with recently developed melting models. Mixing screw equipped with distributive toothed disc mixing element has been considered as an example for modeling. An extensive fully three-dimensional non-Newtonian FEM computations have been carried-out to simulate the melt flow in mixing elements. Screw pumping characteristics have been developed for the elements at various power law indices, and these have been implemented into the composite model of the process. Simulations have been performed for low density polyethylene (LDPE) at various operating conditions, both for starve fed and flood fed extrusion. Fill factor, pressure, temperature and melting profiles have been computed and verified experimentally.