Flow in a Modular Intermeshing Co-rotating Twin Screw Extruder

The flow of viscous power law fluids in the various modules of a modular intermeshing co-rotating twin screw extruder. This includes right-handed and left-handed screw elements and kneading disc assemblies with various staggering angles. The calculations are based on hydrodynamic lubrication theory used a new calculation method based on combining methods by Tadmor, Broyer and Gutfinger, and by Griffith. The behavior of a composite twin screw extruder consisting of assemblies of screw and kneading disc elements is investigated and the potential of having a sequence of fully filled and starved regions is considered. The existence of such distribution of polymer and starvation behavior in a twin screw machine was found in experiments with a polyethylene. The material distribution is reasonably well predicted by the non-Newtonian flow model of this paper.