Simulation of Non-Newtonian Flow of Rubber Compounds in a Pin Barrel Screw Extruder

Abstract A simulation is presented of flow of a rubber compound, modeled as a power law non-Newtonian fluid, in screw designs including screws with slices and a pin barrel extruder. Calculations were carried out using the flow analysis network (FAN) technique. Pressure fields, flux fields, and screw characteristic curves were determined. Introducing non-Newtonian (shear-thinning viscosity) characteristics reduces screw pumping ability. Slices in screw flights produce backward fluxes in the screw channel and reduce pumping capacity. Introduction of pins into the barrel has only a minor effect on screw pumping characteristics, and the pumping capacity of a pin barrel extruder closely resembles that in a screw extruder with slices in its screw flights.