Simplified numerical calculation of the isothermal, three-dimensional, Non-Newtonian flow characteristics of single-screw melt-extruder

Solving the reduced Navier-Stokes equation for the calculation of the flow of non-Newtonian polymer melts in single screw extruders numerical methods are needed. In this study, a numerical model, based on the finite difference method, for the description of the one- and two-dimensional fully developed conveying characteristics of power law fluids in the melt channel will be introduced. Furthermore, the two-dimensional model will be enhanced by considering the real cross-section of the screw channel and introducing adaption factors which approximate the fully developed three-dimensional flow behavior in the screw channel. Finally, a comprehensive comparison with CFD-Simulation results will be done. Therefore, a parametric study with three independent parameters, pitch to diameter ratio, width to height ratio and power law exponent, will be done and both, viscosity- and velocity-profiles as well as the calculated π_m / π_P − characteristics will be compared to CFD-Simulation results.