The Mixing Characteristics For Different Screw Configurations In Co-Rotating Twin Screw Extrusion

In this paper, the flow fields of the combined channels of different screw configurations in intermeshing co-rotating twin screw extrusion were analyzed. The professional package of Computational Fluid Dynamics, POLYFLOW, was used to simulate these flow fields. The three-dimensional isothermal Non-Newtonian model of full filled channel was established. The geometry and the boundary conditions of the models come from the real conditions. The simulations of flow field consist of two parts. One was the steady flow, which is independence on time. The FEM models were achieved by compiling C program. Another is the quasi-steady flow dependence on time, and the time cumulative effect was contained. The FEM models were achieved through GAMBIT, the pre-module of POLYFLOW. The configurations of both simulations were identical. In the simulation of steady flow, the flow fields of seven kinds of channel were analyzed, velocity profile, pressure profile, shear-rate profile, shear viscosity profile and the shear-stress profile were obtained. Post-processor was used to analyze those profiles. The forward transporting performance, axial distributive mixing and the dispersive mixing of seven kinds of screw configurations were analyzed based on those results of the steady flow. In the simulation of quasi-steady flow, a statistics analysis, the method of Particle Tracking Analysis, was used to post-treat the results of the simulation. The results of statistics analysis include the Cumulative Resident Time Distribution and the Resident Time Distribution, the Cumulative maximum shear-rate distribution, the maximum shear-rate of...