Calculation Of Three-Dimensional Particle Trajectories And Polymer Blend Morphology During Compounding In A Twin-Screw Extruder

Three-dimensional Non-Newtonian isothermal flow fields of common screwelement and kneading block element are analyzed with establishing Geometric modelsof different initial angle using the real geometry of barrel and screws. The real velocityon surface of the two elements and pressure of both ends are applied as boundarycondition in FEM analysis. By using a finite element analysis package—ANSYS,velocity profile, pressure profile and viscosity profile of flow fields in the two elementsare obtained. According to the velocity profile of flow fields, the three-dimensional particletrajectories in the two elements are obtained by writing program, thus for the first timethe complex particle path of different materiel flowing in the two elements is computedtheoretically. Using the three-dimensional particle trajectories, the residence timedistribution, the backflow distance, the shear strain, the shear stress and the total shearstrain are calculated and the influences of rotating speed and output on theabove-mentioned physical value are quantified. The droplet dimensions and itsdistribution of disperse phase at the outlet of the two elements are calculated byadopting the previous model of morphology evolution during polymer blending in atwin-screw extruder. This is a tentative job for predicting the blending ability of the mixelements and equipment.