Modeling of Pressure-Induced Melt Removal Melting in Vane Extruder for Polymer Processing

The assembled vane extruder with seven groups of vane plasticizing and conveying units (VPCUs) was designed to study the melting phenomenon and mechanisms in vane extruder. There were two melting stages during the melting process, including the solid-rich melting stage and the melt-rich melting stage, and there were no obvious boundaries between the solids and melts. The pressure-induced melt removal melting was the dominant melting mechanism in the solid-rich stage. The theoretical model of the pressure-induced melt removal mechanism was established. The melting percentage was defined to evaluate the boundaries between the solid-rich melting stage and melt-rich melting stage. The melting percentage is proportional to a three-quarters power of the temperature at stator's inner surface, a quarter power of solids' pressure, as well as inversely proportional to the rotating speed of rotor. By comparing theoretical calculations with experimental measurements of the melting percentage of material low-density polyethylene extruded by the first VPCU, it was indicated that the theoretical model and experimental measurements were consistent with the same tendency.