A theoretical study of the autothermal polymer extrusion process
Polimery 1997, No 2, 111
Energy problems have been theoretically considered in an authothermal extrusion process involving the plasticating system composed of an extruder and anextruder head. The plasticating system was divided into three functional zones: the solid conveying zone, the melting zone and the melt conveying zone. Heat fluxes were determined in each zone, those generated by external friction between the polymer particles, the polymer and the barrel surface, and the polymer and the screw surface (i.e., the screw root and the active surfaces of the screw flight), and those generated by polymer's internal friction. The polymer-convected heat flux and the heat loss flux were evaluated. The energy balance was established for each extruder plasticating zone and for the extruder head. The condition of the autothermal process and the particular forms for the entire plasticating system and the extruder head were formulated. The autothermal process condition enables various quantities to be calculated, e.g., the screw speed required for this type of a process. Extrusion effectivity factors were measured such as extruder's energy efficiency and the total energy consumption per unit mass.