Simulation of the solids conveying zone of a single screw extruder using the tribological properties of differently shaped polymer bulk materials

This work presents the results of extensive experimental trials analyzing the external coefficient of friction of differently shaped polymer bulk solids depending on velocity, temperature, and pressure. Furthermore, a segmented model of the solids conveying zone is applied in combination with an empirical approximation function which describes the external coefficient of friction as a function of pressure, velocity and temperature, a semi-physical/semi-empirical based model that describes the bulk material density as a function of pressure and temperature and a new, physical based, method to estimate the temperature at the interface between the bulk material and the barrel of the cylinder. This new method allows a simplified calculation of the temperature which is essential for modelling the solids conveying zone of a single screw extruder.
The results of the simulation are compared to extrusion experiments using a single screw extruder equipped with three pressure and temperature sensors that allow analyzing the pressure and temperature profile along the barrel.