Physico-Mathematical Model for the Description of the Temperature Development and the Power Consumption in Co-Rotating Twin Screw Extruders

Abstract

Abstract Tightly intermeshing, co-rotating twin-screw extruders are commonly employed for tasks requiring good mixing. The modular constitution of both barrel and screw makes it possible to optimise the extruder configuration for a given task. Even today this optimisation is frequently done by applying the “Trial and Error”-method. Physico-mathematical models enable the process engineer to predict the process behaviour of a chosen extruder configuration and to optimise existing extrusion processes. Increasing demands in mixing quality and efficiency of the processing unit result in efforts to optimise existing extruders with respect to those factors. For this reason knowledge concerning the temperature profile along the screw and the power consumption is essential. We present a new physico-mathematical model for the description of the temperature development. At stages where the analytical solution itself would result in a not satisfying degree of accuracy we used descriptions based on finite element simulation results to achieve the desired exactness. As a result we got a model to describe the temperature development in the screw channel and a model to describe the power consumption in different screw sections. Applying these models it is possible to optimise the process parameters and the screw configuration with only a minimum of preceding experimental investigations.