Non-Isothermal Modeling of Co-Rotating and Contra-Rotating Twin Screw Extruders

Abstract

The quality of the mixing of different raw materials, i.e. the uniformity of the mixture, is a key issue that will determine the morphology and the specific product properties of the resulting compound [1,2]. Numerical simulation of flow in extruder components provides a new insight, both qualitative and quantitative, into those features. 3-D transient numerical simulations of twin screw extruder (TSE) configurations are presented. A special method, the mesh superposition technique (MST), has been introduced to provide a convenient way to model intermeshing TSEs without involving any remeshing complexity [3]. It has been validated in previous work for isothermal cases [4]. To account for the important non-isothermal effects, the method is compared against numerical and experimental results for additional, non-isothermal validation [5]. We present an analysis of different non-isothermal features that characterize the flow induced by a co-rotating as well as a contra-rotating configuration. Both cases are compared in terms of pressure profiles, temperature fields, resulting torque imposed on the screws and from a mixing point of view to illustrate a typical analysis of different TSEs and provide objective information to select the most appropriate configuration for specific process requirements.