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This paper deals with the development of the so called High-Speed-S-Truder. The alternative extrusion concept uses a special plastification sleeve with hundreds of bores surrounding the screw to separate the emerging melt from solid material in the screw channel. To analyze and improve the complex fluid flow in this process CFD-simulations are used. However, the ability of simulating the flow as well as the plastification process is yet not given in any CFD-software. Thus an approach for 3D-CFDsimulations of melting polymeric materials in extrusion processes has been developed. A new material model enables to differ between solid phase and fluid phase in dependence of temperature in just one set of property descriptions. Hence it becomes possible to simulate melting in a single fluid domain without presupposing any melting mechanism. Therefore the model is universally applicable and can be used for the simulation of ordinary extrusion processes under high speed conditions as well as for the investigation and improvement of the melting mechanism in the High-Speed-S-Truder.

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Modeling of consistent rheological and thermodynamic material data for process simulations Any process simulation in polymer engineering is based on conservation equations, which refer to comprehensive knowledge about material properties. These empirically examined properties, such as viscosity, specific enthalpy (specific heat capacity), density, and thermal conductivity are represented in the simulation via mathematical material models. However, the way of gathering rheological and thermodynamic material data influences the accuracy of the material model and thus the simulation output. Hence, the importance of an accurate material model is obvious. With respect to this the influence of measuring methods on the material model and a procedure to model consistent material data at process-relevant heating/cooling rates is described. Modellierung konsistenter rheologischer und thermodynamischer Materialdaten für die Prozesssimulation