Use of Innovative Simulation Techniques to Develop a High-Speed Extrusion Concept Based on Solid-Melt-Separation
Extrusion is one of the most important processes for the processing of plastics. Accordingly strong is the interest to ensure efficient and economic processes. In this case the throughputs reached by the extruder are a primary benchmark. Thus, raising the processable throughputs is desirable.
The greatest potential for the realization of this goal is often seen in the use of fast-rotating screws. But in single screw extrusion still decisive problems dealing with permissible melt temperatures and an appealing extrudate are to solve.
In this thesis, the development of the so-called S-Truder concept is therefore continued by use of innovative simulation techniques. For this purpose, first the existing concept is examined by means of extensive experimental and theoretical work. The focus is set on the generation of process knowledge regarding melting processes and melt flow in the High-Speed-S-Truder. Especially the use of computer simulation methods is thereby of special importance, as these make it possible to get a detailed virtual view into the interior of the machine. A main part of this work is therefore the development of an innovative and universally applicable material model and its implementation in a commercial CFD software. The material model allows the common description of solids and melt as one flowing continuum. Rheological as well as thermodynamic material properties are taken into account, which are represented over a wide temperature range, from room temperature up to the processing temperature. By use of the material model the extrusion with the High-Speed-S-Truder is simulated, analyzed and optimization potentials are revealed.
Based on the information thereby obtained a revised prototype with freely rotating screw sleeve for solid-melt-separation is developed. Because of the unconventional, but yet simple design of the High-Speed-S-Truder, the plastification processes differ in part highly from the known mechanisms. Therefore, also the processes in the new prototype will be made visible in the context of some more CFD simulations using the before developed material model. The constructive changes are proved and optimized. The performance of the new High-Speed-S-Truder is demonstrated by real plastification experiments with current standard plastics (LD-PE, LLD-PE, PS).Lesen Sie die deutsche Zusammenfassung auf Kunststoffe.de
High-Speed Extrusion, Solid-Melt-Separation, Computational Fluid Dynamics (CFD), Modeling, Material model, Rheology
Institute / chair: Fakultät für Ingenieurwissenschaften Abteilung Maschinenbau und Verfahrenstechnik der Universität Duisburg-Essen
Technical consultant for expert services: Prof. Dr.-Ing. Johannes Wortberg (Betreuer), Prof. Dr.-Ing. Christian Bonten
Publication year: 2016
Provider: Wissenschaftlicher Arbeitskreis Kunststofftechnik (WAK) / Kunststoffe.de
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