| Autor: |
Wolff, Rebecca, Rudloff, Johannes, Baudrit, Benjamin, Hochrein, Thomas, Bastian, Martin, Malatyali, Hatice |
| Předmět: |
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| Zdroj: |
AIP Conference Proceedings; 2024, Vol. 3158 Issue 1, p1-6, 6p |
| Abstrakt: |
The co-kneader is a single-screw extruder, which performs an oscillating motion in extrusion direction additionally to rotating. The four rows of kneading pins along the cylinder walls combined with the interrupted screw flights make a high mixing possible, while enabling gentle processing at manageable shear forces and exact temperature control. Although the co-kneader is used for a wide variety of material systems as polyvinylchloride or polyamide and especially for special applications in the industry, its process design is mainly based on experimental trials. Therefore, an analytical model which allows a description of polymer melting and flow in the kneader was developed by Rudloff et al. In this previous work satisfactory simulation results could be achieved when using a retaining ring at the end of the melting zone which causes material backlog. This enables to define the melting start at the begin of the first mixing element and to assume a fully filled melting zone as well as apply dispersed melting models. However, if the co-kneader is operated without a retaining ring, the pellets can pass through the melting zone and only plastic deformation occurs, until the melt film is formed further towards the die by heat conduction. In this paper, a first model approach of plastic energy dissipation (PED) for Co-Kneaders is developed to specify the start of melting more precisely for all configurations. In the model, the energy dissipation was formulated as a function of granulate geometry and weight, mechanical material parameters and degree of granulate deformation. This allows to extend the existing dispersive melting model to include the melting contribution from PED. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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