The results of the PEPTFLOw project are aimed at demonstrating the influence of the screw design on the quality of the extruded polymer. The Polymer flow is observed by Positron Emission Particle Tracking method. Radioactive particles flow was tracked by Magnetic Resonance Imaging (MRI) installed on the Leistritz twin screw extruder used in this Project.
PEPTFLow was supported by the collective Research Program of the European Community. So, european companies were involved and assured the success and the multi disciplinarity of this approach (compounders, extruder manufacturers, masterbatch producers, institut of Research...). Verdict on the Results.
Results and progress of the PEPTFlow project will be usefull to the whole plastic chain supply
- Real vision of what is happenning in the twin screw extruder
- Knowledge based machine design
- Time and costs reduction (for new formulation, new process set up...)
- Optimization of material properties and production (energy reductions)
- Design of new materials and added values materials
- Improved simulation and modelling software
The polymer flow has been measured through different screw configurations (conveying elements, kneading blocks, mixing elements...) with different operating conditions to observe the impact of the screw design on the mixing efficiency (dispersive/distributive mixing).
Then, the Ludovic software was used for the modelling of those different screw configurations. Indeed, Ludovic is very convenient to easily change the operating conditions. Output and screw speed are major parameters of the extrusion process given that they are independant and influence degree of fill, residence time, shear rate... Ludovic is able to quicly fix the main trends of the observed configuration.
Ludovic provided local and total residence time results for the different configurations.tware
As mentionned, local residence time and total residence time are among the best tags to determine characteristics of mixing efficiency (dispersive of distributive) for the different kinds of screw elements.
The provided results help "to validate the Ludovic calculations as to how residence time changes with changes in operating conditions such as output and screw speed". The comparison between the modeled results and the experiments ones shows that the Ludovic simulations results are pretty good : "The conclusion must be that the figures are correct indications of the actual residence time and therefore the Pept experiments and the Ludovic predictions verify each other" (extracted from the final PEPTFlow booklet : Machine Design Handbook, 02/2010).
The following pictures present the comparison between the PEPT experiments and the Ludovic simulations. Those curves show the total residence time regarding to the output and the screw speed. The different values of total residence time (from 30s to 70s on the picture 1, from 40s to 150s on the picture 2) have been modeled with Ludovic and are represented by the black curves. The total residence time which have been measured are represented by the red squares.
Those results prove the pertinence of the Ludovic software to model different screw configurations and analyse the main trends of the twin screw extrusion process. Indeed, with Ludovic, it was possible to realize more configurations than we did with real experiments. Ludovic provided the main trends of Total Residence time for the given screw configurations. We can see on the two pictures that all the Ludovic results are extremly closed to the real measures.
The PEPTFlow project ended on the 31st of Decembre 2009. Results and conclusions are available from the official PEPTlfow web site : http://www.peptflow.com. You can also download the documents from our web site.
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SCC HomePage | The SCC Website : simulation software and applications |
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Read more about PEPTFlow | The PEPTFlow official Website |
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PEPTFlow in video | The Video of the PEPT Experiments |
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PEPTFlow Newsletter - Sept/Oct. 2009 | Download the PEPTFlow Newsletter |
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PEPTFlow Newsletter - Noc/Dec. 2009 | Download the PEPTFlow Newsletter |
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PEPTFlow Machine Design Handbook | Download the PEPTFlow Project Summary (7Mo) |
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Ludovic Software for Twin Screw | Web page of the Ludovic software (twin screw extrusion) |
