Historical Review of Secondary Entry Flows in Polymer Melt Extrusion
| Autor: | Martin Zatloukal, Jan Musil |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Flow visualization
Materials science Polymers and Plastics Renewable Energy Sustainability and the Environment Biomedical Engineering 02 engineering and technology General Chemistry Mechanics 010402 general chemistry 021001 nanoscience & nanotechnology Secondary flow 01 natural sciences 0104 chemical sciences Electronic Optical and Magnetic Materials Deborah number Vortex Flow separation Flow (mathematics) Materials Chemistry Fluid dynamics Electrical and Electronic Engineering 0210 nano-technology Shear flow |
| Zdroj: | Polymer Reviews. 59:338-390 |
| ISSN: | 1558-3716 1558-3724 |
| Popis: | Secondary flow (also termed as stagnation flow, dead space, recirculation zone, and vortex) is rheological phenomenon occurring during flow of polymer melts through abrupt contraction channels as result of flow separation from solid boundary leading to accelerating flow regime with recirculating material in corners. Polymer melt captured in secondary flow slowly rotates in direction opposite to main flow direction and simultaneously moves in third direction through helical motion. This may first reduce flow stability and second increase residence time initiating highly undesirable thermal degradation of polymer melt. Since the first visual experimental observation performed by Tordella and preliminary theoretical prediction made by Langlois and Rivlin at the end of the 1950s, this phenomenon represents one of the most fundamental rheological problems ever with many practical and theoretical impacts discussed here. This comprehensive review written in historical perspective summarizes key factors (... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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