Journal of Applied Mechanical Engineering

Extrudate swell under the effect of radial flow and intrinsic factors to the polymer upstream the die

3^rd International Conference on Fluid Dynamics & Aerodynamics

October 25-26, 2018 | Berlin, Germany

Hela Krir, Abdelhahak Ayadi and Chedly Bradaii

University of Sfax, Tunisia

Scientific Tracks Abstracts: J Appl Mech Eng

Abstract:

It is well known that extrusion is a process that allows polymer melts to be shaped. However, various defects and flow instabilities occur not only to mitigate the production rates but also to influence the appearance and the quality of extrudate products. The influence of intrinsic factors, elastic energy and memory effect, and radial flow on the appearance and the evolution of the extrudate swelling are investigated in the present work. The experiments have been performed with linear polydimethylsiloxane (PDMS) via a capillary rheometer in which a convergent radial flow was created upstream the contraction. The correspondence between the effects of radial flow, entry elastic stored energy and memory effect is discussed. In particular, as the influence of the considered radial flow, extrudate photographs showed that when the gap ratio is reduced, the extrudate swell is lessened than what it is when radial flow geometry is not installed. Moreover, with a narrower gap, the polymer stores less energy during its passage through the die which implies a lower extrudate swelling at the outlet of the die. Results previously mentioned may be related both to shear and elongational components of radial flow.

Biography :

Hela Krir has obtained her Materials Engineering diploma in 2016. Actually, she is a PhD student at the unit of Computational Fluid Dynamics and Transfer Phenomena in the Department of Mechanics at the National Engineering School of Sfax, Tunisia under the supervision of Prof. Abdelhahak Ayadi and Prof. Chedly Bradaii.

E-mail: Krir.hela@hotmail.fr