Characterization of extrusion flow using particle image velocimetry

Abstract

Abstract. The aim of this study was the characterization of polymer flows within an extrusion die using particle image velocimetry (PIV) in very constraining conditions (high temperature, pressure and velocity). Measurements were realized on semi-industrial equipments in order to have test conditions close to the industrial ones. Simple flows as well as disrupted ones were studied in order to determine the capabilities and the limits of the method. The analysis of the velocity profiles pointed out significant wall slip, which was confirmed by rheological measurements based on Mooney's method. Numerical simulations were used to connect the two sets of measurements and to simulate complex velocity profiles for comparison to the experimental ones. A good agreement was found between simulations and experiments providing wall slip is taken into account in the simulation.

Rheology of organoclay assisted extrusion of HDPE using Particle Image Velocimetry

“…Velocimetry is the most common of the direct methods. However, due to the difficulty of managing velocimetry techniques with polymer melts at high temperatures and pressures, there are not many publications in this area as compared to the area of indirect methods (Rodríguez-González et al, 2009, 2010Münstedt et al, 2000;Robert et al, 2004;Fournier et al, 2009;Nigen et al, 2003). There are several variations in velocimetry techniques.…”

“…However, it is time consuming due to its point by point measurement. For transient flows (as in extrusion and injection molding), PIV gives more global picture of the flow pattern; hence, it is used in the study of flow instabilities and wall slip (Fournier et al, 2009). Moreover, LDV does not effectively detect partial slip (Rodríguez-González et al, 2009).…”

“…Direct methods have been employed more recently due to their higher sensitivity to wall slip than the other methods (Archer, 2005;Ansari et al, 2012;Kaoullas and Georgiou, 2013), and they provide 'direct' quantitative measurement of the relative motion of the polymer melt and solid at the interface. These methods include fringe pattern fluorescence recovery after photo bleaching (Migler et al, 1993), hot film (Kraynik and Schowalter, 1981;Lim and Schowalter, 1989), and local velocimetry (Mhetar and Archer, 1998;Rodríguez-González et al, 2010;Münstedt et al, 2000;Robert et al, 2004;Mitsoulis et al, 2003;Fournier et al, 2009;Mackley and Moore, 1986;Nigen et al, 2003) methods. Velocimetry is the most common of the direct methods.…”

Rheo-Particle Image Velocimetry for the Analysis of the Flow of Polymer Melts

“…The reported velocity profiles, however, do not exhibit slip. Fournier et al (2009) characterized the extrusion flow of polycarbonate and polystyrene in a rectangular die with quartz windows by using PIV. The measured velocity profiles in this case, showed good agreement with numerical simulations that considered the influence of slip at the die wall.…”

Influence of short glass fiber reinforcement on the morphology development and mechanical properties of PET/HDPE blends

“…The properties of immiscible polymer blends strongly depend on their morphology determined by the size, size distribution, and shape of distributed particles [8]. In most polymer processing devices, the morphology of the blends develops as a result of interactions initiated by the melt flow through drop breakup and coalescence [9, 10]. The morphology in the blends can be characterized with the viscosity ratio of the components and the capillary number.…”