scholarly journals Chaotic Mixing in a Free Helix Extruder using a New Solution to the Biharmonic Equation

2021 ◽  
Author(s):  
Gregory Campbell ◽  
Ross Taylor ◽  
Mark Wetzel ◽  
Sirisha Bomma ◽  
Shaji Chempath ◽  
...  
Keyword(s):  
Flow Field ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Biharmonic Equation ◽  
Cross Flow ◽  
Chaotic Mixing ◽  
Screw Extruder ◽  
Chaotic Flow ◽  
Single Screw ◽  
Single Screw Extruder

A recently published approach for modeling the cross flow in an extruder channel using a new solution to the biharmonic equation is utilized in a study of chaotic mixing in a free helix single screw extruder. This novel extruder was designed and constructed with the screw flight, also referred to as the helix, detached from the screw core. Each of the screw elements could be rotated independently to obtain chaotic motion in the screw channel. Using the new extruder, experimental evidence for the increased mixing of a dye, for both a Dirac and droplet input, with a chaotic flow field relative to the traditional residence time distribution is presented. These experimental results are compared using the new biharmonic equation-based model. Because of the ability to periodically rotate only the flight/helix, the chaotic mixing results are minimally confounded by the existence of Moffat eddies.

scholarly journals Modelling non-homogeneous flow and residence time distribution in a single-screw extruder by means of Markov chains

2012 ◽  
Vol 50 (8) ◽  
pp. 2141-2154 ◽  
Author(s):  
Denis Ponomarev ◽  
Elisabeth Rodier ◽  
Martial Sauceau ◽  
Clémence Nikitine ◽  
Vadim Mizonov ◽  
...  
Keyword(s):  
Markov Chains ◽  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Screw Extruder ◽  
Homogeneous Flow ◽  
Single Screw ◽  
Single Screw Extruder

Residence Time Distribution in a Single-Screw Extruder Processing Soy-Sweet Potato Mixtures

LWT ◽  
2001 ◽  
Vol 34 (7) ◽  
pp. 478-483 ◽  
Author(s):  
M.O. Iwe ◽  
D.J. Van Zuilichem ◽  
P.O. Ngoddy ◽  
C.C. Ariahu
Keyword(s):  
Sweet Potato ◽  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Screw Extruder ◽  
Single Screw ◽  
Single Screw Extruder

Numerical analysis of mixing performance of mixing section in pin-barrel single-screw extruder

2011 ◽  
Vol 31 (1) ◽  
Author(s):  
Jinnan Chen ◽  
Pan Dai ◽  
Hui Yao ◽  
Tung Chan
Keyword(s):  
Numerical Analysis ◽  
Finite Elements ◽  
Flow Field ◽  
Residence Time ◽  
Particle Tracking ◽  
Mixing Efficiency ◽  
Screw Extruder ◽  
Mixing Performance ◽  
Single Screw ◽  
Single Screw Extruder

Abstract Using the finite elements method, numerical simulations of the flow field of a rubber melt in the mixing sections of a conventional full-flight single-screw extruder and a pin-barrel single-screw extruder were carried out. Particle tracking analysis was used to statistically analyze the mixing state of the rubber melt in the mixing section with pin and that without pin. The mixing performance of both types of mixing section was quantitatively evaluated. The results show that the pins partially disorganize the particle trajectories, change the particle moving directions, and enhance the mixing performance. The particle residence time is longer in the mixing section with pins than in the mixing section with no pin, leading to better mixing in the former. The distributive mixing of particles in both types of mixing section was statistically analyzed. The pins increase the efficiency of stretching and the time-averaged efficiency of stretching, and hence the mixing efficiency. However, further increase in the number of pins does not necessarily enhance the mixing performance.

Effect of Flow Field on Online Shear Viscosity of PP/nano-CaCO3 Composites

2006 ◽  
Author(s):  
Guo Jiang ◽  
Hanxiong Huang
Keyword(s):  
Shear Viscosity ◽  
Chaotic Mixing ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Rheological Analysis ◽  
Single Screw ◽  
Single Screw Extruder ◽  
Mixing Intensity ◽  
Twin Screw ◽  
High Shearing

Polymer nanocomposites have been regarded as a new category of engineering materials and attracted technical and scientific interest. Recently rheological analysis became an effective tool for investigating the microstructures of nanocomposites. However, the online rheological property of nanocomposites during compounding was seldom studied. In this work, two types of screw configurations in twin-screw extruder were selected, one provides high shearing intensity and the other provides high shearing/mixing intensity. In addition, chaotic mixing was induced by installing a single screw extruder with a convective screw at the end of the twin-screw extruder to compound the nanocomposites. The online melt shear viscosity of nanocomposite was measured using Haake ProFlow online rheometer. Effects of high shearing, high shearing/mixing, and chaotic mixing on the online shear viscosity for polypropylene (PP)/nano-calcium carbonate (nano-CaCO3) composites were investigated. The study showed that the chaotic mixing facilitates the processing of the nanocomposite.

Chaotic mixing in a single-screw extruder with a moving internal baffle

2013 ◽  
Vol 54 (1) ◽  
pp. 198-207 ◽  
Author(s):  
Baiping Xu ◽  
Yuejun Liu ◽  
Huiwen Yu ◽  
Lih-Sheng Turng
Keyword(s):  
Chaotic Mixing ◽  
Screw Extruder ◽  
Single Screw ◽  
Single Screw Extruder

Chaotic mixing analysis of a novel single-screw extruder with a perturbation baffle by the finite-time Lyapunov exponent method

2019 ◽  
Vol 39 (3) ◽  
pp. 287-299 ◽  
Author(s):  
Jian Liu ◽  
Xiangzhe Zhu
Keyword(s):  
Lyapunov Exponent ◽  
Finite Time ◽  
Polymer Processing ◽  
Chaotic Mixing ◽  
Mixing Efficiency ◽  
Screw Extruder ◽  
Screw Channel ◽  
Single Screw ◽  
Single Screw Extruder ◽  
Finite Time Lyapunov Exponent

Abstract The single-screw extruder with a perturbation baffle is a novel piece of equipment for polymer processing, in which the polymer melts undergo complex chaotic mixing. In this paper, from a new Lagrangian perspective, the fluid transporting mechanism in chaotic flow of the unwound screw channel was analyzed based on the finite element method. Firstly, two-dimensional velocity distributions in the unwound screw channel were calculated based on the mesh superposition technique. Fluid particle evolution processes in the extruder were tracked based on the fourth-order Runge-Kutta scheme. The numerical method used in this paper was validated by grid independence and experiments obtained from literature. Moreover, the finite-time Lyapunov exponent (FTLE) and Poincaré sections were adopted to discuss the chaotic mixing in the novel single-screw extruder. The effects of baffle width and height on the manifold structures in the flow dynamic system were analyzed. The results show that the homoclinic point of the manifold structure can give rise to chaotic mixing in the single-screw extruder. The height of the baffle is an important parameter to control the chaotic strength. In a way, increasing the height of the baffle can enlarge the kink scale and increase the stretching and folding actions, which results in the decrease of regular regions and an increase of the mixing efficiency in the single-screw extruder.

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