Particle Transport via Three-Dimensional Chaotic Advection to Produce Electrically Conducting Plastics With Powder Additives

1999 ◽  
Author(s):  
R. I. Danescu ◽  
D. A. Zumbrunnen
Keyword(s):  
Carbon Black ◽  
Three Dimensional ◽  
Chaotic Advection ◽  
Chaotic Mixing ◽  
Complex Structures ◽  
Two Dimensional ◽  
Electrical Measurements ◽  
Electrically Conducting ◽  
Scale Structures ◽  
Large Clusters

Abstract Extended micron-scale structures were produced in thermoplastic melts from initially large clusters of conducting carbon black particles transported by three-dimensional chaotic mixing. The structures formed networks that were captured by solidification and rendered the composite materials electrically conducting. A systematic study was carried out to assess the influence of key parameters and relate the electrical properties to the microstructures. Micrographs showed complex structures exhibiting patterns characteristic of chaos. Electrical measurements indicated that conductivity was achieved at carbon black concentrations significantly lower than achievable by common mixing methods, and lower than reported recently for two-dimensional chaotic mixing.

Cellular flow in a partially filled rotating drum: regular and chaotic advection

2017 ◽  
Vol 825 ◽  
pp. 631-650 ◽  
Author(s):  
Francesco Romanò ◽  
Arash Hajisharifi ◽  
Hendrik C. Kuhlmann
Keyword(s):  
Three Dimensional ◽  
Reynolds Numbers ◽  
Chaotic Advection ◽  
Two Dimensional ◽  
Rotating Drum ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Heteroclinic Connection ◽  
Two Dimensional Flow ◽  
Chaotic Streamlines

The topology of the incompressible steady three-dimensional flow in a partially filled cylindrical rotating drum, infinitely extended along its axis, is investigated numerically for a ratio of pool depth to radius of 0.2. In the limit of vanishing Froude and capillary numbers, the liquid–gas interface remains flat and the two-dimensional flow becomes unstable to steady three-dimensional convection cells. The Lagrangian transport in the cellular flow is organised by periodic spiralling-in and spiralling-out saddle foci, and by saddle limit cycles. Chaotic advection is caused by a breakup of a degenerate heteroclinic connection between the two saddle foci when the flow becomes three-dimensional. On increasing the Reynolds number, chaotic streamlines invade the cells from the cell boundary and from the interior along the broken heteroclinic connection. This trend is made evident by computing the Kolmogorov–Arnold–Moser tori for five supercritical Reynolds numbers.

Numerical Simulation for Mechanical Behavior of Carbon Black Filler Particle Reinforced Rubber Matrix Composites

2011 ◽  
Vol 137 ◽  
pp. 1-6
Author(s):  
Qing Li ◽  
Xiao Xiang Yang
Keyword(s):  
Carbon Black ◽  
Mechanical Behavior ◽  
Plane Stress ◽  
Volume Fraction ◽  
Filler Particle ◽  
Three Dimensional ◽  
Rubber Matrix ◽  
Two Dimensional ◽  
Rubber Composites ◽  
Dimensional Plane

In this paper, the micromechanical finite element method based on Representative Volume Element has been applied to study and analyze the macro mechanical properties of the carbon black filled rubber composites by using two-dimensional plane stress simulations and three-dimensional axisymmetric simulations under uniaxial compression respectively. The dependence of the macroscopic stress-strain behavior and the effective elastic modulus of the composites, on particle shape, particle area/volume fraction and particle stiffness has been investigated and discussed. Additionally, the simulation results of the two-dimensional plane stress model and the three-dimensional axisymmetric model are evaluated and compared with the experimental data, which shows that the two-dimensional plane stress simulations generate poor predictions on the mechanical behavior of the carbon black particle reinforced rubber composites, while the three-dimensional axisymmetric simulations appear to give a better prediction.

scholarly journals Coherent structures and chaotic advection in three dimensions

2010 ◽  
Vol 654 ◽  
pp. 1-4 ◽  
Author(s):  
STEPHEN WIGGINS
Keyword(s):  
Dynamical Systems ◽  
Fluid Mechanics ◽  
Coherent Structures ◽  
Three Dimensional ◽  
Point Of View ◽  
Three Dimensions ◽  
Chaotic Advection ◽  
Periodic Flow ◽  
Two Dimensional ◽  
Time Periodic

In the 1980s the incorporation of ideas from dynamical systems theory into theoretical fluid mechanics, reinforced by elegant experiments, fundamentally changed the way in which we view and analyse Lagrangian transport. The majority of work along these lines was restricted to two-dimensional flows and the generalization of the dynamical systems point of view to fully three-dimensional flows has seen less progress. This situation may now change with the work of Pouransari et al. (J. Fluid Mech., this issue, vol. 654, 2010, pp. 5–34) who study transport in a three-dimensional time-periodic flow and show that completely new types of dynamical systems structures and consequently, coherent structures, form a geometrical template governing transport.

Smart Blending: Functional Fine-Scale Structures Formed by Intelligent Agitations in Multi-Component Melts

2003 ◽  
Author(s):  
D. A. Zumbrunnen
Keyword(s):  
Mechanical Properties ◽  
Fluid Mechanics ◽  
Layer Structure ◽  
Chaotic Advection ◽  
Fine Scale ◽  
Electrically Conducting ◽  
Molecular Scale ◽  
Small Feature ◽  
Scale Structures

In viscous melts, turbulence often does not arise. Consequently, opportunities exist for controllably organizing melt components into functional structures that can have very small feature sizes. In this paper, concepts and results of smart blending are described. Smart blending entails the controllable development in situ of a variety of fine-scale structures in the melt by intelligent agitations. Once formed, structures may be useful in the melt or may be captured in applicable products by extrusion and solidification. Chaotic advection is an enabling recent sub-field of fluid mechanics for smart blending since it provides a means to stretch and fold melt domains and evolve a multi-layer structure leading to derivative arrangements, or indirectly manipulate solid additives. Applications include the production of plastics with enhanced mechanical properties, electrically conducting plastics and glasses, low permeation films, membranes, and nano- and molecular-scale composites.

Comparison of numerical methods for light propagating in fibers with high steps of refractive index

2012 ◽  
Vol 20 (1) ◽  
Author(s):  
K. Zegadło ◽  
M. Karpierz
Keyword(s):  
Refractive Index ◽  
Numerical Methods ◽  
Light Propagation ◽  
Chromatic Dispersion ◽  
Three Dimensional ◽  
Complex Structures ◽  
Two Dimensional ◽  
Approximate Methods ◽  
Fast Development ◽  
Numerical Tools

AbstractFast development of complex structures like microstructural fibers, photonic nanowires or slot waveguides requires numerical tools to predict a light propagation. There are many works concerning weakly guided case, but the microstructural fibers need algorithm for a high step of the refractive index. In this paper, three approximate methods are compared. The comparison concerns a structure consisting of circular cores surrounded by cladding for different values of the refractive index steps. Application of these methods in chromatic dispersion case is also presented. It is shown that certain conditions prefer two dimensional scalar algorithms (based on approximated methods) than three dimensional ones. This allows us to implement more efficient and less complicated methods.

scholarly journals DIMENSION REDUCTION USING THE INVERSE STAMPING METHOD

2021 ◽  
Vol 2021 (4) ◽  
pp. 4810-4817
Author(s):  
JAROMIR KASPAR ◽  
◽  
MARCEL SVAGR ◽  
PETR BERNARDIN ◽  
VACLAVA LASOVA ◽  
...  
Keyword(s):  
Graph Theory ◽  
Dimension Reduction ◽  
Automotive Industry ◽  
Three Dimensional ◽  
Stochastic Methods ◽  
Complex Structures ◽  
Two Dimensional ◽  
Crucial Step ◽  
Development Tool ◽  
Wide Range

The aim of this work is to improve the inverse stamping method and increase its robustness. The first, crucial step of inverse stamping is the reduction of the three-dimensional part into a two-dimensional flat plane. There are several methods for reducing the dimension. These are geometrical methods, methods based on graph theory and stochastic methods. We examine the last two methods because of their reliability. These methods can even be used for geometrically complex structures which include holes, hooks and walls perpendicular to the flat plane. An algorithm which combines several methods for dimension reduction is proposed for use for a wide range of parts. Deep drawing is a widely used technology in the automotive industry and inverse stamping is a useful development tool.

scholarly journals A Novel High-Throughput Chaotic Advection Microreactor for the Preparation of Uniform BaSO4 Nanoparticles

2021 ◽  
Author(s):  
Hua Yang ◽  
Shi-Xiao Wei ◽  
Han Chen ◽  
Lang Chen ◽  
Chak-tong Au ◽  
...  
Keyword(s):  
High Throughput ◽  
Three Dimensional ◽  
Volumetric Flow Rate ◽  
Secondary Flows ◽  
Chaotic Advection ◽  
Narrow Particle Size Distribution ◽  
Chaotic Mixing ◽  
Mixing Efficiency ◽  
Size Uniformity ◽  
Average Size

Owing to high mixing efficiency, microreactors are used to synthesize uniform BaSO4 nanoparticles, but application in industrial scale is limited due to poor throughput. In this work, a high-throughput passive four-stage asymmetric oscillating feedback microreactor using chaotic mixing mechanism was developed to prepare BaSO4 nanoparticles of high size uniformity. Three-dimensional unsteady simulations showed that chaotic mixing could be induced by three unique secondary flows (i.e., vortex, recirculation, and oscillation), and the fluid oscillation mechanism was examined in detail. Simulations and Villermaux-Dushman experiments indicate that almost complete mixing in molecular level could be achieved when total volumetric flow rate Qtotal was larger than 10 mL/min, and the prepared BaSO4 nanoparticles were with narrow particle size distribution (PSD). Through the adjustment of Qtotal and reactant concentrations, it is easy to control the average size. An average size of 26 nm with narrow PSD could be achieved at Qtotal = 160 mL/min.

Stability of plane parallel flows of electrically conducting fluids

1953 ◽  
Vol 49 (1) ◽  
pp. 166-168 ◽  
Author(s):  
D. H. Michael
Keyword(s):  
Reynolds Number ◽  
Velocity Profile ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Electrically Conducting ◽  
Plane Parallel ◽  
Parallel Flows ◽  
Lower Reynolds Number ◽  
The Stability ◽  
Conducting Fluids

The ordinary theory of stability of plane parallel flows is considerably simplified by a result due to Squire (2) which says that if a velocity profile becomes unstable to a small three-dimensional disturbance at a given Reynolds number, then it will become unstable to a small two-dimensional disturbance at a lower Reynolds number. This result enables us to restrict investigation of the stability to the cases of two-dimensional disturbances.

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