Computational Fluid Dynamics Simulation of Multiscale Mixing in Anionic Polymerization Tubular Reactors

Xie, Le; Zhu, Liang; Luo, Zheng‐Hong

doi:10.1002/ceat.201500628

Cited by 19 publications

(24 citation statements)

References 29 publications

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“…The quantitative evaluation of mixing performance by experiment is a time‐consuming and expensive task. Computational fluid dynamics (CFD) is a powerful tool that can be used to gain insight into local and macroscopic properties of mixing processes . This paper is aimed to investigate the effects of vibration on the mixing characteristics of two initially stratified miscible fluids in a closed container through a validated CFD model.…”

Section: Introductionmentioning

confidence: 92%

Characterization of fluid mixing in a closed container under horizontal vibrations

Zhan

Sun

et al. 2019

Can J Chem Eng

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The mixing characteristics of two initially stratified miscible fluids in a closed container vibrated horizontally are studied numerically by a validated computational fluid dynamics model. The flow characteristics and interfacial dynamics in the closed vibrating container are analyzed, and the effects of vibration parameters and gravity on mixing efficiency are evaluated both quantitatively and qualitatively. The results show that interfacial instability occurs in the closed container, which leads to interfacial deformation and breakup and quickens mixing. Two distinct stages of the mixing process can be observed in the closed vibrating container. During the macro‐mixing, an increasingly sharp gradient of the concentration field is generated. During the micro‐mixing, the mixing process is dominated by the diffusion of the concentration field and ends up with a nearly homogeneous mixture. The intensification of mixing process by vibration is most pronounced in the absence of static gravity. The gravity can suppress the interfacial instability and retard the mixing process. Over the range of conditions investigated in this paper, vibration is an efficient approach for mixing miscible liquids in a closed container.

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Section: Introductionmentioning

confidence: 92%

Characterization of fluid mixing in a closed container under horizontal vibrations

Zhan

Sun

et al. 2019

Can J Chem Eng

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“…In the last 20 years modeling approaches using CFD simulations to describe polymer reactors have overcome this challenge by using either simplified kinetics, as refs. 15–18 and Fox et al,19–21 and/or “user defined function”, as the group of Luo22–24 to take polymerization reaction into account, which is still numerical demanding. On the contrary, axial dispersion models describe hydrodynamics on macro scale with only one or two parameters, but allow for the implementation of complex polymerization kinetics on micro scale.…”

Section: Introductionmentioning

confidence: 99%

Simulation of Polymer Reactors Using the Compartment Modeling Approach

Cremer-Bujara

Biessey

Grünewald

2019

Macro Reaction Engineering

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A compartment modeling approach based on computational fluid dynamics (CFD) simulations is applied to a simplified static mixer geometry. Compartments are derived from velocity fields obtained from cold CFD simulations. This methodology is based on the definition of periodic flow zones (PFZ) derived from the recurrent flow profile within the static mixer. In general, PFZ can be characterized by two different compartments: flow zones with hydrodynamic behavior of a tubular reactor and dead zones exhibiting a more continuous stirred tank reactor‐like characteristic. In CFD studies the influence of changing fluid properties, for example viscosity, on flow profile due to polymerization progress is considered. In the deterministic compartment model, the continuous flow profile within the static mixer is transformed to basic reactor models interconnected via an exchange stream. To reduce model complexity and the number of model parameters, constant volumes of compartments are assumed. Changes in hydrodynamics are considered by a variable exchange flow rate as a function of Re manipulating residence time in compartments. Simulation studies show the influence of decreasing exchange flow rates with polymerization progress, as Re decreases, resulting in a greater increase of viscosity in dead zones. The reactor performance is qualitatively represented by the simulation results.

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“…White adopted density functional theory–based coarse‐grained Monte Carlo modeling and multiscale simulation technique to simulate the geopolymerization reaction and to determine the molecular mechanisms controlling this process. Xie combined the computational fluid dynamics with the method of moments to form a coupled model to describe multiscale mixing fields in the reactor. The effects of polymerization kinetics on macroscopic and microscopic fields were investigated.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Rheological Behaviors of Polymeric Materials in the Film Casting Process through Multiscale Modeling and Simulation Method

Hang

et al. 2019

Macro Theory & Simulations

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The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/mats.201900001. Multiscale Polymeric materials show the features of different lengths and time scales.In order to achieve optimized applications in practical forming process, it is of significance to understand the evolution of integrated structure-property relationship. In the study, the rheological behaviors of polymeric materials in film casting process are investigated by means of a multiscale modeling and simulation method based on the coarse-grained molecular dynamic (CGMD) method, the primitive path analysis, and the finite element method. The macroscopic properties of the polymeric system are predicted from the microstructure by using a bottom-up method. Based on the entanglement network of macromolecular chains predicted with CGMD simulation, the primitive path analysis method is adopted to evaluate main conformational parameters according to the tube theory, which realizes a bridge from nano to micro scale. The viscoelastic properties of polymeric materials are characterized by using a continuum Phan-Thien-Tanner (PTT) constitutive model, whose rheological parameters are obtained by fitting the distributions of material functions predicted from the tube model. The mathematical model of film casting process is further established based on a membrane model and the corresponding finite element model and details of numerical schemes are introduced. The characteristics of macroscopic rheological behaviors of polymeric melts can hence be investigated from the evolution of microscopic structure, and the phenomena in practical film casting process like the neckin and the edge bead defects in engineering are successfully predicted. 2 of 13) www.advancedsciencenews.com www.mts-journal.de * (

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Computational Fluid Dynamics Simulation of Multiscale Mixing in Anionic Polymerization Tubular Reactors

Cited by 19 publications

References 29 publications

Characterization of fluid mixing in a closed container under horizontal vibrations

Characterization of fluid mixing in a closed container under horizontal vibrations

Simulation of Polymer Reactors Using the Compartment Modeling Approach

Investigation of the Rheological Behaviors of Polymeric Materials in the Film Casting Process through Multiscale Modeling and Simulation Method

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