Quantification of Mixing in RIM Using a Non-Diffusive Two-Phase Flow Numerical Model

Fonte, Cláudio P.; Santos, Ricardo J.; Dias, Madalena M.; Lopes, José Carlos B.

doi:10.2202/1542-6580.2564

Cited by 15 publications

(16 citation statements)

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“…This viscosity value is representative of some RIM formulations, although in the lower end of the viscosity range used in industry. Furthermore, there is a considerable body of experimental data using these fluids from previous works …”

Section: Problem Descriptionmentioning

confidence: 99%

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On the 2D nature of flow dynamics in opposed jets mixers

et al. 2016

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Confined impinging jets (CIJs) are reactors used in processes that require fast mixing. In such equipment two fluids are injected from opposite sides of a chamber, impinging into each other and forming flow structures that enable an effective mixing and reaction. The turbulence analysis shows that the energy is injected from smaller scales, having approximately the injectors width, that feed larger scale structures up to larger vortices that occupy the entire mixing chamber width. This energy distribution has an inverse energy cascade, i. e. it is an inversion of the traditional description of homogeneous 3D turbulence. The typical flow scales of 2D CIJs are clearly shown in this work to be linked to the 2D turbulence energy spectrum and to integral scales of turbulence. Moreover, the turbulence mechanisms in 3D CIJs at transitional flow regimes are shown to be similar to 2D CIJs. This is to our knowledge the first demonstration of 2D turbulence in an industrial mixer/reactor. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2335–2347, 2017

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Section: Problem Descriptionmentioning

confidence: 99%

“…Furthermore, there is a considerable body of experimental data using these fluids from previous works. 27,29,40,42,43,50 The initial condition, was a symmetric and steady state solution, obtained with a no shear wall set at the symmetry plane/ axis, for 2D/3D case, respectively.…”

Section: Boundary Conditionsmentioning

confidence: 99%

On the 2D nature of flow dynamics in opposed jets mixers

et al. 2016

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“…Fig. 2 presents a planar laser-induced fluorescence (PLIF) image of the thin lamina formed by the impingement of both jets being engulfed by vortices that redirect this laminas to the normal direction of the main flow direction [32] where they will be further thinned by a parabolic flow profile [33]. Typically, below the mixing region where the vortices are formed, the RIM mixing chambers are extended through an additional distance of 4D, assuming that t = D/t and _ c ∼ 2t=D.…”

Section: Flow Regime In Cijmentioning

confidence: 99%

“…In the particular case of CIJs for RIM, where the flow is laminar, a lamellar structure is formed after the mixing zone that is further striated in the cylindrical mixing chamber by the parabolic flow profile [33]. The first scale reduction mechanism is the expansion of the jet.…”

Section: Cij Throughputmentioning

confidence: 99%

State of the Art of Mini/Micro Jet Reactors

Santos

Sultan

2013

Chem Eng & Technol

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For over three decades, opposed-jets reactors have been applied particularly for fast complex chemical reactions where mixing affects the final product distribution. The first opposed-jets reactors, i.e., confined impinging jets (CIJ), had cylindrical geometries. With the advent of microreactors, a new type of prismatic opposed-jets reactors has been introduced, the so-called T-jets reactors. The state of the art of the know-how on mixing in CIJ reactors as well as the current state of the art of T-jets reactors is described. T-jets and CIJ are generally small-scale devices, ensuring that these units can mix fluids within very short mixing times on the order of milliseconds. The small scale has the disadvantage of compromising the reactors' throughput. This fact can prevent the dissemination of this type of mixers to applications where conventional reactors, such as stirred tanks, are used. Attention is paid to the issue on how to scale up opposed-jets reactors without compromising mixing times. A short analysis of the main research questions to be answered in this field is made.

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“…A mixing device that explores complex flow patterns for fast mixing of fluids is the confined impinging jets (CIJ) mixer [14][15][16][17][18], which is based on the principle that the energy dissipated from two impinging jets promotes mixing rapidly and without movable mechanical parts [19]. The flow dynamics in CIJ were proven to be mainly two-dimensional (2D) in nature [20], and so 2D computational fluid dynamics (CFD) simulations are often used to study these mixers.…”

Section: Introductionmentioning

confidence: 99%

Proper Orthogonal Decomposition and Statistical Analysis of 2D Confined Impinging Jets Chaotic Flow

et al. 2019

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Proper orthogonal decomposition (POD) is shown to be a statistical operation that identifies the main characteristics of chaotic flows and separates them into a few modes. The dynamic chaotic flow is obtained from two-dimensional (2D) computational fluid dynamics simulations, for different Reynolds numbers, of a confined impinging jets mixer. POD enables reconstruction of the dynamic flow from a few modes that are related to coherent flow structures. The POD flow reconstruction enables a large compression of the flow data set. The decomposition of the flow field into orthogonal modes related to coherent structures provides direct insight into the mixing dynamics and scales which are not accessible from flow dynamics statistic quantities, which were introduced in the context of turbulence and are here applied to chaotic flow.

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Quantification of Mixing in RIM Using a Non-Diffusive Two-Phase Flow Numerical Model

Cited by 15 publications

References 0 publications

On the 2D nature of flow dynamics in opposed jets mixers

On the 2D nature of flow dynamics in opposed jets mixers

State of the Art of Mini/Micro Jet Reactors

Proper Orthogonal Decomposition and Statistical Analysis of 2D Confined Impinging Jets Chaotic Flow

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