Experimental study of mixing enhancement of viscous liquids in confined impinging jets reactor at low jet Reynolds numbers

Shi, Z.B.; Li, wei-feng; Du, Ke-jiang; Liu, Haifeng; Wang, Fuchen

doi:10.1016/j.ces.2015.08.014

Cited by 23 publications

(10 citation statements)

References 26 publications

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“…The velocity dynamics at the impact point of an opposed jets mixer has a complex quasi‐oscillatory behaviour that is described with detail in previous works . The flow in opposed jets at chaotic flow regimes, where the Reynolds number is still in the laminar range, has been mainly assessed from the frequencies of flow oscillations . The frequency of the jets oscillations is set from the rate of formation of the vortices that issue from the jets impingement point creating a vortex street throughout the mixing chamber.…”

Section: Resultsmentioning

confidence: 99%

“…29,33,36,42 The flow in opposed jets at chaotic flow regimes, where the Reynolds number is still in the laminar range, has been mainly assessed from the frequencies of flow oscillations. 29,33,[51][52][53][54][55] The frequency of the jets oscillations is set from the rate of formation of the vortices 29 that issue from the jets impingement point creating a vortex street throughout the mixing chamber. Figure 3 shows a short sequence of flow maps from 2D simulation over a period of 0:24s, which is long enough to show the evolution of a vortex over a distance larger than one chamber width (>D).…”

Section: Turbulence Dynamics In 2dmentioning

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: Resultsmentioning

confidence: 99%

Section: Turbulence Dynamics In 2dmentioning

confidence: 99%

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

et al. 2016

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“…For some industrial formulations, the Reynolds number from the lower viscosity stream is often above this range, but the flow features are mainly determined from the smaller Re stream 25 . Detailed analysis of flow regimes in CIJs from PLIF and other visualization techniques is well established in the literature 34–36 …”

Section: Cfd Modelmentioning

confidence: 99%

Rheokinematics for product development—Formulation screening in rotational rheometers

et al. 2022

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Product formulations for industrial processes are typically developed at laboratory scale. However, the mixing conditions are not easily mimicked in the laboratory. A rotational device is proposed in this study as a fast laboratory‐scale formulation development, which enables mimicking the mixing conditions in the industrial process. The geometrical configurations of the rotational device are from rheometry devices (plate‐plate and cone‐plate). The main advantages of this method are the small amounts of raw materials and shorter testing times. This methodology is applied to an industrial case study, the reaction injection molding (RIM) process. The mixing length scales evolution in the rotational rheometer were matched to those in RIM machines. The main novelty of this study is the introduction of a protocol that bridges the processing conditions at laboratory using small amounts of raw materials to high throughput continuous flow reactors.

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“…Effective mixing up to scales required for polymerization depends on the combined engulfment of the two monomer streams that only occurs when dynamic structures are formed in the CIJ mixing chamber (Lee et al, 1980). Several authors have studied the mixing in CIJs from flow visualizations and reported two distinct flow regimes, segregated and chaotic flow regime (Lee et al, 1980;Tucker and Suh, 1980;Johnson et al, 1996;Johnson, 2000b;Santos et al, 2008;Santos et al, 2009;Fonte et al, 2015;Shi et al, 2015). Figure 1 shows PLIF images of mixing of a jet dyed with rhodamine, represented in dark colour, and a clear jet for both flow regimes.…”

Section: Introductionmentioning

confidence: 99%

Fully resolved modelling and simulation of micromixing in confined impinging jets

Brito

Dias

Santos

et al. 2020

Chemical Engineering Science

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Confined Impinging Jets (CIJs) are fast mixing meso sized devices for fast reaction applications, where two opposed jets contact the reactants that are mixed by chaotic flow patterns in very short times. Fully resolved CFD chemical reaction in CIJs is out of reach for engineering practice since on the order of 10 11 computational cells would be required. This paper presents a theoretical methodology to describe micromixing in CIJs using a lamellar model that considers the dynamics of striation thinning and diffusion at the interface of the mixing fluids. A lamellar micromixing (LM) model based on mixing evolution functions was applied to simulate chemical reactions. The evolution of mixing scales in CIJs was also studied from fully-resolved CFD simulations that validate the mixing scales predicted from theoretical models. This LM model completely describes the experimental results, and it is thus directly applicable to the design of CIJs technology for chemical processes.

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Experimental study of mixing enhancement of viscous liquids in confined impinging jets reactor at low jet Reynolds numbers

Cited by 23 publications

References 26 publications

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

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

Rheokinematics for product development—Formulation screening in rotational rheometers

Fully resolved modelling and simulation of micromixing in confined impinging jets

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