Experimental study of micromixing in curved tube reactors by the reactive tracer method

Rożeń, A.; Kopytowski, Janusz

doi:10.1016/j.cherd.2020.04.042

Cited by 2 publications

(3 citation statements)

References 37 publications

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“…A similar influence of the initial orientation of the contact surface on the rate of mixing of passive traces in the tubular mixers of curved geometry (helical coils, inverted pipe bends, CFI and CFR) was earlier reported by Mansour et al (2017;2020b) and Khot et al (2019). Rożeń and Kopytowski (2020) recently confirmed this effect for reactive mixing in the twisted bend mixer. Finally, the total area stretch of the material surface and the flow average energetic efficiency of mixing were calculated.…”

Section: Resultssupporting

confidence: 82%

“…Chaotic advection intensifies mixing in a macroscale by narrowing the residence time distribution of fluid elements (Castelain et al, 2000). It also may accelerate mixing in a microscale by enhancing the stretching of material lines (Yamagishi et al, 2007) or by accelerating molecular diffusion of substrates towards the reaction zone (Boesinger et al, 2005;Rożeń and Kopytowski, 2020).…”

Section: Introductionmentioning

confidence: 99%

“…Liang and Zhang (2014) used competitive and consecutive diazo coupling reactions to prove that mixing in the helical coil can be enhanced by reshaping Dean vortices due to cyclic contraction and expansion of the tube cross-section for the Reynolds number exceeding 500. Rożeń and Kopytowski (2020) applied competitive-parallel reactions, i.e. acid-base neutralisation and alkaline ester hydrolysis, to identify the effect of a periodic flow reorientation and an initial inclination of the contact surface of mixed reactant solutions to the curvature plane of the first pipe bend.…”

Section: Introductionmentioning

confidence: 99%

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Chemical and Process Engineering

Rożeń,

Kopytowski

2021

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The energetic efficiency of mixing is studied numerically in a continuous flow mixer constructed from a sequence of alternately twisted pipe bends. Counter-rotating vortices present in the curved channels and known as Dean vortices narrow the distribution of the residence time of fluid elements and accelerate the generation of a new material surface without obstructing the main flow and increasing the risk of fouling or flow stoppage. Cyclic twisting of the pipe curvature allows for quick reorientation of Dean vortices. The reorientation induces chaotic advection in a stable three-dimensional flow and speeds up mixing. The effect of computational domain discretisation for the low and medium Reynolds numbers (20 < Re < 2000) on the head loss, primary and secondary flow, residence time distribution, and the energetic efficiency of generation of the inter material surface is determined. The energetic efficiency is calculated in the time space, a standard approach in modelling reactive micromixing, and at the reactor exit. The maximum energetic efficiency is determined for Re ≈ 600 ÷ 700. It is also found that the initial orientation of the material surface to the pipe curvature has a significant impact on the energetic efficiency of mixing.

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