Segregated regions in continuous laminar stirred tank reactors

Arratia, Paulo E.; Lacombe, Justin; Shinbrot, Troy; Muzzio, Fernando J.

doi:10.1016/j.ces.2003.06.003

Cited by 31 publications

(14 citation statements)

References 21 publications

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“…documented the complex structural patterns occurring in un-baffled laminar stirred tanks and the mixing mechanisms responsible for chaotic mixing on them. More recently, Arratia et al (2004) explored mixing and flow patterns in continuous stirred tanks operated in laminar regimes. In this communication, we expand those observations to the context of typical bioreactor geometries, using simple visualization techniques to demonstrate the most common mixing pathologies (deviations from the assumption of a perfectly mixed environment) observable in laminar and transitional stirred tanks.…”

Section: Introductionmentioning

confidence: 99%

Experimental visualization of mixing pathologies in laminar stirred tank bioreactors

Álvarez

Guzmán

Elias

2005

Chemical Engineering Science

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Section: Introductionmentioning

confidence: 99%

Experimental visualization of mixing pathologies in laminar stirred tank bioreactors

Álvarez

Guzmán

Elias

2005

Chemical Engineering Science

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“…Arratia et al, 20 Bonnot et al, 4 and Cabaret et al 21,22 used a digital camera for recording in the course of the experiment and obtained the curve of mixing time t by extracting G values from RGB images before and after uniform mixing. A similar method was used to extract RGB images in the video before and after uniform mixing, the mean value of R in each RGB image was calculated, and thereby the curve of corn syrup concentration M changing with time t was obtained.…”

Section: Mixing Experimentsmentioning

confidence: 99%

Study on double-shaft mixing paddle undergoing planetary motion in the laminar flow mixing system

Zhang

et al. 2015

Advances in Mechanical Engineering

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This article has studied the impact of double-shaft mixing paddle undergoing planetary motion on laminar flow mixing system using flow field visualization experiment and computational fluid dynamics simulation. Digital image processing was conducted to analyze the mixing efficiency of mixing paddle in co-rotating and counter-rotating modes. It was found that the double-shaft mixing paddle undergoing planetary motion would not produce the isolated mixing regions in the laminar flow mixing system, and its mixing efficiency in counter-rotating modes was higher than that in co-rotating modes, especially at low rotating speed. According to the tracer trajectory experiment, it was found that the path line of the tracer in the flow field in co-rotating modes was distributed in the opposite direction to the path line in counterrotating modes. Planetary motion of mixing paddle had stretching, shearing, and folding effects on the trajectory of the tracer. By means of computational fluid dynamics simulation, it was found that axial flows and tangential flows produced in co-rotating and counter-rotating modes have similar flow velocity but opposite flow directions. It is deduced from the distribution rule of axial flow, radial flow, and tangential flow in the flow field that axial flow is the main reason for causing different mixing efficiencies between co-rotating and counter-rotating modes.

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“…The RTD of a system represented by a rigid pipe and laminar flow is a specific case typical for the food industry, for flow in micro-channels, in meso-reactors and micro-reactors [7]. Modeling of mixing processes in deterministic laminar flows has not received much attention, and detailed description of such flows is still lacking, though utility of these systems is significant [8]. The models that demand moderate computational time and still accurate enough to be practically useful are to be developed [9].…”

Section: Introductionmentioning

confidence: 99%