Determination of Mixing Times with Helical Ribbon Impeller for Non‐Newtonian Viscous Fluids Using an Advanced Imaging Method

Chhabra, R.P.; Bouvier, Laurent; Delaplace, Guillaume; Cuvelier, Gérard; Domenek, Sandra; André, Christophe

doi:10.1002/ceat.200700320

Cited by 9 publications

(3 citation statements)

References 11 publications

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“…8–10 For each run, a colorimetric diagnosis was applied based on the image analysis captured by the webcam. More details about the tracer injection and colorimetric diagnosis are given elsewhere 9–11. In this work, we used the evolution of the level of brightness of the green color S , captured on a digital image representing the tank, to reconstruct the homogenization progress.…”

Section: Methodsmentioning

confidence: 99%

An arrangement of ideal reactors as a way to model homogenizing processes with a planetary mixer

Delaplace¹,

Bouvier²,

Moreau³

et al. 2010

AIChE J.

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This article investigates ways of modeling the homogenization mechanism occurring when mixing highly viscous Newtonian fluids with a planetary mixer. In particular, an arrangement of ideal reactors containing a perfect-mixed zone sweeping out a torus reactor is proposed to represent the dynamics of the mixing process. The originality of the arrangement of ideal reactors developed is due to the time-dependent location of the perfect-mixed zone in the torus which mimics the periodic revolution motion of the agitator around the vertical and central axis in the vessel. To ascertain the reliability of the method proposed, tracer injections were carried out with a planetary mixer named TRIAXE V R system. It is shown that modeling results are in close agreement with experimental ones on the whole range of impeller revolution speeds tested. The model proposed captures well the physical mixing phenomena.

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Section: Methodsmentioning

confidence: 99%

An arrangement of ideal reactors as a way to model homogenizing processes with a planetary mixer

Delaplace¹,

Bouvier²,

Moreau³

et al. 2010

AIChE J.

View full text Add to dashboard Cite

show abstract

“…These geometries are almost universally employed in the blending of complex fluids, as they all possess low power draw in laminar flow. Direct torque measurement has been performed to obtain power curves in laminar flow (Fradette et al, 2007;Zhang et al, 2013;Fontaine et al, 2013), whilst flow measurements have been found using both intrusive methods such as Laser Doppler Anemometry (Jahangiri, 2007) and nonintrusive methods investigating opaque systems (Patel et al, 2014;Ihejirika and Ein-Mozaffari, 2007) and transparent varieties (Stobiac et al, 2014;Chhabra et al, 2007;Shervin et al, 1991). PIV measurements have become prevalent as the method of choice for non-intrusive determination of flow fields, owing to their non-intrusive nature and ease of application.…”

Section: Figure 1: Typical Butterfly Impellermentioning

confidence: 99%

“…Ozcan-Taskin & Nienow (1995) investigated flow fields and calculated mixing times for low elasticity fluids using a fibre-optic technique, additionally calculating mixing times in viscoelastic media, whilst a colorimetric method was adopted by Chhabra et al (2007).…”

Section: Figure 1: Typical Butterfly Impellermentioning

confidence: 99%

Mixing of Newtonian and viscoelastic fluids using “butterfly” impellers

Ramsay

Simmons

Ingram

et al. 2016

Chemical Engineering Science

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The mixing of high viscosity and viscoelastic fluids may be performed in industry using a "butterfly" impeller, which has received scant attention. This paper describes the characterisation of these impellers using both Newtonian and viscoelastic (Boger) fluids with an identical base viscosity under laminar flow conditions in batch tanks without baffles. Measurements are made using two rotational speeds (N = 30 or 60 rpm) over a wide range of impeller to tank diameter ratios from 0.53 to 0.98.Particle Image Velocimetry (PIV) and Planar Laser Induced Fluorescence (PLIF) have been used to determine local velocity fields, shear rates, flow numbers and mixing times respectively, with impeller power number Po obtained from torque measurements. A down-pumping flow pattern is observed, with maximum normalised velocities of 25% of the impeller tip speed observed in the axial plane, increasing to 60% in the rotational plane due to solid body rotation. Angle resolved measurements found these to be slightly increased as the impeller passes the image plane, with viscoelastic fluids displaying a greater uniformity of velocity across the image planes due to elastic energy storage. Maximum shear rates are greatest between the impeller and the wall, yet remain low i.e. O (10) s -1 . Mixing times obtained from PLIF show that mixing times in viscoelastic fluids show a slight reduction compared to the Newtonian equivalent. The impeller power number was determined as Po = 0.6 in the turbulent regime, while the laminar constant K p and the Metzner-Otto constant k s were equal to 122 and 16.0 respectively. Highlights: "Butterfly" impellers used for processing of viscoelastic fluids. Low impeller Power number Po due to low blade area. Maximum shear rates of 17 s -1 in region between impeller and wall at N = 60 rpm. Mixing times longer in viscoelastic fluids due to elastic effects.

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Incompressible SPH modeling and analysis of non-Newtonian power-law fluids, mixing in a microchannel with an oscillating stirrer

2016

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Determination of Mixing Times with Helical Ribbon Impeller for Non‐Newtonian Viscous Fluids Using an Advanced Imaging Method

Cited by 9 publications

References 11 publications

An arrangement of ideal reactors as a way to model homogenizing processes with a planetary mixer

An arrangement of ideal reactors as a way to model homogenizing processes with a planetary mixer

Mixing of Newtonian and viscoelastic fluids using “butterfly” impellers

Incompressible SPH modeling and analysis of non-Newtonian power-law fluids, mixing in a microchannel with an oscillating stirrer

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