Flow studies in an in-line Silverson 150/250 high shear mixer using PIV

Espinoza, C.J.U.; Simmons, Mark; Alberini, Federico; Mihailova, Olga; Rothman, D.; Kowalski, Adam

doi:10.1016/j.cherd.2018.01.028

Cited by 14 publications

(12 citation statements)

References 26 publications

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“…This could be due to the fact that for this particular hole size, the rotor doesn't entirely cover the top and bottom rows of holes. Similar results to this have been found byEspinoza et al (2018), who used particle image velocimetry (PIV) to study the flow field of an in-line Silverson mixer. They also concluded that the flow was non-uniform across the rows of holes in the stator screen.…”

supporting

confidence: 82%

Linking power and flow in rotor-stator mixers

John

Panesar

Kowalski

et al. 2019

Chemical Engineering Science

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The relationship between power and flow characteristics of batch rotor-stator mixers has been studied using CFD simulations with experimental power validation. The mixer studied was the Silverson L5M batch mixer with the standard emulsor head. The size of the holes in the screen and the constriction of the base hole were changed in small increments. The MRF technique was used to model rotor rotation. A model is developed in this study which links the power and flow numbers of the mixer. Since power is easy to measure experimentally, one can use this model to predict the flow number by measuring torque. A second model is also developed which allows one to predict the flow number using solely the geometry of the mixing head. This study greatly enhances our understanding of the relationship between power, flow and mixer geometry in rotor-stator mixers.

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supporting

confidence: 82%

Linking power and flow in rotor-stator mixers

John

Panesar

Kowalski

et al. 2019

Chemical Engineering Science

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“…(Fig. 3, 4 and 5), scattering the laser required for effective PIV measurement [38]. As the distance from the tip was increased further, there was an increase in the observed velocity in all cases, with the exception of the glycerol and CMC solutions ( Fig.…”

Section: Comparative Assessment Of the Performance Of The Investigatementioning

confidence: 87%

“…PIV experimentation was conducted using a similar approach to that as detailed by Gabriele and co-authors [32] and Espinoza and co-authors [38], with some modifications required for the specific experimental setup in this study, and updates to the PIV setup, as detailed in Fig. 1 The delay between each frame in an image pair, ∆t d , was chosen in relation to the maximum displacement that a particle could travel in the defined interrogation window.…”

Section: Piv Experimentation and Processing Of Datamentioning

confidence: 99%

Characterisation of flow behaviour and velocity induced by ultrasound using particle image velocimetry (PIV): Effect of fluid rheology, acoustic intensity and transducer tip size

O’Sullivan

Espinoza

Mihailova

et al. 2018

Ultrasonics Sonochemistry

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Acoustic streaming phenomena of ultrasound propagation through liquid media was investigated experimentally employing particle image velocimetry (PIV). Parameters associated with the ultrasonic processor of ultrasonic amplitude (i.e., acoustic power) and transducer tip diameter (i.e., surface area), as well as, fluid rheology (i.e., water, glycerol solution and CMC solution), were studied for their effects on overall flow behaviour and fluid velocity. PIV yielded velocity gradient maps, demonstrating the acoustic streaming phenomena of ultrasound and its associated flow behaviour as a function of ultrasonic amplitude and fluid rheology, whereby increasing amplitude allowed for greater penetration of the acoustic-beam through the bulk of the fluid, and increasing fluid rheology yielded the converse effect. Moreover, upon impingement of the acoustic-beam with the base of vessel, vortex formation occurred, yielding a recirculation pattern. The maximum observed fluid velocities for water, glycerol solution and CMC solution were 0.329 m s, 0.423 m s, and 0.304 m s, respectively (large diameter sonotrode tip for an ultrasonic amplitude of 80%). Furthermore, shear rates were attained (maximum values of 24.25 s), and Reynolds numbers were determined in order to assess the degree of turbulence as a function of investigated parameters.

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“…Note that the jet attaches to the leading edge of the stator and that the jet only fills a small portion of the slot [8,11,12]. This gives rise to a re-circulation region in the slots and, consequently, a "back-flow" of fluid that re-enters the slot from the bulk without passing the rotor [5,8,12,15,17,18].…”

Section: The Rotor-stator Mixermentioning

confidence: 99%

Rotor-Stator Mixers: From Batch to Continuous Mode of Operation—A Review

Håkansson

2018

Processes

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Although continuous production processes are often desired, many processing industries still work in batch mode due to technical limitations. Transitioning to continuous production requires an in-depth understanding of how each unit operation is affected by the shift. This contribution reviews the scientific understanding of similarities and differences between emulsification in turbulent rotor-stator mixers (also known as high-speed mixers) operated in batch and continuous mode. Rotor-stator mixers are found in many chemical processing industries, and are considered the standard tool for mixing and emulsification of high viscosity products. Since the same rotor-stator heads are often used in both modes of operation, it is sometimes assumed that transitioning from batch to continuous rotor-stator mixers is straightforward. However, this is not always the case, as has been shown in comparative experimental studies. This review summarizes and critically compares the current understanding of differences between these two operating modes, focusing on shaft power draw, pumping power, efficiency in producing a narrow region of high intensity turbulence, and implications for product quality differences when transitioning from batch to continuous rotor-stator mixers.

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Flow studies in an in-line Silverson 150/250 high shear mixer using PIV

Cited by 14 publications

References 26 publications

Linking power and flow in rotor-stator mixers

Linking power and flow in rotor-stator mixers

Characterisation of flow behaviour and velocity induced by ultrasound using particle image velocimetry (PIV): Effect of fluid rheology, acoustic intensity and transducer tip size

Rotor-Stator Mixers: From Batch to Continuous Mode of Operation—A Review

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