On the CFD modelling of Taylor flow in microchannels

Gupta, Raghvendra; Fletcher, David F.; Haynes, Brian S.

doi:10.1016/j.ces.2009.03.018

Cited by 312 publications

(211 citation statements)

References 52 publications

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“…It is thus imperative to refine mesh far beyond the unphysical ranges. Gupta et al 38 provide very useful guidelines on mesh resolution and solver settings to accurately model microchannel flows using ANSYS Fluent. Figure 4(b) also shows the change in flow regime from MDF to ADF while changing the mesh resolution.…”

Section: B Code Validationmentioning

confidence: 99%

A numerical study on the dynamics of droplet formation in a microfluidic double T-junction

et al. 2015

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In this study, droplet formations in microfluidic double T-junctions (MFDTD) are investigated based on a two-dimensional numerical model with volume of fluid method. Parametric ranges for generating alternating droplet formation (ADF) are identified. A physical background responsible for the ADF is suggested by analyzing the dynamical stability of flow system. Since the phase discrepancy between dispersed flows is mainly caused by non-symmetrical breaking of merging droplet, merging regime becomes the alternating regime at appropriate conditions. In addition, the effects of channel geometries on droplet formation are studied in terms of relative channel width. The predicted results show that the ADF region is shifted toward lower capillary numbers when channel width ratio is less than unity. The alternating droplet size increases with the increase of channel width ratio. When this ratio reaches unity, alternating droplets can be formed at very high water fraction (wf ¼ 0.8). The droplet formation in MFDTD depends significantly on the viscosity ratio, and the droplet size in ADF decreases with the increase of the viscosity ratio. The understanding of underlying physics of the ADF phenomenon is useful for many applications, including nanoparticle synthesis with different concentrations, hydrogel bead generation, and cell transplantation in biomedical therapy. V C 2015 AIP Publishing LLC. [http://dx

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Section: B Code Validationmentioning

confidence: 99%

A numerical study on the dynamics of droplet formation in a microfluidic double T-junction

et al. 2015

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“…Also, for the formation of the bubbles, a threshold value of wall contact angle for different capillary number was proposed. Gupta et al 20 carried out CFD simulation of Taylor flow in circular channel of diameter 0.5 mm and length of 10d having air and water as the working fluids using commercial software Fluent. The VOF method, CSF method and QUICK scheme were adopted and suggested the use of finer mesh near the wall in order to capture wall liquid film.…”

Section: Numerical Studies On Microfluidic Slug Flowmentioning

confidence: 99%

Numerical Study on Bubble Dynamics and Two-Phase Frictional Pressure Drop of Slug Flow Regime in Adiabatic T-junction Square Microchannel

Kishor

Chandra

Khan

et al. 2017

Chem.Biochem.Eng.Q.

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In this study, bubble dynamics and frictional pressure drop associated with gas liquid two-phase slug flow regime in adiabatic T-junction square microchannel has been investigated using CFD. A comprehensive study on the mechanism of bubble formation via squeezing and shearing regime is performed. The randomness and recirculation profiles observed in the squeezing regime are significantly higher as compared to the shearing regime during formation of the slug. Further, effects of increasing gas velocity on bubble length are obtained at fixed liquid velocities and simulated data displayed good agreement with available correlations in literature. The frictional pressure drop for slug flow regime from simulations are also obtained and evaluated against existing separated flow models. A regression correlation has also been developed by modifying C-parameter using separated flow model, which improves the prediction of two-phase frictional pressure drop data within slug flow region, with mean absolute error of 10 %. The influences of fluid properties such as liquid viscosity and surface tension on the two-phase frictional pressure drop are also investigated and compared with developed correlation. The higher liquid viscosity and lower surface tension value resulted in bubble formation via shearing regime.

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“…The inner cylinder is rotated at a certain speed. On reaching the critical speed of rotation there are formed axially symmetric toroidial vortex structures -Taylor vortices [3]. The aim is to show the advantages and disadvantages of two possible methods of mathematical modeling of hydrodynamic instabilities which are arising in sealing gaps.…”

Section: Introductionmentioning

confidence: 99%

Comparison of two methods of mathematical modeling in hydrodynamic sealing gap

Krutil

Fojtášek

Dvořák

2015

EPJ Web of Conferences

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Abstract. The aim of work is to compare two possible methods of mathematical modeling of hydrodynamic instabilities. This comparison is performed by monitoring the formation and evolution of Taylor vortices in hydrodynamic sealing gap. Sealing gaps are a part of the hydraulic machines with the impeller, such as turbines and pumps, and they have an effect on the volumetric efficiency of these devices. This work presents two examples of sealing gaps. These examples are closed sealing gap and modified sealing gap with expansion chamber. On these two examples are applied procedures of solution contained in CFD software (ANSYS Fluent 14.5). In ANSYS Fluent is two possible basic approaches of solution this task: the moving wall method and the sliding mesh method. The result of work is monitoring the impact of the expansion chamber on the formation of hydrodynamic instabilities in the sealing gap. Another result is comparison of two used methods of mathematical modeling, which shows that both methods can be used for similar tasks.

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On the CFD modelling of Taylor flow in microchannels

Cited by 312 publications

References 52 publications

A numerical study on the dynamics of droplet formation in a microfluidic double T-junction

A numerical study on the dynamics of droplet formation in a microfluidic double T-junction

Numerical Study on Bubble Dynamics and Two-Phase Frictional Pressure Drop of Slug Flow Regime in Adiabatic T-junction Square Microchannel

Comparison of two methods of mathematical modeling in hydrodynamic sealing gap

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