Effects of dispersed phase viscosity on drop deformation and breakup in inertial shear flow

Komrakova, Alexandra; Shardt, Orest; Eskin, Dmitry; Derksen, J. J.

doi:10.1016/j.ces.2014.12.012

Cited by 30 publications

(23 citation statements)

References 30 publications

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“…However, as a limitation of our simulation technique (and every other diffuse interface method), the interface width extends over a few computational grid cells. The ratio between ζ and the droplet diameter d is termed the Cahn number Ch = ζ/d (Komrakova et al 2015b), and extreme values of Ch are undesirable. Hence the relative separation between d and ζ needs to be considered.…”

Section: Length Scalesmentioning

confidence: 99%

See 1 more Smart Citation

Droplet–turbulence interactions and quasi-equilibrium dynamics in turbulent emulsions

Mukherjee

Safdari²,

Shardt³

et al. 2019

J. Fluid Mech.

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We perform direct numerical simulations (DNSs) of emulsions in homogeneous, isotropic turbulence using a pseudopotential lattice-Boltzmann (PP-LB) method. Improving on previous literature by minimizing droplet dissolution and spurious currents, we show that the PP-LB technique is capable of long, stable simulations in certain parameter regions. Varying the dispersed phase volume fraction φ, we demonstrate that droplet breakup extracts kinetic energy from the larger scales while injecting energy into the smaller scales, increasingly with higher φ, with the Hinze scale dividing the two effects. Droplet size (d) distribution was found to follow the d −10/3 scaling (Deane & Stokes 2002). We show the need to maintain a separation of the turbulence forcing scale and domain size to prevent the formation of large connected regions of the dispersed phase. For the first time, we show that turbulent emulsions evolve into a quasi-equilibrium cycle of alternating coalescence and breakup dominated processes. Studying the system in its state-space comprising kinetic energy E k , enstrophy ω 2 and the droplet number density N d , we find that their dynamics resemble limit-cycles with a time delay. Extreme values in the evolution of E k manifest in the evolution of ω 2 and N d with a delay of ∼ 0.3T and ∼ 0.9T respectively (with T the large eddy timescale). Lastly, we also show that flow topology of turbulence in an emulsion is significantly more different than singlephase turbulence than previously thought. In particular, vortex compression and axial straining mechanisms become dominant in the droplet phase, a consequence of the elastic behaviour of droplet interfaces.

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Section: Length Scalesmentioning

confidence: 99%

“…2017) and droplet breakup in Stokes (Liu, Valocchi & Kang 2012) and inertial (Komrakova et al. 2015 b ) shear flows. Some examples of the PP-LB method in particular are simulations of multiple bubble dynamics (Gupta & Kumar 2008), droplet deformation and breakup in shear flow (Xi & Duncan 1999; Biferale et al.…”

Section: Introductionmentioning

confidence: 99%

Droplet–turbulence interactions and quasi-equilibrium dynamics in turbulent emulsions

Mukherjee

Safdari²,

Shardt³

et al. 2019

J. Fluid Mech.

Self Cite

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“…In this case, the fourth breakup mechanism ‐ burst breakup ‐ occurs. This type of drop breakup was discussed previously by Komrakova et al and Shao et al, who performed numerical simulations of single drop breakup. Burst breakup was missing in the classification of drop breakup mechanisms outlined by Solsvik et al, most likely because the experimental conditions and technique did not allow them to capture such an event.…”

Section: Resultsmentioning

confidence: 54%

“…The implementation of the method was verified and then validated by simulation of the gravity‐driven rise of a single drop, drop deformation, and breakup in a simple shear flow . Then it was applied to simulations of liquid‐liquid dispersions .…”

Section: Introductionmentioning

confidence: 99%

Single drop breakup in turbulent flow

Komrakova

2019

Can J Chem Eng

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The breakup process of a single drop in homogeneous isotropic turbulence was studied using direct numerical simulations. A diffuse interface free energy lattice Boltzmann method was applied. The detailed visualization of the breakup process confirmed breakup mechanisms previously outlined such as initial, independent, and cascade breakups. High-resolution simulations allowed to visualize another drop breakup mechanism, burst breakup, which occurs when the mother drop has a large volume, and the flow is highly turbulent. The simulations indicate that the type of the breakup mechanism is a strong function of mother drop size and energy input. Large mother drops in highly turbulent flow fields are more likely to burst, producing a large number of drops of the size close to the Kolmogorov length scale. Small drops in moderate turbulence tend to break only once (initial breakup). The interfacial energy of a drop was tracked as a function of time during drop deformation and breakage. The maximum energy level of the deformed mother drop was compared to commonly used estimates of critical energy necessary to break a drop. Our results show that these reference levels of critical energy are usually underestimated. Moreover, in some cases even if the critical energy level was exceeded, the drop did not break because the time of the interaction between the drop and the eddies was not enough to finish the breakup. The numerical insight presented here can be used as a guideline for the selection of assumptions and simplifications behind breakup kernels.

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“…Since the interface is moving, interfacial tension is taken into consideration in the motion equation [26,27].…”

Section: Motion Equationmentioning

confidence: 99%

Numerical Simulation of Residual Oil Flooded by Polymer Solution in Microchannels

et al. 2018

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This paper establishes a flow equation using non-Newtonian fluid mechanics and defines the deformation of residual oil using numerical computation in order to conduct a study on the flow law of residual oil in microchannels of rock during polymer flooding, the influence of flooding fluid elasticity on the deformation of residual oil, and flooding mechanism of viscoelastic displacing fluid. Computation shows that advancing contact angle increases and receding contact angle decreases as the viscosity ratio decreases. The higher elasticity of polymer solution with higher concentration or molecular weight leads to significantly more obvious deformation of residual oil and benefits migration and stripping of residual oil. The impact of the initial wetting angle of residual oil film on deformation is analyzed. A smaller initial wetting angle corresponds to a bigger change of advancing contact angle and smaller change of receding contact angle. A better understanding of the flooding process is gained via a study on residual oil deformation in polymer flooding. Consequently, oil flooding efficiency and oil recovery can be enhanced. This is the hydrodynamic mechanism of enhanced oil recovery (EOR) by polymer flooding.

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Effects of dispersed phase viscosity on drop deformation and breakup in inertial shear flow

Cited by 30 publications

References 30 publications

Droplet–turbulence interactions and quasi-equilibrium dynamics in turbulent emulsions

Droplet–turbulence interactions and quasi-equilibrium dynamics in turbulent emulsions

Single drop breakup in turbulent flow

Numerical Simulation of Residual Oil Flooded by Polymer Solution in Microchannels

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