Break-up of a drop in a stirred tank

Hančil, V.; Rod, Vladimír

doi:10.1016/0255-2701(88)80015-1

Cited by 24 publications

(12 citation statements)

References 6 publications

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“…Moreover, the number of data was not relevant on a statistical point of view (less than 100 breakage events for most of tested conditions). Realizing this, Hančil and Rod (1988) tested breakup dynamics of single drop with controlled size in a stirred tank; they indicated that the number of daughter drops increases with the mother drop size and presents to be a random variable over 2 by averaging. Similar conclusion was made by Bahmanyar and Slater (1991) from the observations in a rotating contact disc system, reporting that two to three child drops are commonly produced, with five drops at the most.…”

Section: Experimental Investigations On Single Drop Breakupmentioning

confidence: 99%

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Experimental investigation on single drop breakage in two-stream impinging microchannels

Bellettre

Montillet

et al. 2021

Exp Fluids

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Experimental study on drop breakage is carried out in the microchannels utilizing head-on impingement configuration by observing single drop breakup process. In this study, the breakage of oil drops with diameter ranging from 30 to 200 μm is investigated in the vicinity of flows impingement region by using high-speed photography at varied flow rate conditions. The most prominent phenomenon of the single drop breakup in the two streams impinging flow field is that the drop tends to break into multiple fragments. The breakage time and the number of daughter drops in the resulting population are statistically analysed and found to be highly dependent on the mother drop size and energy dissipation rate. Two different micro-system geometries, the 600-600 system and the 600-300 system, are compared to evaluate the advantages and disadvantages of swirl flow developed due to the off-axis layout of inlet channels in the 600-300 system. The results show that swirl flow establishes a low pressure area acting as the dead zone, where drop can be trapped and then drastically stretched to breakup. Compared with the 600-600 system, the detrimental effect of swirl flow inside the 600-300 system on increasing the breakage time can be offset by much greater amount of daughter drops generated. In general, the 600-300 system performs more effectively than the 600-600 system because of the less isotropic flow feature. And this superiority is more distinct when energy dissipation rate is higher. Acronyms Ca Capillary number,-DDSD daughter drop size distribution,-Re Reynolds number,-SSI swirl strength index,-We Weber number,-Wet Weber number in turbulent flow,-We* Weber number defined in this study,

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Section: Experimental Investigations On Single Drop Breakupmentioning

confidence: 99%

“…Device (m 2 /s 3 ) 0 (mm) (ms) ( 0 ) Konno et al (1983) Stirred tank 0.25-1.4 0.26-1 1.4-6.9 2.6-4.4 Hančil and Rod (1988) Stirred tank -0.9-2.1 2.7-26.7…”

Section: Refmentioning

confidence: 99%

Experimental investigation on single drop breakage in two-stream impinging microchannels

Bellettre

Montillet

et al. 2021

Exp Fluids

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“…Binary breakup, when a mother drop splits into two daughter drops of equal or comparable size, is commonly assumed in modelling. However, experimental observations show that satellites and sub‐satellites can also be generated. The consistent conclusion among the published data on a single drop breakup is that the number of daughter drops is an increasing function of a mother drop size.…”

Section: Resultsmentioning

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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“…The breakage birth term

{PB}^{+}

characterized the gain of drops from mother drop breakup with diameter

d_{j}

β ((),, d_{i}, d_{j})

is the volumetric density distribution of daughter drops with diameter

d_{i}

generated from this process, as proposed by Bahmanyar and Slater 37 :

β ((),, d_{i}, d_{j}) = 3 n_{dd} ((), n_{dd} - 1) \frac{{d_{i}}^{5}}{{d_{j}}^{6}} {[1 - {((), \frac{d_{i}}{d_{j}})}^{3}]}^{n_{dd} - 1},

where

n_{dd}

is the mean number of daughter drops and can be defined by empirical equation 38 :

n_{dd} = 2 + C_{normaln 1} {(\frac{d_{j}}{d_{crit}} - 1)}^{C_{n 2}},

…”

Section: Population Balance Modelmentioning

confidence: 99%

Drop sizes and population balance model for a Karr column

Zhang

Mumford

et al. 2021

AIChE Journal

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Drop sizes were investigated and measured in a Karr column. A stagewise population balance model was presented considering drop breakage and coalescence. The same breakage mechanisms observed in the single drop study were also found in column. The breakage probability model was selected by comparing the model from single drop study and the widely used models. Model parameters were calculated based on a two‐step optimization method. The results showed that the drop sizes decreased with an increase in reciprocating intensity, but changed slightly with phase velocities. The predicted drop sizes were compared to the experimental data in previous studies and good agreement was achieved. Finally, the population balance model along with some existing correlations were compared with the experimental data. It was found that the population balance model and correlations with the low agitation term provided better predictions of drop sizes in the Karr column. Transport Phenomena and Fluid Mechanics: Karr column, drop size distribution, population balance model, parameter optimization.

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Break-up of a drop in a stirred tank

Cited by 24 publications

References 6 publications

Experimental investigation on single drop breakage in two-stream impinging microchannels

Experimental investigation on single drop breakage in two-stream impinging microchannels

Single drop breakup in turbulent flow

Drop sizes and population balance model for a Karr column

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