Bubble splitting under gas–liquid–liquid three‐phase flow in a double T‐junction microchannel

Abstract

in Wiley Online Library (wileyonlinelibrary.com)Gas-aqueous liquid-oil three-phase flow was generated in a microchannel with a double T-junction. Under the squeezing of the dispersed aqueous phase at the second T-junction (T2), the splitting of bubbles generated from the first T-junction (T1) was investigated. During the bubble splitting process, the upstream gas-oil two-phase flow and the aqueous phase flow at T2 fluctuate in opposite phases, resulting in either independent or synchronous relationship between the instantaneous downstream and upstream bubble velocities depending on the operating conditions. Compared with two-phase flow, the modified capillary number and the ratio of the upstream velocity to the aqueous phase velocity were introduced to predict the bubble breakup time. The critical bubble breakup length and size laws of daughter bubbles/slugs were thereby proposed. These results provide an important guideline for designing microchannel structures for a precise manipulation of gas-liquid-liquid three-phase flow which finds potential applications among others in chemical synthesis.

Manipulation of gas-liquid-liquid systems in continuous flow microreactors for efficient reaction processes

“…Compared with the extensive gas-liquid and liquid-liquid two-phase flow studies in microreactors [23,[45][46][47][48], limited research has been paid to the case of gas-liquid-liquid microflow [11,12,19,29]. A considerable fraction of the literature work in the latter case was focused on hydrodynamics therein [13,14,17,18,49,50], and few on the investigation of mass transfer property [12,14] and the preliminary exploration of the potential applications [21,29,30,38]. Fig.…”

“…Herein, the dispersed phase could be either the discrete bubbles and droplets (e.g., pattern (G-W)/ O as shown in Fig. 1a; the number of bubbles and droplets in a unit cell can vary depending on the operating conditions, which designates different sub-regimes (i) to (iii)) [13,14,18,50,52], or double emulsions that consist of bubbles encapsulated in the droplet of one liquid phase (e.g., pattern G/O/W as shown in Fig. 1b) [17].…”

“…Alternatively, other flow configurations under gas-liquid-liquid slug flow could be designed in the microreactor to provide a direct gas-oil and water-oil contact, such as separately dispersed bubbles and aqueous droplets in the continuous organic phase ((G-W)/O in Fig. 6c) [13,14,50,52] and double emulsions (G/O/W in Fig. 6c) [17].…”

“…1 mm, but this dimension could be extended reasonably to a few millimeters as long as the benefits due to miniaturization is kept [11]. Fluids delivered into the microreactor are commonly mixed and subsequently dispersed into the reaction microchannel via micromixers (e.g., based on a T- [12][13][14], Y- [15,16] or cross-junction [17][18][19], or flow-focusing geometry [16,20]) or membranes [21,22]. Due to the laminar flow nature and the dominance of interface…”

Dynamics and controllability of droplet fusion under gas–liquid–liquid three-phase flow in a microfluidic reactor

“…Yue et al 21 identied the conditions for creating gas-liquid-liquid ow patterns of slug ow and parallel-slug ow along a serpentine channel. Liu et al 22 studied the characteristics of bubble splitting under three-phase ow in a double T-junction microchannel, revealing the critical breaking length and the size of the sub-bubble/slug. More recently, Liu et al 23 further investigated the effects of the threephase slug sub-regime ow on hydrodynamics and local mass transfer, conrming that the alternate bubble and droplet ow is in favor of mass transfer.…”