Slug-flow generation

Figure 7.5 Five steps of Taylor (slug) flow generation. Dispersed gas phase is introduced through side channel while wetting continuous phase is introduced through main channel.

Kashid, M.N., Renken, A., and Kiwi-Minsker, L. (2010) CFD modelling of liquid-liquid multiphase microstructured reactor slug flow generation. 

Figure 1.17 Example of slug-flow generation back into the original liquid phases using a and liquid phase separation on a chip fabricated phase separator that comprises numerous very from polytetrafluoroethylene (capped with light- narrow but high-aspect-ratio ducts at the outlet, transmissive perfluoroalkoxy). Here, chloroform Water phase is colored, whereas the chloroform (organic phase) and water form the segmented is colorless, flow stream, which is subsequently separated...

The first flow pattern zone corresponds to the isolated bubble (IB) regime where the bubble generation rate is much higher than the coalescence rate. It includes both bubbly flow and/or slug flows and is present up to the onset of coalescence process domination. The second zone is the coalescing bubble (CB) regime, which is... 

Experimentally generated data have quantitatively shown a tendency of increased solids deposition at lower gas mass flow rate in slug flows except that, below a certain amount of solids mass flow rate, the deposition becomes independent of the gas flow rate, which is due to particle fluidised motion before a slug flow commences. Further work will focus on experiments with a wider range of flow conditions using sophisticated measuring tools to validate the model and to build up a quantitative protocol for the description of solids deposition in conveying pipes. 

Bubble induced secondary flow Moving bubbles generate secondary flows and wakes which promote local mixing near the membrane surface. Slug flow also results in an annular falling film as displaced liquid flows downward between the slug and the tube wall. 

Slug flow At higher velocities, the waves generated are so large that their crests can touch the upper surface of the channel, and it is possible that this surface will become wetted by the liquid under these conditions. 

The Heck-Matsuda reaction has also been subjected to continuous flow chemistry conditions, as reported by Wirth et al. [100]. The reaction that was studied involved the reaction between an in situ generated diazonium ion and/r-fluorostyrene to give ( )-/ -fluorostilbene (Scheme 1.35) and the device used by this group relied on a segmented flow (liquid-liquid slug flow) to increase reaction rates in microfluidic flow. They used perfluorodecalin as an inert and immiscible liquid spacer. 

In the first step, the influence of ultrasound on the slug flow of a liquid-liquid two-phase system in a channel was monitored with a high-speed camera. The observable influence is mainly due to bubbles with vibrating surfaces that are formed due to the ultrasound irradiation. Thus, unstable emulsions are generated within the segments, which themselves remain. In order to quantify the influence of ultrasound, the hydrolysis of p-nitrophenyl acetate (42) was utilized. Microstructures of varying material (PEEK, glass) with different... 

Two-phase liquid-gas slug flow is usually generated by injection of one (gas) phase in a continuous stream of the second (liquid) phase to generate well-ordered... 

Cas/Liquid Micro Flow Dispersive Mixers Generating Slug and Annular Patterns... 

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