A short presentation summarising the main results of the paper “Effect of Soluble Surfactants on the Kinetics of Thinning of Liquid Bridges during Drops Formation and on Size of Satellite Droplets” by Nina Kovalchuk, Emilia Novak and Mark Simmons recently published in Langmuir is now available as the LiveSlides on Langmuir web-site and is directly connected to this open access paper.
This animation shows the reconstructed interfacial wave structure in a falling liquid film using Multi-Pin Film Sensor (MPFS). MPFS comprises of 2 X 5 axial planes x 64 circumferential pin electrodes (i.e. 640 points measurement). MPFS can provide film thickness data with high temporal and spatial distribution for upward /downward annular flows in time, circumferential and axial coordinates, δ(t,θ,z). The pipe diameter used was 127 mm. The animation shows non-coherent wave structure.
1) A paper “Transition from stratified to non-stratified oil–water flows using a bluff body” by Kyeong Hyeon Park, Maxime Chinaud and Panagiota Angeli has been published in Experimental Thermal and Fluid Science. In this paper the effect of a transverse cylindrical rod immersed in water on the flow patterns and interfacial characteristics of an oil–water pipe flow is investigated experimentally. The cylinder is used to passively actuate the transition from stratified to non-stratified flows and to localise the formation of waves and the detachment of drops. The studies are carried out in an acrylic test section with 37 mm ID [ Read More ]
A paper “Effect of surfactant concentration and viscosity of outer phase during the coalescence of a surfactant-laden drop with a surfactant-free drop” by Emilia Nowak, Nina Kovalchuk, Zhizhao Che and Mark Simmons have been published in Colloids and Surfaces A: Physicochemical and Engineering Aspects. The paper is a result of collaborations between the University of Birmingham and Imperial College London. Abstract This work focuses on the coalescence of two water drops, one of which contains surfactant. The coalescence was carried out in surrounding silicone oils of various viscosities. It has been found that, in all the studied cases, the outward [ Read More ]
Memphis Programme well represented at the ICMF 2016 International Conference on Multiphase Flow, Florence, Italy, May 22 – 27, 2016. THE NEXT-GENERATION PREDICTIVE TOOLS FOR MULTIPHASE FLOWS by Omar K. Matar, Imperial College London, UK. The ability to predict the behaviour of multiphase flows accurately, reliably, and efficiently addresses a major challenge of global economic, scientific, and societal importance. These flows are central to micro-fluidics, virtually every processing and manufacturing technology, oil and-gas, nuclear, and biomedical applications. Significant advances have been made in the numerical procedures to simulate these flows; examples of these include the use of Large Eddy [ Read More ]
The team of the University of Birmingham has published a paper “Effect of Soluble Surfactants on the Kinetics of Thinning of Liquid Bridges during Drops Formation and on Size of Satellite Droplets“ in Langmuir. Abstract The results of an experimental study on thinning and breakage of liquid bridges during detachment of a drop from the tip of a capillary are presented for a series of surfactant solutions (including cationic, anionic, and nonionic surfactants) over a broad range of molecular masses, values of critical micelle concentration, and concentrations. The used experimental protocol revealed that the kinetics of the bridge thinning depends much more on the [ Read More ]
An image of water rotating in what appears to be slow motion is one of the winning entries in a major engineering photography competition. Great media coverage as follows: EPSRC https://www.epsrc.ac.uk/newsevents/news/2015photocomp/ (press release); The Guardian (https://www.theguardian.com/science/gallery/2016/mar/21/award-winning-images-of-science-in-action#img-2); The Irish Examiner (http://www.irishexaminer.com/examviral/science-world/15-stunning-pictures-from-the-engineering-and-physical-sciences-competition-you-need-to-see-388643.html); The Daily Mail (http://www.dailymail.co.uk/news/article-3501702/London-Underground-photo-winners-science-photo-contest.html); http://home.bt.com/tech-gadgets/tech-news/15-stunning-pictures-from-the-engineering-and-physical-sciences-competition-you-need-to-see-11364047381328; It is also the main story on the Imperial College Faculty of Engineering webpage (http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_22-3-2016-11-24-19).
This video illustrates the features of churn flow for gas/silicone oil (330 Pa s) in a vertical 290 mm ID,7m long column at gas superficial velocity of 0.555 m/s. In this experiment, quantification of the flow patterns and slug/churn flow transition was studied by means of Electrical Capacitance Tomography (ECT) in which the characteristics of gas/liquid slug flows such as: void fraction; frequency of periodic structures; Taylor bubble velocity; lengths of Taylor bubbles and liquid slugs were measured and analysed. The intend, now, is to model such complex flows. Video is taken by Shara Mohammed as part of her [ Read More ]
Please follow the link to view the full higher resolution videos: Complex cross junction microchannel Complex cross junction microchannel I Complex cross junction microchannel II