Flow of Gas-Liquid Foams in Narrow Complex Geometries

Lead Research Organisation: Aberystwyth University
Department Name: Inst of Mathematical and Physical Sci

Abstract

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Publications

10 25 50
 
Description 1) As part of the consortium, the Aberystwyth team developed bubble-scale numerical simulations of foam flows in constricted channels. There were three strands to this:

i) introducing new geometries (for example sudden and gradual contractions) to existing numerical simulation tools to reflect industrial applications of foams.

In this regard, we worked with BTG to determine the properties of foams in varicose veins. This work represents a step-change in the theory of how foam sclerotherapy works; two articles have been published, the second jointly with our industrial sponsors. We expect this work to influence how sclerotherapy of varicose veins is used and its efficacy assessed, although BTG have now withdrawn from research in this area.

In addition, we worked with experimentalists at Birmingham University both to provide simulations that aimed to reproduce and explain their experiments and to provide numerical tools to analyse their experimental results. That comparison work showed that for dry foams at fairly low flow-rates the theoretical predictions are very good, work that has also been submitted for publication.

ii) accommodating finite liquid fraction in the simulation codes.

We first extended the Viscous Froth Model, a well-established model for the flow of 2D foams, to moderately wet foams, providing a new simulation tool for foam researchers. That work is published.

We then developed a new code that simulates the flow of 2D foams with arbitrary liquid fraction (see the last video at users.aber.ac.uk/sxc/foam_movies.html). We still need to validate the results against experiments (again with our consortium partners in Birmingham). Due to their high accuracy the simulations are rather slow, so this is taking a long time. Further, while we understand how to extend the simulations to 3D wet foams, which would be a major breakthrough, we first need to find ways to speed up the calculations.

iii) accounting for surfactant redistribution during flow and film rupture.

We have successfully incorporated film-level surfactant transport for dry foams in the Viscous Froth Model and, for what we believe is the first time, provided predictions of the influence of bubble pressures on this transport. This resulted in multiple outputs, with Vitasari and Zaccagnino as first author. For example, our simulations predict a maximum possible flow rate for simple foam structures in narrow channels, above which the movement of surfactant molecules leads to foam breakdown. The model was also applied to foams made from dairy proteins, in a collaboration with researchers from Rennes, France. This work, published in 2019, used the flow properties of foams to assess the ability of different products obtained from cows' milk to act as surfactants.

2) An unexpected shared interest with our Cambridge collaborators in the self-healing properties of soap films led to work on the way in which a particle falling through a foam in a confined domain deforms the films. We were able to explain the role of the (contact) angle at which the film touches the particle in determining the size of the small bubble that is sometimes trapped behind the particle. We plan to extend this work to investigate the consequent absorption of energy by the foam, and its possible uses in suppressing damage from explosions.



3) In related work, we have worked with colleagues to show how the curvature of the channel in which bubbles sits can be tuned to drive their motion. We have predicted the resistance to twist of a simple foam structure in a cylinder, with possible biological implications. And we have used bubbles as a model of energy-minimizing structures to predict how to subdivide a circular region into parts of given area using the least amount of material.
Exploitation Route We anticipate that the codes that we have developed, and the results that they have generated, will influence academics working on foam rheology.
Industrial uses of our work are likely in determining the way in which foams are used for sclerotherapy, i.e. the treatment of varicose veins, and how to use foams as explosion suppressors.
Sectors Aerospace, Defence and Marine,Healthcare

 
Description Our work on varicose vein sclerotherapy has influenced how the partner company BTG assess and market their varicose vein treatments. We have been able to explain how the Bingham number and a measure of the bubble size distribution provides the information they need to explain the efficacy of their treatment, which may lead to increased sales.
First Year Of Impact 2020
Sector Healthcare
Impact Types Economic

 
Description GCRF Networking Grant
Amount £8,115 (GBP)
Organisation Aberystwyth University 
Sector Academic/University
Country United Kingdom
Start 06/2019 
End 09/2019
 
Description Industrial sponsorship
Amount £66,000 (GBP)
Organisation BTG 
Sector Private
Country United Kingdom
Start 10/2017 
End 09/2020
 
Description Researcher Links Workshop: Translating Knowledge Into Innovation
Amount £2,000 (GBP)
Organisation British Council 
Sector Charity/Non Profit
Country United Kingdom
Start 03/2018 
End 04/2018
 
Description UK Fluids Network Short Research Visit
Amount £860 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 09/2017 
End 09/2017
 
Description UK Fluids Network Short Research Visit
Amount £620 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 05/2019 
End 06/2019
 
Title A viscous froth model adapted to wet foams 
Description This dataset comprises the data from which we drew our conclusions concerning our extension of a "viscous froth" model to the dynamics of a wet foam in a Hele-Shaw cell. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact A publication 
 
Title Data for "An analytic velocity profile for pressure-driven flow of a Bingham fluid in a curved channel" 
Description Data and numerics to re-generate the data for the article "An analytic velocity profile for pressure-driven flow of a Bingham fluid in a curved channel" by Roberts and Cox 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Impact Still too early to say 
URL https://pure.aber.ac.uk/portal/en/datasets/data-for-an-analytic-velocity-profile-for-pressuredriven-...
 
Title Simulations of quasi-static foam flow through a diverging-converging channel 
Description Data to support a publication 
Type Of Material Database/Collection of data 
Provided To Others? No  
Impact Publication 
 
Title Supporting Information for Simulation of surfactant transport during the rheological relaxation of two-dimensional dry foams 
Description Data to supplement the article: F. Zaccagnino, A. Audebert and S.J. Cox (2018) Simulation of surfactant transport during the rheological relaxation of two-dimensional dry foams. For each of the figures listed in 00_Phys_Rev_E_98_022801_Data.pdf, which also gives contextual information, we provide the raw data (text files with extension .dat) which was generated by either the simulation code or the experiment (the two files with filenames ending "measurements.dat"). Each .dat file consists of comma-separated columns of numbers. The first line indicates the contents of each column, with reference to the notation in the published article. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact Has supported further work on dairy foams and the model has now been extended to bulk foams 
URL https://pure.aber.ac.uk/portal/en/datasets/supporting-information-for-simulation-of-surfactant-trans...
 
Title Supporting information for "Stability of a Twisted Plateau Border with Line Tension and Bending Stiffness" 
Description Surface evolver file: twister.fe Data from SE: For each set of simulated data on each of figures 4 to 6, there is a separate file, with file name containing by the figure number, the value of $T$ and the value of $B$. Each line is a critical value of the PB length $\ell$ and/or the twist angle $\theta$. This is the last line of data from a sequence of increasing $\ell$ or $\theta$, just before the instability occurs. Each file has five columns, giving (i) the value of $T$, (ii) the value of $B$, (iii) the PB length $\ell$, (iv) the twist angle $\theta$, (v) the total surface area of the vanes. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact None as yet. 
URL https://pure.aber.ac.uk/portal/en/datasets/supporting-information-for-stability-of-a-twisted-plateau...
 
Title Supporting material for "Bubble entrainment by a sphere falling through a horizontal soap foam" 
Description Surface Evolver geometry files for the calculations described in the article 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Impact This supports the publication "Bubble entrainment by a sphere falling through a horizontal soap foam" 
URL https://pure.aber.ac.uk/portal/en/datasets/supporting-material-for-bubble-entrainment-by-a-sphere-fa...
 
Description Dairy Protein Foams 
Organisation French National Institute of Agricultural Research
Department INRA Rennes Centre
Country France 
Sector Public 
PI Contribution We helped with the design of an experiment, provided background information on foam dynamics, and used the data to validate a numerical model of foam dynamics.
Collaborator Contribution They prepared a range of samples from which to prepare foams and carried out the rheological testing of these samples and physico-chemical interpretation of the results
Impact Two published papers and several conference presentations. Multi-disciplinary: maths / physics / process engineering from our side, and chemistry/chemical engineering from theirs.
Start Year 2017
 
Description Foam schlerotherapy 
Organisation BTG
Country United Kingdom 
Sector Private 
PI Contribution We will develop models of foam flow in veins
Collaborator Contribution The company will fund a PhD student
Impact No outputs yet. Multidisciplinary: applied maths/chemical engineering/biomedical engineering
Start Year 2016
 
Description School Visit (Hereford) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact I ran a workshop on foam geometry for 15 A-level students at Hereford Sixth Form College. The students were interested in the interaction between mathematics and physics in research.
Year(s) Of Engagement Activity 2018
 
Description Soapbox science 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Soapbox Science: an event for outreach program of the research project to the general public at Swansea City Centre. The event was held on 23 June 2018.
Year(s) Of Engagement Activity 2018
URL http://soapboxscience.org/2018-2/
 
Description University Open Day activity on Foams 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Undergraduate students
Results and Impact I presented a demonstration on the shapes of soap films, and bubbles, and they way in which these observations inspire mathematical models of foams.
Year(s) Of Engagement Activity 2017,2018