From Kinetic Theory to Hydrodynamics: re-imagining two fluid models of particle-laden flows

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Engineering

Abstract

A number of important technologies involve the manipulation of particle-laden flows. These include pharmaceuticals manufacturing, power plant technologies, food processing, and many others. Various environmental protection and safety issues are rooted in the understanding of the dynamics of granular flows, for example, avalanches, sandstorms, and city air pollution. Models for these are traditionally derived from analogies with dilute gases at the statistical level, and from conventional fluid mechanics at the continuum level. Rapid granular flows are, however, known experimentally to display a variety of rheological and flow physics not seen in conventional fluid flows.

Previous research in modelling rapid granular flows has co-opted transport models developed for rarefied gases under strong non-equilibrium. This approach produces constitutive equations that incorporate high order gradient terms (the best known of which are the Burnett and super-Burnett set of equations). However, this higher order hydrodynamics is known to violate several fundamental thermodynamic and mechanical properties.

Alternative phenomenological approaches have been developed separately, which draw on continuum mechanics approaches. These, however, cannot at present always claim to provide good predictions of the various phenomena exhibited by rapid granular flows. Flow behaviour in the moderate solid volume fraction regime, and the transitions between different flow regimes, are still complex, controversial and problematic.

In this project we will attempt to resolve some of these problems by developing and testing sophisticated new models within a two-fluid approach to dilute granular flows. These models will be founded on a sound understanding of both the micro-scale fluid dynamics and the non-equilibrium particle statistics. Better resolution of the fundamental physics of both particle/particle and fluid/particle interactions will enable new constitutive equations that leapfrog the predictive capabilities of phenomenological models. Our new models will be implemented in the open source computational fluid dynamics software OpenFOAM, in a form suitable for both future research and industrial simulation.

Publications

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Casanova S (2019) Surface-Controlled Water Flow in Nanotube Membranes. in ACS applied materials & interfaces

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Agius Anastasi A (2018) Raman spectroscopy of gallium ion irradiated graphene in Diamond and Related Materials

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Reddy M (2019) Recasting Navier-Stokes equations in Journal of Physics Communications

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Pillai R (2018) Dynamics of Nanodroplets on Vibrating Surfaces. in Langmuir : the ACS journal of surfaces and colloids

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Dockar D (2019) Mechanical Stability of Surface Nanobubbles. in Langmuir : the ACS journal of surfaces and colloids

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Datta S (2021) Acoustothermal Nucleation of Surface Nanobubbles. in Nano letters

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Perumanath S (2020) Molecular physics of jumping nanodroplets. in Nanoscale

 
Description - We have discovered new behaviour for small scale fluids (such as thin films and droplets) in contact with vibrating surfaces and developed a universal theory to describe them.
- We have discovered how gas viscosity behaves in small microscale channel flow problems, and relate that to the frequency of collisions.
- We have developed a new theoretical framework for the standard fluid equations to be re-casted and handle more complex fluid dynamics problems.
- We have discovered a very high mechanical stability of nanobubbles that rest on solid surfaces, and developed a new theoretical model that predict it.
- We have carried out experiments and simulation of fluid flow through new nanotubes and we now have a better understanding on the effect of wall chemistry on the fluid transport; we developed a new multiscale method that is able to compare with prototype scale membranes in experiments.
- We discovered new molecular scale behaviour of how droplets merge to become one single droplet.
Exploitation Route - The methods and new science can be used to design breakthrough filtration membranes for water or chemical separation.
- The methods and new insights can be used to understand and design problems where rapid drying is required.
- The new insights can be used to design self-cleaning surfaces, or understand cloud formation better.
- The new insights can be used to improve ultra-sonic cleaning of complex surfaces, drug targeting using ultrasonic frequency, and waste water treatment
Sectors Aerospace, Defence and Marine,Agriculture, Food and Drink,Chemicals,Digital/Communication/Information Technologies (including Software),Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology

 
Description - Our main findings have been used to inspire new research in academia, and open up new research directions. - Key methods that were developed and findings have received interest from industry, and are currently being used to design cooling membranes for high processing chips, photolithography machines that produce the chips, or in-lab prototype membranes for desalination applications.
First Year Of Impact 2019
Sector Education,Electronics,Manufacturing, including Industrial Biotechology
Impact Types Societal,Economic

 
Description Advanced hybrid method for pore-scale simulation of shale gas flows
Amount $2,800,000 (USD)
Organisation King Fahd University of Petroleum and Minerals 
Sector Academic/University
Country Saudi Arabia
Start 03/2018 
End 03/2021
 
Description Efficient Multi-Scale Engineering Simulations: Dynamic Optimisation of Particle Solvers
Amount £100,000 (GBP)
Funding ID eCSE13-20 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 01/2019 
End 11/2019
 
Description RAEng Chair in Emerging Technologies
Amount £1,300,000 (GBP)
Funding ID CiET1718\54 
Organisation Royal Academy of Engineering 
Sector Charity/Non Profit
Country United Kingdom
Start 03/2018 
End 09/2020
 
Description New pilot consultancy with ASML 
Organisation ASML Holding
Country Netherlands 
Sector Private 
PI Contribution Initial pilot study running DSMC flow simulations for the company
Collaborator Contribution Knowledge exchange and description of industrial case studies
Impact This is an industrial consultancy project. The outcomes of the software that we are generating is being tested by the company ASML on their case problems.
Start Year 2019
 
Description BBC Scotland Radio interview 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Discussion of recent research outcomes in more layman terms
Year(s) Of Engagement Activity 2018
URL https://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-45471403
 
Description Inaugural Lecture 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Many academics from around Scotland attended this lecture entitled "A World in a Grain of Sand". It sparked many questions and discussions afterwards regarding the history of the research area presented.
Year(s) Of Engagement Activity 2018
URL https://www.youtube.com/watch?v=8O4crC0w23c
 
Description Press release from research on bubbles 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Press release of a recent research of nano bubbles. This research was also published in a journal, with one of our simulations on the front cover. This and the press release led to more than 1000 readers of our paper within the first few months.
Year(s) Of Engagement Activity 2019
URL https://acs.altmetric.com/details/54020894/news
 
Description Press release on new research of nano droplets 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Press release of new research outcomes in the top journal (Physical Review Letters); picked up by many blogs, which has received many views at international scale. This has work has now been cited more than the journal's annual impact factor.
Year(s) Of Engagement Activity 2019
URL https://aps.altmetric.com/details/56970896/news
 
Description Public Engagement Workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Study participants or study members
Results and Impact Carried out a workshop among research team to design and build rigs for the Edinburgh Science Festival. Impact is not measurable just yet, until participation in festival.
Year(s) Of Engagement Activity 2019