Microbubble cloud generation from fluidic oscillation: underpinning fluid dynamics
Lead Research Organisation:
University of Sheffield
Department Name: Chemical & Biological Engineering
Abstract
Microbubbles received an intensive study for various generation mechanisms in the 1990s. The state of the art is currently perceived as being the Venturi method, which pumps both gas and liquid. As the density of liquids are usually a thousand fold higher than gases, it is inherently less energy efficient than the recently patented mechanism by the PI that produces microbubbles on the scale of the pore (as small as 20 microns) with high holdup (~40% is achievable currently), uniformly sized and spaced so non-coalescent, plumes with less energy use than the same flow rate of fine bubbles (1-2mm). For the smallest scale of microbubbles, industrial processes use the saturated liquid release method (6 bar compression), with nucleation of 30-60 micron bubbles, but with high coalescence rates so a very wide range of bubble sizes in a turbulent flow are created. We estimate that our fluidic oscillation method saves 90-95% of the electricity with a similar savings in the capital cost (no expensive saturation system and large pumps are needed to pump the saturated liquid). Field trials are underway to demonstrate the feasibility of replacing solids removal systems in water purification by this method. We have identified at least 25 potential applications and over 40 companies interested in the technology.The difficulty is that the industrial applications and engineering implementations are outstripping our fundamental understanding of the mechanism for microbubble generation and how it depends on the situation, operating conditions, and the controlling fluidic circuit design. We believe that there are potential medical applications (drug delivery, gas exchange in the blood) if the methodology can be extended to nanoscale bubbles with the same features of monodispersity and energy efficiency. In order to understand how to match the microbubble transfer requirement to the fluidic circuitry and generation devices for the various applications identified already, we must build computational models that are accurate predictors, as well as validating them and understanding the dynamics qualitatively from visualization and velocimetry studies under many representative conditions.Because of the extremely low cost of microbubbles produced by this methodology, mixing and gas transfer mechanisms that have never previously used microbubbles, is possible. Without accurate engineering design tools and a thorough scientific understanding, the implementation of such systems will be hit or miss and even when they work as in all our successful applications to date, they are certainly not optimal. As the technology is disruptive in that the change of infrastructure to exploit the potential energy and capital savings will drive change across several industries, the design and implementation protocols adopted at early stages become set in stone . But if the processes implemented are non-optimal, these non-optimalities will persist through at least one capital cycle. There are many instances in engineering of systems where the rules of design have not changed for a century (since they work), even though re-visiting them could achieve substantial savings. Thus, this proposal is extremely timely as design flaws adopted now may be long term costly, even though the potential improvement over current practise is breath-taking.In this proposal, we will bring to bear the state-of-the-art in flow visualization and velocimetry, with multiphase flow and engineering modelling, and a range of experimentation in fluidic circuitry and resultant microbubble dynamics, some of which has been pioneered by the investigators, to develop the full toolset to design microbubble generation systems tuned to the application system dynamics.
Planned Impact
The impact plan focuses on the commercial exploitation path for energy efficient microbubble generation and low power consumption, high yield plasma microreactors (other technology patented by the PI and used in conjunction with microbubble dispersal). The current plan is to spin out a company this year to exploit the greater than 40 industrial contacts in more than ten application areas for these technologies, frequently combined as discussed in the generic beneficiary description. The University of Sheffield has a company incubator (fusionIP) which has been planning the commercial development of these patents over the past 18 months, and expects to spin out a company this summer for commercial management of the patents and to engage with potential endusers and commercial partners to arrange the engineering design, installation, commissioning and operational knowledge to have the technologies taken up. The supply chain is in place for microbubble applications, but not yet for ozone-UV dosing applications. The list of applications currently under R&D investigation with potential endusers and partners includes: 1. Algal biofuels production. 2. Biodiesel production. 3. Wastewater aeration. 4. Anaerobic digestor intensification for more biogas production and removal of CO2 to upgrade fuel quality. 5. Anammox (ammonia removal) intensification. 6. Solids removal by flotation in water purification (replacing dissolved air flotation). 7. Solids removal by flotation in minerals separations. 8. Intensified evaporation / heat transfer, such as in desalination. 9. Yeast production. 10. Beer and bioethanol production. 11. Ozone dosing for water purification -- organics removal, disinfection. 12. Ozone dosing for wastewater disinfection. 13. Dual ozone-UV breakdown of organics such as pesticides or metallocyanides. 14. Dual ozone-UV breakdown of biochemical byproducts in bioreactors. 15. Aeration of fish farms (aquaculture). 16. Ozone dosing in HF for cleaning solution for silicon wafers. 17. Microbubble dosing / extraction replacing gas-liquid spargers/scrubbers in commodity chemicals production, potentially CO2 dissolution in carbon capture systems. 18. Selective oxidation based on control of ozone levels in organic synthesis or for analytic chemistry (ozonolysis). 19. Gas-lift enhanced oil recovery (requires 30-50 micron size bubbles, cheaply produced) 20. CO2 flooding for enhanced oil recovery with microbubbles which avoids the channelling instability. 21. Hot gas microbubble injection for enhanced oil recovery which achieves similar improvement. 22. Oil-water separation enhancement by flotation effect for offshore separators and oil spill remediation. 23. Drag reduction in oil pipelines. 24. Fats, oils, and grease effluent separation as a feedstock for biodiesel. 25. Microfoam production for processed foods. 26. Oxygenation of oxygen depleted water recycled through PEM hydrogen fuel cells.
Publications
Mulakhudair AR
(2017)
Inactivation combined with cell lysis of Pseudomonas putida using a low pressure carbon dioxide microbubble technology.
in Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)
Mulakhudair A
(2016)
Exploiting microbubble-microbe synergy for biomass processing: Application in lignocellulosic biomass pretreatment
in Biomass and Bioenergy
Mulakhudair A
(2017)
Exploiting ozonolysis-microbe synergy for biomass processing: Application in lignocellulosic biomass pretreatment
in Biomass and Bioenergy
Kamaroddin M
(2020)
Optimization and cost estimation of microalgal lipid extraction using ozone-rich microbubbles for biodiesel production
in Biocatalysis and Agricultural Biotechnology
Javed F
(2019)
"Pushing and pulling" the equilibrium through bubble mediated reactive separation for ethyl acetate production
in Reaction Chemistry & Engineering
Hodgkinson R
(2022)
Extensional flow affecting shear viscosity: Experimental evidence and comparison to models
in Journal of Rheology
Hanotu J
(2012)
Microflotation performance for algal separation.
in Biotechnology and bioengineering
Hanotu J
(2017)
Aerator design for microbubble generation
in Chemical Engineering Research and Design
Hanotu J
(2014)
Harvesting and dewatering yeast by microflotation
in Biochemical Engineering Journal
Hanotu J
(2017)
Aerator design for microbubble generation
in Chemical Engineering Research and Design
Description | We demonstrated that * microbubble clouds with average bubble size ~100microns mix liquid ~10 times faster than fine bubbles * microbubble clouds smaller than average bubble size ~100 microns are essentially transient in mass transfer, exchanging all the mass with their immediate boundary layer that is thermodynamically possible within the first millisecond of contact time. Thereafter they are boundary layer limited in diffusion. * we scaled up fluidic oscillation to at least 1000m^3/hr through the oscillator * we scaled down fluidic oscillation to <~0.5 lpm through the oscillator * we developed a microbubble accelerated evaporator * we developed the ability to distill multicomponent liquids with highly nonequilibrium enhancements to the phase partitioning, including splitting azeotropes (ethanol-water, methanol-toluene, IPA-water) * we developed a microbubble condenser concept that, along with microbubble evaporation, was exploited by the undergraduate winners of the 2015 BP Ultimate Field Trip |
Exploitation Route | Along with IP holders Perlemax, the University of Sheffield has won (started Jan 2016) a grant to demonstrate / validate microbubble distillation and microbubble accelerated fermentation (both aerobic and anaerobic) from InnovateUK for the bioethanol sector (£2.2m). Participation from all three UK bioethanol plant operators. InnovateUK have also recently funded the same partners to exploit microbubbles for biogas sweetening and AD acceleration. We have a fulsome collaboration with Viridor on the stripping of ammonia from landfill leachate, the most pernicious component, and a holistic "circular economy" solution to their leachate disposal problem. |
Sectors | Agriculture, Food and Drink,Chemicals,Energy,Environment,Manufacturing, including Industrial Biotechology |
Description | ACAL Energy was awarded a KTP in partnership with UoS -- for miniaturisation of the bubble generation device for inclusion on vehicle (2012-14). Concept was proven with prototypes developed -- awaiting further investment / licensing with OEMs. Miniaturised bubble generator is being evaluated by Air Products for industrial wastewater treatment applications. AECOM Design Build is just starting a KTP on scale up of the approach to very large scale wastewater treatment works. Due to commercial decisions made by AECOM Global, the company has closed down Design Build operations and the license reverted to Perlemax, which has an FP7 grant on wastewater aeration finishing, and has agreed a contract with MetroVancouver for testing the most recent product design. Xeros has also begun a KTP exploiting the microbubble technology. Perlemax, Suprafilt, and UoS were awarded an IB Catalyst exploiting microbubble distillation from InnovateUK for bioethanol production, with support from three UK bioethanol manufacturers. Perlemax and 6 EU partners were awarded an ERA-NET industrial biotech award for bio-butanol production from microbubble distillation (UoS are subcontractor). Microbubble technology is being developed with commercial partners for distillation for in situ product removal for a range of fermentation products as well as flotation separations of biomass. One of the observations during this project was that all vessels used to house microbubble characterisation experiments were "squeaky clean". A doctorate on using microbubbles to scrub fouling from several surfaces was undertaken, with substantial defouling effect for membranes such as reverse osmosis membranes used for desalination. Also, preliminary studies were undertaken in the doctorate to show effectiveness in removal of biofilms. A small feasibility study from NBIC (National Biofilms Innovation Centre) resulted in unoptimized studies showing a factor of twenty rate increase over the current industrial practise with the same performance effectiveness. We are now seeking to build an industrial consortium from the bio/pharma and specialty/fine chemicals sectors for pilot scale *continuous* clean-in-place testing of this unexpected outcome of the grant. |
First Year Of Impact | 2018 |
Sector | Agriculture, Food and Drink,Chemicals,Energy,Environment |
Impact Types | Economic |
Description | Detoxification and Multi-Resource Recovery from Landfill Leachate |
Amount | £95,078 (GBP) |
Funding ID | NE/P016820/1 |
Organisation | Natural Environment Research Council |
Department | NERC Catalyst Grant |
Sector | Public |
Country | United Kingdom |
Start | 04/2017 |
End | 06/2018 |
Description | Energy Catalyst Round 4 |
Amount | £299,848 (GBP) |
Funding ID | 81773-494638 TS/P007848/1 |
Organisation | Innovate UK |
Sector | Public |
Country | United Kingdom |
Start | 03/2017 |
End | 02/2018 |
Description | Industrial Biotech Catalyst |
Amount | £2,211,665 (GBP) |
Funding ID | EP/N011511/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 01/2016 |
End | 12/2018 |
Description | Knowledge Transfer Partnership |
Amount | £140,000 (GBP) |
Funding ID | 1006336 |
Organisation | Innovate UK |
Sector | Public |
Country | United Kingdom |
Start | 01/2015 |
End | 12/2016 |
Description | Knowledge Transfer Partnership |
Amount | £175,000 (GBP) |
Funding ID | 8714 |
Organisation | Innovate UK |
Sector | Public |
Country | United Kingdom |
Start | 08/2012 |
End | 07/2014 |
Description | Knowledge Transfer Partnership |
Amount | £140,000 (GBP) |
Funding ID | 1006335 |
Organisation | Innovate UK |
Sector | Public |
Country | United Kingdom |
Start | 01/2015 |
End | 12/2016 |
Description | Plasma and Fluidic Assisted Electrocatalysis for Chemical Storage of Renewable Electricity |
Amount | £201,381 (GBP) |
Funding ID | EP/R000409/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 09/2017 |
End | 08/2019 |
Description | Programme Grant |
Amount | £5,700,000 (GBP) |
Funding ID | EP/K001329/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 10/2012 |
End | 09/2016 |
Description | Research Grant |
Amount | £2,000,000 (GBP) |
Funding ID | BB/K020633/1 |
Organisation | Biotechnology and Biological Sciences Research Council (BBSRC) |
Sector | Public |
Country | United Kingdom |
Start | 10/2013 |
End | 09/2016 |
Description | c1net Proof of Concept Microbubble enhanced gas exchange in a methanotroph gas fermenter |
Amount | £50,000 (GBP) |
Funding ID | POC-19-zimmerman-C1net |
Organisation | Biotechnology and Biological Sciences Research Council (BBSRC) |
Sector | Public |
Country | United Kingdom |
Start | 02/2017 |
End | 05/2018 |
Description | Algal biodiesel production |
Organisation | Monte Cristo Engineering & Development |
Country | United States |
Sector | Private |
PI Contribution | We developed, based on exploratory discussions with Monte Cristo and Perlemax, a microbubble and plasma mediated method for esterification and hydrolysis, particularly applicable for biodiesel production, that exploits microbubble distillation. |
Collaborator Contribution | Perlemax invented the approach and with Monte Cristo, proposed the pilot plant design and campaign to develope the upscaling. |
Impact | A licensing and collaboration agreement is in place between Perlemax and Monte Cristo, which includes £5m in the wider partnership on the production of algal biodiesel using this approach for the demonstration plant. |
Start Year | 2012 |
Description | Algal biodiesel production |
Organisation | Perlemax |
Country | United Kingdom |
Sector | Private |
PI Contribution | We developed, based on exploratory discussions with Monte Cristo and Perlemax, a microbubble and plasma mediated method for esterification and hydrolysis, particularly applicable for biodiesel production, that exploits microbubble distillation. |
Collaborator Contribution | Perlemax invented the approach and with Monte Cristo, proposed the pilot plant design and campaign to develope the upscaling. |
Impact | A licensing and collaboration agreement is in place between Perlemax and Monte Cristo, which includes £5m in the wider partnership on the production of algal biodiesel using this approach for the demonstration plant. |
Start Year | 2012 |
Description | Cleaning with plasma microbubbles and beads |
Organisation | Perlemax |
Country | United Kingdom |
Sector | Private |
PI Contribution | Brainstormed the possibility that ozone microbubbles will defoul / regenerate catalyst active sites for cleaning on Xeros' polymer cleaning beads. Organised a feasibility study to use the prototype developed in this grant to conduct a feasibility study. The team came up with new designs for better plasma microreactors (more durable materials). |
Collaborator Contribution | Perlemax sponsored the doctoral studentship of Dr Tom Holmes, which included pilot scale trials of the first prototype developed in this grant in final effluent from a municipal wastewater treatment plant. Perlemax hired a consultant to plan the development work with Xeros. Xeros sponsored a feasibility study to use the ozone microbubble generator as an in situ disinfection and cleaning agent, joint with their patented polymer beads. They have subsequently filed a patent with me as co-creative inventor. |
Impact | The partnership is just completing a KTP funded by InnovateUK for technology transfer and development work. We expect the collaboration to continue and are currently exploring the nature and components of the next stage of development work. |
Start Year | 2012 |
Description | Cleaning with plasma microbubbles and beads |
Organisation | Xeros Technology Group |
Country | United Kingdom |
Sector | Private |
PI Contribution | Brainstormed the possibility that ozone microbubbles will defoul / regenerate catalyst active sites for cleaning on Xeros' polymer cleaning beads. Organised a feasibility study to use the prototype developed in this grant to conduct a feasibility study. The team came up with new designs for better plasma microreactors (more durable materials). |
Collaborator Contribution | Perlemax sponsored the doctoral studentship of Dr Tom Holmes, which included pilot scale trials of the first prototype developed in this grant in final effluent from a municipal wastewater treatment plant. Perlemax hired a consultant to plan the development work with Xeros. Xeros sponsored a feasibility study to use the ozone microbubble generator as an in situ disinfection and cleaning agent, joint with their patented polymer beads. They have subsequently filed a patent with me as co-creative inventor. |
Impact | The partnership is just completing a KTP funded by InnovateUK for technology transfer and development work. We expect the collaboration to continue and are currently exploring the nature and components of the next stage of development work. |
Start Year | 2012 |
Description | Durable plasma reactor electrodes with nanoceramic coating |
Organisation | Cambridge Nanolitic Ltd |
Country | United Kingdom |
Sector | Private |
PI Contribution | We determined that a novel dielectric material and coating approach was needed to solve the manufacturing tolerance problem for our electrodes, and subsequently the material should be as durable as possible. |
Collaborator Contribution | Cambridge Nanolitic has developed such a thin, tightly controlled deposition tolerance, material and coatings delivery approach, for which we used their materials and expertise (and that of colleagues Dr Aleksey Yerokhin and Professor Allan Matthews) to implement in our prototype in the Xeros' KTP. |
Impact | The partnership recently won an InnovateUK Materials and Manufacturing award that is commencing this spring, for further developments towards the production of a final prototype that can be mass produced. |
Start Year | 2015 |
Title | APPARATUS AND METHOD FOR THE TREATMENT OF A SUBSTRATE WITH OZONE BUBBLES |
Description | Apparatus (200) for the treatment of one or more substrates comprising a treatment chamber configured to receive a liquid medium and one or more substrates; a supply of a treatment gas comprising ozone; and one or more conduits to convey said treatment gas to a bubble generator (41) wherein said bubble generator is operable to form bubbles of said treatment gas in said liquid medium, wherein the apparatus comprises a multiplicity of solid particles (46). A method of treating one or more substrates, the method comprising agitating said one or more substrates in a treatment formulation comprising a multiplicity of solid particles, a liquid medium and bubbles of ozone. |
IP Reference | WO2016203252 |
Protection | Patent application published |
Year Protection Granted | 2016 |
Licensed | Commercial In Confidence |
Impact | Laundry company Xeros is prosecuting the commercial development of the patent, in partnership with the University of Sheffield and spinout compay Perlemax. |
Title | BUBBLE GENERATION TO STRIP COMPONENTS OF A LIQUID |
Description | Uses of a method of producing small bubbles of gas in a liquid include gas transfer in airlift bioreactors and anaerobic digesters, and particle separation. The method uses a source of the gas under pressure, a conduit opening into a liquid and oscillating the gas passing along the conduit. The oscillation is effected by a fluidic oscillator, comprising a diverter that divides the supply into respect outputs, each output being controlled by a control port, wherein the control ports are interconnected by a closed loop. Separation of algae from water involves delivering a laminar flow of microbubbles in the range 10 to 100 µm diameter. Such bubbles also deliver a laminar flow in bioreactors that delivers enhanced liquid flow despite the small bubbles, which improves mixing and also enhances efficiency of gas exchange and retention of the bubbles in the reactor. In an anaerobic digester, the microbubbles strip waste gas and deliver nutrients. In particle separation, a pH-adjusting gas adjusts the pH in the boundary layer surrounding each bubble to inhibit repulsion between bubbles and particles. |
IP Reference | WO2014060740 |
Protection | Patent application published |
Year Protection Granted | 2014 |
Licensed | Commercial In Confidence |
Impact | EU R3Water grant for pilot and industrial scale testing on wastewater sludge digesters |
Title | FLUIDIC OSCILATORS |
Description | A new fluidic oscillator is described comprising at least one inlet port (57) in communication with at least two outlets (61) via a nozzle region A and two outlet conduits (58, 62), the two outlet conduits being separated from each other by a splitter region and each outlet conduit comprising a resonance chamber (60) in fluid communication with the conduit. The resonance chambers are key in controlling the oscillation of the device and the fluidic oscillator is operated through a new acoustic switching mode. |
IP Reference | WO2020208250 |
Protection | Patent application published |
Year Protection Granted | 2020 |
Licensed | Commercial In Confidence |
Impact | This new oscillator has been demonstrated to achieve very rapid removal of ammonia from wastewaters and digester centrates, with tuneable liquid volumes, via microbubble distillation. A waste management company has supported pilot scale trials for landfill leachate remediation with this oscillator making the liquid treatment volumes readily engineered via conventional size plumbing. |
Title | MASS TRANSFER PROCESSES WITH LIMITED SENSIBLE HEAT EXCHANGE |
Description | A process of mass transfer is described which utilises latent heat transfer with little or sensible heat transfer. In a preferred process microbubbles are used under certain conditions of contact with a liquid phase to ensure highly effective mass transfer between a gaseous and liquid phase with significantly less than expected or little or no sensible heat transfer. The present invention in part provides a means by which the known state of a cold liquid of varying depths can be changed using a hot gas injected via a micro bubble inducing internal mixing without allowing the resultant mixture to reach equilibrium thereby ensuring the transfer process becomes continuous. Thus a process is described wherein at least one gaseous phase is contacted with at least one liquid phase such that the heat ratio of the system (AA) is maintained at an a value of greater than 0.5, and the mass transfer is effected by passing a gaseous phase comprising microbubbles through a liquid phase of thickness no more than 10 cm. |
IP Reference | WO2014079993 |
Protection | Patent granted |
Year Protection Granted | 2014 |
Licensed | Commercial In Confidence |
Impact | Arranged an industrial consortium of the bioethanol production and supply chain to promote pilot and industrial scale trialling. Licensing to a USA biodiesel engineering and development company for specific uses in intensification of biodiesel production. |
Company Name | Perlemax |
Description | A spinout company from the University of Sheffield. Registered during the grant period, Perlemax was created to exploit the two patents on which this grant is based: energy efficient microbubbles and plasma microreactors. The microbubble patent was transferred with the shareholders' agreement in January 2011, and the plasma microreactor patent is being transferred in July 2012. Perlemax is seeking to form a joint venture company with a water sector services company to exploit the patents in the municipal wastewater / water treatment sector. |
Year Established | 2011 |
Impact | Spinout company created for R&D commercial development of the patents. |
Company Name | REEPEL LTD |
Description | Reepel is a vertical farming company that has a unique selling point in how it engages with the circular economy for novel fertilizers that use waste ammonia and carbon capture technology, exploiting fluidic engineering design including microbubbles for microgation and Desai Artificial Lichen (like dispersed small biofilms complexed around microbubbles) with in situ surface cleaning / removal of biofilms due to dispersed microbubbles. |
Year Established | 2020 |
Impact | The company has won, as part of a consortium of partner companies, an InnovateUK and a BEIS grant (confidential at the moment), for UK-based R&D on the technology. It already has a demonstration in Dubai and is short-listed for facilities implementation in some Middle East sustainable cities projects. |
Website | https://www.reepel.co.uk/ |
Description | Contributed as a technical expert to a television episode on mysterious occurrences in seas/ waterways |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | I contributed to the technical content and was interviewed on the Discovery Channel series "Mysteries of the Deep" (Season 1) on the topic of bio/chemical methane microbubble releases from the ocean floor in the Bermuda Triangle, and how such localized releases cause "sinkholes" due to density variation on the ocean surface. The stronger the release, the more likely that craft experiencing such a "sinkhole" would crash to the bottom of the ocean, arriving with significant momentum, potentially decimated on impact. Releases are accompanied by electrokinetic effects on the surfaces of any vessel in passed by the plume, which can build up substantial charge/potential, similar to a Vandergraaf device, playing havoc with controls and radio transmissions. The producers had documented significant releases, vented from volcanic activity or from pockets captured from bio/chemical activity, as well as anecdotal encounters of "boiling seas", and were looking for the science underpinning methane microbubble plumes. |
Year(s) Of Engagement Activity | 2020 |
URL | https://www.sheffield.ac.uk/cbe/news/professor-zimmerman-stars-new-show-discovery-channel |
Description | Feature Article in the Times of London based on my interview, by Tom Whipple, Science writer |
Form Of Engagement Activity | A magazine, newsletter or online publication |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Media (as a channel to the public) |
Results and Impact | Feature Article in The Times of London 13 April 2021 by Tom Whipple, science writer, explaining how our work on microbubble mediated heat transfer explained the previously unexplained original Mpemba effect experiments. The Mpemba effect has baffled scientists and the general public since it was popularized by Mpemba and Osborne in 1969. The Royal Society of Chemistry conducted an international competition in 2012 for the best solution to this mystery, known to have puzzled Aristotle and commented on by da Vinci. My study of microbubble mediated heat transfer gave a constructive model that correlated the original experiments, which have otherwise never been explained. More can be found about the first paper, sequels and a keynote address at the 15th International Conference on Heat Transfer, Fluid Mechanics, and Thermodynamics (2021) where the role of microbubbles is explained. |
Year(s) Of Engagement Activity | 2021 |
URL | https://www.sheffield.ac.uk/cbe/news/cracked-cold-case-why-boiling-water-freezes-faster |