|Wetting||Viscous Fingering||Porous Media|
|Energy Efficiency||Renewable Energy||Carbon Reduction (CCS)|
|Buildings||Subsurface heat recovery||Carbon sequestration|
|Natural Hazards||Natural Environment|
|Deep Sea Mining||Ice|
The work of the BPI, which is very wide ranging, covers large areas of fluid mechanics and surface science. It may be useful to look at the list of publications on the BPI web site from the past 2 years (and longer) to get an in depth idea of the research.
All the students, post-docs and faculty at the BPI are members of the University of Cambridge, and enjoy the same academic freedom as all other members of the University; our research is not directed by any external body. Over the past 20 years, the BPI has become an internationally recognised centre of excellence in fluid mechanics and surface science, with a distinguishing feature being the collaboration across subjects and the use of fundamental and new knowledge to inform a very wide range of problems with immediate relevance for the processes in the Earth, the environment or industry.
The BPI is highly interdisciplinary, and we have many colleagues with whom we collaborate both in the University of Cambridge and more broadly with the UK and globally. The academic freedom, the spirit of intellectual curiosity and the vast range of fundamental and important problems for which our research can provide new insights, are key.
In the papers you will find that our research involves both experiments and theoretical calculations and includes the following subjects :
- geophysical and geological fluid mechanics, including the dynamics of volcanic eruptions and the ash plumes produced during large explosive eruptions, and the processes below surface driving these eruptions including the cooling and crystallisation of magma; the processes controlling the formation of planetary interiors, and the fluid mechanics of mixing in the deep ocean, which informs models of climate change given that the ocean has a large mass and hence capacity for thermal energy and carbon dioxide. We are also interested in sea ice formation and its impact on ocean circulation, the dynamics of glaciers and their coupling with subglacial systems, and the dynamics of river recharge and discharge and the erosion of topography by rivers.
- environmental fluid mechanics, including the dynamics of gravity driven flows and buoyant plumes, with relevance for the air flows in hospitals and other buildings (on the web site you can see a very current film about our work in modelling the ventilation of hospitals relevant for the present coronavirus pandemic), and also experimental and theoretical models of avalanche dynamics, relevant for landslides and also snow avalanches. We have some highly novel experimental systems which enable measurement of the forces between particles in such flows as well as the speed of the particles, and this has the potential to transform models of these phenomena, which are becoming increasingly important for civil defence in mountainous areas. There is also a programme on desert dune migration and structure, which is of particular relevance in the context of promoting sustainable agriculture, and sustainable use of terrestrial ecosystems (avoiding desertification).
- Our work on air flows in buildings is also relevant for the design of low energy buildings which use ideas of natural ventilation to reduce the energy associated with ventilation and cooling. In this work, we have been developing innovative control strategies to identify how to minimise the energy use associated with ventilation systems. We are also exploring the dynamics of bubble plumes used for oxygenation of water reservoirs, and particle plumes, which are relevant for understanding the environmental impact of possible deep sea mining processes.
- the fluid mechanics of carbon capture and storage (CCS), which is one part of the IPCC plan to reduce atmospheric carbon emissions, especially for processes which are hard to decarbonise, including cement and steel manufacture. Our work focusses on the flow of CO2 at high pressure through subsurface porous rocks (aquifers) in order to understand where CO2 spreads if it is sequestered into such aquifers at depths of 2-3km below the surface, and how it interacts with and displaces the brine which presently occupies many of these aquifers. The complexities of and research interest in these flows arise from the often heterogeneous structure of the rock, and the density and viscosity contrast between the CO2 and the original brine in the reservoir, leading to gravity driven flow and capillary trapping and dissolution of some of the CO2. Our work involves experimental modelling of the flow through model porous media, to test theories of the efficiency and security of storage. We are also interested in the fluid mechanics of drilling wells; many wells will be need to be drilled to access subsurface aquifers if we are to implement CCS at scale, and understanding more about the fluid mechanics of drilling will help in this endeavour.
- experiments and modelling of micro-encapsulation of various materials with relevance for drug delivery in the body for example. The encapsulation process involves the formation of a near-spherical surface of material to enclose the reactive agent. The surface is created through formation of an emulsion, and then the addition of the encapsulant material to the surface of droplets in the emulsion. These are sintered to form a shell, and they then enclose the material within. They may have a size of order a few microns, and have a range of purposes, from protecting active materials within biological washing powders prior to their use, to providing a novel means of drug delivery in the body. A novel application of some of this work has been directed to the clean up of polluted waste water which is produced in some industrial processes.
- there is a large research effort exploring the surface chemistry associated with the deposition of material on the walls of machines or pipes or other surfaces, sometimes known as fouling. In many industrial processes, such deposits can build up on surfaces, degrading the performance of the systems (such as in heat exchangers for example) : determining how to reduce the build up of such deposits, or to remove such deposits is key across industry, and especially the chemicals industry. This fundamental work is also relevant for modelling some of the flows which can occur in porous rocks, where the interaction of the fluids with the solid surfaces can have a leading order impact on the flow evolution.
- other research is exploring the process of corrosion on surfaces, and developing approaches to reduce this corrosion; this is important for large structures, such as offshore wind turbines, which are exposed to very hostile conditions with salty water.
- research on the fundamental processes involved in droplet break up and the development of models to predict such droplet break up using numerical computation. We have world leading approaches to such modelling which is relevant for modelling atomisation, particularly of non-Newtonian fluids (i. e., the break up of a liquid into a series of droplets such as occurs with spray painting, or with ink jet printing).
- We have also been interested in geothermal power generation and the associated problem of heat storage in aquifers and the potential for seasonal cycling of energy so that there is an energy source in winter captured in the summer: these processes rely on flow through porous aquifers, and this forms another strand of our current interests in flow in porous rocks. Our research focusses on how hot water spreads through a porous aquifer, carrying the thermal energy, and the potential to recover this thermal energy at a later time by drawing this water back out from the aquifer.
There are many other problems which we are exploring as well. If you would like the research papers explaining some of the above problems in more detail please look at our web site, or get in touch.
Comment on the BPI and Energy Transition
As you will see from the wide range of research, we have a strong interest in helping to understand the science of climate change, including the work on ice dynamics and ocean mixing, and we have many projects related to the energy transition and the decarbonisation of the energy system, where our work is providing important new insights into new technologies, including CCS, energy storage, low energy building design, wind turbine optimisation. We also hold an annual Masterclass in Energy Supply and Demand to which all students in Cambridge can apply to attend - at this we have a host of speakers presenting the facts and data about the present and future energy system, in particular focussing on the technology and other challenges associated with decarbonising the energy system.
The energy transition requires a large number of scientists and engineers to work with government, industry and society to try to assess and select optimal solutions for a decarbonised energy system. There are many choices and challenges with developing a decarbonised energy supply system and energy supply mix: it needs to have sufficient capacity to supply the energy which the world uses, both presently and going forward and we need to determine the fraction of this energy supply which each technology might contribute (eg wind or solar or geothermal or hydroelectric, or nuclear, …). Also knowledge of the present energy supply system is clearly very important in informing these decisions. On the demand side, there are very many technical challenges to develop new machines and other systems which can be powered by the new energy supply system, which will be largely delivered as electricity, or perhaps as hydrogen - compared to today, where we have a significant amount of energy delivered to the user in the form of natural gas (eg for heating over 20 million homes in the UK) or in petrol or diesel (for powering vehicles) which need to be replaced with electric vehicles or perhaps hydrogen powered vehicles, and alternative heating systems, which might include district heating systems or heat pumps, or other solutions. There are significant natural resource implications if all passenger vehicles become electric, given the large number of new batteries that we would need to manufacture. We also need new solutions for powering cargo ships and air travel. In addition, there are numerous opportunities for more efficient use of energy through new technological solutions, and better design, especially with buildings. Then the cement and steel industries, which are responsible for a significant fraction of global CO2 emissions, may require the development of CCS and the invention of lower carbon manufacturing processes. Finally, biofuels with carbon capture, offer a possible means to achieve negative emissions.
For all of these problems, there is an enormous amount of important work to be done, on policy and economics as well as the science and engineering, and we are engaged in some of these problems in the BPI. Our hope is that many students and other researchers will join in this major activity to help address both the overarching questions of technology choices moving forward (since there are many different solutions) and the detailed questions which require detailed technical / engineering or research work in each part of the energy system - both relating to the supply and the demand sides, as well as energy efficiency.
As you will appreciate, industry plays a central role in the energy supply and energy demand systems, and so it is crucial that we collaborate and work constructively with industry across the whole spectrum to help translate our technical innovations into creating the new decarbonised energy system, and also to help influence the choices made by industry going forward using our detailed technical knowledge. As the energy infrastructure undergoes this enormous transition, there is a need for civilised discussion and debate, and the BPI as with other venues in the University, provides an ideal platform for such discussions.
We all want to evolve to a decarbonised energy system as rapidly as possible, but this is an enormous endeavour, and it will require tremendous innovation and collaboration.