Multi-scale particle-flow interactions in deformable porous structures

It is not often in engineering or physical science that an opportunity arises to improve the lives of people all around the world and substantially reduce a major demand on global energy resources. Solving the problem of cleaning clothes in cold water is such an opportunity. This project offers the chance to travel inside a familiar every-day activity and actually see the physical processes that take place inside dirty clothes as they are washed. Chemical process are of course relevant, but the physical processes are in many ways the DNA of the cleaning process, giving structure & function to everything else that takes place. The challenge is to develop a fully mechanistic understanding of the physical processes that pertain to the task of washing garments clean in cold water. While chemical processes are undoubtedly of great importance, the absence of appreciable thermal energy in a cold-water environment puts much greater emphasis on the role of mechanical energy. It is this fact that makes the daily chore of washing clothes in cold water such a burden for so many people in developing countries in terms of time and effort. There is an urgent need to optimize the cleaning effect of the available mechanical energy (and better still, to reduce the total amount required) in order to deliver considerable benefits to the approximately 3 billion people whose clothes still have to be washed by hand, and also to lower the amount of electricity that is consumed of those who wash by machine.The idea of this project is to separate the mechanical cleaning process into key sets of interactions concerning soil, fabric and fluid while considering all relevant scales. Over this range, we will determine the magnitude of the forces that bind soil material together in particles, cause soil particles to adhere to fabric fibres, deform fabric weaves in the presence of fluid flows, and that are required during the process of garment washing. The approach will be to make precise measurements of these forces in test soils & fabrics under controlled laboratory conditions, develop theoretical models of the relevant physical processes based on the experimental data, and ultimately to manufacture & test prototype washing simulators that incorporate the knowledge gained from the measurement & modelling work. These ideas have the potential to transform the ways that washing processes are evaluated and that new cleaning products are tested prior to implementation. The novelty of the project derives in part from the multi-scale approach of the investigation and also from the objective of measuring & visualizing mechanical cleaning action under controlled reproducible conditions. The adventure of the project comes from the breadth of the problem being tackled and from the depth of physical insight that is being sought.

(1) Consumers The principal beneficiaries of the project will be the ca. 3 billion people around the world who still rely on washing by hand to ensure clean clothes and domestic fabrics. These people, often women in developing countries, can spend up to 15 hours a week washing their family's clothes. Great pride is taken in carrying out the task thoroughly, with an excellent quality of final cleanliness achieved. By improving the efficiency and speed of the hand washing operation, the quality of life of billions of women could be improved. Consumers will benefit from from a range of improved hand-washing powder formulations and cleaning regimes for effective cold water clothes washing. A secondary benefit for consumers is the accompanying reduction in energy and water consumption that is possible by the application of improved cold water washing formulations and techniques. This will result in a cost saving, and a reduction in the environmental impact of these operations. As commercial sponsors of the project, P&G will ensure that consumers benefit in the ways described. (2) Washing Powder Formulators, manufacturers and suppliers The project aims to deliver a set of outputs that will enable washing powder manufacturers to formulate more effective cold water laundry washing formulations for hand washing applications. This will generate a competitive market advantage, and offer unique selling points (USP) and distinctive selling points (DSP) for specific products placed in hand-washing dominated markets. As commercial sponsors and partners in the research, P&G will ensure that this happens. (3) Textile manufacturers This group could benefit from research outputs that enable the cleanability of different fabrics to be tested systematically under a range of realistic cold water hand washing conditions. Presentations at relevant international textile conferences will ensure that this happens (4) Washing Machine Manufacturers The primary focus of this project is to determine the forces taking place in hand washing. However, the majority of consumers in Western markets use automatic or semi-automatic washing machines to clean their laundry. The outputs of this project are also relevant to range of forces present in automatic washing machines, and could help manufacturers of these machines to optimise their washing programme cycles. We propose to present the project findings through the trade journal press. (5) Manufacturers and users of conventional and synthetic membrane filters Conventional filters and pressure-driven membrane separations have much in common with the flow thorough fabrics. It is expected that the outputs will be of benefit to those who supply and use filters with a high fouling tendency, that require regular chemical cleaning. (6) Water and energy utility companies These organisations will benefit from the reduction in the consumers' use of water and energy that results from the implementation of more effective cold water hand washing regimes. Publications in the trade and peer reviewed literature will highlight the potential benefit of the research to the operation of these organisations. (7) Local, regional and national policy makers The potential reduction in the time spent carrying out laundry operations in developing countries (operations which are primarily carried out by women) represents a profound opportunity for meaningful development in other areas such as education, sport, business or recreation. We plan to make policy makers aware of the potential life-changing opportunities that would arise from large amounts of additional time potentially becoming available to this section of the community. Awareness of such opportunities will be raised by press releases to local and national media through P&G, who invest substantially in a range of advertising media.