How well do models of particle motion represent industrial reality?

Granular or particulate materials are common in nature and in process engineering, particularly as products such as instant foods, pharmaceuticals and consumer goods such as washing powders. Compared with simple fluids, they show interesting and useful behaviour, from kinetic free-flow in some circumstances to slow friction-dominated motion in others. In recent years there has been much progress in modelling their behaviour, particularly using the Discrete Element Method (DEM), in which each particle is considered separately and its interactions with its neighbours computed in order to predict its next position. Many industrial companies are now using such methods for design and process prediction but testing of such models against reality is difficult because the systems of interest are usually opaque and often held within metal-walled containers. This project will make use of a cutting-edge technique for tracking particle motion called Positron Emission Particle Tracking (PEPT) to map particle behaviour in a set of experiments which will be simultaneously modelled using DEM. The goal is to devise calibration tests for models which are able to discriminate between good and bad modelling approaches. The work is collaborative with a number of industrial partners through the International Fine Particle Research Institute (IFPRI), a US-based organisation of international industrial members, many of whom will be actively participating in the work through their in-house modelling teams. The ideal candidate will have an interest in coding to develop protocols to enable processing and comparison of large data sets, as well as an interest in the physics and engineering of particulate systems.

The beneficiaries of the research and training of the CDT will be UK industry, the graduates of the programme, the wider academic community, and consumers :

(i) UK industry: the formulation sector is wide and diverse, and our industry partners are world-leading in a number of areas; foods (PepsiCo, Mondelez, Unilever), HPC (P+G, Unilever), fine chemicals (Johnson Matthey, Innospec), pharma (AstraZeneca, Pfizer, Imerys) and aerospace (Rolls-Royce). All projects are cocreated with industry, and cofunded - the majority will be EngD students based in company sites. Industry will benefit in a number of ways: (i) from a supply of trained graduates in this critical area, with > 90% of graduates of the programme to date getting jobs in formulation companies, and (ii) through participation in industry-academia research projects in which students work within the company on projects of practical value, (iii) through the synergy possible between companies in different non-competitive sectors (we have current projects between Mondelez and P+G, and Johnson Matthey and Unilever resulting from CDT linkages). We will also work with Catapult Centres, including the National Formulation Centre at CPI and the MTC at Coventry, to enhance the industry relevance of the CDT and train students in modern manufacturing methods.

(ii) Graduates of the programme: students are trained in a critical area where graduates are in short supply, obtain training and experience of the issues involved in industrial and collaborative research, present their work at external and internal meetings and get good jobs (>90% within formulation companies). Many of our graduates are now reaching senior positions in industry, and one, Dr Stewart Welch of Rolls Royce, is now the representative of Rolls-Royce on our Industrial Management Committee. In the next 5 years we will build at least 50 new projects with companies, creating EngD and PhD graduates, a new generation of leaders for the formulation industries.

(iii) Wider academic community in the UK and elsewhere. We will ensure that students on the programme write papers (as many as possible with industrial co-authors) on formulation projects. This is a vital part of the CDT, as it both ensures and demonstrates the academic quality of the programme. We have published extensively in areas such as; soft solid mixing processes (Unilever, Johnson Matthey; see Hall et al., Chem.Eng. Res. Des. 91, 2156-2168, 2013); food materials for enhanced mouthfeel, low-salt and low-sugar delivery, (Pepsico, Nestle, Mondelez; such as Moakes et al RSC Advances 5, 60786-60795, 2015); design of innovative cleaning strategies (Unilever, GSK, Heineken, P+G; Food Bioprod. Proc., 93, 269-282, 2015); characterisation of domestic cleaning processes (washing machines and dishwashers) to minimise water usage (P+G; Chem.Eng Sci., 75, 14, 2012); in-vitro models for formulated product breakdown and nutrient and drug delivery in the mouth, stomach and GI tract; EngD work followed up by BBSRC and industry funding (Eur J Nutr. 55, 2377-2388, 2016); dynamics of spray driers (P+G, AIChE J 61 1804-1821 2015; Chem. Eng. Sci. 162, 284-299, 2017), and ways to reduce waste in soyamilk production (Unilever; Innovative Food Science & Emerging Technologies, 41, 47-55, 2017).

(iv) consumers: many of the companies we work with are involved in Fast Moving Consumer Goods, where research has direct consumer benefit, for example in the creation of low fat foods that have high-fat mouthfeel. In addition, the overall aim of the programme is to develop sustainable formulated products and processes; such materials will be better for the environment and consumers.