BA, MEng, Chemical Engineering, University of Cambridge, 1989
PhD, Chemical Engineering, University of British Columbia, 1994
Visiting Academic, Technical University of Braunschweig, 2008-
ScD, University of Cambridge, 2013
Cambridge/Canterbury Fellow, 2015
CEng, CSci, FIChemE
Our interests lie in the study of soft solids and surfaces, with particular applications in the food, pharma and chemicals industries.
We study the formation and processing behaviour of structured semi-solid materials. The main area of interest is in solid-liquid pastes or doughs, composed of particulate solids surrounded by continuous liquid phase(s). These are common in the food, detergent, agro-chemicals, pharmaceutical and catalysis industries, and are frequently formed into particular shapes by extrusion. The underlying physics is complex and we use aspects of plasticity theory, fluid mechanics, rheology and soil mechanics to describe these systems. We also work on bubbly liquids and complex food fluids.
This work is part of the Paste, Powder and Polymer Processing Group activity, in association with Sarah Rough, Bart Hallmark and David Scott and continues the activity started by John Bridgwater and Malcolm Mackley. Our activities are focused around
- Fundamental studies : investigations of phenomena, such as wall slip, liquid phase migration, agglomeration or fracture;
- Process modelling : developing models of paste forming processes, such as rolling/calendering or screen extrusion;
- Product design : relating function, processing and formulation to deliver particular product properties.
- Rheology: using modern devices and theory to describe how soft solids deform and flow, and respond to formulation and processing
Ongoing projects include the extrusion of tungsten carbide pastes (with Sarah Rough) to understand monitor micro-structural development and defect formation, the rheology of bubbly liquids (aka cake batters and foamed cement, with Bart Hallmark), and extrusion-spheronisation of pharmaceutical materials (with Sarah Rough).
Fouling and Cleaning Mechanisms
A whole class of unwanted micro-structured materials can be found as fouling deposits on heat transfer surfaces, in distribution systems and other equipment. Fouling is a common (and expensive) operating problem in many processes, particularly the food industry, where the deposits formed can act as harbours for other problem species (e.g. bacteria ). This work relates to long-standing efforts in heat transfer and approaches the problem at three related scales:
- Fundamental studies of deposit formation and removal, with particular focus on deposit structure and modelling;
- Design, control and operation of individual heat exchanger units, both in production and during cleaning (e.g. for aspectic processing);
- Design and operation of large heat transfer networks, such as are used in energy intensive processes.
Recent work has lookied at water scaling on copper surfaces (with Stuart Clarke) and novel, non-disruptive, in-situ methods for studying the growth or removal of soft layers in conjunction with John Chew (University of Bath). The soft layers include biofilms and protein matrices undergoing swelling for controlled release.
Our interest in cleaning in the food sector has expanded into studies of the flow behaviour of liquid jets impinging on vertical walls and their cleaning behaviour. This work (in conjunction with John Davidson) features collaborations with TU Braunschweig, TU Dresden and DAMTP here in Cambridge.
The paper by Ishiyama et al. (see below) brought the strands of soft-solids and fouling together in a unified framework for managing fouling and cleaning cycles, where deposit ageing (converting deposit from a soft solid to a hard material) is a key factor. The Matlab code for this work is available from Dr Edward Ishiyama.
Ian was awarded an ScD by the University of Cambridge for his work in this field in 2013.
Details of folk who are working with or have worked with Ian are given on the P4G website.
Please note that I am not hosting research interns in 2017 owing to the Department's move to West Cambridge over this period.
Other Professional Activities
Ian is the Editor-in-Chief (Food) of the IChemE journal Food & Bioproducts Processing
IChemE University Accreditation Assessor
IChemE Food & Drink Subject Interest Group
EHEDG Working Party on tank cleaning
Wang, S., Schlüter, F., Gottschalk, N., Scholl, S., Wilson, D.I. and Augustin, W. (2016) Aseptic zero discharge fluid dynamic gauging for measuring the thickness of layers of soft solids on surfaces, Chemie Ingenieur Technik, 88(10), 1530-1538.
Bhagat, R.K. and Wilson, D.I. (2016) Flow in the thin film created by a coherent turbulent water jet impinging on a vertical wall, Chem. Eng. Sci, 152, 606-623.
Bryan, M.P., Rough, S.L. and Wilson, D.I. (2015) Investigation of static zones and wall slip through sequential ram extrusion of contrasting micro-crystalline cellulose-based pastes, J. Non-Newtonian Fluid Mech., 220, 57-68.
Gomes da Cruz, L., Ishiyama, E.M., Boxler, C., Augustin, W.A., Scholl, S. and Wilson, D.I. (2015) Value pricing of surface coatings for mitigating heat exchanger fouling, Food Bioproducts Proc., 93, 343-363.
Bryan, M.P., Atherton, L.N., Duffield, S., Rough, S.L. and Wilson, D.I. (2015) Stages in spheronisation: evolution of pellet size and shape during spheronisation of microcrystalline cellulose-based paste extrudates, Powder Tech., 270, 163-175 .
Collett, C.H., Ardon, A., Bauer, U., Chapman, G., Chaudan, E., Hallmark, H., Pratt, L., Torres-Perez, M.D., Wilson, D.I. (2015) A portable extensional rheometer for measuring the viscoelasticity of pitcher plant and other sticky liquids in the field, Plant Methods, 11:16.
Ian is called by his second name : he is D.I. Wilson on publications (listed on the P4G website).
Ian was awarded the Bingham Fluid Medal at the 2013 biannual Viscoplastic Fluids: From Theory to Application conference held in Reuil-Malmaison, Paris, from 18-21 November 2013. This informal award (not to be confused with the Eugene Bingham Medal given by the Society of Rheology) is given biennially and recognises the contribution of members of the viscoplastic fluids community. In awarding the medal, Prof Ian Frigaard noted that "Ian tackles real problems, with significant complexity in both the materials and the processing aspects. Yet he tries to find simple answers and give practically applicable results, often significant in being able to advance our scientific knowledge. The community appreciates his dedication to the field and many contributions in semi-solid materials, pastes, fouling, food processing and rheology."
Ian (on right) receiving his Bingham chocolate medal from Anthony Wachs (IFP, on left) and Ian Frigaard (UBC, centre) © J. Non-Newtonian Fluid Mechanics (2015)