Dr Ian Wilson

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Reader in Chemical Engineering

Position	Reader
College	Jesus
Qualifications/honours	BA, MEng, Chemical Engineering, University of Cambridge, 1989 PhD, Chemical Engineering, University of British Columbia, 1994 Visiting Senior Lecturer, University of Auckland, 2000 Visiting Academic, Technical University of Braunschweig, 2008- FIChemE, CEng, CSci
Address	Department of Chemical Engineering and Biotechnology University of Cambridge New Museums Site Pembroke Street Cambridge CB2 3RA, UK
Email	diw11@cam.ac.uk
Telephone	+44 (0)1223 (3)34791
Research group	Powder and Paste Processing

Research description

Our interests lie in the following two areas, with particular applications in the food and chemicals industries.

Micro-Structured Materials

We are interested in studying 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 rheology and soil mechanics to describe these systems. This work is part of the Paste and Powder Processing Group activity, in association with Sarah Rough and David Scott. Our activities are focused around

• Fundamental studies : investigations of phenomena, such as 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 and drying of tungsten carbide pastes (with Sarah Rough) to understand monitor micro-structural development and defect formation, chocolate processing (with Alex Routh) and the rheology of Marmite® and cake batters (with Geoff Moggridge). We have also been working on novel processing routes to generate structured materials, particularly involving thermal processing routes.

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 focused on retrofit and design for crude oil fouling (in refinery pre-heat trains) and novel, non-disruptive, in-situ methods for studying the growth or removal of soft layers in conjunction with Bill Paterson and John Chew  (now at Bath).

We have recently 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.

Research keywords

paste, powder, food, fouling, cleaning

Key publications

Chesterton, A.K.S., Meza, B.E., Moggridge, G.D., Sadd, P.A. and Wilson, D.I. (2011) 'Rheological characterisation of cake batters generated by planetary mixing: Elastic versus viscous effects', J. Food Engineering, 105, 332-342.

Pogiatzis, T,  Ishiyama, E.M., Paterson, W.R.,Vassiliadis, V.S. and D.I.Wilson (2012) ‘Identifying optimal cleaning cycles for heat exchangers subject to fouling and ageing’, Applied Energy, 89, 60–66.

Zhang, M., Rough, S.L., Ward, R. Sieler, C. and Wilson, D.I. (2011) ‘A comparison of ram extrusion by single-holed and multi-holed dies for extrusion-spheronisation of microcrystalline-cellulose based pastes’, International Journal of Pharmaceutics, 416, 210-222.

Gordon, P.W., Brooker, A.D., Chew, Y.M.J., Wilson, D.I. and York, D.W. (2010) ‘A scanning fluid dynamic gauging technique for probing surface layers’, Measurement Sci. Tech., 21, 085103.

Other information

For a full list of publications, see http://www.ceb.cam.ac.uk/publications/DIWilson.html