Project summary: Computational models of microwave food processing
Researchers at Greenwich University have recently developed methods to improve the computationally demanding modelling of electromagnetic field and heat and mass transfer in the food and cavity of microwave ovens.

The basic science of the electromagnetic fields and the heat and mass transfer relevant to microwave cooking are well understood. What has not been quantitatively analysed is the systematic coupling between these phenomena. This coupling often controls the whole process because of the sensitive dependence of the electromagnetic properties on the local temperature and, especially, the moisture content. Research carried out by Dr Tim Tilford of Greenwich University has enabled a realistic, fully coupled mathematical model to be constructed and tested in two paradigm configurations: the first concerns the cooking of chilled food where moisture transport occurs throughout the sample and the second simulates thawing in an oven with a turntable.

The writing of the code was plagued by the multitude of disparate time and length scales such as pore size, thermal and electromagnetic penetration depths, and melting and diffusive time scales. These hurdles were overcome by using modern methods of scientific computation and a code now exists which has the potential to improve the design of both microwave ovens and microwave food products. Ultimately it is hoped that the code will allow the optimal design of products for rapid and uniform heating within the microwave oven.

The UK market for frozen and chilled ready meals is estimated at some £2 billion (sources: British Frozen Food Federation, Chilled Food Association). Professor Philip Richardson, from CCFRA said, This project has allowed us to explore opportunities presented by new computational and modelling approaches when applied to a traditionally complex sector of new product development and product assessment.

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