Engineering Doctorate: The development and application of advanced CFD methods to study the 
fundamentals of bubble 
growth and boiling

This engineering doctorate represents an exciting opportunity to perform Ph.D level research with a very 
strong industrial context, based jointly at one of the world’s top technical universities, and an exciting 
and dynamic science and engineering consulting company based in Zürich, Switzerland.
The boiling process is fundamental to the design and safety of water-cooled nuclear reactors, and to 
many other classes of industrial plant. Whilst liquid water is an excellent coolant steam is a very poor 
one. An understanding of how, and ability to predict just where and when, liquid water becomes steam 
is correspondingly vital. A two-phase mixture of steam and water is too complex to be simulated 
directly. To date, modelling is consequently empirical, based on phase-averaged CFD approaches, 
requiring multiple closure relations for vapour-to-liquid and wall-to-flow mass, momentum and energy 
exchanges, with idealized geometries imposed on the vapour/liquid interface. Good progress has been 
made in developing and tuning these complex semi-empirical models, embedded in current state of the 
art commercial CFD. However, they need more secure foundations, with their empirical parts based on 
more fundamental and detailed understanding of the underlying phenomena. Contributing to this 
detailed understanding is at the heart of this EngD project.
Our intention is that computationally large Direct Numerical Simulations (DNS) of bubble growth and 
boiling will be performed, and their results used to develop semi-mechanistic models for incorporation 
in CFD treatments used to analyse nuclear plant. The models to be constructed must incorporate 
mechanistically the relevant physical processes; conjugate heat transfer within the adjacent solid 
surface, vapour generation, and the growth and formation of the vapour-liquid interface.
This work is a collaboration between the Ascomp company, in Zürich, and the Nuclear Research Group 
at Imperial College in London. Ascomp, with its close links to ETH Zurich, is a dynamic, young science 
and engineering consulting company, and the developer of the advanced interface-tracking CFD code 
Transat. The research group at Imperial is the largest nuclear thermal hydraulics research group in the 
UK, and has long-standing interests in nuclear thermal hydraulics and boiling.
The research engineer will be required to divide his time between the two locations, in Zürich and in 
London, working on the development and analysis of these models. It will be necessary to work in close 
collaboration with the developers of the Transat code, as inevitably it will be found that modeling within 
the code needs to be augmented and improved. We thus seek someone with a sound understanding of 
the physical and mathematical basis of fluid mechanics, and with sufficiently high-level computational 
skills to convert this understanding to successful computer code.
You should have a very good first degree in a relevant subject (science, engineering, or mathematics or 
physics could all be perfectly appropriate). The main requirements are physical insight, mathematical 
competence and computational skills, and great industry and enthusiasm.
In exchange, you will gain an engineering doctorate in an exciting international project, working with 
acknowledged experts in their fields.All candidates (UK, EU and ‘Overseas’) will be eligible for a four year, 
£21,000 net pa  bursary, and will receive tuition fees at the ‘Home’ rate. ‘Overseas’ candidates will need to 
seek additional support, or use their  own resources, to cover the additional ~£16,000 pa cost of Overseas 
fees.

For further details of the post contact Dr Simon Walker s.p.walker@imperial.ac.uk +44 (0)20 7594 7058  
Interested applicants should send an up-to-date curriculum vitae to Dr Walker on the above e-mail 
address.  Suitable candidates will then be invited and required to complete an electronic application 
form at Imperial College London in order for their qualifications to be addressed by College Registry.

For information on the Nuclear EngD: 
http://www.dalton.manchester.ac.uk/study/postgraduateanddoctoralstudy/nuclearengd /.