Direct simulation of liquid metal nucleate boiling in the presence of magnetic fields

Nucleate boiling occurs when a solid surface is heated above an adjacent liquid’s saturation temperature. In this scenario, vapour forms at preferential nucleation sites on the heated surface. While there has been much research into the computational modelling of nucleate boiling [1, 2], there have been comparatively fewer studies into the boiling of liquid metals, especially in the presence of magnetic fields. This is despite the relevance to nuclear fusion blanket design.

Fusion blankets are multi-purpose chambers that surround plasma in a tokamak reactor. A critical role of the blanket is to transfer nuclear heat (arising from high-kinetic energy bombarding neutrons) away from the first wall and into a steam generator where the steam is subsequently used to drive a turbine in a standard thermodynamic steam cycle.

In the context of fusion, a Lithium-Lead eutectic is often used as a working fluid. This metal flows in the presence of strong magnetic fields, inducing electric currents. Magnetohydrodynamic (MHD) body forces act on the fluid (the Lorentz force). This MHD effect opposes the motion of the metal and lowers the flow rate for a given pump head; typically, flow rates are too low to transfer sufficient heat from the first-wall to prevent thermal damage.

A proposed solution to this is to allow the coolant to boil. The advantage of this is twofold: 1) nucleate boiling is a highly effective method of heat transfer due to the high latent heat of vaporisation of typical working fluids. 2) In the vapour phase, the Lorentz force is much less severe. This allows for greater flow rates (and therefore enhanced heat transfer) for the same pressure drop along a given duct length.

This PhD will focus on developing the necessary computational fluid dynamics (CFD) tools to effectively model bubble nucleation in metals subject to strong magnetic fields. Such a tool does not currently exist, and the study of such flows is currently predominantly undertaken experimentally (with limited insights and high cost due to the fact metals are not transparent to visible wavelengths of light). The magnetic field alters bubble nucleation dynamics (bubble shape, departure diameter and frequency, nucleation site density, etc.). Once developed and validated against existing experimental data in the literature [3], the tool will be used to perform fundamental flow physics studies in both pool and flow boiling configurations to better understand the complex flow physics involved.

In this project, you will join a team of researchers active in MHD [4], heat transfer and nucleate boiling modelling [1,2], leveraging the combined knowledge of the group. You will have opportunities to collaborate with researchers at UKAEA.

Eligibility

Applicants should have, or expect to achieve, at least a 1st class degree (or international equivalent) in a relevant discipline (physics, engineering or applied maths). Ideally, you will have, or expect to achieve, an MSc or integrated masters at merit or distinction (or international equivalent) in a relevant discipline.

Applicants should have strong computer programming skills in C++.

Funding

At The University of Manchester, we offer a range of scholarships, studentships and awards at university, faculty and department level, to support both UK and overseas postgraduate researchers.

For more information, visit our funding page or search our funding database for specific scholarships, studentships and awards you may be eligible for.

This project is also eligible for the Osborne Reynolds top-up Scholarship which provides an additional £1500 per year top-up to other funding sources for outstanding candidates. Successful applicants will be automatically considered for this top-up.

Before you apply

We strongly recommend that you contact the supervisor for this project before you apply.

How to apply

Apply online through our website: https://uom.link/pgr-apply-fap

When applying, you’ll need to specify the full name of this project, the name of your supervisor, if you already having funding or if you wish to be considered for available funding through the university, details of your previous study, and names and contact details of two referees.

Your application will not be processed without all of the required documents submitted at the time of application, and we cannot accept responsibility for late or missed deadlines. Incomplete applications will not be considered.

After you have applied you will be asked to upload the following supporting documents:

• Final Transcript and certificates of all awarded university level qualifications
• Interim Transcript of any university level qualifications in progress
• CV
• Contact details for two referees (please make sure that the contact email you provide is an official university/work email address as we may need to verify the reference)
• English Language certificate (if applicable)

If you have any questions about making an application, please contact our admissions team by emailing [Email Address Removed].

EDI

Equality, diversity and inclusion is fundamental to the success of The University of Manchester, and is at the heart of all of our activities. We know that diversity strengthens our research community, leading to enhanced research creativity, productivity and quality, and societal and economic impact.

We actively encourage applicants from diverse career paths and backgrounds and from all sections of the community, regardless of age, disability, ethnicity, gender, gender expression, sexual orientation and transgender status.

We also support applications from those returning from a career break or other roles. We consider offering flexible study arrangements (including part-time: 50%, 60% or 80%, depending on the project/funder).