A funded 3-year UK/EU PhD studentship is available in the research group of Professor Paul Bowen and the High Temperature Research Centre (HTRC), School of Metallurgy and Materials at the University of Birmingham, with a stipend of £14,777 per year.
The HTRC is a unique casting, design, simulation and advanced manufacturing research facility. It focusses on the key design and manufacturing aspects of investment casting and related technologies.
Aero engine performance is strongly influenced by the temperature of the hot gas stream that enters the turbine, higher temperatures equating to higher efficiencies. The arduous mechanical loads, thermal and corrosive operating conditions that turbine components must endure can only be satisfied by cast nickel superalloy single crystals. With gas temperatures 300 °C greater than the melting temperature of the alloys from which blades, nozzle guide vanes and seal segments are manufactured, both thermal barrier coatings and advanced internal air cooling systems are required to resist inward diffusion of heat and to reject heat from within the load bearing elements back in to the external environment. The air required for cooling is taken from the compressor; whilst increased air flow through a component may increase the cooling effect it reduces the overall effectiveness of the turbine. Although already highly developed, further advances in cooling effectiveness are being researched under the ESPRC Programme Grant on Transpiration Cooling Systems for Jet Engine Turbines and Hypersonic Flight (1), a partnership between the Universities of Birmingham, Oxford and Southampton and Imperial College London. Novel multi-wall component designs and manufacturing methods have been developed in which the gas flow path is optimised, ensuring maximum capture and rejection of heat at minimum cooling air flow rates (2). However, modelling has shown that high cooling effectiveness in multi-wall monolithic or transient liquid phase bonded structures results in high thermal and consequent strain gradients with potential degradation of low cycle fatigue life (3).
Using the facilities of the HTRC and Fracture and Fatigue Group (Rolls-Royce UTC), the project seeks to study and quantify experimentally the effects of the high thermal and strain gradients arising in multi-wall superalloy single crystal turbine blade components under conditions that replicate those arising during aero engine operation. Informed by component geometries designed at Oxford’s Thermofluids Institute and lifing models from the Solid Mechanics and Materials Engineering Group, elevated temperature low cycle fatigue specimens and testing protocols will be developed. Investigations will focus on the rôles of key component features, accounting for inherent variations of feature geometry from the model(led) ideal that arise during casting, machining and joining. The effect of crystal anisotropy will also be considered and results used to validate and further refine models developed within the partnership.
The candidate will have a 1st Class Undergraduate or Masters degree (or equivalent) in Materials Science, Mechanical Engineering, Physics or a related discipline. A background in mechanical testing and/or materials processing and characterisation would be advantageous.
Candidates should provide a cover letter summarising your research interests and suitability for the position, the contact details of two referees and a curriculum vitae. Please send a copy directly to Prof Paul Bowen and Prof Nick Green.
Any informal enquiries of questions can be made to Paul Bowen: [Email Address Removed] or Nick Green [Email Address Removed] .