Modelling Gas Turbine Blade Degradation in a High Fidelity Digital Twin

The hot aerofoils in a gas turbine operate within an extremely hostile environment. Whilst the materials used are selected on the basis of their ability to survive in this environment, it is such that the aerofoils degrade with time. When the operating conditions of the gas turbine and levels of contaminants ingested change, this can adversely alter the predicted life time of the aerofoils. This leads to reduced reliability and greater costs for the gas turbine manufacturer and user. The project will therefore seek to improve understanding of gas turbine aerofoil base material and coating corrosion, oxidation and creep mechanisms and the models used to describe these forms of degradation. The models will be used with high-fidelity digital twins to predict the effect of gas turbine aerofoil degradation on potential aerofoil service lives. Gas turbine manufacturers are developing digital twins for their gas turbine aerofoils to improve their predicted lives and to tailor their potential designs to a particular gas turbine's manufacture, operating history and possible repair. Such digital twins go far beyond conventional record keeping, and involve the development of a toolkit of models for different potential degradation mechanisms.

Aim: The main aim of this PhD is to improve the understanding of the mechanisms that govern gas turbines vane degradation to optimise components design and lifetimes.
This will include quantifying the effects of the cooling systems, analysing the thermo-mechanical performance of superalloys and coatings and understanding the evolution of hot corrosion. To reach the aim of this PhD project, the following objectives have been defined.
Objectives:
1. To validate CFD and FEA models against experimental and/or computational results.
2. To model the effects of internal and external cooling simultaneously.
3. To understand the mechanisms that govern the condensation of alkali vapours that initiate hot corrosion.
4. To create a time dependent model of metal loss using laboratory data.
5. To model the thermo-structural performance of nickel-based superalloys and TBCs.

The main methodologies to be used are computational fluid dynamic (CFD) modelling, finite element analysis (FEA) and statistical analysis of materials damage; all of which require validation by comparison with data from real gas turbines.