Gas Turbine Stator-Well Flow and Heat Transfer.

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Gas turbines are a common form of combustion engine, used to either generate electrical energy or thrust depending on the application. These machines are comprised of a compressor, combustor, and turbine which act to extract energy from high temperature and high-pressure air to generate power. The internals of the turbine region consist of many stages of fixed and rotating blades attached to discs, which are designed to withstand the extreme temperatures and forces applied from the gas that passes through the mainstream. In order to maximise the service life of a gas turbine, the heat transfer to the disc surfaces must be carefully predicted to reduce wear and prevent failure, with overhaul and maintenance costs being a significant cost to the engine supplier. Detailed knowledge of the flow conditions and temperatures within the turbine is therefore vital in making these predictions, helping to identify improvements to the turbine design to extend its operational life. One aspect of the fluid flow within the turbine is the interactions between the cavities created between the rotating (rotor) and fixed (stator) blade sets, known as "stator wells". These cavities have small clearances, which limits the ability to vent hot air and inject cooling air within these gaps, resulting in high rates of heat transfer to the disc surfaces. The complexity of the fluid dynamics in these regions has limited the level of detail computational methods have been able to resolve, with flow characteristics such as ingestion, re-ingestion, purge and leakage all leading to further questions on the interactions within the cavities.The aim of this research is to use a coupled conjugate heat transfer (CHT)/computational fluid dynamics (CFD) solver to understand the fundamental fluid dynamics and heat transfer characteristics occurring within the turbine stator wells. This software will be developed to form a theoretical model of the test cases and then solved using the boundaries given from experimental data. Validation will be performed using existing experimental data from the in-house compressor cavity rig before being applied to turbine stator well problem.