The research is within the Turbomachinery Research Centre (TRC) at the University of Bath. It is an experimental project investigating ingress and heat transfer in gas turbines. A iCASE studentship has been provided by Siemens to support this project.
Ingress in gas turbines is one of the most important of the cooling-air problems facing engine designers, and considerable international research effort has been devoted to finding acceptable design criteria. It occurs when hot gas from the mainstream gas path is ingested into the wheel-space between the turbine disc and its adjacent casing. Rim seals are fitted at the periphery of the system, and a sealing flow of coolant is used to reduce or prevent ingress. However, too much sealing air reduces the engine efficiency, and too little can cause serious overheating, resulting in damage to the turbine rim and blade roots.

The Turbomachinery Research Centre (TRC) at the University of Bath has investigated the effects of ingress experimentally, theoretically and computationally over the last 11 years. This research has taken place in collaboration with Siemens across two highly successful projects jointly funded by the EPSRC. Both of these projects involved the design and manufacture of fully-instrumented rotating disc rigs used to study the effects of ingress in engine-representative gas-turbine wheel-spaces. In parallel with the experimental programmes, theoretical models developed at Bath have been used extensively in the analysis and interpretation of the measured data obtained from the rigs.

It is proposed to expand this study to investigate the effects of ingress in a two-stage turbine stator well configuration, representative of a typical industrial engine design. Temperature measurements on the rotating disc surfaces will be used to determine the adiabatic effectiveness and heat transfer coefficients in the presence of ingress. Emphasis will be placed on translating experimental and analytical techniques from a separate project at Bath (EP/P003702/1) investigating heat transfer in compressor rotor discs. A theoretical model developed enables the steady-state Nusselt numbers, and their confidence intervals, to be accurately determined.

Feasibility studies will be conducted using the existing Bath rotating rigs to develop ideas and instrumentation. The proposed project will, for the first time, apply new analysis methods and improved measurement technique capability to heat transfer tests on turbine discs. The PhD student is expected to assist a postdoctoral research associate in the design, construction and commissioning of the test rig, and take a leading role in conducting the experimental measurements. Temperature measurements on the rotating disc surfaces will be used to determine the adiabatic effectiveness and heat transfer coefficients in the presence of ingress.

The successful completion and implementation of this research through improved engine design should result in a competitive advantage for Siemens.