Experimental Aerothermal Study of Internal Jet Engine Structures

Sammanfattning: In commercial aviation, efficiency improvements may be gained by aerodynamic optimisation of its structural components, such as the intermediate compressor duct (ICD) and the turbine rear structure (TRS). These components have frequently been overlooked in favour of compressor and turbine module optimisation. This means that publicly available information on these structural components is relatively sparse, even though such components may offer substantial weight reduction and, with the introduction of hydrogen as aviation fuel, novel synergistic component integration. This thesis presents heuristic solutions to meet modern demands for verification data on two commercial aviation engine components, the ICD and TRS. The work spans separate research projects and addresses both method development and test facility design. The development of two measurement methods is presented. First, detailed uncertainty analysis of multi-hole probe implementation in the TRS has led to a 50\% reduction in uncertainty regarding total pressure measurement. Furthermore, a modern approach to measuring convective heat transfer has been developed and implemented on the outlet guide vane in the TRS. Neither of the two approaches presented here is limited to applications in the TRS or ICD and may be used in other applications. The aerothermal performance of the TRS for two different Reynolds numbers, several flow coefficients and three different surface roughness numbers have been investigated, and novel results on transition location, streamlines, heat transfer and loss distribution are presented. The second part of the thesis describes the design of a new, low speed, 2.5 stage low-pressure compressor (LPC) facility, built to investigate novel concepts of hydrogen integration in the ICD. Methods developed in the TRS are adopted and implemented in the new facility. A pre-study of the LPC and ICD instrumentation shows that compressor performance may be measured with better than 1% uncertainty using gas path studies.