Development of Rayleigh Index Measurement Techniques for Swirl-stabilized Lean Premixed Combustion

The research presented in this work was conducted with the aim of using OH* chemiluminescence measurement techniques to aid in the understanding of heat release dynamics in premixed flames exhibiting thermoacoustic instabilities. Research was conducted on two experimental flames, one operating at atmospheric pressure and the second at engine-relevant high pressure. 3D reconstructions of the atmospheric flame were created for cases when a non-axisymmetric helical vortex core was observed, and thermoacoustic energy transfer fields were produced from these results. Positive and negative energy transfer regions were found to precess with the vortex core. In the high-pressure combustor, characteristics of the heat release fluctuations were determined in 2D, finding that the oscillation in heat release rate occurred as an axial wave propagating from the fuel nozzle. An analysis of the fluctuations in coupling between acoustics and heat release over time was also performed, indicating significant changes in the axial wave behaviour.M.A.S.2016-05-25 00:00:0