Velocity Fields in a High Pressure Liquid Fueled Swirl-stabilized Lean Partially-premixed Combustor

This thesis investigates thermoacoustic velocity coupling in a lean, partially-premixed, liquid fueled gas turbine combustor operating at engine relevant conditions. Temporally resolved velocity fields are calculated through stereoscopic particle image velocimetry running at 5 kHz. Low velocity data yield is typical of such high pressure flames, so a new spatio-temporal data reconstruction algorithm is developed and implemented here to aid with the analysis of the measured velocity fields. Velocity measurements from six cases are studied here: gas phase velocities from two non-reacting and two reacting flows, and liquid phase velocities (on fuel droplets) from two other reacting cases. While the acoustic fields and the fuel flux into the combustor are found to have periodic oscillations corresponding to the thermoacoustic frequency, the velocity fields do not exhibit any relevant coherent oscillations. It therefore appears that, for the combustor being studied here, the thermoacoustic oscillations are a result of the fuel flow coupling, as opposed to vortex-acoustic-flame interactions.M.A.S.2017-05-31 00:00:0