Time-resolved prediction of Jet A spray using time-resolved flame chemiluminescence along with scarce Mie scattering and ILIDS data

Time-resolved spray characteristics were predicted using time-resolved flame chemiluminescence coupled with low-speed Mie scattering and Interferometric Laser Imaging for Droplet Sizing data. A gas turbine model combustor that featured self-excited thermoacoustics was employed. Jet-A was sprayed at the center of the combustor, generating a power of 10 kW. The experiments were performed at a fixed fuel-air equivalence ratio of 0.6. For time lags ranging from -25 to 25 ms, the relations between the flame chemiluminescence and the number as well as the diameter of the droplets were obtained using 20 repeats of the experiment. The number and diameter of the droplets are negatively correlated to the flame chemiluminescence for zero time lag between the measurements, but positively correlated for a time lag of 15 ms. The above correlations and the time-resolved flame chemiluminescence data were used to predict the time-resolved variations of both the number of droplets and their diameter. The above analysis and the developed tools are of significant importance, as they facilitate understanding the time-resolved spray characteristics in liquid-fueled gas turbine combustors featuring thermoacoustics.