Near-nozzle atomization characteristics of GTL-Jet A-1 fuel blends at combustor relevant conditions using shadowgraph measurements

To achieve the goal of sustainable aviation, the aviation industry is considering blends of conventional and alternative jet fuels to achieve clean combustion. To this end, it is essential to understand the atomization characteristics of jet fuel blends better to gain additional insights into their ignition and combustion phenomena. Thus, this study explores the atomization characteristics of alternative-conventional jet fuel blends, i.e., blends of jet fuel derived from natural gas (Gas-To-Liquid, GTL) with Jet A-1 fuels at varying proportions (0, 50 %, 75%, and 100%) under non-reacting conditions at elevated ambient pressures (100 and 500 kPa) and ambient temperatures (300 and 350 K). Towards this goal, a simplex atomizer is used to experimentally investigate the macroscopic atomization characteristics, such as spray cone angle, sheet dynamics and breakup distance, and axial velocity variation at two pressure differentials across the atomizer (300 and 900 kPa). The results demonstrate that the influence of elevated ambient temperature has a stronger correlation with the near-nozzle atomization characteristics. For the type of nozzle studied, the far-field cone angle of jet fuel blends decreased from 70 ° to 60 ° with the increase in ambient gas pressure from 100 to 500 kPa. Under the conditions studied, the blend of 50% GTL-50%Jet A-1 exhibited an earlier onset of liquid-sheet instability, characterized using the second-order statistical moment, when compared to GTL and Jet A-1 fuels. Furthermore, the 50% GTL-50%Jet A-1 blend exhibited shorter liquid-sheet breakup distance than that of 75% GTL-25%Jet A-1 blend. The results presented here will assist in gaining additional insights into their ignition and combustion performance at relevant conditions.