Spray characteristics of natural gas-based alternative jet fuel at high pressure ambient conditions

Abstract

Alternative fuel like Gas-To-Liquid (GTL) jet fuel derived from natural gas is gaining importance in aviation industry due to their cleaner-burning nature. In this context, this study focuses on the role of ambient conditions on the atomization characteristics of GTL jet fuel at inert conditions, and the outcomes are compared with those of the reference, Jet A-1 fuel. For this purpose, a simplex atomizer, commonly utilized as a pilot-injector in aviation combustors for ignition at sea-level and in high-altitude relight conditions, is considered. The local atomization characteristics like droplet concentration, mean diameter and droplet mean axial velocity are obtained experimentally by employing the phase Doppler anemometry technique at different conditions (ambient gas pressures of 100, 500, and 900 kPa, and ambient temperature at 400 K). The fuel dispersion parameters are measured at different locations far from the atomizer while maintaining the pressure differentials across the atomizer at 300 and 900 kPa. For the conditions studied, the dispersion features are greatly influenced by the ambient conditions. At higher ambient gas pressures, GTL jet fuel exhibited higher droplet concentrations than conventional fuel, and smaller droplet and Sauter mean diameters. This difference in droplet characteristics can positively influence the energy release patterns of GTL jet fuel in a combustion environment.