Experimental investigation of kerosene single droplet ignition and combustion under simulated high-altitude pressure and temperature conditions

This study experimentally investigates the ignition and combustion characteristics of single kerosene droplet under simulated high-altitude conditions, focusing on the effects of reduced ambient pressure (100 kPa–20 kPa) and temperature (293 K–253 K). Results show that spark assisted ignition time exhibits a strong inverse power-law dependence on ambient pressure and a non-linear relationship with ambient temperature. At reduced pressures, significantly longer heat accumulation periods are required for ignition, with delayed and more variable ignition behaviour. The combustion process displays distinct stages of droplet swelling, preferential gasification, and disruptive microexplosions, which intensify and become more irregular as pressure decreases. Flame temperature and structure are also strongly pressure-sensitive, with reduced buoyancy at low pressures resulting in more spherical flames and increased flame standoff ratios. While ambient temperature has limited influence on burning rate and microexplosion intensity, it amplifies variability when combined with pressure reduction.