LAUSR

In this study, the effects of varying initial droplet diameters (D0) and laser ignition energies on the continuous laser ignition and combustion characteristics of isolated aviation kerosene droplets were investigated. Two high-speed cameras were employed to capture the macroscopic morphology of droplets and flame shapes, while chemiluminescence images of CH* were monitored. The burning rate (K) was calculated based on the evolution of droplet diameter. A method to measure the minimum ignition energy (MIE) of a single droplet was proposed. The results indicated that the combustion process was roughly divided into three phases, and two fragmentation events of the droplet were observed: micro-explosions and puffing. The K increased with the consumption of the droplet. As D0 increased, the K of the droplet also increased, while the ignition delay time (tign) decreased slightly. The differences in tign and K between smaller and larger droplets were found to be influenced by their varying degrees of fragmentation and gas accumulation. As the laser power increased, the degree of primary fragmentation enhanced while tign decreased. Furthermore, the MIE required for a kerosene droplet with D0 = 1.42 mm was determined to be 0.98 J. The continuous laser ignition regime for a liquid droplet was observed to provide heat and disturbances within the droplet, resulting in varying degrees of fragmentation and ultimately leading to gas accumulation. Additionally, hot plasma was detected during the early stages of combustion. The interaction between these two aspects eventually ignites the entire droplet.