Ignition and Combustion Characteristics of Al/n-Heptane Nanoslurry Fuel Droplets via a Laser-Ignition Model

The ignition and combustion characteristics of a single 20 (% by weight) Al/n-Heptane nanoslurry fuel droplet with oleic acid as surfactant was studied under the laser ignition model. The ignition delay time of the oleic acid/n-Heptane blended fuel droplet is lower than that of the n-Heptane fuel droplet, and its burning process is divided into three stages, namely, steady combustion of the n-Heptane, microexplosion combustion of the n-Heptane, and steady combustion of the oleic acid. When the laser hits the droplet of the oleic acid/n-Heptane, it has strong microexplosion and reburning. Compared with the oleic acid/n-Heptane droplet, the ignition delay time of the Al/n-Heptane nanoslurry droplet is significantly reduced and the burning time is slightly decreased, and the burning process only has two stages, i.e., microexplosive combustion stages of the n-Heptane and the oleic acid, respectively. When the laser hits the Al/n-Heptane nanoslurry fuel droplet, the morphology of the droplet that is heated by the laser but not ignited hardly changes during the falling process, while the morphology of the burning droplet changes greatly.