Aluminum Particle Ignition Studies

Experiments have been performed to study the combustion criteria of aluminum particles at atmospheric pressure. The primary goal is to quantify the outcome for a particle into which thermal energy has been deposited. Experiments utilized instantaneous joule heating of an aluminum wire. Once the particle was generated, it fell under gravity and the flight was recorded by video; in some cases, the ignited particle quenched or fragmented, and the residue was collected for SEM and EDS imaging. This provided information related to the aluminum oxide shell which was formed when combustion occurred. These experiments produced particles of approximately 150450 microns in the arc heating tests. In a second set of experiments, particles were produced under more observable time scales. This provided observation of the oxide skin, which is known to influence the ignition process. This experiment utilized a pressure pulse to eject a small droplet of molten aluminum through a small orifice. From this experiment, particle sizes ranging 2–3 mm were produced.