Ignition and combustion of levitated magnesium and aluminum particles in carbon dioxide

This article considers ignition and combustion of single particles of magne sium and aluminum in carbon dioxide at pressures 0.1-2 NPa. An experimental setup with an electrodynamic levitator inside a high-pressure chamber was employed. The CO2-laser was used for heating to ignition of the particles. The results show that ignition mechanisms of Mg and Al in CO2 are different Experiments with Mg indicate the existence of the critical partial pressur e Of CO2, whereas the ignition probability of Al particles in CO2 is low bu t independent on pressure. Analysis of flame images and combustion paramete rs shows that the mechanism of Mg particle burning in CO2 corresponds to co nventional models of vapor-phase diffusion-controlled combustion, whereas i n the case. of Al exothermic processes on the particle surface or close to it play a leading part in the burning process.