Investigations On Ignition And Combustion Process Of A Magnesium Particle In CO₂

The burning of magnesium particles in the gas, which mainly consists of CO₂, is the essential energy release process of magnesium-based propellant. So the study of ignition and combustion of a magnesium particle in CO₂ will lay the foundation and provide the technological guidance for the energy conversation of magnesium-based propellant efficiently.Based on the summary of research ways of mental particles ignition and combustion in different gases, the experimental system used in this paper is improved. During the ignition and combustion, the structure of particle and flame is observed clearly and the particle temperature is recorded directly, with the help of Xe-lamp, high speed camera, micro lens, micro tungsten-rhenium and so on. The light spectrum of flame, concluding the information of gas phase component, is detected by a spectrometer. The influence of environmental pressure on the ignition and combustion characteristics of a magnesium particle is also studied. By the means of SEM and EDS, the structure and the composition of combustion production are analyzed.The ignition process of a magnesium particle in CO₂ is analyzed from the aspects of energy and stress. Considering the conservation of energy and the force balance between the oxide film and mental core, a magnesium ignition model is established. The influence of particle size and environmental temperature on the ignition delay time is also analyzed with numerical calculation.The space around the magnesium particle is divided into three zones by metal particle surface, oxide surface, flame and infinity. Based on the relative position between oxide surface and flame, the process of combustion can be divided into two stages. Considering the gas phase combustion and HSR simultaneously, a three zones combustion model is established. The influence of environmental temperature and CO₂ concentration on the particle combustion is analyzed with numerical calculation.