Experimental investigation on the ignition and combustion characteristics of a single magnesium particle in air

In this study, millimeter-sized magnesium particles are ignited using a CO$_2$ laser. The flame structure, particle temperature, heat release region, and spectral information of the burning magnesium particle are determined. The experimental results show that the developing process of the particle temperature can be divided into five stages: gradually rising stage, steady stage, sharply rising stage, high-temperature stage, and descent stage. Through a series of ignition experiments, the ignition temperature of a magnesium particle $\approx$ 3 mm in air is estimated to be 900–940 K. During steady combustion, the maximum diameters of the flame and of the heat release region are found to be greater than the particle diameter approximately by a factor of 1.9 and 3–3.5, respectively. The experimental results also suggest that the combustion of magnesium in air should be controlled by vapor diffusion from the particle surface.