Experimental and numerical study on ignition and combustion characteristics of boron-magnesium composite powders

A high-pressure laser ignition and combustion system with adjustable oxidizer gas atmosphere is established to investigate the ignition and combustion characteristics of boron-magnesium (BM) composite powders. An ignition and combustion model of BM powders is established and validated in the present study. The results show that increasing water content, O₂ content and Mg content all result in shorter ignition delay time of BM powders, among which the effect of water content is the most obvious. However, ignition delay time increases as pressure increases. The combustion time decreases with increasing Mg content and ambient pressure but increases with water content. With the increase of O₂ content, combustion time of BM powders first increases and then decreases, which means a critical O₂ content exists above which combustion time decreases. The results show that there exists a trade-off between ignition and combustion performance of BM composite powders.