Study on the laser irradiation characteristics of Al/Mg fuel-rich propellant at lower ambient pressures

An experimental study of the ignition and combustion characteristics of Al/Mg fuel-rich propellant at lower ambient pressures was performed. Measurements were obtained in a sealed vessel capable of reaching pressures as low as 0.1 atm with the application of vacuum pump. The ignition delay time was obtained by photodiodes which monitor the laser signal and flame signal; the linear burning rate of propellant was obtained by processing the continuous high-speed video images. The experimental results show that the reduction in pressure caused a longer ignition delay time, this dependence will get weaker as the externally applied heat flux increased; the linear burning rate reduced with the reduction of pressure, even reduced about 47% at 0.1atm compared to constant pressure.