环境氧含量和压力对铝镁贫氧推进剂燃烧性能的影响

为研究不同海拔处大气氧含量(氧体积分数)变化对铝镁贫氧推进剂燃烧特性的影响,采用激光辐射点火,使用高速摄影仪记录推进剂的点火与燃烧过程,并利用红外测温仪测量推进剂的表面温度及火焰温度,研究了环境氧含量与压力对推进剂的点火过程、火焰温度和燃速的影响。结果表明,环境气体氧含量高于推进剂热解产物中氧含量时,点火气相化学反应主要发生在推进剂热解产物与环境气体的扩散区,初现焰远离推进剂表面,但随着压力增加,扩散区与推进剂表面之间距离减小;火焰温度与环境氧含量和压力线性正相关;压力与环境氧含量增加时,铝镁贫氧推进剂燃速增加,压力和环境氧含量对铝镁贫氧推进剂燃速的影响符合B数理论,压力是影响推进剂燃速的主要因素,但随着压力增加,压力对燃速的影响相对减小,压力从0.1 MPa增加到1.5 MPa时,压力和环境氧含量的燃速敏感系数比从200下降到40。

Effect of Environment Oxygen Content and Pressure on the Combustion of Aluminum-magnesium Fuel-rich Propellant

To study the effect of environment oxygen content (oxygen volume fraction) at different altitudes on the combustion characteristics of aluminum-magnesium fuel-rich propellant, the laser radiation ignition was used. The ignition and combustion process of the propellant was recorded by a high-speed camera, and the surface temperature and flame temperature of the propellant were measured by an infrared thermometer. The effect of environment oxygen content and pressure on the ignition process, flame temperature and burning rate of the propellant was investigated. The results show that gas phase reaction of propellant ignition occurs mainly in the diffusion zone of propellant thermal decomposition products and environment gas, and the first flame is away from the propellant surface when the environment oxygen content is higher than oxygen content in thermal decomposition products, but the distance between the diffusion zone and the propellant surface decreases as the pressure increases. The flame temperature is in linearly positive proportion with the environment oxygen content and pressure. The burning rate of aluminum-magnesium fuel-rich propellant increases with the increase of pressure and environment oxygen content and the effect of them on burning rate is accord with B-number theory, the pressure is the main factor affecting the burning rate, however, as the pressure increases, the effect of pressure on the burning rate is relatively reduced. The burning rate sensitivity coefficient ratio of pressure and environment oxygen content is decreased from 200 to 40 when pressure is increased from 0.1 MPa to 1.5 MPa.