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借助高速摄影手段研究了激光点燃B/KNO3点火药过程中的二次燃烧现象,拍摄速度2000fps。建立了反应性光声模型,与G-R模型的区别在于考虑了化学反应项。用该模型模拟了激光点火过程。结果表明,二次燃烧现象是存在的,其中,第一次燃烧是激光支持的燃烧,第二次燃烧是药剂的自持燃烧。第二次燃烧现象能否出现与激光点火初期体系的热量积累有关,如果化学反应放出的热量大于在此过程中散失的热量,则体系的温度最终可以达到药剂的发火点,从而进入自持燃烧阶段即二次燃烧阶段,否则,药剂就不能被点燃,二次燃烧现象就不会出现。随着入射激光能量的增加,热积累过程缩短,两次燃烧的时间间隔减小。
Using high-speed photographic means to study the secondary combustion in the process of laser ignition of B / KNO3 gunpowder, the shooting speed of 2000fps. A reactive photoacoustic model is established, which is different from the G-R model in that the chemical reaction term is considered. The model was used to simulate the laser ignition process. The results show that the secondary combustion phenomenon exists, in which the first combustion is laser-supported combustion, and the second combustion is the self-sustained combustion of the medicament. If the second combustion phenomenon is related to the heat accumulation in the initial stage of laser ignition, if the heat released by the chemical reaction is greater than the heat lost in the process, the temperature of the system can finally reach the ignition point of the agent to enter the self-sustaining combustion stage That is, the second combustion stage, otherwise, the agent can not be ignited, the secondary combustion phenomenon will not appear. As the incident laser energy increases, the heat accumulation process is shortened, and the time interval between two combustion decreases.