基于新型半导体激光系统的B/KNO3/PF点火特性

为了研究点火系统的发火性能和点火特性,设计了一种新型可自检半导体激光点火系统和以微米级B/KNO3/酚醛树脂(PF)为装药的激光点火器。采用热重-差示扫描量热技术(TG-DSC)、扫描电子显微镜(SEM)、透射电镜(TEM)、能谱仪(EDS)、激光反射率和发射光谱等测试获取了药剂的形貌尺寸、元素分布、热性能、激光吸收效率和药剂粒子激发谱线等性能参数;通过激光点火系统启动点火器发火研究了激光脉宽对B/KNO3/PF药剂发火性能和点火特性的影响。结果显示:较大PF质量比(4.8%)的和较小颗粒(平均粒径6.97μm)的B/KNO3/PF药剂在DSC曲线中起始反应温度降低,放热量增加。点火器点火启动分为一次点火和二次点火两个过程,激光脉宽对点火器的点火特性有显著影响。当激光脉宽为5 ms和10 ms时,点火器能够正常发火,其50%发火能量分别为6.23 mJ和12.54 mJ。通过调节激光的脉宽和能量,获得点火器的一次点火延迟时间为3.50~4.69 ms,二次点火延迟时间为7.23~8.08 ms,火焰持续时间为58~83.5 ms;当激光脉宽为2 ms时,激光点火系统无法激励点火器正常发火。这种特性与半导体脉冲激光能量输出规律相符合。

Ignition Characteristics of B/KNO3/PF Based on Semiconductor Laser System

Semiconductor laser ignition system has not only been widely applied in safe and reliable ignition but also possesses obvious advantaged for anti-jamming in complex electromagnetic environment,due to its small size,light mass and energy transmission by optical fiber.To investigate the ignition characteristics of laser igniter,a new type of semiconductor laser system and laser igniter filled with micron-sized B/KNO3/PF were designed and prepared.TG-DSC,SEM,TEM,EDS,laser reflectance and Laser induced breakdown spectroscopy were used to study the thermal behavior,morphology,distribution of element,laser absorption efficiency,and emission spectra of B/KNO3/PF.Then the ignition characteristics of B/KNO3/PF igniter were studied by the semiconductor laser ignition system.The results showed that the initial reaction temperature of B/KNO3/PF decreased and the heat release increased with the higher PF mass ratio and the smaller particle size in the DSC curve.The ignition process of the laser igniter can be divided into two stages:first ignition and secondary ignition.The pulse laser had a significant effect on the igni-tion characteristics of the igniter.The igniter could normally ignite with the 50%ignition energy of 6.23 mJ and 12.54 mJ,respectively,when the laser pulse were 5 ms and 10 ms.The first ignition delay time of 3.50-4.69 ms,secondary ignition delay time of7.23-8.08 ms,and flame duration of 58-83.5 ms were produced in the laser igniter by changing the laser pulse and energy.The laser ignition system cannot motivate the igniter to fire normally when the laser pulse was 2 ms.These characteristics were consistent with the energy output law of semiconductor laser.