不同氧/燃比的硼-硝酸钾的激光点火特性

Laser Ignition Performance of Boron-Potassium Nitrate Composite at Different Oxygen/Fuel Ratio

硼-硝酸钾是一种重要的含能材料,其氧/燃比与药剂的点火和燃烧性能有密切关系。为了掌握氧/燃比与激光点火性能的关系,对不同配比的硼-硝酸钾及其酚醛树脂掺杂物进行激光点火特性实验研究、热力学参数计算分析和热分析。结果表明,硼-硝酸钾的激光点火过程由激光烧蚀、热化学反应和自持燃烧等阶段构成;随着硼质量分数从30%增加到70%,50%发火的激光点火阈值存在一个最小值,分别为7.6 mJ(m(B):m(KNO_3):50:50)和4.05 mJ(m(B):m(KNO_3):m(酚醛树脂):40:50:5);激光点火延迟时间与激光点火能量密度的关系近似为线性递减关系,并且具有较低激光点火能量阈值的配比也具有较短的激光点火延迟时间;酚醛树脂将B-KNO_3的化学反应起始温度从556℃降低到548℃,化学反应放热量从1.86 kJ/g增大到2.21 kJ/g,提高了激光点火感度和缩短了点火延迟时间。

Boron-potassium nitrate is an important energetic material, whose ignition and burning performances depend on the oxygen/fuel ratio closely. The laser ignition of B-KNO3 composites and doped composites by phenolic resin at different oxygen/fuel ratios were experimentally studied , thermodynamically calculated, and thermally analyzed. The laser ignition process consists of laser ablation, thermal chemical reaction, and combustion. The laser ignition threshold of 50% fire has minimum of 7.6 mJ （B-KNO3 ：50/50） and 4.05 mJ （B-KNO3-phenolic resin：40/ 50/5） with the increase of boron fraction from 30% to 70% . The laser ignition delay time decreases with the laser energy density linearly, moreover the composite of lower laser ignition threshold also has shorter ignition delay time. Because of the onset temperature of reaction of B-KNOa from 556℃to 548℃ and released heat from 1.86 kJ/g to 2.21 kJ/g in case of admix of phenolic resin to B-KNOa, its laser ignition sensitivity and ignition delay time becomes higher and shorter respectively.