Studies into laser ignition of unconfined propellants
Studies into laser ignition of unconfined propellants
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DOI：
10.1002/1521-4087(200112)26:5
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发表时间：
2001-12-01
影响因子：
1.8
通讯作者：
Leach, CJ
中科院分区：
文献类型：
--
作者：
Ahmad, SR;Russell, DA;Leach, CJ
在激光点火测试之前，分析了三种不同固体发动机推进剂的光谱吸收特性。挤压双基 (EDB) 推进剂在 250-550 nm 波长带内表现出 >95% 的吸收，而铸造双基 (CDB) 在 375-800 nm 之间延伸的更宽波段内表现出类似的吸收。复合样品 (CP) 在 250-800 nm 波段表现出约 90% 的均匀光谱吸收。使用 Ar 离子激光器平均 500 nm 输出进行的点火测试表明，由于炭黑材料的存在，双基推进剂在点火前会发生爆燃。在激光功率密度24~125 W(.)cm(-2)范围内,双基推进剂爆燃和点火的激光能量密度阈值分别在2~2.5 J(.)cm(-2)和40~215 J(.)cm(-2)之间。复合推进剂没有观察到爆燃，并且发现对于相同范围的激光功率密度，阈值点火能量在11-18 J(.)cm(-2)范围内。根据该推进剂的点火图，发现该波长下的点火阈值能量约为 18 J(.)cm(-2)，并且实际上与激光功率密度无关。在近红外波长（780 nm）内，EDB 推进剂不易点燃，因为在此波长下其反射率相对较高。对于相似的功率密度水平，点火阈值在 19-23 J(.)cm(-2) 之间。结果表明，推进剂的可燃性是通过促进爆燃而增强的。
Prior to laser ignition tests, spectral absorption properties of three different solid motor propellants were analysed. The extruded double base (EDB) propellant exhibited >95% absorption over the 250-550 nm wavelength band whereas, the cast double base (CDB) showed similar absorption over a wider band extending between 375-800 nm. The composite sample (CP) showed a uniform spectral absorption at about 90% over 250-800 nm band. Ignition tests using an average of 500 ran output from an Ar-ion laser showed that the double base propellants undergo deflagration prior to ignition due to the presence of carbon black material. Within the laser power density range of 24-125 W(.)cm(-2), the threshold laser energy densities for deflagration and ignition in the double base propellant were found to be between 2-2.5 J(.)cm(-2), and 40-215 J(.)cm(-2), respectively. No deflagration was observed for the composite propellant, and the threshold ignition energy was found to be within the range, 11-18 J(.)cm(-2) for the same range of laser power densities. From the ignition map for this propellant, the threshold energy for ignition at this wavelength was found to be approximately 18 J(.)cm(-2) and was practically independent of laser power density. In the near infrared wavelength (780 nm) the EDB propellant was not readily ignitable due to its comparatively much higher reflectance at this wavelength. The ignition threshold values were found to be between 19-23 J(.)cm(-2) for a similar power density level. The results indicate that the ignitability of propellants is enhanced through the promotion of deflagration.