PRISME EA 4229, Université d'Orléans, 18020 Bourges, France.
French-German Research Institute of Saint-Louis, 68300 Saint-Louis, France.
Molecules. 2020 May 12;25(10):2276. doi: 10.3390/molecules25102276.
Low-vulnerability propellants are propellants designed to resist unintended stimuli to increase safety during transport, storage and handling. The substitution of usual nitrocellulose-based gun propellants with these new materials allows maintaining interior ballistics performances while increasing the safety. In this paper, the pyrolysis, ignition and combustion of such propellants are investigated in order to study conditions leading to a safe and reproducible ignition. Low-vulnerability propellants studied are made of different ratios of hexogen (RDX) and nitrocellulose (NC). Three compositions are studied by varying weight percentages of RDX and NC: 95-5, 90-10 and 85-15 for respective weight percentages of RDX-NC. Pyrolysis of these propellants is studied with two different experimental setups: a flash pyrolysis device linked to a gas chromatograph coupled to a mass spectrometer (Py-GC-MS) and a closed-volume reactor coupled to a mass spectrometer. Different molecules, like NO, CO, CHCOCH or CHNCHNCH, are obtained during the decomposition of these propellants. Laser ignition of these propellants is studied in a cylindrical closed-volume reactor using a laser diode. Several combustion characteristics, such as ignition delays, maximal overpressures and combustion rates are given for the three propellants using the pressure signals. Moreover, ignition energies are also investigated. Obtained results are compared to the few available literature data. A particular behavior is noticed for the 90-10 propellant. The experimental data collected should serve in the future to have a better understanding of the chemical reactions driving the combustion process of these low-vulnerability propellants.
低易损性推进剂是指为抵抗意外刺激而设计的推进剂，以提高在运输、储存和处理过程中的安全性。用这些新材料替代通常的硝化纤维素基枪用推进剂，可以在提高安全性的同时保持内部弹道性能。本文研究了这些推进剂的热解、点火和燃烧，以研究导致安全和可重复点火的条件。研究的低易损性推进剂由不同比例的六硝炸药（RDX）和硝化纤维素（NC）制成。通过改变 RDX 和 NC 的重量百分比，研究了三种组成：95-5、90-10 和 85-15，分别为 RDX-NC 的相应重量百分比。使用两种不同的实验装置研究了这些推进剂的热解：与气相色谱仪和质谱仪（Py-GC-MS）相连的闪速热解装置和与质谱仪相连的封闭体积反应器。在这些推进剂的分解过程中，得到了 NO、CO、CHCOCH 或 CHNCHNCH 等不同的分子。使用压力信号研究了这些推进剂在圆柱形封闭体积反应器中的激光点火。对于三种推进剂，给出了点火延迟、最大超压和燃烧速率等几个燃烧特性。此外，还研究了点火能量。将得到的结果与少数可用的文献数据进行了比较。对于 90-10 推进剂，注意到了一种特殊的行为。收集的实验数据将来应该有助于更好地理解这些低易损性推进剂的燃烧过程中驱动化学反应的机制。
