添加有机氟化物的固体复合推进剂对EPDM绝热材料烧蚀特性研究

Investigation on Ablation Effects of Propellant ContainingOrganic Fluoride on EPDM Insulation Materials

关键词:  抑制团聚  凝聚相  绝热材料烧蚀  粒子冲刷  三元乙丙橡胶（EPDM）

Key words:  Agglomeration depression  Condensed phase  Ablation of insulation materials  Particle erosion  Ethylene-Propylene-Diene Monomer （EPDM）

摘要:

分别在三组元、四组元固体复合推进剂的基础上制备了添加有机氟化物（OF）的高铝含量（18%）固体复合推进剂，利用高过载烧蚀模拟发动机考察了燃烧室压强为7MPa的条件下，上述推进剂对于三元乙丙橡胶绝（EPDM）热材料的烧蚀特性。结果表明，在OF为3%取代添加量的情况下，添加OF的推进剂配方相比于常规空白配方，对绝热材料的最大线烧蚀率可降低30%以上；对于四组元推进剂，含有OF的推进剂燃烧还能够有效抑制燃烧室的凝聚相沉积。实验通过分析推进剂的燃面特性、高过载烧蚀模拟发动机燃烧室沉积物组成、试验后绝热材料表面炭层结构、推进剂包覆材料表面沉积物形貌，探讨了配方中OF对于降低推进剂烧蚀特性的机理。分析认为，由于添加OF的推进剂燃烧能够形成粒径更小的凝聚相燃烧粒子，从而降低了它们在发动机流场中的动量，进而抑制其对于绝热材料的冲刷作用，致使烧蚀特性下降。

Abstract:

The high-aluminized (18%) solid composite propellants containing organic fluoride compound (OF) were prepared based on the three-component and four-component solid composite propellant formulations. The high-overload rocket motor for ablation simulation tests was employed to investigate the ablation effects of the above propellants on the Ethylene-Propylene-Diene Monomer （EPDM） insulation materials under the condition of the combustion chamber pressure of 7MPa. The results show that, in the cases that the substitution amount of OF is 3% in the formulations, the maximum linear ablation rate of the OF-containing propellants can be reduced by more than 30% comparing with the conventional blank formulations, and in the cases of four-component propellants, the OF-containing propellant can also effectively suppress the deposition of the condensed products in the rocket motor chamber. The study also discussed the ablation-reducing mechanism of propellants containing OF by investigating the burning surface characteristics of the propellants, analyzing the composition of the condensed depositions in the combustion chamber of the high-overload rocket motor, observing the surface carbon layer structures of the insulation materials after the experiments and characterizing the morphology of the surface deposition on the propellants’ coating material. According to above analysis, the ablation-reducing mechanism of OF-containing propellants is attributed to the formation of smaller condensed combustion particles, which leads to their less momentum in the flow field, thereby suppresses the scouring effect on the insulation material and finally reduces the ablation properties.