甲烷-乙烷混合推进剂深度过冷技术的实验研究

针对甲烷采用液氮过冷可能发生甲烷冰堵风险,提出了在甲烷中添加乙烷，制备凝固温度更低的甲烷-乙烷混合推进剂的新方案，搭建实验系统测试了甲烷-乙烷凝固温度变化规律。研究发现，随着甲烷含量提高，混合推进剂凝固温度先降低后升高。当甲烷、乙烷比例为0.71∶0.29时，混合推进剂达到最低凝固温度，约73.0 K。当采用常压饱和液氮对混合推进剂过冷时，控制甲烷含量在0.52~0.81间可避免推进剂冻结。相较于常压饱和甲烷，防冻结区的混合推进剂密度提高了24.0%~38.4%，液相存在温区增大至35.7 K~40.5 K。此外，甲烷-乙烷混合推进剂具有理论比冲高、再生冷却性能佳、结焦与积碳小等优势。所提出的甲烷-乙烷混合推进剂在火星探测等任务中具有可观的应用前景。

Experimental Study on Deep Subcooled Technology of Mixed Methane ethane Propellant

Selecting liquid nitrogen to provide methane subcooling could produce methane ice blockage. A new scheme to prepare mixed methane ethane propellant with lower solidification temperature by adding ethane to methane is proposed, and a test platform is set up to test the variation of solidification temperature of the liquid mixtures of methane and ethane. The results show that the solidification temperature of the mixed propellant decreases first and then increases with the increase of methane content. When the ratio of methane to ethane is 0.71 to 0.29, the lowest solidification temperature of the mixed propellant is reached, which is about 73.0 K. When the mixed propellant is supercooled by saturated liquid nitrogen at atmospheric pressure, the freezing of the propellant can be avoided by controlling the methane content between 0.52 and 0.81. Compared with methane saturated at atmospheric pressure, the density of the mixed propellant in the anti freeze zone increases by 24.0%~38.4%, and the existence temperature of the liquid phase increases to 35.7 K~ 40.5 K . In addition, the proposed mixed propellant has the advantages of high theoretical specific impulse, good regenerative cooling performance, small coking and carbon deposition. The proposed mixed methane ethane propellant has considerable application prospects in Mars exploration and other missions.