Abstract In planned planetary explorations, cryogenic liquids such as liquid hydrogen (LH2), liquid oxygen (LOX), and liquefied natural gases (LNG) are used as fuel and oxidants in the propulsion systems of spacecraft. Such explorations require long-term storage of those cryogens, as well as heat insulation technology to protect the heat from the outside and pressure control technology to suppress rises in pressure due to gas evaporation in the propellant tank. However, current vent systems that discharge the evaporated gas to the outside of the spacecraft are suboptimal because the propellant’s uncertain position in the tank when the spacecraft operates in microgravity environments causes a significant loss of propellant during venting. In response, we examined a method using a mixing jet in a thermodynamic vent system (TVS) that adjusts the tank pressure by cooling the inside of the tank and reducing boil-off gas. In this study, a verification experiment on the TVS performed by jet mixing using simulated liquid (LN2) was carried out. Subcooled mixing jets were supplied under vent-free conditions, and it was possible to reduce the temperature and pressure in the test tank. On the other hand, it was found that depending on the liquid level and supply flow rate of the mixing jet, the tip of the mixing jet could not reach the free surface, and reduction of tank pressure could not be realized.

中文翻译：

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未来低温推进系统推进剂罐热力通风系统的地面试验与数值计算

摘要 在有计划的行星探索中，航天器的推进系统使用液氢（LH2）、液氧（LOX）和液化天然气（LNG）等低温液体作为燃料和氧化剂。这种探索需要长期储存这些冷冻剂，以及隔热技术以保护外部热量和压力控制技术以抑制由于推进剂罐中气体蒸发引起的压力上升。然而，当前将蒸发的气体排放到航天器外部的通风系统是次优的，因为当航天器在微重力环境中运行时推进剂在罐中的不确定位置会导致在通风过程中推进剂的大量损失。作为回应，我们研究了一种在热力通风系统 (TVS) 中使用混合射流的方法，该系统通过冷却罐内并减少蒸发气体来调节罐压力。在本研究中，通过使用模拟液体 (LN2) 的喷射混合对 TVS 进行了验证实验。在无排气孔的条件下提供过冷混合射流，并且可以降低测试罐中的温度和压力。另一方面，发现根据混合射流的液位和供应流量，混合射流的尖端无法到达自由表面，并且无法实现罐压的降低。在无排气孔的条件下提供过冷混合射流，并且可以降低测试罐中的温度和压力。另一方面，发现根据混合射流的液位和供应流量，混合射流的尖端无法到达自由表面，并且无法实现罐压的降低。在无排气孔的条件下提供过冷混合射流，并且可以降低测试罐中的温度和压力。另一方面，发现根据混合射流的液位和供应流量，混合射流的尖端无法到达自由表面，并且无法实现罐压的降低。