CFD investigation on thermodynamic characteristics of on-orbit cryogenic tank during reorientation process.

For a typical aerospace exploration mission, engine restart operation is usually encountered in which propellant slosh and reorientation are necessary. In this process, a series of thermodynamic characteristics including slosh, gas-liquid interfacial movement and deformation could be experienced. Understanding the associated performance could provide support for the design of on-orbital fluid management. In this paper, a computational fluid dynamics (CFD) model is introduced to study the thermodynamic behavior of fluid field distribution under variable conditions. The results show that the model can simulate the tank continuously
under different orbital operating conditions, and obtain detailed information such as the duration of different stages. Whether it is necessary to consider phase change in the model is also discussed. In addition, on the premise that the baffle can be used to suppress the sloshing, it’s found that the baffle effect differs with the liquid level. When the liquid level is 18.5% higher than the baffle, the baffle will lose its effect. Besides, the sloshing performance of the fluid varies with different types of propellant. In general, this study proposes the behavior of cryogenic fluids under different operations, and the results provide a reference for space propellant management and sequence setup.