Analysis of LN2 Filling, Draining, Stratification and Sloshing Experiments

Kurzfassung

The accurate prediction of the mechanical and thermodynamic behavior of cryogenic liquids in tanks of liquid propelled rocket stages is critical for the design of the tank layout, the pressurization system, and the control algorithm. To analyse the behavior of cryogenic liquids in tanks before and during flight, a set of LN2 experiments with a cryogenic tank with a volume of 711 l was performed. In the first test campaign, first mode sloshing and damping was investigated at different fill levels. In the second test campaign, the stratifica-tion of the liquid and wall temperature behavior during LN2 tank fillingof the unchilled tank, during chilled tank draining, and at a constant fill level was investigated.In the third test campaign, the pressure evolution during first mode sloshing was investigated at different helium concentration levels. For each test campaign, a representative case is presentedand analysed in the current paper. Furthermore, numerical predicitions using the commercial flow solver Flow-3Dand an in-house tool to determine the tank pressure evolution are com-pared with the experiments, showing good agreement.