LARGE-SCALE TANK ACTIVE SLOSHING DAMPING SIMULATION AND EXPERIMENT

Kurzfassung

Future re-ignitable cryogenic upper stages per-form long ballistic coasting phases in Earth orbit. During those coasting phases, the tanks are loaded with liquid propellants and propellant sloshing occurs due to external disturbances or attitude change maneuvers. The sloshing pro-pellant motion induces reaction forces and tor-ques acting on the space vehicle structure, e.g. rocket upper stages. To keep the upper stage at the desired target attitude, the guidance, naviga-tion, and control (GNC) algorithm commands thruster firings to counter disturbances, some of which come from the fluid forces. At Airbus DS, the Final Phase Simulator FiPS® aims at simu-lating the coupling between fluid mechanics, GNC, and rigid body dynamics. The force pre-dictions of the FiPS® software were validated by linear lateral water sloshing experiments with an accuracy of 8 % for forces. Furthermore, active sloshing damping by closed-loop control was demonstrated within the FiPS simulation envi-ronment and currently preparations are on-going to validate the control of the sloshing with the watertank mounted on a Hexapod.