Lateral Sloshing Analysis by CFD and Experiment for a Spherical Tank

Propellant sloshing is one of the potential sources of disturbance which affects the stability and structural integrity of space vehicles. In this study, using a small scale model of the first Korean lunar orbiter fuel tank, which is partially filled with liquid fuel, the dynamic lateral sloshing has been simulated by CFD analysis for various fill-levels. Spherical tank geometry was assumed, because it is one of the options for the fuel tank. After applying an accelerated motion to the fuel tank, the dynamic sloshing forces exerted on the tank wall in lateral directions during a free sloshing motion were measured and analyzed to identify the sloshing frequencies. The results show very good consistency with the mathematical and experimental studies from available sources in NASA technical reports. A simple inexpensive experimental work was also performed successfully to verify the fundamental slosh frequency. The methodology developed here would be useful for understanding the slosh dynamics and for modeling of the propellant sloshing in a fuel tank of an arbitrary geometry.