Fluid Mechanics and Tankage Design for Low Gravity Environments

Book excerpt: Electric propulsion systems for space vehicles must be able to restart and operate at zero and low gravity. This operation can be achieved if the tankage delivers only single-phase propellants. The requirements for feed systems of electric engines are described briefly. Also, the 1.85-second drop- test facility is described and the testing techniques are discussed. The minimum energy principle is presented along with a method for determining the direction of mass transfer in tapered tubes and liquid-vapor interface shapes in an annular space between concentric cylinders. Possible feed systems for electric engines are given, which utilize surface tension for fluid positioning and transfer. Zero-gravity and static-fluid configurations in cylindrical and spherical containers are discussed along with experimental observations. The interface 'overshoot' of the equilibrium zero-gravity configuration is also discussed.