Microgravity Mass Gauging with Capacitance Sensing: Sensor Design and Experiment

The use of capacitance sensors for fuel mass gauging has been inconsideration since the early days of manned space flight. However, certaindifficulties arise when considering tanks in microgravity environments. Surfacetension effects lead to fluid wetting of the interior surface of the tank,leaving large interior voids, while thrust/settling effects can lead todispersed two-phase mixtures. With the exception of Electrical CapacitanceVolume Tomography (ECVT), few sensing technologies are well suited formeasuring annular, stratified, and dispersed fluid configurations as well ashandling the additional complications of mechanical installation inside aspherical tank. To optimize the design of future ECVT based spherical tank massgauging sensors, different electrode plate layouts are considered, and theireffect on the performance of the sensor as a fuel mass gauge is analyzedthrough the use of imaging and averaging techniques.