System and Method for Fluid Dynamic Mass Gauging

Fluid Dynamic Mass Gauging (FDMG) is a microgravity-compatible system that applies principles of fluid dynamics, the ideal gas law, and thermodynamics to determine the volume of an incompressible fluid within a tank by measuring the compressible volume in the same tank. In a simplified embodiment, the determination of the remaining volume of the fluid within a given storage tank can be calculated from a time measurement of a pressure change during a filling or venting process applied to the storage tank. The process may be automated and features low mass and volume requirements, enabling its use in any gravitational or inertial environment with minimal hardware modifications. The novel system can determine the volume of a non-condensing, incompressible fluid within a rigid tank of known or unknown volume without requiring the use of bulky equipment in microgravity locations with fixed or limited free space. The accurate measurement of the remaining fluid in a tank is an essential measurement for safe space operations. However, accurately measuring an unknown volume of liquid in microgravity presents significant challenges. Mass measurement systems such as the Space Linear Acceleration Mass Measurement Device (SLAMMD), the Zero Gravity Mass Measurement Device (ZGMMD), and the Body Mass Measurement Device (BMMD) have been used to attempt such measurements, but with only limited success. By these approaches, the tank to be measured has to be able to be moved, and that movement needs to be regular and constant. Thus, any fixed, rigid tank, such as the Water Storage System (WSS) Resupply Tank (RST) that is currently in use on the International Space Station, cannot be measured accurately by these methods. NASA Ames has developed a Fluid Dynamic Mass Gauging (FDMG) system to accurately determine the volume of an incompressible fluid within a tank via measurement of the remaining compressible volume within the tank.