Ultrasonic measurement of the geometric parameters of gaseous voids in low gravity fluid containers

A demonstration system for the ultrasonic gaging of fluids in low-gravity has been designed and tested. For purposes of simplification, it was assumed that vapor within a liquid container in low-gravity would form a spherical bubble which would float freely in the container. The project was designed to show that ultrasonic techniques could be used to determine the geometry of the resulting sphere given a worst-case tranducer arrangement. The motivation was to simplify transducer mounting requirements so that propellant or other storage vessels could be fitted with ultrasonic gaging systems with a single or perhaps a few transducer penetration. Data was collected from a planar array of transducers. The high error expected due to the low triangulation was reduced by maximizing the amount of data collected. This was accomplished using the transducers in both pulse/echo and pitch/catch operational modes.