Investigation of technique for measuring liquid volume under micro-gravity conditions

Measurement of liquid volume under the micro-gravity condition is an important aspect of space technology. In an attempt to create an effective and low-cost measurement system a Helmholtz resonance technique was applied. Two different liquids were tested. We used water and liquid nitrogen as test liquids, the latter to confirm the applicability of this measurement technique to cryogens. It was found that the measurement technique using Helmholtz resonance is applicable under micro-gravity conditions. However, it was also found that obtaining accurate velocity of sound is important for the measurement. The measurement of spatial temperature distribution in the container is necessary to apply this measurement technique to cryogens because the velocity of sound has strong temperature dependency. (C) 2002 Elsevier Science Ltd. All rights reserved.