LAUSR

Propellant volumetric measurement based on the cavity acoustic resonance may be a promising alternative in the microgravity environment. This article experimentally analyzes the features of Helmholtz-resonance dynamics under some conditions, which may be confronted in on-orbit applications. Instead of the traditional Helmholtz model, an analytical 1-D model, validated by experimental data, is proposed to measure the propellant volume in the tank based on cavity resonant mechanisms. Experimental data show that influences of liquid–gas interfaces and droplets in the tank have limited influence on the Helmholtz-resonance mechanism and the corresponding volumetric measurement. However, droplets partly or fully penetrating in the neck segment significantly change the feature of cavity resonance and thus degrade the corresponding measurement performance.