Parameter analysis of on-orbit volumetric measurement using cavity resonance

Abstract

Propellant volumetric measurement based on the cavity acoustic resonance may be a promising alternate in space microgravity environment. The present paper concentrates on the influences of the hemispherical structure of the tank, steady/unsteady non-flat continuous propellant-gas interface, and propellant's compressibility on the acoustic resonant frequency of the system. A one dimensional mathematical acoustic resonant model, where acoustic perturbation dynamics only in the axial coordinate is considered, based on conservations of mass and momentum is provided and compared with numerical simulations by COMSOL software and experiments conducted by the previous research. Results show that analytical predictions by the present model keep consistent with numerical simulations and experiments. While the structure of a hemispherical tank can influence the resonant frequency, the present model can optimizationally compensate such effect. The continuous non-flat propellant-gas interface changes the resonant frequency. A flatter interface leads to smaller influence. On the other hand, the unsteady low-frequency low-amplitude wave-like movement of the propellant-gas interface imposes negligible effluence on the resonant frequency of the tank. Finally, the propellant compressibility is quantitatively shown to be negligible for most propellants.