Experimental Characterization of Non-Isothermal Sloshing in Microgravity

TL;DR

This paper presents an experimental study of non-isothermal sloshing in microgravity, analyzing how heat transfer and thermal stratification affect liquid dynamics and pressure fluctuations in cryogenic tanks during parabolic flights.

Contribution

It provides detailed experimental data on thermodynamic evolution and fluid behavior during non-isothermal sloshing, aiding validation of models for cryogenic fluid management in space.

Findings

Thermal mixing significantly influences liquid dynamics.

Destratification causes large pressure and temperature fluctuations.

Data supports validation of numerical models for non-isothermal sloshing.

Abstract

Sloshing of cryogenic liquid propellants can significantly impact a spacecraft's mission safety and performance by unpredictably altering the center of mass and producing large pressure fluctuations due to the increased heat and mass transfer within the tanks. This study, conducted as part of the NT-SPARGE (Non-isoThermal Sloshing PARabolic FliGht Experiment) project, provides a detailed experimental investigation of the thermodynamic evolution of a partially filled upright cylindrical tank undergoing non-isothermal sloshing in microgravity. Sloshing was induced by a step reduction in gravity during the 83rd European Space Agency (ESA) parabolic flight, resulting in a chaotic reorientation of the free surface under inertia-dominated conditions. To investigate the impact of heat and mass transfer on the sloshing dynamics, two identical test cells operating with a representative fluid, HFE-7000, in single-species were considered simultaneously. One cell was maintained in isothermal conditions, while the other started with initially thermally stratified conditions. Flow visualization, pressure, and temperature measurements were acquired for both cells. The results highlight the impact of thermal mixing on liquid dynamics coupled with the significant pressure and temperature fluctuations produced by the destratification. The comprehensive experimental data gathered provide a unique opportunity to validate numerical simulations and simplified models for non-isothermal sloshing in microgravity, thus contributing to improved cryogenic fluid management technologies.