Interface reorientation of cryogenic liquids under non-isothermal boundary conditions

• We performed experiments on the interface reorientation from 1 g to almost 0 g.
• Wall temperature gradients (0.2–2.9 K/mm) as well as LAr and LCH4 were used.
• The reorientation depends on the gradient value and the liquid properties.
• The wall superheat influence is shown through the deflection of the contact line.
• A simulation shows a qualitative agreement with previous experimental results.

We investigate the capillary driven oscillations of the liquid–vapor interface in cryogenic systems under non-isothermal boundary conditions. The oscillations took place in a partly filled cylinder during the interface reorientation from its 1 g equilibrium position to the microgravity equilibrium position after a step reduction of gravity. The latter was achieved by dropping the experimental device in the drop tower of Bremen, providing 4.7 s of microgravity. Liquid argon (Tsat=87.3K at 1013 hPa) and liquid methane (Tsat=111.7K at 1013 hPa) were used as experimental liquids. Axial wall temperature gradients, corresponding to a linear increase of the wall temperature, were applied above the interface position prior to the experiments with values varying between 0.2 K/mm and 2.9 K/mm. Both liquids showed a qualitatively similar reorientation behavior. The reorientation characteristics were found to depend on the value of the applied gradient and on the material properties of the experimental liquids. Numerical simulation showed a good qualitative agreement with a previous experiment with 1.34 K/mm using liquid argon, demonstrating main characteristic features of the experiment.