The influence of gravity levels on the self-transport of bubbles on the superaerophilic wedge surface

Efficiently separating and collecting the bubbles (oxygen and hydrogen) produced by water electrolysis is crucial for space exploration. The superaerophilic wedge surface (SWS) holds promise for handling gas in microgravity, as it enables spontaneous and directional bubble transport driven by Laplace pressure gradients. However, existing studies on SWS-based bubble transport have so far been conducted mainly under Earth's gravity, and its actual performance in a microgravity environment remains unexplored. In this work, we developed a numerical model to study the effect of gravity level on the self-transport of bubbles on the SWS and verified the reliability of the simulation results using samples with similar properties. Systematic researches find that reduced gravity enhances bubble transport, eliminates volume constraints, and improves capture efficiency. In microgravity, the SWS can capture and transport bubbles exceeding 1000 μL, surpassing conventional critical volume limits. Moreover, lower temperatures, larger wedge angles, and wider narrow-end widths all contribute to faster bubble transport by increasing the surface energy release rate. These results provide valuable insights for advancing bubble management in space-based electrolysis systems.