Pressure-Driven Phase Separation Based on Modified Porous Mesh for Liquid Management in Microgravity.

Surface tension becomes the main force influencing the gas-liquid interface in microgravity environment. The instability of the gas-liquid distribution is a menace for spacecraft missions. Passive phase separation based on porous material is a promising technique for microgravity liquid management and advanced life support systems. Here, the mechanism of pressure-driven phase separation based on porous material is experimentally investigated, highlighting the synergistic influence of single-phase flow, breakthrough failure, and self-healing ability on liquid acquisition capability. The major parameters characterizing the separation efficiency are the breakthrough threshold pressure and the flow resistance. A fabrication strategy which elicits the surface wettability and maintains the original surface morphology is proposed and verified to increase the critical breakthrough threshold pressure without introducing extra flow resistance. Moreover, the modified mesh is integrated into a screen channel liquid acquisition device. The improvement of the overall separation performance is evaluated in an antigravity delivery experiment, where the acceleration of liquid is -g0. It has been demonstrated that the fabrication strategy increases the achievable flow rate over 80% and the reseal flow rate over 200% for gas-free water delivery. This work enriches the understanding of phase separation based on porous material and provides an alternative method for liquid management in microgravity.