Study on the evolution and stability of gas–liquid interfaces based on composite structures on the sidewall surface of a microchannel*

The gas–liquid interface plays a crucial role in reducing the flow resistance of superhydrophobic surfaces. However, this interface is highly unstable and prone to collapse under flow shear, environmental pressure fluctuations, phase transitions, and diffusion between dissolved gases and free gases. Once the gas–liquid interface collapses, the flow resistance increases rapidly. Therefore, it is necessary to study the stability of the gas–liquid interface. This paper considers a three dimensional (3D)-printed composite structure combining transverse posts and reentrant structures in a microchannel. This structure effectively improves the stability of the gas–liquid interface, allowing it to maintain stability even on surfaces made of hydrophilic materials. Under the effect of the transverse posts, the length of the gas–liquid interface above the groove increases from micrometers to millimeters. The lattice Boltzmann method is applied to analyze how the composite structure effectively improves the stability of the gas–liquid interface. Through analysis of the interface collapse process, the factors affecting the stability of the gas–liquid interface in this structure are explored, providing a theoretical foundation for structural optimization.