A strategy for anti-icing and drag reduction in marine applications via in situ gas injection

Icing and sailing resistance are major challenges in marine engineering. This work achieves efficient drag reduction and anti-icing effects through in situ gas injection (ISGI) into porous superhydrophobic surfaces. The core of this strategy lies in enhancing the stability of the Cassie-Baxter state through the design of a porous nested structure and using an interconnected micropore to actively regulate the surface air layer. Additionally, a piezoelectric air pump (PAP) is used to replace traditional air supply devices, achieving compact size and low energy consumption. Experimental results demonstrate that this method can quickly restore the air layer on a completely wetted superhydrophobic surface. At high Reynolds numbers, ISGI can maintain a stable air layer on the superhydrophobic surface, reducing wall shear stress, with the maximum drag reduction rate approaching 30%. In cold environments, ISGT technology forms an "air armor" on the droplet surface, preventing condensation inside the microstructure, which extends the freezing time by up to 5 times. Moreover, ISGI can form a dense air spring on the porous steel surface, reducing the vertical velocity gradient inside the droplet and effectively suppressing Plateau-Rayleigh instability. This study provides technical support for improving the operational efficiency and reliability of marine engineering equipment in harsh environments.