Molecular dynamics of thermally assisted depinning and spreading of the exuded droplet from liquid-containing nanopore

GT Zhang and SF Chen and ZC Wang and BH Tong and YH Sun and DY Tu, INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER, 158, 107873 (2024).

DOI: 10.1016/j.icheatmasstransfer.2024.107873

Nano liquid-containing porous surfaces have been widely used in porous self-lubricating materials such as spacecraft momentum wheel bearing assemblies. The temperature of the lubricant for the frictional heat has an important effect on the self-lubricating behavior on the pores surface. To reveal the depinning and spreading characteristics of the exuded thermal droplets at the orifices, the kinetic model of the lubricant exudation under the influence of the thermophysical field was established by the molecular dynamics. The mechanical mechanism of liquid exudation assisted by the thermophysical field is revealed combined with the pinning of the three-phase contact lines during the nucleation of droplets and the spreading characteristics of the depinning droplets. The results indicate that as the temperature of the liquid lubricant increases, the density of the liquid near-wall of the pore decreases and the thermal movement of the liquid molecules enhances, increasing the exudation velocity and the slip length of liquid at the wall. And the pinning force on the three-phase contact line and the depinning energy barrier of droplets all decrease. Higher temperatures promote the spreading of droplets to form a lubricating film. This research contributes to enriching the kinetic theory of liquid exudation from porous liquidcontaining friction surfaces.

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