Towards efficient and sustaining condensation via hierarchical meshed surfaces : A 3D LBM study

Condensation is of fundamental importance for a wide range of energy, environmental, and engineering applications. Extensive efforts have been made to boost droplet growth and condensation efficiency via delicately designing micro/nanostructured surfaces. However, simultaneously achieving rapid droplet growth and removal is still challenging. This study investigates the condensation on hierarchical mesh-covered surfaces employing the mesoscopic kinetic-based lattice Boltzmann method (LBM). The mechanism of dynamic growth and transport of droplets inside and outside the micro-pores is unraveled by resolving the heat transfer process and tracking the solid-liquid-vapor interactions. The proposed meshed surface realizes a robust self-refresh capability to clear the pinned droplets timely. The deterioration of hydrophobicity is avoided, contributing to a sustaining and prolonged dropwise condensation. The optimal case cuts down the droplet residence time and departure radius of 18% and 17% through rational design of mesh structures, respectively. Besides, the number of large droplets throughout the condensation process can also be reduced to different levels. The results can provide viable references to design various desirable meshed surfaces, facilitating efficient condensation in diverse engineering scenarios and applications.