Bubble nucleation on grooved surfaces with hybrid wettability: Molecular dynamics study under a transient temperature boundary condition.

• Effects of patterned wettability on bubble nucleation over grooved surfaces were investigated. • A transient temperature boundary condition was used to approximate radiative heating. • The bubble growth rate on the all-hydrophilic groove is found to be the fastest. • BphoSphi surface can mostly facilitate the nucleation of bubble. • BphiSpho surface presents an apparent enhancement of the maximum heat flux. Mechanisms of bubble nucleation need a better understanding, especially for heterogeneous surfaces with different wettability. In this study, the bubble nucleation and the heat transfer performance on grooved surfaces with different hybrid wettability under a transient temperature boundary condition was investigated by characterizing the contact-line movement using molecular dynamics simulation. The bubble growth rate on the all-hydrophilic groove is faster than the other grooved surfaces. The grooved surfaces with patterned wettability, especially the B pho S phi (hydrophobic bottom wall and hydrophilic sidewall) surface, can facilitate the nucleation of the bubble. Meanwhile, an apparent enhancement of the maximum heat flux was found for the B phi S pho (hydrophilic bottom wall and hydrophobic sidewall) surface. This work provides insights into the mechanisms of enhancing the boiling heat transfer under irradiation condition by the contact line movement during bubble nucleation on structured surfaces. [ABSTRACT FROM AUTHOR]