Tuning surface hybrid-wettability to enhance the vapour film phenomenon induced by boiling heat transfer: Molecular dynamics. (July 2022)

• Record Type: Journal Article
• Authors: Guo, Wenting; Zeng, Liangcai; Lu, Yan; Chen, Juan
• Is Part Of: International communications in heat and mass transfer. Volume 136(2022)
• Publication Date: 2022-07
• Subjects: Vapour layer -- Rapid boiling -- Hybrid wettability -- Molecular dynamics; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Heat -- Transmission; Mass transfer; Periodicals; 621.4022
• DOI: 10.1016/j.icheatmasstransfer.2022.106172
• Languages: English
• ISSNs: 0735-1933

Abstract

Abstract: Vapour lubrication has great potential in high-temperature microchannel lubrication systems. However, it is challenging to design the most-optimized surface for enhancing the vapour film phenomenon due to the mechanism of interaction between wettability and the solid–liquid–gas interface phenomenon induced by boiling heat transfer, which is not explicit. In this study, molecular dynamics simulation is performed to analyse the evaporation behaviour of surfaces with different wettability. The simulation results show that a hybrid-wettability surface enhances the vapour film phenomenon caused by boiling heat transfer, which is reflected in the vapour generation rate and vapourization efficiency. The vapour film generation rate increases significantly with increasing hydrophilicity; with increasing hydrophobicity, the vapourization efficiency increases significantly. On this basis, a more comprehensive and systematic analysis optimization design theory of hybrid-wettability optimized surfaces is established: the distribution of wetting, the hydrophobic-surface ratio ( λ ) and the number of wetting structures are the key factors of surface design. For the optimized surface with pattern 2, λ = 0.64 and number = 4, the vapour film generation rate is 60% higher than that of a pure hydrophobic surface, and the efficiency is 33.8% higher than that of a pure hydrophilic surface. This study is relevant because it can provide a feasible optimization design method for improving the phenomenon of heated surface-induced vapour film.