电场下液滴合并自弹跳行为的分子动力学研究

在工程上通常利用滴状冷凝提高冷凝换热效率、进而强化传热.而当冷凝液滴发生合并自弹跳时,冷凝换热系数是传统滴状冷凝的1.3至1.5倍,因此液滴合并自弹跳现象对冷凝传热强化的贡献是非常大的.一些宏观实验和理论研究表明,加入外电场能进一步促进冷凝液滴合并自弹跳的频率和高度,但在纳米尺度下是否仍遵守这一规律还未可知,因此本文使...

Molecular Dynamics Simulation of Water Droplet Coalescence-induced Jumping in an Electric Field

Dropwise condensation is significantly more efficient at heat transfer than filmwise condensation in energy and industrial application.Recently,coalescence-induced droplet self-jumping on superhydrophobic surface has attracted more attention due to enhancing heat transfer(1.3 to 1.5 times normal) compared with state-of-the-art dropwise condensation,which has great contributions to further efficiency increase on condensation heat transfer.Previous studies showed that the electric field had the potential applications to coalescence-induced droplet self-jumping for the efficiency and height enhancement experimentally and theoretically,however,most of mechanisms focused on the macroscale droplets which are limited and inconclusive on nano/microscale droplets.Therefore,we employ the molecular dynamic(MD) simulations to investigate coalescence-induced nanodroplet self-jumping under constant voltage field at the molecular level,the simulation results show that the coalescence-induced jumping is significantly affected by the direction and strength of perpendicular electric field:suppressed in an upward but augmented in an downward electric field at a particular field strength range by improving the jumping velocity of coalesced droplet,which is called the electric-field-enhanced jumping interval.