The study of vapor condensation on surface has important engineering significance. The condensation nucleation process of vapor on substrates with different pillar structures is studied through molecular dynamic simulation. The condensation droplets on the pillar with various heights and solid fractions exhibit Wenzel state, Cassie state and the transformation from Wenzel state to Cassie state. The results show that the condensation efficiencies are correlated with the state of droplet and it is explained from the perspective of heat transfer. For the Wenzel state, the droplet fills the gap of pillar and the form of the heat conduction change with the growth of cluster. In the initial of condensation droplets, the heat conduction is similar with various heights of pillar. As the condensation droplets grow, the efficiency of heat conduction enhances with the increasing of height of pillar. For the Cassie state, the form of heat conduction is perpetual during the condensation process with the thermal resistance of the droplet dominated due to the droplets suspended on the pillar. The efficiency of heat transfer is insensitive to the height of pillar. The form of heat conduction for the transformation state transforms from Wenzel state to Cassie state leading to the reduction of condensation rate. The droplet formed in the Wenzel state has the higher transfer efficiency than the Cassie one.

表面蒸气凝结的研究具有重要的工程意义。通过分子动力学模拟研究了蒸汽在具有不同柱结构的基底上的凝结成核过程。柱上具有不同高度和固体分数的冷凝液滴表现出Wenzel状态，Cassie状态以及从Wenzel状态到Cassie状态的转变。结果表明，冷凝效率与液滴的状态有关，并从传热的角度对其进行解释。对于Wenzel态，液滴填充柱的间隙，并且随着簇的生长，热传导的形式发生变化。在凝结液滴的初始阶段，热传导与不同高度的柱相似。随着凝结水滴的增长，导热效率随着柱高的增加而提高。对于卡西状态，在冷凝过程中永久存在热传导形式，由于液滴悬浮在柱子上，因此液滴的热阻占主导地位。传热效率对支柱的高度不敏感。转变态的热传导形式从Wenzel态转变为Cassie态，导致凝结率降低。在Wenzel状态下形成的液滴比Cassie液滴具有更高的转移效率。传热效率对支柱的高度不敏感。转变态的热传导形式从Wenzel态转变为Cassie态，导致凝结率降低。Wenzel状态下形成的液滴比Cassie液滴具有更高的转移效率。传热效率对支柱的高度不敏感。转变态的热传导形式从Wenzel态转变为Cassie态，导致凝结率降低。在Wenzel状态下形成的液滴比Cassie液滴具有更高的转移效率。