Assessing the impact of disjoining pressure on thin-film evaporation with atomistic simulation and kinetic theory
Assessing the impact of disjoining pressure on thin-film evaporation with atomistic simulation and kinetic theory
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DOI：
10.1063/5.0010467
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发表时间：
2020-05
影响因子：
4
通讯作者：
Xiaoman Wang;Yang Li;J. Malen;A. McGaughey
中科院分区：
文献类型：
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作者：
Xiaoman Wang;Yang Li;J. Malen;A. McGaughey
采用分子动力学模拟方法验证了Hertz-Knudsen-Schrage（HKS）方程在分离压力下的有效性。设计了一个非平衡态分子动力学模拟系统，用于直接提取Lennard-Jones流体的蒸发质量通量。从非平衡MD模拟和补充平衡MD模拟获得评估HKS关系所需的温度、压力、性质和分离压力。MD直接蒸发质量通量与HKS关系式计算的质量通量相差在10%以内。我们定义了一个蒸发Kapitza长度，估计液体的传导和蒸发热阻是相等的。我们建议，表面结构，促进膜厚度相当于或小于蒸发Kapitza长度，但大于吸附膜厚度，将最大限度地提高蒸发速率。
Molecular dynamics (MD) simulations are applied to validate the Hertz–Knudsen–Schrage (HKS) relation for the evaporation mass flux in the presence of disjoining pressure. A non-equilibrium MD simulation system is designed to directly extract the evaporation mass flux for a Lennard-Jones fluid. The temperatures, pressures, properties, and disjoining pressure required to evaluate the HKS relation are obtained from the non-equilibrium MD simulation and complementary equilibrium MD simulations. The direct MD evaporation mass flux and that from the HKS relation agree within 10%. We define an evaporation Kapitza length that estimates where the liquid conduction and evaporation thermal resistances are equal. We propose that surface structures that promote film thicknesses comparable to or smaller than the evaporation Kapitza length, but larger than the adsorbed film thickness, will maximize the evaporation rate.