基于固-液界面传热的异质结冰过程模拟
Heterogeneous Icing Process Under the Influence of Solid-water Interfacial Heat Transfer
-
摘要: 采用分子动力学模拟方法研究了基于固-液界面传热的铂表面异质结冰过程。结果表明,对于疏水表面而言,界面传热是影响结冰过程的主要因素,一方面,疏水表面的界面热阻较大,通过疏水表面将水冷却至低温所需的时间较长,因而增加了冰成核时间;另一方面,由于水分子在降温过程中可以逐渐排列成类冰结构,因此从形成冰核到液膜全部冻结的时间变短。对于亲水表面而言,固-液界面传热过程的影响较弱,固-液界面处较强的吸附作用可以诱导水分子排成类冰结构,是亲水表面促进结冰的主要原因。Abstract: In this work, molecular dynamics simulation was employed to study the icing process on a platinum surface under the influence of the solid-water interfacial heat transfer. It is found that the heat transfer can play a significant role in the heterogeneous icing process, particularly for hydrophobic surfaces with weak interfacial bonding. The ice nucleation occurs slowly since the water molecules have to be cooled down by the interfacial heat transfer. However, the ice can grow faster on a surface with the effect of heat transfer, because the water molecules can be re-arranged in ice-like structure during the cooling period. As the interfacial bonding strength increases, the effect of interfacial heat transfer can be neglected, and the icing process can be enhanced, which is attributed to the high free energy barrier and weak diffusion effect. The findings in this paper provide an in-depth understanding of the effect of the interfacial bonding on the heterogeneous icing process.