Investigation of microscopic mechanisms for water-ice phase change propagation control
Investigation of microscopic mechanisms for water-ice phase change propagation control
复制标题
DOI：
10.1016/j.ijheatmasstransfer.2021.122357
复制
发表时间：
2022-03
影响因子：
5.2
通讯作者：
Yu-Kai Weng;Seungha Shin;K. Kihm;Mohammad M. Bahzad;D. Aaron
中科院分区：
文献类型：
--
作者：
Yu-Kai Weng;Seungha Shin;K. Kihm;Mohammad M. Bahzad;D. Aaron
为了从根本上理解和有效控制冻结传播，考虑石墨烯-水表面相互作用，研究了热力学和结构条件对水-冰相变过程的影响。通过分析分子动力学模拟的原子数据，研究了相变过程中的相变传播以及相变过程中的结构和能量性质。原子迁移率与相变热力学驱动力之间的竞争影响了冻结传播速度，导致冰快速生长的最佳温度出现在252 K。此外，取决于与水接触的冰表面的取向的水-冰界面能改变界面结构稳定性，从而改变冻结传播，即，较高的界面能导致更快的冰传播。因此，我们认为可以通过调节冰晶的取向来控制水-冰相变的传播。在这项研究中，表面相互作用或石墨烯-水相互作用影响水-表面界面附近的能量。能量变化重新排列冰晶或表面结构以达到最稳定的冰表面构型或最小能量状态，其中冰晶的基面与石墨烯表面平行。由于冰在垂直于基面的方向上的传播速度最慢，因此冰在平行于石墨烯表面的方向上可以生长得更快。这项研究的结果为多功能冷冻铸造及其更广泛的应用提供了冰传播控制机制的见解。
The influence of thermodynamic and structural conditions on water-ice phase change process was investigated with consideration of graphene-water surface interactions for fundamental understanding and effective control of freezing propagation. The phase change propagation as well as structural and energetic properties during the phase change were examined by analyzing atomic data from molecular dynamics simulations. The freezing propagation speed is affected by the competition between atomic mobility and thermodynamic driving force for phase change, which causes an optimal temperature for fast ice growth to appear at 252 K. In addition, the water-ice interfacial energy, which depends on the orientation of the water-contacting ice surface, changes interfacial structural stability and thus freezing propagation, i.e., a higher interfacial energy leads to a faster ice propagation. Therefore, we suggest that the water-ice phase change propagation can be controlled by adjusting the orientation of ice crystal. The surface interactions, or graphene-water interactions in this research, affect the energetics near the water-surface interface. The energetic change rearranges the ice crystal or surface structures to reach the most stable ice-surface configuration or minimum energy state, in which the basal plane of the ice crystal is parallel with the graphene surface. As ice propagation is the slowest perpendicular to the basal plane, ice can grow faster parallel to graphene surface. The findings from this study provides insights to ice propagation control mechanisms for versatile freeze casting and its broader applications.