水分子在固液界面的热输运的理论研究

Heat transfer at Liquid-Solid interface is a combined process of thermal conduction and thermal convection between water molecules themselves and water molecules and solid interface. In thermal conduction process, heat is transferred via molecular vibrations (phonon transportation). Meanwhile, in thermal convection process, heat is transferred via molecular motions (mass transportation). The research of heat transfer at Liquid-Solid interface may help us understand many energy and resource related issues, such as how to improve the water cooling efficiency. In developed countries, more 80% electricity generated at thermoelectric facilities is dependent on cooling water and almost 50% national water withdrawal is taken by water cooling. It is beneficial to understand the microscopic process of water cooling, that how heat is transferred by the water molecules at the Liquid-Solid interface, if one tends to improve energy efficiency and save water resources. .In the former work of researchers, thermal conduction or thermal convection is considered separately, and the influence of the microscopic interfacial patterns is usually neglected. In the framework of statistical mechanics and fluid dynamics, we attempt to use molecular dynamics simulations to integrate thermal conduction and thermal convection together in one theoretical model to investigate the microscopic process of heat transfer by water molecules. We attempt to understand the influence of the microscopic patterns and other properties such as wetting and roughness, etc. towards heat transfer process, which might provide a possible way to improve the heat transfer efficiency by modulating those interfacial properties in applications.

固液界面的热输运是一个包括了水分子与固体界面，水分子与水分子之间热传导与热对流的物理过程。热传导依靠分子间振动传热，热对流依靠分子移动传热。固液界面热输运的研究，有助于我们理解很多能源相关问题，例如改进水冷系统效率。发达国家中80%的电能产生需要水冷系统，同时水冷系统蓄水量约占总蓄水量的50%。因此，固液界面的热输运机理的研究，有助于降低能耗和节约水资源。.在以往关的研究中，热传导和热对流的作用通常被孤立考虑，同时缺少具有微观结构（Microscopic Patterns）新界面材料的热输运研究。在本项目中，我们将结合统计物理和流体力学，通过分子动力学模拟的手段来建立一个综合考虑了热传导和热对流的理论模型，从而完整地分析固液界面的热输运的微观动力学过程。我们将重点考虑壁面的微观结构以及其他性质包括润湿性和粗糙度等对水分子热输运过程的影响，从而为工程应用提出可行思路。

水分子在界面的热输运作为一种典型的界面输运现象，在海水淡化，表面蒸发，生物膜表面过程，水电能源转化，信号转换等宏观过程中起了重要作用，因此在理论研究与实际应用中具有重要意义。在本研究课题中，我们主要围绕水分子在固液界面输运（质量输运）与界面热传导过程（能量输运）这两个方面出发，采用分子动力学模拟并结合量化计算的方法，详细分析了输运过程中涉及的动力学过程与统计性质，从微观上机制上为理解界面水的输运现象提供了理论支持。在具体研究内容上，我们考察了（1）碳纳米管的缺陷对水分子等颗粒分子在热泳输运的阻碍，（2）石墨烯上的Armstrong水桥的稳定性与输运特征，（3）黑磷烯界面反常的热输运各向异性，（4）金属氧化物界面的盐溶液的反常输运速度弯曲现象，（5）二维材料界面的润湿特性与热输运特征等。作为第一作者或通讯作者，课题组的相关科研成果发表1区期刊3篇（1篇JPCL（影响因子9.35）与2篇Nanoscale（影响因子7.76）），2区期刊4篇（PRB，JPCC，PCCP，JSTAT各一篇），以其他作者身份发表2篇研究论文。项目负责人在研期间，部分研究成果获得科技媒体报道，并在2017年获得瑞士联邦政府卓越学者奖，前往苏黎世联邦理工学院（ETH）开展合作研究。