Sun Chengzhen, Zhou Runfeng, Zhao Zhixiang, Bai Bofeng
State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Shaanxi 710049, China.
School of Urban Planning and Municipal Engineering, Xi'an Polytechnic University, Shaanxi 710048, China.
J Phys Chem Lett. 2020 Jun 18;11(12):4678-4692. doi: 10.1021/acs.jpclett.0c00591. Epub 2020 Jun 3.
Nanoconfined fluids (NCFs), which are confined in nanospaces, exhibit distinctive nanoscale effects, including surface effects, small-size effects, quantum effects, and others. The continuous medium hypothesis in fluid mechanics is not valid in this context because of the comparable characteristic length of spaces and molecular mean free path, and accordingly, the classical continuum theories developed for the bulk fluids usually cannot describe the mass and energy transport of NCFs. In this Perspective, we summarize the nanoscale effects on the thermodynamics, mass transport, flow dynamics, heat transfer, phase change, and energy transport of NCFs and highlight the related representative works. The applications of NCFs in the fields of membrane separation, oil and gas production, energy harvesting and storage, and biological engineering are especially indicated. Currently, the theoretical description framework of NCFs is still missing, and it is expected that this framework can be established by adopting the classical continuum theories with the consideration of nanoscale effects.
纳米受限流体（NCFs）被限制在纳米空间中，表现出独特的纳米尺度效应，包括表面效应、小尺寸效应、量子效应等。由于空间的特征长度与分子平均自由程具有可比性，流体力学中的连续介质假设在此情况下并不成立，因此，为宏观流体发展起来的经典连续介质理论通常无法描述纳米受限流体的质量和能量传输。在这篇展望文章中，我们总结了纳米尺度效应在纳米受限流体的热力学、质量传输、流动动力学、传热、相变和能量传输方面的影响，并突出了相关的代表性研究工作。特别指出了纳米受限流体在膜分离、石油和天然气生产、能量收集与存储以及生物工程领域的应用。目前，纳米受限流体的理论描述框架仍然缺失，期望通过采用考虑纳米尺度效应的经典连续介质理论来建立这一框架。
