Karim Kazi Ehsanul, Barisik Murat, Bakli Chirodeep, Kim BoHung
School of Mechanical Engineering, University of Ulsan, Daehak-ro 93, Namgu, Ulsan 680-749, Republic of Korea.
Department of Mechanical Engineering, University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA.
Phys Chem Chem Phys. 2024 Jul 17;26(28):19069-19082. doi: 10.1039/d4cp01068j.
The quasi-frictionless water flow across graphitic surfaces offers vast opportunities for a wide range of applications from biomedical science to energy. However, the conflicting experimental results impede a clear understanding of the transport mechanism and desired flow control. Existing literature proposes numerous modifications and updated boundary conditions to extend classical hydrodynamic theories for nanoflows, yet a consensus or definitive conclusion remains elusive. This study presents a critical review of the proposed modifications of the pressure driven flow or the Hagen-Poiseuille (HP) equations to estimate the flow enhancement through carbon nanotubes (CNTs). For such a case, we performed (semi-)classical molecular dynamics simulations of water flow in various sizes of CNTs, applied the different forms of boundary definitions from the literature, and derived HP equation models by implementing these modifications. By aggregating seven distinct experimental datasets, we tested various flow enhancement models against our measurements. Our findings indicate that including the interfacial layering-based dynamic slip-definition in the proposed HP equations yields accurate estimations. While considering interfacial viscosity predicts the individual CNT experiments well, using the experimental viscosity yields better estimations of measurements for the water flow enhancement through membranes of CNTs. This critical review testing existing literature demonstrates how to refine continuum fluid mechanics to predict water flow enhancement at the nanoscale providing holistic multiscale modeling.
跨石墨表面的准无摩擦水流为从生物医学到能源等广泛应用提供了巨大机遇。然而，相互矛盾的实验结果阻碍了对传输机制和理想流动控制的清晰理解。现有文献提出了众多修正和更新的边界条件，以扩展用于纳米流的经典流体动力学理论，但仍难以达成共识或得出明确结论。本研究对为估算通过碳纳米管（CNT）的流量增强而对压力驱动流或哈根 - 泊肃叶（HP）方程提出的修正进行了批判性综述。对于这种情况，我们对不同尺寸碳纳米管中的水流进行了（半）经典分子动力学模拟，应用了文献中不同形式的边界定义，并通过实施这些修正推导了HP方程模型。通过汇总七个不同的实验数据集，我们针对我们的测量测试了各种流量增强模型。我们的研究结果表明，在所提出的HP方程中纳入基于界面分层的动态滑移定义可得出准确的估计值。虽然考虑界面粘度能很好地预测单个碳纳米管实验，但使用实验粘度能更好地估计通过碳纳米管膜的水流增强测量值。这一对现有文献进行测试的批判性综述展示了如何完善连续介质流体力学，以预测纳米尺度的水流增强，从而提供整体多尺度建模。
