Abstract
Sampson's theory for hydrodynamic resistance across a zero-length orifice was developed over a century ago. Although a powerful theory for entrance/exit resistance in nanopores, it lacks accuracy for relatively small-radius pores since it does not account for the molecular interface chemistry. Here, Sampson's theory is revisited for the finite slippage and interfacial viscosity variation near the pore wall. The corrected Sampson's theory can accurately predict the hydrodynamic resistance from molecular dynamics simulations of ultrathin nanopores.6 MoreReceived 19 February 2020Accepted 1 October 2020DOI:https://doi.org/10.1103/PhysRevResearch.2.043153Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasFlows in porous mediaGeophysical fluid dynamicsGranular flowsInteratomic & molecular potentialsInterfacial flowsMicrofluidicsVan der Waals interactionFluid DynamicsAtomic, Molecular & Optical
Highlights
Advances in experimentation [1,2,3,4,5] and computational studies [6,7,8] of fluids in nanoconfinement have led to the observation of unique properties of fluids
The flow rates are dictated by the entrance/exit hydrodynamic resistance governed by the viscous energy dissipation
Hydrodynamic entrance/exit resistance was obtained for hourglass pores by modifying the prefactor in the Sampson formula based on finite-element calculations
Summary
Advances in experimentation [1,2,3,4,5] and computational studies [6,7,8] of fluids in nanoconfinement have led to the observation of unique properties of fluids. In CNTs, accurate calculation of slip lengths, from experimentally measured permeation rates [9], depends on the accuracy of the theory used to obtain the entrance/exit resistance. Hydrodynamic entrance/exit resistance was obtained for hourglass pores by modifying the prefactor in the Sampson formula based on finite-element calculations [18,21]. We show that the lower hydrodynamic resistance in graphene compared to that of the Sampson formula is due to the finite slippage at the edge of the pore This is confirmed by modifying the molecular dynamics (MD). The resistance obtained from MD simulations for the hydrophilic pore (with no slip) matches the resistance predicted by the Sampson formula. In addition to MD simulations, steady-state Navier-Stokes (NS) continuum simulations are carried out where the hydrodynamic resistance matches the values predicted by the corrected Sampson formula (see Appendix C for more details on NS simulations)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
