On the Anisotropy of Gas-Transfer Processes in Nanochannels and Microchannels

V. Ya Rudyak, E. V. Lezhnev, D. N. Lubimov

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The method of stochastic molecular modeling, developed by us for calculating the transport coefficients of rarefied gas in a bulk, is generalized to describe transport processes in confined conditions. The phase trajectories of the studied molecular system are simulated stochastically, and the simulation of the dynamics of a molecule is split into processes. First, its shift in configuration space is realized, and then a possible collision with other molecules is played out. The calculation of all observables, in particular, the transport coefficients is carried out by averaging over an ensemble of independent phase trajectories. The interaction of gas molecules with a boundary is described by specular or specular-diffuse laws. The efficiency of the algorithm is demonstrated by calculating the self-diffusion coefficient of argon in a nanochannel. The accuracy of modeling is investigated, its dependence on the number of particles and phase trajectories used for averaging. The viscosity of rarefied gases in the nanochannel is systematically studied. It is shown that it is nonisotropic, and its difference along and across the channel is determined by the interaction of gas molecules with the channel walls. By changing the material of the walls, it is possible to significantly change the viscosity of the gas, and it can be several times greater than in the volume, or less. The indicated anisotropy of viscosity is recorded not only in nanochannels, but also in microchannels.

Translated title of the contributionОб анизотропии процессов переноса газа в нано- и микроканалах
Original languageEnglish
Pages (from-to)108-115
Number of pages8
JournalVestnik St. Petersburg University: Mathematics
Issue number1
Publication statusPublished - Mar 2022


  • diffusion
  • molecular modeling
  • nanochannel
  • rarefied gas
  • transfer processes
  • viscosity




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