Title: Second-order slip condition considering Langmuir isothermal adsorption for rarefied gas microflows

Authors: Nam T.P. Le; Thoai N. Tran; Minh H. Dang

Addresses: Faculty of Mechanical Engineering, Industrial University of Ho Chi Minh City, Vietnam ' Faculty of Mechanical Engineering, Industrial University of Ho Chi Minh City, Vietnam ' Division of Construction Computation, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam; Faculty of Civil Engineering, Ton Duc Thang University, Ho Chi Minh City, Vietnam

Abstract: Effect of the slip boundary condition on rarefied gas flow simulations plays an important role to understand the behaviour of gas microflows in MEMS. Several second-order slip conditions were proposed by the models of the kinetic theory of gases to simulate the rarefied gas microflows, in which the so-called classical second-order slip condition was derived from the Karniadakis et al. model. In this paper, a new second-order slip condition is proposed to employ with the Navier-Stokes-Fourier equations for simulating the rarefied gas flows in microchannels. It is derived by combining the Langmuir isothermal adsorption and the Karniadakis et al. model, with the aim of achieving a more realistic physical model. The pressure-driven back-forward-step, the Couette and pressure-driven Poiseulle rarefied gas flows in microchannels are investigated to validate our new second-order slip condition. Slip velocities using our new second-order slip condition are better than those using the conventional Maxwell and the so-called classical second-order slip conditions, and are in very good agreement with the DSMC data for all cases considered.

Keywords: Langmuir isothermal adsorption; new second-order slip condition; slip velocity; rarefied gas flows.

DOI: 10.1504/PCFD.2020.108515

Progress in Computational Fluid Dynamics, An International Journal, 2020 Vol.20 No.4, pp.201 - 208

Received: 06 Jul 2019
Accepted: 07 Sep 2019

Published online: 03 Jul 2020 *

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