Direct Simulation Monte Carlo investigation of fluid characteristics and gas transport in porous microchannels

Abstract

The impetus of the current research is to use the direct simulation Monte Carlo (DSMC) algorithm to investigate fluid behaviour and gas transport in porous microchannels. Here, we demonstrate DSMC’s capability to simulate porous media up to 40% porosity. In this study, the porous geometry is generated by a random distribution of circular obstacles through the microchannel with no interpenetration between the obstacles. The influence of the morphology along with rarefaction and gas type on the apparent permeability is investigated. Moreover, the effects of porosity, solid particle’s diameter and specific surface area are considered. Our results demonstrate that although decreasing porosity intensifies tortuosity in the flow field, the tortuosity reduces at higher Knudsen numbers due to slip flow at solid boundaries. In addition, our study on two different gas species showed that the gas type affects slippage and apparent gas permeability. Finally, comparing different apparent permeability models showed that Beskok and Karniadakis model is valid only up to the early transition regime and at higher Knudsen numbers, the current data matches those models that take Knudsen diffusion into account as well.

Numerical Study of Gas Flow in Super Nanoporous Materials Using the Direct Simulation Monte-Carlo Method

“…All the solid walls were assumed to be fully diffuse, and heat transfer to the solid porous structure was ignored [ 51 , 52 ]. Detail of the present DSMC model [ 3 , 53 ] and the validity of the results are explained thoroughly in our previous works [ 3 , 12 , 13 , 14 , 19 , 54 ].…”

“…The variable hard sphere (VHS) model [ 20 ] was employed to simulate intermolecular collisions, and the no-time-counter (NTC) scheme [ 20 ] was chosen for the collision partner selection model. In the present simulations, each computational cell contained at least 20 simulator particles (i.e., PPC = 20), and the time-step size was chosen to be about one-third of the mean collision time and in the order of 10 −12 s [ 3 , 13 ]. Although surface adsorption and diffusion can contribute to gas transport in super nanoporous materials [ 47 , 48 , 49 , 50 ], these aspects are neglected in the present DSMC simulations.…”

“…Gas flow in microporous and super nanoporous (also known as mesoporous) materials with pore sizes ranging between and [ 1 ] has recently attracted considerable attention because of its vast prospective industrial applications such as gas storage and sensing, mass separation, batteries, catalysis, and optics. The performance in many of these applications depends critically on the characteristics of transport phenomena (i.e., heat and mass transfer) through internal pore space [ 2 , 3 , 4 ]. Therefore, enhancing our understanding of the multiscale transport phenomena in porous media is required to support the development of such micro- and nanodevices [ 5 ].…”

Fluid flow and heat transfer in microchannel heat sinks: Modelling review and recent progress

“…Their results found that increasing the corner radius could improve the quality flow. Shariati et al [93] applied the DSMC method to study the fluid flow and gas transport in porous microchannels. Their results verified the ability of DSMC to solve microporous media, and concluded that this method could effectively simulate micro-porous media with porosity of 40%.…”

An Investigation of Transition Flow in Porous Media by Event Driven Molecular Dynamics Simulation

“…In addition, Tomadakis and Sotirchos (1993) studied tortuosity in the medium of randomly distributed and overlapping capillary channels. Shariati et al (2019) investigated effects of porosity and solid particle diameter on porosity of random spheres and relationship between Kn and tortuosity.…”