Micro- and nanoscale non-ideal gas Poiseuille flows in a consistent Boltzmann algorithm model

Abstract

The direct simulation Monte Carlo method in the consistent Boltzmann algorithm model has been developed and expanded for non-ideal gas predictions. The enhanced collision rate factor is determined by considering the excluded molecular volume and shadowing/screening effects based on the Enskog theory. The parameter for the attraction strength is also determined by comparison with the classical thermodynamics theory. Different pressure-driven gas Poiseuille flows in micro-and nanoscale channels are investigated. The van der Waals effect leads to a higher mass flow rate and different friction and heat transfer characteristics on the wall surface, compared to the results in the perfect gas model. The results also show that the van der Waals effect is dependent not only on the pressure but also on the channel size. A higher driving pressure or a smaller channel size will result in a larger van der Waals gas effect.

Real gas transport through nanopores of varying cross-section type and shape in shale gas reservoirs

“…Comparison of analytic solutions and molecular simulation data of ψ with p for nitrogen transfer in nanopores with different h of a rectangular section. Note: The Legend "Molecular simulation" is the gas transfer data at a relatively high pressure modeled by Wang and Li with the direct simulation Monte Carlo method [53]. .…”

An Enskog based Monte Carlo method for high Knudsen number non-ideal gas flows

“…Therefore its results agree well with the GEMC results in velocity profiles at inlet and outlet but deviate remarkable from the GEMC in the temperature field. At the same time, the reversal temperature distributions near the wall surface do not occur in the GEMC results as they do in the CBA simulations [21,22], which indicate that additional collision process should be modified to deal with the interaction between molecules and wall surfaces after the additional displacement in CBA. As a result, the present GEMC works better than the other two popular numerical methods for modeling of high Knudsen number non-ideal gas flows.…”

“…Such flows with both high Knudsen numbers and high densities have never been effectively and correctly predicted though many efforts have been made in the past decade [18][19][20][21][22][25][26][27]49]. Here we present our results of such flow using the GEMC method.…”

“…Alexander et al [17] proposed a consistent Boltzmann algorithm (CBA), which modified DSMC by introducing an additional displacement in the advection process and an enhanced collision rate in order to obtain the van der Waals equation of state for dense gases [18]. The consistent Boltzmann algorithm has been used for simulation of nuclear flow [19], surface properties [20], and micro-and nanochannel flows [21,22]. However, it was found that the introduction of CBA into DSMC did not only revise the equation of state (EOS) but also changed the fluid transport properties [23].…”

A Model for Real Gas Transfer in Nanopores of Shale Gas Reservoirs

“…Under so high pressure, gas transport mechanisms in nanopores of shale gas reservoirs are different from those in adsorptive gas separation, heterogeneous catalysis and electrochemical process, which are under low pressure [24]. Under high pressure, gas density is high, and van der Waals force between gas molecules is large, whose effects on gas transport can't be ignored.…”