Hybrid atomistic-continuum multiscale method for fluid flow with density variation in microchannels

Vu, Van Huyen; Trouette, Benoît; To, Quy‐Dong; Chénier, Eric

doi:10.1108/hff-11-2016-0473

Cited by 3 publications

(3 citation statements)

References 37 publications

(69 reference statements)

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“…Hybrid multi‐scale models offer a tractable alternative to purely atomistic or MD approaches, especially for more complex problems. For instance, hybrid methods using the concept of Geometric Decomposition of the solution domain, in which the continuum Navier–Stokes equations are solved in one region of the domain and atomistic molecular dynamics in another region, have been proposed by several researchers . The transport of microscopic and macroscopic information is done through an overlap region at the boundary of two adjacent regions.…”

Section: Introductionmentioning

confidence: 99%

An improved hybrid continuum‐atomistic four‐way coupled model for electrokinetics in nanofluidics

2019

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In this study, an efficient hybrid continuum‐atomistic method is proposed to study electrokinetic transport of aqueous solutions in nanofluidics. The aqueous phase is considered as a continuous phase containing immersed ion particles. The behavior of the system is then simulated through utilization of an improved hybrid continuum‐atomistic four‐way coupled approach, including the MultiPhase Particle‐In‐Cell method for the short‐ranged interaction between the ion particles, the Brownian force for the collision between the aqueous phase molecules and the ion particles, and a wall force accounting for the short‐ranged interaction of ions and walls. The validation of the proposed model with the results of Molecular Dynamics simulations suggests that this model can be a promising approach for studying the electrokinetic phenomena in more complicated geometries where the Molecular Dynamics approach is computationally prohibitive. Finally, the effects of electrokinetic parameters, such as the height of the channel, the external electric field, and bulk ionic concentration, on the electroosmotic flow in a nanochannel are investigated and discussed.

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Section: Introductionmentioning

confidence: 99%

An improved hybrid continuum‐atomistic four‐way coupled model for electrokinetics in nanofluidics

2019

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“…There have been many studies for rarefied gas flows in nano/micro devices using direct simulation Monte Carlo (DSMC) and computational fluid dynamics (CFD) (Mizzi et al , 2007; White et al , 2013; Vu et al , 2018; Beskok, 2001; Shu et al , 2005; Zhou et al , 2017). The DSMC method can be used to solve the fluid dynamics problem for the entire rarefaction regimes (Bird, 1994).…”

Section: Introductionmentioning

confidence: 99%

Investigation of non-equilibrium boundary conditions considering sliding friction for micro/nano flows

Assam

Kalkote

Dongari

et al. 2019

HFF

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Purpose Accurate prediction of temperature and heat is crucial for the design of various nano/micro devices in engineering. Recently, investigation has been carried out for calculating the heat flux of gas flow using the concept of sliding friction because of the slip velocity at the surface. The purpose of this study is to exetend the concept of sliding friction for various types of nano/micro flows. Design/methodology/approach A new type of Smoluchowski temperature jump considering the viscous heat generation (sliding friction) has recently been proposed (Le and Vu, 2016b) as an alternative jump condition for the prediction of the surface gas temperature at solid interfaces for high-speed non-equilibrium gas flows. This paper investigated the proposed jump condition for the nano/microflows which has not been done earlier using four cases: 90° bend microchannel pressure-driven flow, nanochannel backward facing step with a pressure-driven flow, nanoscale flat plate and NACA 0012 micro-airfoil. The results are compared with the available direct simulation Monte Carlo results. Also, this paper has demonstrated low-speed preconditioned density-based algorithm for the rarefied gas flows. The algorithm captured even very low Mach numbers of 2.12 × 10−5. Findings Based on this study, this paper concludes that the effect of inclusion of sliding friction in improving the thermodynamic prediction is case-dependent. It is shown that its performance depends not only on the slip velocity at the surface but also on the mean free path of the gas molecule and the shear stress at the surface. A pressure jump condition was used along with the new temperature jump condition and it has been found to often improve the prediction of surface flow properties significantly. Originality/value This paper extends the concept of using sliding friction at the wall for micro/nano flows. The pressure jump condition was used which has been generally ignored by researchers and has been found to often improve the prediction of surface flow properties. Different flow properties have been studied at the wall apart from only temperature and heat flux, which was not done earlier.

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“…The hybrid atomistic-continual multiscale method was used in Vu et al (2018) for studies of gas flow in long microchannels subject to density variations. The authors demonstrated that this method enables effective computer simulations of large-scale problems with the accurate prediction of small-scale transmissions (slip velocity, temperature jump, thin condensation films etc.…”

Section: Introductionmentioning

confidence: 99%

Heat transfer of incompressible flow in a rotating microchannel with slip boundary conditions of second order

Авраменко

Dmitrenko

Shevchuk

et al. 2018

HFF

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Purpose The paper aims to consider heat transfer in incompressible flow in a rotating flat microchannel with allowance for boundary slip conditions of the first and second order. The novelty of the paper encompasses analytical and numerical solutions of the problem, with the latter based on the lattice Boltzmann method (LBM). The analytical solution of the problem includes relations for the velocity and temperature profiles and for the Nusselt number depending on the rotation rate of the microchannel and slip velocity. It was demonstrated that the velocity profiles at high rotation rates transform from parabolic to M-shaped with a minimum at the channel axis. The temperature profiles tend to become uniform (i.e. almost constant). An increase in the channel rotation rate contributes to the increase in the Nusselt number. An increase in the Prandtl number causes a similar effect. The trend caused by the effect of the second-order slip boundary conditions depends on the closure hypothesis. It is shown that heat transfer in a flat microchannel can be successfully modeled using the LBM methodology, which takes into account the second-order boundary conditions. Design/methodology/approach The paper is based on the comparisons of an analytical solution and a numerical solution, which employs the lattice Boltzmann method. Both mathematical approaches used the first-order and second-order slip boundary conditions. The results obtained using both methods agree well with each other. Findings The analytical solution of the problem includes relations for the velocity and temperature profiles and for the Nusselt number depending on the rotation rate of the microchannel and slip velocity. It was demonstrated that the velocity profiles at high rotation rates transform from parabolic to M-shaped with a minimum at the channel axis. The temperature profiles tend to become uniform (i.e. almost constant). The increase in the channel rotation rate contributes to the increase in the Nusselt number. An increase in the Prandtl number causes the similar effect. The trend caused by the effect of the second-order slip boundary conditions depends on the closure hypothesis. It is shown that heat transfer in a flat microchannel can be successfully modeled using the LBM methodology, which considers the second-order boundary conditions. Originality/value The novelty of the paper encompasses analytical and numerical solutions of the problem, whereas the latter are based on the LBM.

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Hybrid atomistic-continuum multiscale method for fluid flow with density variation in microchannels

Cited by 3 publications

References 37 publications

An improved hybrid continuum‐atomistic four‐way coupled model for electrokinetics in nanofluidics

An improved hybrid continuum‐atomistic four‐way coupled model for electrokinetics in nanofluidics

Investigation of non-equilibrium boundary conditions considering sliding friction for micro/nano flows

Heat transfer of incompressible flow in a rotating microchannel with slip boundary conditions of second order

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