Simulation of rarefied gas flow in a microchannel with backward facing step by two relaxation times using Lattice Boltzmann method – Slip and transient flow regimes

Ahangar, Ehsan Kamali; Ayani, Mohammad Bagher; Esfahani, Javad Abolfazli

doi:10.1016/j.ijmecsci.2019.05.025

Cited by 25 publications

(6 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In contrast, in Bird's cases, the vortices formed were under subsonic flow conditions, and the limitation of the Knudsen number for vortex formation is 0.88. This Knudsen number limiting the vortex formation was reduced to 0.82 in the work of Ahangar et al 1 and 0.662 in Ref. 10.…”

Section: E Failure Of Vortex Loop Formationmentioning

confidence: 90%

Numerical investigation of rarefied vortex loop formation due to shock wave diffraction with the use of rorticity

2021

View full text Add to dashboard Cite

When compressed gas is ejected from a nozzle into a low-pressure environment, the shock wave diffracts around the nozzle lip and a vortex loop will form. The phenomenon has been widely investigated in the continuum flow regime, but how the shock diffraction and vortex behave under rarefied flow conditions has not received as much attention. It is necessary to understand this transient flow in rarefied environments to improve thrust vector control and avoid potential contamination and erosion of spacecraft surfaces. This work provides numerical results of the vortex loop formation caused by shock wave diffraction around a 90 • corner using the direct simulation Monte Carlo method and the compressible Navier-Stokes equations with the appropriate Maxwell velocity slip and the von Smoluchowski temperature jump boundary conditions. The Mach number and rarefaction effects on the formation and evolution of the vortex loop are discussed. A study of the transient structures of vortex loops has been performed using the rorticity concept. A relationship of mutual transformation between the rorticity and shear vectors has been discovered, demonstrating that the application of this concept is useful to understand vortex flow phenomena.

show abstract

Section: E Failure Of Vortex Loop Formationmentioning

confidence: 90%

Numerical investigation of rarefied vortex loop formation due to shock wave diffraction with the use of rorticity

2021

View full text Add to dashboard Cite

show abstract

“…It was found that this simulation method could be effectively applied to the Couette flow, the force driven Poiseuille flow, the time-dependent force driven Womersley flow, the porous plate flow, and the channel flow with a surface-mounted block, and could avoid the leakage of wall mass and eliminate the error caused by an external force. Ahangar et al [70] employed the LBM method to simulate the flow of rarefied gas in the microchannels with backward facing step, and used a model of two relaxation times when slipping and transient flow. Their results concluded that the LBM was consistent with the DSMC method, and the LBM could be better than the DSMC method.…”

Section: Lattice Boltzmann Methods (Lbm)mentioning

confidence: 99%

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

Gao

Yang

et al. 2022

Thermal Science and Engineering Progress

View full text Add to dashboard Cite

“…Ahangar et al [136] simulated the rarefied gas flow in a microchannel with BF step using LB method and two relaxation times (TRTs) in slip and transient flow regimes. The effects of Knudsen number on the velocity and vortex formation were investigated in this paper.…”

Section: Channels With Sudden Variation Of the Cross-sectional Areamentioning

confidence: 99%

“…In another work by Ahangar et al [137], the heat transfer and fluid flow in a microchannel with a micro-step was studied in slip and transition flow regimes using the LB method. Similar to the previous work [136], TRTs in slip and transient flow regimes are applied for solving the fluid velocity; however, single-relaxation-time is carried out for handling of heat transfer. They depicted that the pressure values change from nonlinear to linear form by increasing the Kn.…”

Section: Channels With Sudden Variation Of the Cross-sectional Areamentioning

confidence: 99%

See 1 more Smart Citation

A review of rarefied gas flow in irregular micro/nanochannels

Taassob

Bordbar

Kheirandish

et al. 2021

J. Micromech. Microeng.

View full text Add to dashboard Cite

In today’s complex micro–electro–mechanical systems (MEMS), investigation of flow through irregular micro/nanochannels, such as bended channels, variable cross-sectional area channels, and those with rough surfaces, can contribute considerably to efficient designing of the microdevices and to gain a better understanding of the flow structure in these geometries. The present paper reviews the prominent studies published in literature on rarefied gas flow through these types of complex geometries. The main focus of the study is to explore the physical aspects of the findings and the analyses provided in support of the results. Finally, the areas in which a gap exists in literature and could be subjects of future studies are introduced.

show abstract

Simulation of rarefied gas flow in a microchannel with backward facing step by two relaxation times using Lattice Boltzmann method – Slip and transient flow regimes

Cited by 25 publications

References 36 publications

Numerical investigation of rarefied vortex loop formation due to shock wave diffraction with the use of rorticity

Numerical investigation of rarefied vortex loop formation due to shock wave diffraction with the use of rorticity

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

A review of rarefied gas flow in irregular micro/nanochannels

Contact Info

Product

Resources

About