scholarly journals Thermal Lattice Boltzmann Model for Nonisothermal Gas Flow in a Two-Dimensional Microchannel

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Youssef Elguennouni ◽  
Mohamed Hssikou ◽  
Jamal Baliti ◽  
Mohammed Alaoui

In this paper, the Thermal Lattice Boltzmann Method (TLBM) is used for the simulation of a gas microflow. A 2D heated microchannel flow driven by a constant inlet velocity profile Uin and nonisothermal walls is investigated numerically. Two cases of micro-Poiseuille flow are considered in the present study. In the first case, the temperature of the walls is kept uniform, equal to zero; therefore, the gas is driven along the channel under the inlet parameters of velocity and temperature. However, in the second one, the gas flow is also induced by the effect of temperature decreasing applied on the walls. For consistent results, velocity slip and temperature jump boundary conditions are used to capture the nonequilibrium effects near the walls. The rarefaction effects described by the Knudsen number, on the velocity and temperature profiles are evaluated. The aim of this study is to prove the efficiency of the TLBM method to simulate Poiseuille flow in case of nonisothermal walls, based on the average value of the Nusselt number and by comparing the results obtained from the TLBM with those obtained using the Finite Difference Method (FDM). The results also show an interesting sensitivity of velocity and temperature profiles with the rarefaction degree and the imposed temperature gradient of the walls.

2002 ◽  
Vol 68 (672) ◽  
pp. 2186-2194 ◽  
Author(s):  
Takeshi SETA ◽  
Ryoichi TAKAHASHI ◽  
Kenichi OKUI ◽  
Eisyun TAKEGOSHI

2008 ◽  
Vol 19 (12) ◽  
pp. 1847-1861 ◽  
Author(s):  
M. BOTTI ◽  
G. GONNELLA ◽  
A. LAMURA ◽  
F. MASSAIOLI ◽  
V. SOFONEA

We propose a thermal lattice Boltzmann model to study gaseous flow in microcavities. The model relies on the use of a finite difference scheme to solve the set of evolution equations. By adopting diffuse reflection boundary conditions to deal with flows in the slip regime, we study the micro-Couette flow in order to select the best numerical scheme in terms of accuracy. The scheme based on flux limiters is then used to simulate a micro-lid-driven cavity flow by using an efficient and parallel implementation. The numerical results are in very good agreement with the available results recovered with different methods.


Author(s):  
Keqiang Xing ◽  
Yong Tao

The lattice Boltzmann method (LBM) as a relatively new numerical scheme has recently achieved considerable success in simulating fluid flows and associated transport phenomena. However, application of this method to heat transfer problems has been at a stage of infancy. In this work, a thermal lattice Boltzmann model is employed to simulate a two-dimensional, steady flow in a symmetric bifurcation under constant temperature and constant heat flux boundary conditions. The bifurcation effects on the heat transfer and fluid flow are investigated and comparisons are made with the straight tube. Also, different bifurcation angles are simulated and the results are compared with the work of the other researchers.


Entropy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 133 ◽  
Author(s):  
Junjie Ren ◽  
Qiao Zheng ◽  
Ping Guo ◽  
Chunlan Zhao

In the development of tight gas reservoirs, gas flow through porous media usually takes place deep underground with multiple mechanisms, including gas slippage and stress sensitivity of permeability and porosity. However, little work has been done to simultaneously incorporate these mechanisms in the lattice Boltzmann model for simulating gas flow through porous media. This paper presents a lattice Boltzmann model for gas flow through porous media with a consideration of these effects. The apparent permeability and porosity are calculated based on the intrinsic permeability, intrinsic porosity, permeability modulus, porosity sensitivity exponent, and pressure. Gas flow in a two-dimensional channel filled with a homogeneous porous medium is simulated to validate the present model. Simulation results reveal that gas slippage can enhance the flow rate in tight porous media, while stress sensitivity of permeability and porosity reduces the flow rate. The simulation results of gas flow in a porous medium with different mineral components show that the gas slippage and stress sensitivity of permeability and porosity not only affect the global velocity magnitude, but also have an effect on the flow field. In addition, gas flow in a porous medium with fractures is also investigated. It is found that the fractures along the pressure-gradient direction significantly enhance the total flow rate, while the fractures perpendicular to the pressure-gradient direction have little effect on the global permeability of the porous medium. For the porous medium without fractures, the gas-slippage effect is a major influence factor on the global permeability, especially under low pressure; for the porous medium with fractures, the stress-sensitivity effect plays a more important role in gas flow.


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