Provide a suitable range to include the thermal creeping effect on slip velocity and temperature jump of an air flow in a nanochannel by lattice Boltzmann method

2017 ◽  
Vol 85 ◽  
pp. 143-151 ◽  
Author(s):  
Arash Karimipour
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Slip Velocity ◽  
Temperature Jump ◽  
Air Flow ◽  
Boltzmann Method

scholarly journals Numerical analysis of forced convection heat transfer in a rectangular micro-channel totally filled with Ag/ water nano fluid in slip flow regime using the lattice Boltzmann method

2021 ◽  
Vol 321 ◽  
pp. 04008
Author(s):  
Kaouther Ben Ltaifa ◽  
Annunziata D’Orazio ◽  
Arash Karimipour ◽  
Hacen Dhahri
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Slip Velocity ◽  
Temperature Jump ◽  
Micro Channel ◽  
Slip Coefficient ◽  
Nano Fluid ◽  
Boltzmann Method

Numerical simulation reported on heat transfer and fluid flow in a two-dimensional rectangular micro channel totally filled with Ag/water. The first –order slip/jump boundary conditions were uniformly imposed to the up and bottom walls. The governing conservation equations are translated in dimensionless form using the thermal Single Relaxation Time (T-SRT) modified Lattice Boltzmann Method (LBM) with double distribution functions (DDFs). The viscous dissipations effects are adopted into the energy equation. Effects of nanoparticle volume fraction φ, slip coefficient, B, on the flow of Nano fluid and heat transfer were studied. The results were interpreter in terms of slip velocity; temperature jump and Nusselt number. Based on the results found, it can be concluded that decreasing the values of slip coefficient enhances the convective heat transfer coefficient and consequently the Nusselt number (Nu) but increases the slip velocity at the wall and temperature jump values.

scholarly journals Lattice Boltzmann method simulation of the gas heat conduction of nanoporous material

2020 ◽  
Vol 24 (6 Part A) ◽  
pp. 3749-3756
Author(s):  
Ya Han ◽  
Shuai Li ◽  
Hai-Dong Liu ◽  
Weipeng Cui
Keyword(s):  
Thermal Conductivity ◽  
Heat Conduction ◽  
Lattice Boltzmann Method ◽  
Knudsen Number ◽  
Lattice Boltzmann ◽  
Size Effects ◽  
Temperature Jump ◽  
Boundary Scattering ◽  
Nanoporous Material ◽  
Boltzmann Method

In order to deeply investigate the gas heat conduction of nanoporous aerogel, a model of gas heat conduction was established based on microstructure of aerogel. Lattice Boltzmann method was used to simulate the temperature distribution and gas thermal conductivity at different size, and the size effects of gas heat conduction have had been obtained under micro-scale conditions. It can be concluded that the temperature jump on the boundary was not obvious and the thermal conductivity remained basically constant when the value of Knudsen number was less than 0.01; as the value of Knudsen number increased from 0.01 to 0.1, there was a clear temperature jump on the boundary and the thermal conductivity tended to decrease and the effect of boundary scattering increased drastically, as the value of Knudsen number was more than 0.1, the temperature jump increased significantly on the boundary, furtherly, the thermal conductivity decreased dramatically, and the size effects were significantly.

LATTICE BOLTZMANN METHOD IN SIMULATION OF THERMAL MICRO-FLOW WITH TEMPERATURE JUMP

2006 ◽  
Vol 17 (05) ◽  
pp. 603-614 ◽  
Author(s):  
ZHI-WEI TIAN ◽  
CHUN ZOU ◽  
ZHAO-HUI LIU ◽  
ZHAO-LI GUO ◽  
HONG-JUAN LIU ◽  
...  
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Gas Flow ◽  
Heat Dissipation ◽  
Temperature Jump ◽  
Velocity Slip ◽  
Boundary Treatment ◽  
Boundary Velocity ◽  
Micro Flow ◽  
Boltzmann Method

We simulate the gas flow and heat transfer in micro-Couette flow by the lattice Boltzmann method (LBM). A new boundary treatment is adopted in the numerical experiment in order to capture the velocity slip and the temperature jump of the wall boundary. Velocity and temperature profiles are in good agreement with the analytic results, which exhibits the availability of this model and boundary treatment in describing thermal micro-flow with viscous heat dissipation. We also find the upper boundary's temperature jump is zero at the critical Ec, which is around 3.0 with different Kn.

Lattice Boltzmann Method for Steady Gas Flows in Microchannels With Imposed Slip Wall Boundary Condition

2007 ◽  
Author(s):  
Seckin Gokaltun ◽  
George S. Dulikravich
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Slip Velocity ◽  
Lattice Structure ◽  
Solid Wall ◽  
Distribution Functions ◽  
Gas Flows ◽  
Wall Boundary ◽  
Wall Boundary Conditions ◽  
Boltzmann Method

In this paper, we use a lattice Boltzmann method (LBM) for simulation of rarefied gas flows in microchannels at the slip flow regime. LBM uses D2Q9 lattice structure and BGK collision operator with single relaxation time. The solid wall boundary conditions used in this paper are based on the idea of bounceback of the non-equilibrium part of particle distribution in the normal direction to the boundary. The same idea is implemented at inlet and exit boundaries as well as at the wall surfaces. The distribution functions at the solid nodes are modified according to imposed density and slip velocity values at the wall boundaries. Simulation results are presented for microscale Couette and Poiseuille flows. The results are validated against analytical and/or experimental data for the slip velocity, nonlinear pressure drop and mass flow rate at various flow conditions. It was observed that the current application of LBM can accurately recover the physics of microscale flow phenomena in microchannels. The type of boundary treatment used in this study enables the implementation of coupled simulations where the flow properties at the regions near the wall can be obtained by other numerical methods such as the Direct Simulation Monte Carlo method (DSMC).

LATTICE BOLTZMANN METHOD FOR SIMULATING GAS FLOW IN MICROCHANNELS

2004 ◽  
Vol 15 (02) ◽  
pp. 335-347 ◽  
Author(s):  
G. H. TANG ◽  
W. Q. TAO ◽  
Y. L. HE
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Slip Velocity ◽  
Gas Flow ◽  
Specular Reflection ◽  
Gas Flows ◽  
Friction Factors ◽  
Isothermal Gas ◽  
Boltzmann Method ◽  
Good Agreement

Isothermal gas flows in microchannels is studied using the lattice Boltzmann method. A novel equation relating Knudsen number with relaxation time is derived. The slip-velocity on the solid boundaries is reasonably realized by combining the bounce-back reflection with specular reflection in a certain proportion. Predicted characteristics in a two-dimensional microchannel flow, including slip-velocity, nonlinear pressure drop, friction factors, velocity distribution along the streamwise direction and mass flow rate, are compared with available analytical and experimental results and good agreement is achieved.

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