scholarly journals Microflow Simulations via the Lattice Boltzmann Method

2011 ◽  
Vol 9 (5) ◽  
pp. 1128-1136 ◽  
Author(s):  
Nikolaos Prasianakis ◽  
Santosh Ansumali
Keyword(s):  
Exact Solution ◽  
Knudsen Number ◽  
Lattice Boltzmann ◽  
Order Of Convergence ◽  
Kinetic Equations ◽  
Closed Form Solutions ◽  
Lattice Boltzmann Simulations ◽  
Simulation Results ◽  
Boltzmann Method ◽  
Stationary Planar

AbstractThe exact solution to the hierarchy of nonlinear lattice Boltzmann kinetic equations, for the stationary planar Couette flow for any Knudsen number was presented by S. Ansumali et al. [Phys. Rev. Lett., 98 (2007), 124502]. In this paper, simulation results at a non-vanishing value of the Knudsen number are compared with the closed-form solutions for the higher-order moments. The order of convergence to the exact solution is also studied. The lattice Boltzmann simulations are in excellent agreement with the exact solution.

Lattice Boltzmann Simulations on the Charging Procedure of a Solar Storage Tank With Immersed Phase Change Materials

2015 ◽  
Author(s):  
Yan Su
Keyword(s):  
Phase Change ◽  
Lattice Boltzmann ◽  
Storage Tank ◽  
Phase Change Materials ◽  
Energy Charge ◽  
Transient Temperature ◽  
Lattice Boltzmann Simulations ◽  
Simulation Results ◽  
Boltzmann Method ◽  
Temperature And Flow Fields

The transient charging procedure of a rectangular solar storage tank with immersed tubes filled by phase change materials (PCM) have been simulated by a Lattice Boltzmann Method (LBM). The energy charge speeds for the storage tank with and without the PCM have been compared. The transient temperature and flow fields including melting of the PCM are also presented. The transient interfaces between fluid and solid are clearly shown. The enhancement of the energy storage capability due to the PCM is calculated based on the simulation results. Also the effects of the arrangement of the PCM are discussed.

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.

scholarly journals Study on droplet nucleation position and jumping on structured hydrophobic surface using the lattice Boltzmann method

2021 ◽  
pp. 149-149
Author(s):  
Gaojie Liang ◽  
Lijun Liu ◽  
Haiqian Zhao ◽  
Cong Li ◽  
Nandi Zhang
Keyword(s):  
Lattice Boltzmann Method ◽  
Significant Influence ◽  
Lattice Boltzmann ◽  
Hydrophobic Surface ◽  
Numerical Results ◽  
Nucleation Mode ◽  
Droplet Nucleation ◽  
Simulation Results ◽  
The Individual ◽  
Boltzmann Method

In this study, droplet nucleation and jumping on the conical microstructure surface is simulated using the Lattice Boltzmann Method (LBM). The nucleation and jumping laws of the droplet on the surface are summarized. The numerical results suggest that the height and the gap of the conical microstructure exhibit a significant influence on the nucleation position of the droplet. When the ratio of height to the gap of the microstructure(H/D) is small, the droplet tends to nucleate at the bottom of the structure. Otherwise, the droplet tends to nucleate towards the side of the structure. The droplet grown in the side nucleation mode possesses better hydrophobicity than that of the droplet grown in the bottom nucleation mode and the droplet jumping becomes easier. Apart from the coalescence of the droplets jumping out of the surface, jumping of individual droplets may also occur under certain conditions. The ratio of the clearance to the width of the conical microstructure(D/F) depends on the jumping mode of the droplet. The simulation results indicate that when the D/F ratio is greater than 1.2, the coalescence jump of droplets is likely to occur. On the contrary, the individual jump of droplets is easy to occur.

Simulation of Interface Deformation in Shear Flow Using Binary Fluid Lattice Boltzmann Model

2002 ◽  
Author(s):  
Naoki Takada ◽  
Akio Tomiyama ◽  
Shigeo Hosokawa
Keyword(s):  
Shear Flow ◽  
Lattice Boltzmann ◽  
Fluid Model ◽  
Kinetic Equations ◽  
Three Dimensional ◽  
Lattice Boltzmann Model ◽  
Repulsive Interaction ◽  
Binary Fluid ◽  
Two Phases ◽  
Boltzmann Method

In this paper, we describes the simulations of two- and three-dimensional interfacial motions in shear flow based on the lattice Boltzmann method (LBM), in which a macroscopic fluid flow results from averaging collision and translation of mesoscopic particles and an interface can be reproduced in a self-organizing way by repulsive interaction between particles. A new scheme in the binary fluid model is proposed to simulate motions of immiscible two phases with different mass densities, and examined in numerical analysis of bubble motions under gravity in a circular tube and deformation of bubble under shear stress. For higher Reynolds numbers, a finite difference-based lattice Boltzmann scheme is applied to the kinetic equations of particle to improve numerical stability, which can capture break-up motions of bubble. Parallel computing in LBM is also discussed briefly for efficient speeding up.

Lattice Boltzmann Simulations for Thermal Conductivity Estimation in Heterogeneous Materials

2009 ◽  
Vol 283-286 ◽  
pp. 364-369 ◽  
Author(s):  
M.R. Arab ◽  
Bernard Pateyron ◽  
Mohammed El Ganaoui ◽  
Nicolas Calvé
Keyword(s):  
Thermal Conductivity ◽  
Porous Medium ◽  
Lattice Boltzmann ◽  
Numerical Study ◽  
Theoretical Models ◽  
Short Description ◽  
Physical Parameters ◽  
Two Dimensional ◽  
Lattice Boltzmann Simulations ◽  
Boltzmann Method

For simulating flows in a porous medium, a numerical tool based on the Lattice Boltzmann Method (LBM) is developed with regards to the classical D2Q9 model. A short description of this model is presented. This technique, applied to two-dimensional configurations, indicates its ability to simulate phenomena of heat and mass transfer. The numerical study is extended to estimate physical parameters that characterize porous materials, like the so-called Effective Thermal Conductivity (ETC) which is of our interest in this paper. Obtained results are compared with those which could be found analytically and by theoretical models. Finally, a porous medium is considered to find its ETC.

Numerical Simulation of Surface Roughness Effects in Laminar Lubrication Using the Lattice-Boltzmann Method

2007 ◽  
Vol 129 (3) ◽  
pp. 603-610 ◽  
Author(s):  
Gunther Brenner ◽  
Ahmad Al-Zoubi ◽  
Merim Mukinovic ◽  
Hubert Schwarze ◽  
Stefan Swoboda
Keyword(s):  
Velocity Field ◽  
Surface Texture ◽  
Lattice Boltzmann ◽  
Load Capacity ◽  
Three Dimensional ◽  
Hydrodynamic Characteristics ◽  
Real Surface ◽  
Roughness Effects ◽  
Lattice Boltzmann Simulations ◽  
Boltzmann Method

The effect of surface texture and roughness on shear and pressure forces in tribological applications in the lubrication regime is analyzed by means of lattice-Boltzmann simulations that take the geometry of real surface elements into account. Topographic data on representative surface structures are obtained with high spatial resolution with the application of an optical interference technique. The three-dimensional velocity field past these surfaces is computed for laminar flow of Newtonian fluids in the continuum regime. Subsequently, pressure and shear flow factors are obtained by evaluating the velocity field in accordance with the extended Reynolds equation of Patir and Cheng (1978, ASME J. Tribol., 100, pp. 12–17). The approach allows an efficient determination of the hydrodynamic characteristics of microstructured surfaces in lubrication. Especially, the influence of anisotropy of surface texture on the hydrodynamic load capacity and friction is determined. The numerical method used in the present work is verified for a simplified model configuration, the flow past a channel with sinusoidal walls. The results obtained indicate that full numerical simulations should be used to accurately and efficiently compute the characteristic properties of film flows past rough surfaces and may therefore contribute to a better understanding and prediction of tribological problems.

LATTICE BOLTZMANN SIMULATIONS OF DROP–DROP INTERACTIONS IN TWO-PHASE FLOWS

2005 ◽  
Vol 16 (01) ◽  
pp. 25-44 ◽  
Author(s):  
KANNAN N. PREMNATH ◽  
JOHN ABRAHAM
Keyword(s):  
Shear Flow ◽  
Lattice Boltzmann ◽  
Flow Model ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Drop Deformation ◽  
Simple Shear Flow ◽  
Two Phase ◽  
Lattice Boltzmann Simulations ◽  
Boltzmann Method

In this paper, three-dimensional computations of drop–drop interactions using the lattice Boltzmann method (LBM) are reported. The LBM multiphase flow model employed is evaluated for single drop problems and binary drop interactions. These include the verification of Laplace–Young relation for static drops, drop oscillations, and drop deformation and breakup in simple shear flow. The results are compared with experimental data, analytical solutions and numerical solutions based on other computational methods, as applicable. Satisfactory agreement is shown. Initial studies of drop–drop interactions involving the head-on collisions of drops in quiescent medium and off-center collision of drops in the presence of ambient shear flow are considered. As expected, coalescence outcome is observed for the range of parameters studied.

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