Lattice Boltzmann non-equilibrium extrapolation method for modeling hydrodynamic compatibility conditions at curved porous-fluid interfaces

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Gholamreza Imani ◽  
Mohsen Mozafari-Shamsi
Keyword(s):  
Fluid Flow ◽  
Lattice Boltzmann ◽  
Fluid Interfaces ◽  
Compatibility Conditions ◽  
Content Type ◽  
Fine Mesh ◽  
Lattice Boltzmann Simulation ◽  
Flow Through ◽  
Boltzmann Method ◽  
Non Equilibrium

Purpose The lattice Boltzmann simulation of fluid flow in partial porous geometries with curved porous-fluid interfaces has not been investigated yet. It is mainly because of the lack of a method in the lattice Boltzmann framework to model the hydrodynamic compatibility conditions at curved porous-fluid interfaces, which is required for the two-domain approach. Therefore, the purpose of this study is to develop such a method. Design/methodology/approach This research extends the non-equilibrium extrapolation lattice Boltzmann method for satisfying no-slip conditions at curved solid boundaries, to model hydrodynamic compatibility conditions at curved porous-fluid interfaces. Findings The proposed method is tested against the results available from conventional numerical methods via the problem of fluid flow through and around a porous circular cylinder in crossflow. As such, streamlines, geometrical characteristics of recirculating wakes and drag coefficient are validated for different Reynolds (5 ≤ Re ≤ 40) and Darcy (10−5 ≤ Da ≤ 5 × 10−1) numbers. It is also shown that without applying any compatibility conditions at the interface, the predicted flow structure is not satisfactory, even for a very fine mesh. This result highlights the importance of the two-domain approach for lattice Boltzmann simulation of the fluid flow in partial porous geometries with curved porous-fluid interfaces. Originality/value No research is found in the literature for applying the hydrodynamic compatibility conditions at curved porous-fluid interfaces in the lattice Boltzmann framework.

Application of lattice Boltzmann method to curved boundaries for simulating nanofluid flow in an L-Shape enclosure

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shayan Naseri Nia ◽  
Faranak Rabiei ◽  
M. M. Rashidi
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Natural Convection ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Curved Boundaries ◽  
Content Type ◽  
Curved Boundary ◽  
Shape Models ◽  
Boltzmann Method

Purpose This paper aims to use the Lattice Boltzmann method (LBM) to numerically simulate the natural convection heat transfer of Cu-water nanofluid in an L-shaped enclosure with curved boundaries. Design/methodology/approach LBM on three different models of curved L-shape cavity using staircase approach is applied to perform a comparative investigation for the effects of curved boundary on fluid flow and heat transfer. The staircase approximation is a straightforward and efficient approach to simulating curved boundaries in LBM. Findings The effect of curved boundary on natural convection in different parameter ranges of Rayleigh number and nanoparticle volume fraction is investigated. The curved L-shape results are also compared to the rectangular L-shape results that were also achieved in this study. The curved boundary LBM simulation is also validated with existing studies, which shows great accuracy in this study. The results show that the top curved boundary in curved L-shape models causes a notable increase in the Nusselt number values. Originality/value Based on existing literature, there is a lack of comparative studies which would specifically examine the effects of curved boundaries on natural convection in closed cavities. Particularly, the application of curved boundaries to an L-shape cavity has not been examined. In this study, curved boundaries are applied to the sharp corners of the bending section in the L-shape and the results of the curved L-shape models are compared to the simple rectangular L-shape model. Hence, a comparative evaluation is performed for the effect of curved boundaries on fluid flow in the L-shape enclosure.

scholarly journals Lattice Boltzmann Simulation of Permeability and Tortuosity for Flow through Dense Porous Media

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Ping Wang
Keyword(s):  
Porous Media ◽  
Fluid Flow ◽  
Lattice Boltzmann ◽  
Flow Direction ◽  
Flow Simulation ◽  
The Body ◽  
Lattice Boltzmann Simulation ◽  
Sphere Radius ◽  
The Media ◽  
Boltzmann Method

Discrete element method (DEM) is used to produce dense and fixed porous media with rigid mono spheres. Lattice Boltzmann method (LBM) is adopted to simulate the fluid flow in interval of dense spheres. To simulating the same physical problem, the permeability is obtained with different lattice number. We verify that the permeability is irrelevant to the body force and the media length along flow direction. The relationships between permeability, tortuosity and porosity, and sphere radius are researched, and the results are compared with those reported by other authors. The obtained results indicate that LBM is suited to fluid flow simulation of porous media due to its inherent theoretical advantages. The radius of sphere should have ten lattices at least and the media length along flow direction should be more than twenty radii. The force has no effect on the coefficient of permeability with the limitation of slow fluid flow. For mono spheres porous media sample, the relationship of permeability and porosity agrees well with the K-C equation, and the tortuosity decreases linearly with increasing porosity.

Lattice Boltzmann simulation of convective flow and heat transfer in a nanofluid-filled hollow cavity

2019 ◽  
Vol 29 (9) ◽  
pp. 3075-3094
Author(s):  
Qiang Pu ◽  
Farhad Aalizadeh ◽  
Darya Aghamolaei ◽  
Mojtaba Masoumnezhad ◽  
Alireza Rahimi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Rayleigh Number ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Boltzmann Method

Purpose This paper aims to to simulate the flow and heat transfer during free convection in a square cavity using double-multi-relaxation time (MRT) lattice Boltzmann method. Design/methodology/approach The double-MRT lattice Boltzmann method is used, and the natural convection fluid flow and heat transfer under influence of different parameters are analyzed. The D2Q5 model and D2Q9 model are used for simulation of temperature field and flow field, respectively. The cavity is filled with CuO-water nanofluid; in addition, the thermo-physical properties of nanofluid and the effect of nanoparticles’ shapes are considered using Koo–Kleinstreuer–Li (KKL) model. On the other hand, the cavity is included with an internal active hollow with constant thermal boundary conditions at its walls and variable dimensions. It should be noted that the dimensions of the internal hollow will be determined by as aspect ratio. Findings The Rayleigh number, nanoparticle concentration and the aspect ratio are the governing parameters. The heat transfer performance of the cavity has direct relationship with the Rayleigh number and solid volume fraction of CuO-water nanofluid. Moreover, the configuration of the cavity is good controlling factor for changing the heat transfer performance and entropy generation. Originality/value The originality of this work is using double-MRT lattice Boltzmann method in simulating the free convection fluid flow and heat transfer.

The coupled lattice Boltzmann simulation of free convection in a finned L-shaped cavity filled with nanofluid

2019 ◽  
Vol 30 (3) ◽  
pp. 1478-1496
Author(s):  
Peng Zhang ◽  
Muhammad Aqeel Ashraf ◽  
Zhenling Liu ◽  
Wan-Xi Peng ◽  
David Ross
Keyword(s):  
Free Convection ◽  
Lattice Boltzmann Method ◽  
Entropy Generation ◽  
Lattice Boltzmann ◽  
Convection Heat Transfer ◽  
Numerical Approach ◽  
Content Type ◽  
Lattice Boltzmann Simulation ◽  
Free Convection Heat ◽  
Boltzmann Method

Purpose This paper aims to investigate the free convection, heat transfer and entropy generation numerically and experientially. A numerical/experimental investigation is carried out to investigate the free convection hydrodynamically/thermally and entropy generation. Design/methodology/approach The coupled lattice Boltzmann method is used as a numerical approach which keeps the significant advantages of standard lattice Boltzmann method with better numerical stability. On the other hand, the thermal conductivity and dynamic viscosity are measured using modern devices in the laboratory. Findings Some correlations based on the temperature at different nanofluid concentration are derived and used in the numerical simulations. In this regard, the results will be accurate with respect to using theoretical properties of nanofluid, and close agreements will be detected between present results and the previous numerical and experimental works. The numerical investigation is done under the effect of Rayleigh number (103 < Ra < 106), volume concentration of nanofluid (?? = 0.5, 1, 1.5, 2, 2.5 and 3%) and thermal configuration of the cavity (Cases A, B, C and D). Originality/value The originality of the present work lies in coupling of the lattice Boltzmann method with experimental observations to analyse the free convection in a cavity.

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