Double MRT thermal lattice Boltzmann simulation for MHD natural convection of nanofluids in an inclined cavity with four square heat sources

Author(s):  
Tao Zhang ◽  
Defu Che
2013 ◽  
Vol 17 (3) ◽  
pp. 877-890 ◽  
Author(s):  
Mahmoud Jourabian ◽  
Mousa Farhadi ◽  
Darzi Rabienataj ◽  
Abbas Abouei

In the present study, a double-population thermal lattice Boltzmann was applied to solve phase change problem with natural convection in an eccentric annulus. The simulation of melting process from a concentrically and eccentrically placed inner hot cylinder inside an outer cold cylinder with Prandtl number of 6.2, Stefan number of 1 and Rayleigh number of 105 was carried out quantitatively. It was found that the position of the inner cylinder inside the outer cylinder significantly influence the flow patterns including the size and shape of two formed vortexes. It is also observed that the maximum of liquid fractions occurs where the inner cylinder is mounted at the bottom of outer cylinder.


2007 ◽  
Vol 21 (01) ◽  
pp. 87-96 ◽  
Author(s):  
C. S. NOR AZWADI ◽  
T. TANAHASHI

In this paper, a three-dimensional (3D) thermal lattice Boltzmann model is proposed to simulate 3D incompressible thermal flow problem. Our model is based on the double-distribution function approach. We found that a new and simple lattice type of eight-velocity model for the internal energy density distribution function can be developed, where the viscous and compressive heating effects are negligible. Numerical results of 3D natural convection flow in a cubic cavity are presented.


2019 ◽  
Vol 30 (7) ◽  
pp. 3635-3652
Author(s):  
Shihua Lu ◽  
Jianqi Zhu ◽  
Dongyan Gao ◽  
Weiwei Chen ◽  
Xinjun Li

Purpose This study aims to show the importance of natural convection of supercritical fluid in an inclined cavity. The heat transfer performance of natural convection can be improved. Design/methodology/approach A model of an inclined cavity was set up to simulate the natural convection of supercritical fluid. The influence of inclined angles (30 to approximately 90°) and pressures (8 to approximately 12 MPa) are analyzed. To ascertain flow and heat transfer of supercritical fluid natural convection, this paper conducts a numerical investigation using the lattice Boltzmann method (LBM), which is proven to be precise and convenient. Findings The results show that the higher heat transfer performance can be obtained with an inclined angle of 30°. It is also presented that the heat transfer performance under pressure of 10 MPa is the best. In addition, common criterion number correlations of average Nusselt number are also fitted. Originality/value These study results can provide a theoretical reference for the study of heat transfer of supercritical fluid natural convection in engineering.


2019 ◽  
Vol 356 ◽  
pp. 240-252 ◽  
Author(s):  
Hamidreza Khakrah ◽  
Payam Hooshmand ◽  
Mohammad Yaghoub Abdollahzadeh Jamalabadi ◽  
Sina Azar

2018 ◽  
Vol 877 ◽  
pp. 366-371
Author(s):  
Bidyut B. Gogoi

The work in this manuscript deals with the numerical simulation of natural convection in a staggered cavity with the help of a recently developed two-dimensional double Multiple-Relaxation-Time (MRT) thermal Lattice Boltzmann method (LBM). In the last decade, there has been a rapid rise in the development of Lattice Boltzmann methods. However, its application in the simulation of natural convection from a staggered cavity has been carried out for the first time in this study. A careful undermining into the existing literature of heat and mass transfer reveal that study of natural convections in cross-sectional cavities is notably absent. Therefore, in this manuscript, we attempt to review the recently developed method and tried to analyze its implementation on natural convection in a staggered cavity with four differentially heated vertical walls. The problem geometry has eight boundaries. It is a staggered cavity with adiabatic horizontal walls and differentially heated vertical walls. The flow inside the thermally driven staggered cavity has been carefully studied for Rayleigh numbers 103, 104 and 105. The velocity and pressure boundary conditions are determined by a non-equilibrium extrapolation rule. As no benchmark results are available in the literature for this relatively new problem, we carry out its simulation with the help of a yet another well established scheme. This scheme is a higher-order compact (HOC) scheme with fourth order spatial accuracy and second order temporal accuracy. Our results show that there is a very good agreement between both these methods which exemplifies the accuracy and credibility of our results.


2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
L. El Moutaouakil ◽  
Z. Zrikem ◽  
A. Abdelbaki

Laminar natural convection in a water filled square enclosure containing at its center a horizontal hexagonal cylinder is studied by the lattice Boltzmann method. The hexagonal cylinder is heated while the walls of the cavity are maintained at the same cold temperature. Two orientations are treated, corresponding to two opposite sides of the hexagonal cross-section which are horizontal (case I) or vertical (case II). For each case, the results are presented in terms of streamlines, isotherms, local and average convective heat transfers as a function of the dimensionless size of the hexagonal cylinder cross-section (0.1≤B≤0.4), and the Rayleigh number (103≤Ra≤106).


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