A lattice Boltzmann analysis of the conjugate natural convection in a square enclosure with a circular cylinder

2019 ◽  
Vol 71 ◽  
pp. 31-44 ◽  
Author(s):  
Lei Wang ◽  
Yong Zhao ◽  
Xuguang Yang ◽  
Baochang Shi ◽  
Zhenhua Chai
Keyword(s):  
Natural Convection ◽  
Circular Cylinder ◽  
Lattice Boltzmann ◽  
Square Enclosure ◽  
Conjugate Natural Convection

Natural convection of power-law nanofluid in a square enclosure with a circular cylinder: An immersed boundary-lattice Boltzmann study

2018 ◽  
Vol 29 (11) ◽  
pp. 1850105
Author(s):  
Dinggen Li ◽  
Haifeng Zhang ◽  
Peixin Ye ◽  
Zihao Yu
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Circular Cylinder ◽  
Power Law ◽  
Temperature Difference ◽  
Lattice Boltzmann ◽  
Immersed Boundary ◽  
Square Enclosure ◽  
Nanoparticle Diameter ◽  
Power Law Index

In this paper, natural convection of power-law Al2O3-water nanofluids with temperature-dependent properties in a square enclosure with a circular cylinder is studied. The governing equations of the flow and temperature fields are solved by the lattice Boltzmann method (LBM), and the curved velocity and thermal boundary conditions are treated by immersed boundary method (IBM). The effects of Rayleigh number, power-law index, nanoparticle volume fractions, radius of circular cylinder, nanoparticle diameter and temperature difference on flow and heat transfer characteristics are discussed in detail. The results indicate that the heat transfer rate is increased with the increases of Rayleigh number, radius of circular cylinder and temperature difference, while it generally decreases with an increase in power-law index and nanoparticle diameter. Additionally, it is observed that there is an optimal volume fraction at which the maximum heat transfer enhancement is obtained, and the value of it is found to increase slightly with decreasing the nanoparticle diameter, and to increase remarkably with increasing the temperature difference.

scholarly journals Lattice Boltzmann Simulation of Natural Convection in an Annulus between a Hexagonal Cylinder and a Square Enclosure

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
L. El Moutaouakil ◽  
Z. Zrikem ◽  
A. Abdelbaki
Keyword(s):  
Natural Convection ◽  
Rayleigh Number ◽  
Cross Section ◽  
Lattice Boltzmann ◽  
Square Enclosure ◽  
Lattice Boltzmann Simulation ◽  
Laminar Natural Convection ◽  
Heat Transfers ◽  
Boltzmann Method ◽  
Vertical Case

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).

Lattice Boltzmann Computations of Natural Convection Heat Transfer of Nanofluid in a Square Cavity Heated by Protruding Heat Source

2020 ◽  
Vol 12 (4) ◽  
Author(s):  
Mustapha Faraji ◽  
El Mehdi Berra
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Source ◽  
Inclination Angle ◽  
Lattice Boltzmann ◽  
Base Fluid ◽  
Numerical Code ◽  
Convection Flow ◽  
Square Enclosure ◽  
Rayleigh Numbers

Abstract This paper reported the mathematical modeling and numerical simulation of natural convection flow of Cu/water nanofluid in a square enclosure using the lattice Boltzmann method (LBM). The cavity is heated from below by heat source and cooled by the top wall. The vertical walls are adiabatic. After validating the numerical code against the numerical and experimental data, simulations were performed for different Rayleigh numbers (104–0.5 × 107), nanoparticles volume fractions (0–8%), and cavity inclination angle (0 deg–90 deg). The effects of the studied parameters on the streamlines, on isotherms distributions within the enclosure, and on the local and average Nusselt numbers are investigated. It was found that heat transfer and fluid flow structure depend closely on the nanoparticle concentration. Results show differences in stream separation between a base fluid and the nanofluid. Also, adding small nanoparticles fractions, less than 6%, to the base fluid enhances the heat transfer for higher Rayleigh numbers and cavity inclination angle less than 30 deg. It is concluded that the optimal dilute suspension of copper nanoparticles can be applied as a passive way to enhance heat transfer in natural convection engineering applications.

scholarly journals Comparison of the Finite Volume and Lattice Boltzmann Methods for Solving Natural Convection Heat Transfer Problems inside Cavities and Enclosures

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
M. Goodarzi ◽  
M. R. Safaei ◽  
A. Karimipour ◽  
K. Hooman ◽  
M. Dahari ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Finite Volume Method ◽  
Finite Volume ◽  
Lattice Boltzmann ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Square Enclosure ◽  
Volume Method

Different numerical methods have been implemented to simulate internal natural convection heat transfer and also to identify the most accurate and efficient one. A laterally heated square enclosure, filled with air, was studied. A FORTRAN code based on the lattice Boltzmann method (LBM) was developed for this purpose. The finite difference method was applied to discretize the LBM equations. Furthermore, for comparison purpose, the commercially available CFD package FLUENT, which uses finite volume Method (FVM), was also used to simulate the same problem. Different discretization schemes, being the first order upwind, second order upwind, power law, and QUICK, were used with the finite volume solver where the SIMPLE and SIMPLEC algorithms linked the velocity-pressure terms. The results were also compared with existing experimental and numerical data. It was observed that the finite volume method requires less CPU usage time and yields more accurate results compared to the LBM. It has been noted that the 1st order upwind/SIMPLEC combination converges comparatively quickly with a very high accuracy especially at the boundaries. Interestingly, all variants of FVM discretization/pressure-velocity linking methods lead to almost the same number of iterations to converge but higher-order schemes ask for longer iterations.

Sign in / Sign up

Export Citation Format

Share Document