Lattice Boltzmann simulation of 3D natural convection in a cuboid filled with KKL-model predicted nanofluid using Dual-MRT model

2019 ◽  
Vol 29 (1) ◽  
pp. 365-387 ◽  
Author(s):  
Alireza Rahimi ◽  
Abbas Kasaeipoor ◽  
Emad Hasani Malekshah ◽  
Mohammad Mehdi Rashidi ◽  
Abimanyu Purusothaman
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Natural Convection ◽  
Lattice Boltzmann Method ◽  
Entropy Generation ◽  
Lattice Boltzmann ◽  
Three Dimensional ◽  
Local Heat Transfer ◽  
Content Type ◽  
Boltzmann Method

Purpose This study aims to investigate the three-dimensional natural convection and entropy generation in a cuboid enclosure filled with CuO-water nanofluid. Design/methodology/approach The lattice Boltzmann method is used to solve the problem numerically. Two different multiple relaxation time (MRT) models are used to solve the problem. The D3Q7–MRT model is used to solve the temperature field, and the D3Q19 is used to solve the fluid flow of natural convection within the enclosure. Findings The influences of different Rayleigh numbers (103 < Ra < 106) and solid volume fractions (0 < f < 0.04) on the fluid flow, heat transfer, total entropy generation, local heat transfer irreversibility and local fluid friction irreversibility are presented comprehensively. To predict thermo–physical properties, dynamic viscosity and thermal conductivity, of CuO–water nanofluid, the Koo–Kleinstreuer–Li (KKL) model is applied to consider the effect of Brownian motion on nanofluid properties. Originality/value The originality of this work is to analyze the three-dimensional natural convection and entropy generation using a new numerical approach of dual-MRT-based lattice Boltzmann method.

Nanofluid flow and heat transfer due to natural convection in a semi-circle/ellipse annulus using modified lattice Boltzmann method

2019 ◽  
Vol 29 (12) ◽  
pp. 4746-4763 ◽  
Author(s):  
Qingang Xiong ◽  
Arash Khosravi ◽  
Narjes Nabipour ◽  
Mohammad Hossein Doranehgard ◽  
Aida Sabaghmoghadam ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Lattice Boltzmann Method ◽  
Entropy Generation ◽  
Lattice Boltzmann ◽  
Temperature Fields ◽  
Shape Effect ◽  
Nanofluid Flow ◽  
Content Type ◽  
Boltzmann Method

Purpose This paper aims to numerically investigate the nanofluid flow, heat transfer and entropy generation during natural convection in an annulus. Design/methodology/approach The lattice Boltzmann method is used to simulate the velocity and temperature fields. Furthermore, some special modifications are applied to make the lattice Boltzmann method capable for simulation in the curved boundary conditions. The annulus is filled with CuO-water nanofluid. The dynamic viscosity of nanofluid is estimated using KLL (Koo-Kleinstreuer-Li) model, and the nanoparticle shape effect is taken account in calculating the thermal conductivity. On the other hand, the local/volumetric entropy generation is used to show the irreversibility under influence of different parameters. Findings The effect of considered governing parameters including Rayleigh number (103<Ra < 106); nanoparticle concentration (0<<0.04) and configuration of annulus on the flow structure; temperature field; and local and total entropy generation and heat transfer rate are presented. Originality/value The originality of this work is using of lattice Boltzmann method is simulation of natural convection in a curved configuration and using of Koo–Kleinstreuer–Li correlation for simulation of nanofluid.

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.

Fluid flow and heat transfer of a stratified system during natural convection – influence of chamfered corners

2019 ◽  
Vol 29 (2) ◽  
pp. 470-486 ◽  
Author(s):  
Alireza Rahimi ◽  
Aravindhan Surendar ◽  
Aygul Z. Ibatova ◽  
Abbas Kasaeipoor ◽  
Emad Hasani Malekshah
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Natural Convection ◽  
Entropy Generation ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Three Dimensional ◽  
Immiscible Fluids ◽  
Content Type ◽  
Flow And Heat Transfer

Purpose This paper aims to investigate the three-dimensional natural convection and entropy generation in the rectangular cuboid cavities included by chamfered triangular partition made by polypropylene. Design/methodology/approach The enclosure is filled by multi-walled carbon nanotubes (MWCNTs)-H2O nanofluid and air as two immiscible fluids. The finite volume approach is used for computation. The fluid flow and heat transfer are considered with combination of local entropy generation due to fluid friction and heat transfer. Moreover, a numerical method is developed based on three-dimensional solution of Navier–Stokes equations. Findings Effects of side ratio of triangular partitions (SR = 0.5, 1 and 2), Rayleigh number (103 < Ra < 105) and solid volume fraction (f = 0.002, 0.004 and 0.01 Vol.%) of nanofluid are investigated on both natural convection characteristic and volumetric entropy generation. The results show that the partitions can be a suitable method to control fluid flow and energy consumption, and three-dimensional solutions renders more accurate results. Originality/value The originality of this work is to study the three-dimensional natural convection and entropy generation of a stratified system.

Natural convection heat transfer of nanofluid inside a cavity containing rough elements using lattice Boltzmann method

2019 ◽  
Vol 29 (10) ◽  
pp. 3659-3684 ◽  
Author(s):  
Rasul Mohebbi ◽  
Mohsen Izadi ◽  
Nor Azwadi Che Sidik ◽  
Gholamhassan Najafi
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Aspect Ratio ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Convection Heat ◽  
Nanofluid Flow ◽  
Content Type ◽  
Boltzmann Method

Purpose This paper aims to study the natural convection of a nanofluid inside a cavity which contains obstacles using lattice Boltzmann method (LBM). The results have focused mainly on various parameters such as number and aspect ratio of roughness elements and different nanoparticle volume fraction. The isotherms and streamlines are presented to describe the hydrodynamics and thermal behaviors of the nanofluid flow throughout the enclosure. Design/methodology/approach The methodology of this paper consists of mathematical model, statement of the problem, nanofluid thermophysical properties, lattice Boltzmann method, LBM for fluid flow, LBM for heat transfer, numerical strategy, boundary conditions, Nusselt (Nu) number calculation, code validation and grid independence. Findings Natural convection heat transfers of a nanofluid inside cavities with and without rough elements have been studied. Lattice Boltzmann technique has been used as numerical approach. The results showed that at higher Rayleigh number (Ra = 106), there are denser streamlines near the left (source) and right wall (sink) which results in better cooling and enhances convective heat rejection to the heat sink. After a distinctive aspect ratio of rough elements (A = 0.1), change in streamline pattern which arises from increasing of aspect ratio does not have an important effect on isotherms. Results indicate that for lower Rayleigh number (Ra = 103), no variation in average Nu is observed with increasing in number of roughness, while for higher one (Ra = 106) average Nu decreases from N = 0 (smooth cavity) up to N = 4 and then remains constant (N = 6). Originality/value Currently, no argumentative and comprehensive extraction can be concluded without fully understanding the role of different arrangement of roughness. Some geometrical parameters such as aspect ratio, number and position of rough elements have been considered. Also, the effect of nanoparticle concentration was studied at different Ra number. Briefly, using LBM, this paper aims to investigate the natural convection of a nanofluid flow on the thermal and hydrodynamics parameters in the presence of rough element with various arrangements.

Numerical analysis of free convection and entropy generation in a cavity using compact finite-difference lattice Boltzmann method

2019 ◽  
Vol 30 (2) ◽  
pp. 977-995 ◽  
Author(s):  
HamidReza KhakRah ◽  
Payam Hooshmand ◽  
David Ross ◽  
Meysam Jamshidian
Keyword(s):  
Heat Transfer ◽  
Rayleigh Number ◽  
Finite Difference ◽  
Free Convection ◽  
Lattice Boltzmann Method ◽  
Entropy Generation ◽  
Lattice Boltzmann ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Boltzmann Method

Purpose The purpose of this paper is to investigate the compact finite-difference lattice Boltzmann method is used to simulate the free convection within a cavity. Design/methodology/approach The finite-difference discretization method enables the numerical simulations to be run when there are non-uniform and curvilinear grids with a finer near-wall grid resolution. Furthermore, the high-order method is applied in the numerical approach, which makes it possible to go with relatively coarse mesh in respect to simulations, which used classical lattice Boltzmann method. The configuration of the cavity is set to sine-walled square. In addition, the cavity is filled with Al2O3-water nanofluid, and the Koo–Kleinstreuer–Li model is used to estimate the properties of nanofluid. Findings The nanoparticle (Al2O3) concentration in the base fluid (water) is considered in a range of 0-0.04. The nanofluid flow and heat transfer are investigated in laminar regime with Rayleigh number in the range of 103-106. The second law analysis is used to study the effects of different governing parameters on the local and volumetric entropy generation. The Rayleigh number, configuration of the cavity and nanoparticle concentration are considered as the governing parameters. The results are mainly focused on the flow structure, temperature field, local and volumetric entropy generation and heat transfer performance. Originality/value The originality of this study is using of a modern numerical method supported by an accurate prediction for nanofluid properties to simulate the flow and heat transfer during natural convection in a cavity.

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.

Effect of hot obstacle position on natural convection heat transfer of MWCNTs-water nanofluid in U-shaped enclosure using lattice Boltzmann method

2019 ◽  
Vol 29 (1) ◽  
pp. 223-250 ◽  
Author(s):  
Yuan Ma ◽  
Rasul Mohebbi ◽  
Mohammad Mehdi Rashidi ◽  
Zhigang Yang
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Content Type ◽  
Boltzmann Method

Purpose This paper aims to numerically investigate the natural convection heat transfer of multi-wall carbon nanotubes (MWCNTs)-water nanofluid in U-shaped enclosure equipped with a hot obstacle by using the lattice Boltzmann method. Design/methodology/approach The combination of the three topics (U-shaped enclosure, different positions of the hot obstacle and MWCNTs-water nanofluid) is innovative in the present study. In total, 15 different positions of the hot obstacle have been arranged, and the effects of pertinent parameters such as Rayleigh numbers, the solid volume fraction of the MWCNTs nanoparticles on the flow field, temperature distribution and the rate of heat transfer inside the enclosure are also investigated. Findings It is found that the average Nusselt number increased by raising the Rayleigh number, and so did the nanoparticle solid volume fraction regardless the position of the hot obstacle. Moreover, enclosures where the hot obstacle is located at the bottom region proved to provide a better rate of heat transfer at high Rayleigh number (106). It is concluded that at a low Ra number (103-105), the higher heat transfer rate and Nu number will be obtained when the hot obstacle is located in the left or right channel. Originality/value In the literature, no trace of studying the natural convection of nanofluids in U-shaped enclosures with heating obstacles was found. Also, MWCNTs were less used as nanoparticles. As the natural convection of nanofluids in thermal engineering applications would expand the existing knowledge, the current researchers conducted a numerical study of the natural convection of Maxwell nanofluid with MWCNTs in U-shaped enclosure equipped with a hot obstacle by using lattice Boltzmann method.

Study on fluid flow and heat transfer in fluid channel filled with KKL model-based nanofluid during natural convection using FVM

2019 ◽  
Vol 29 (8) ◽  
pp. 2622-2641
Author(s):  
Yongsheng Rao ◽  
Zehui Shao ◽  
Alireza Rahimi ◽  
Abbas Kasaeipoor ◽  
Emad Hasani Malekshah
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Natural Convection ◽  
Entropy Generation ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Temperature Fields ◽  
Bejan Number ◽  
Content Type ◽  
Flow And Heat Transfer

PurposeA comprehensive study on the fluid flow and heat transfer in a nanofluid channel is carried out. The configuration of the channel is as like as quarter channel. The channel is filled with CuO–water nanofluid.Design/methodology/approachThe Koo–Kleinstreuer–Li model is used to estimate the dynamic viscosity and consider the Brownian motion. On the other hand, the influence of nanoparticles’ shapes on the heat transfer rate is considered in the simulations. The channel is included with the injection pipes which are modeled as active bodies with constant temperature in the 2D simulations.FindingsThe Rayleigh number, nanoparticle concentration and the thermal arrangements of internal pipes are the governing parameters. The hydrothermal aspects of natural convection are investigation using different approaches such as average Nusselt number, total entropy generation, Bejan number, streamlines, temperature fields, local heat transfer irreversibility, local fluid friction irreversibility and heatlines.Originality/valueThe originality of this work is investigation of fluid flow, heat transfer, entropy generation and heatline visualization within a nanofluid-filled channel using a finite volume method.

Entropy generation optimization for MHD natural convection of a nanofluid in porous media-filled enclosure with active parts and viscous dissipation

2017 ◽  
Vol 27 (2) ◽  
pp. 379-399 ◽  
Author(s):  
M.A. Mansour ◽  
Sameh Elsayed Ahmed ◽  
Ali J. Chamkha
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Viscous Dissipation ◽  
Entropy Generation ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Convection Flow ◽  
Negative Effects ◽  
Content Type ◽  
Volume Method

Purpose This paper aims to investigate the entropy generation due to magnetohydrodynamic natural convection flow and heat transfer in a porous enclosure filled with Cu-water nanofluid in the presence of viscous dissipation effect. The left and right walls of the cavity are thermally insulated. There are heated and cold parts, and these are placed on the bottom and top wall, respectively, whereas the remaining parts are thermally insulated. Design/methodology/approach The finite volume method is used to solve the dimensionless partial differential equations governing the problem. A comparison with previously published woks is presented and is found to be in an excellent agreement. Findings The minimization of entropy generation and local heat transfer according to different values of the governing parameters are presented in details. It is found that the presence of magnetic field has negative effects on the local entropy generation because of heat transfer and the local total entropy generation. Also, the increase in the heated part length leads to a decrease in the local Nusselt number. Originality/value This problem is original, as it has not been considered previously.

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