An experimental/numerical hydrothermal analysis on natural convection and TiO2-SiO2/W-EG nanofluid’s properties in a hollow/finned cavity

2020 ◽  
Vol 30 (10) ◽  
pp. 4563-4581 ◽  
Author(s):  
Mahshid Zaresharif ◽  
Fatemeh Zarei ◽  
Ali Mohammad Ranjbar ◽  
Loke Kok Foong ◽  
David Ross
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Design Methodology ◽  
Heat Transfer Performance ◽  
Square Cavity ◽  
Modern Approach ◽  
Content Type ◽  
Different Temperatures ◽  
The Stability ◽  
Boltzmann Method

Purpose This paper aims to provide an experimental/numerical analysis of free convection within a hollow/finned cavity. Design/methodology/approach The hollow square cavity is equipped with eight active fins which have a similar configuration and different temperatures. Furthermore, four different thermal arrangements are considered to determine the order of temperature for each fin. The coupled lattice Boltzmann method is used, which not only maintains the considerable advantages of standard lattice Boltzmann method such as accuracy but also enhances the stability of this method. Findings The cavity is filled with TiO2-SiO2/Water-Ethylene Glycol nanofluid. The thermal conductivity and dynamic viscosity of nanofluid are experimentally measured using high-precision devices in six concentrations of the nanoparticle. In this study, some main parameters, including a range of Rayleigh number (103 < Ra < 106), the concentration of nanofluid (0.5 to 3 Vol.%) and thermal arrangements of fins, are considered. The effects of these main parameters on the flow, isotherms, heat transfer performance and entropy generation are studied. Originality/value The originality of this paper is combining the numerical simulation (lattice Boltzmann method) using a modern approach with experimental observations of nanofluid’s properties.

3D investigation of natural convection of nanofluids in a curved boundary enclosure applying lattice Boltzmann method

2018 ◽  
Vol 28 (8) ◽  
pp. 1827-1844 ◽  
Author(s):  
Mehdi Hosseini Abadshapoori ◽  
Mohammad Hassan Saidi
Keyword(s):  
Natural Convection ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Design Methodology ◽  
Volume Fraction ◽  
Relaxation Times ◽  
Simple Algorithm ◽  
Curved Boundaries ◽  
Content Type ◽  
Boltzmann Method

Purpose The purpose of this paper is to investigate the natural convection behavior of nanofluids in an enclosure. The enclosure is a 3D capsule with curved boundaries filled with TiO2-water nanofluid. Design/methodology/approach In this paper, a multiple relaxation times lattice Boltzmann method (MRT-LBM) has been used. Two-component LBM has been conducted to consider the interaction forces between nanoparticles and the base fluid. Findings Results show that the enhanced Nusselt number (Nu*) increases with the increase in volume fraction of nanoparticles (ϕ) and Ra number and decrease of nanoparticle size (λ). Additionally, the findings indicate that increasing volume fraction beyond a certain value decreases Nu*. Originality/value This paper presents a MRT model of lattice Boltzmann in a 3D curved enclosure. A correlation is also presented based on the current results for Nu* depending on Ra number, volume fraction and size of nanoparticles. Furthermore, a comparison for the convergence rate and accuracy of this model and the SIMPLE algorithm is presented.

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.

Lattice Boltzmann method for nanofluid flow and heat transfer in a curve-ended T-shaped heat exchanger

2019 ◽  
Vol 29 (1) ◽  
pp. 21-42 ◽  
Author(s):  
Alireza Rahimi ◽  
Hesam Bakhshi ◽  
Ali Dehghan Saee ◽  
Abbas Kasaeipoor ◽  
Emad Hasani Malekshah
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Nanofluid Flow ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Boltzmann Method

Purpose The study aims to study the nanofluid flow and heat transfer in a T-shaped heat exchanger. For the numerical simulations, the lattice Boltzmann method is used. Design/methodology/approach The end of each branch of the heat exchanger is considered a curve wall that requires special thermal and physical boundary conditions. To improve the thermal performance of the heat exchanger, the CuO–water nanofluid, which has better heat transfer performance with respect to pure water, is used. The dynamic viscosity of nanofluid is estimated by means of KKL model. Several active fins and solid bodies are implanted within the heat exchanger with different thermal arrangements. Findings In the present work, different approaches such as heatline visualization, local and total entropy generation analysis, local and total Nusselt variation are used to detect the impact of different considered parameters such as Rayleigh number (103 < Ra < 106), solid volume fraction of nanofluid (φ = 0,0.01,0.02,0.03 and 0.04 vol. per cent) and thermal arrangements of internal bodies (Case A, Case B, Case C and Case D) on the fluid flow and heat transfer performance. Originality/value The originality of this work is to analyze the two-dimensional natural convection and entropy generation using lattice Boltzmann method.

Free convection analysis in a Γ-shaped heat exchanger using lattice Boltzmann method employing second law analysis and heatline visualization

2019 ◽  
Vol 29 (9) ◽  
pp. 3056-3074 ◽  
Author(s):  
HamidReza KhakRah ◽  
Mehdi Mohammaei ◽  
Payam Hooshmand ◽  
Navid Bagheri ◽  
Emad Hasani Malekshah
Keyword(s):  
Heat Transfer ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Nanofluid Flow ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Second Law Analysis ◽  
Boltzmann Method

PurposeThe nanofluid flow and heat transfer within a heat exchanger, with different thermal arrangements of internal active bodies, are investigated.Design/methodology/approachFor the numerical simulations, the lattice Boltzmann method is utilized. The KKL model is used to predict the dynamic viscosity of CuO-water nanofluid. Furthermore, the Brownian method is taken account using this model. The influence of shapes of nanoparticles on the heat transfer performance is considered.FindingsThe results show that the platelet nanoparticles render higher average Nusselt number showing better heat transfer performance. In order to perform comprehensive analysis, the heatline visualization, local and total entropy generation, local and average Nusselt variation are employed.Originality/valueThe originality of this work is carrying out a comprehensive investigation of nanofluid flow and heat transfer during natural convection using lattice Boltzmann method and employing second law analysis and heatline visualization.

Numerical simulation of vapor bubble growth on a vertical superheated wall using lattice Boltzmann method

2015 ◽  
Vol 25 (5) ◽  
pp. 1214-1230 ◽  
Author(s):  
Tao Sun ◽  
Weizhong Li ◽  
Bo Dong
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Phase Change ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Nucleate Boiling ◽  
Numerical Results ◽  
Heat Transfer Mechanism ◽  
Content Type ◽  
Boltzmann Method

Purpose – The purpose of this paper is to test the feasibility of lattice Boltzmann method (LBM) for numerical simulation of nucleate boiling and transition boiling. In addition, the processes of nucleate and transition boiling on vertical wall are simulated. The heat transfer mechanism is discussed based on the evolution of temperature field. Design/methodology/approach – In this paper, nucleate boiling and transition boiling are numerically investigated by LBM. A lattice Boltzmann (LB) multiphase model combining with a LB thermal model is used to predict the phase-change process. Findings – Numerical results are in good agreement with existing experimental results. Numerical results confirm the feasibility of the hybrid LBM for direct simulations of nucleate and transition boiling. The data exhibit correct parametric dependencies of bubble departure diameter compared with experimental correlation and relevant references. Research limitations/implications – All the simulations are performed in two-dimensions in this paper. In the future work, the boiling process will be simulated in three-dimensional. Practical implications – This study demonstrated a potential model that can be applied to the investigation of phase change heat transfer, which is one of the effective techniques for enhance the heat transfer in engineering. The numerical results can be considered as a basic work or a reference for generalizing LB method in the practical application about nucleate boiling and transition boiling. Originality/value – The hybrid LBM is first used for simulation of nucleate and transition boiling on vertical surface. Heat transfer mechanism during boiling is discussed based on the numerical results.

Aerodynamic simulation of a high-pressure compressor stage using the lattice Boltzmann method

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jerome de Laborderie ◽  
Cedric Babin ◽  
Fabrizio Fontaneto
Keyword(s):  
High Pressure ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Compressor Stage ◽  
Mean Flow ◽  
Content Type ◽  
High Pressure Compressor ◽  
Boltzmann Method ◽  
Operating Points ◽  
Pressure Compressor

Purpose The present paper aims at evaluating the lattice Boltzmann method (LBM) on a high-subsonic high-pressure compressor stage at nominal regime. Design/methodology/approach The studied configuration corresponds to the H25 compressor operated in a closed-loop test rig at the von Karman Institute. Several operating points are simulated with LBM for two grids of successive refinements. A detailed analysis is performed on the time-averaged flow predicted by LBM, using a comparison with experimental and existing RANS data. Findings The finest grid is found to correctly predict the mean flow across the machine, as well as the influence of the rotor tip gap size. Going beyond time-averaged data, some flow analysis is performed to show the relevance of such a high-fidelity method applied to a compressor configuration. In particular, vortical structures and their evolution with the operating points are clearly highlighted. Spectral analyses finally hint at a proper prediction of tonal and broadband contents by LBM. Originality/value The application of LBM to high-speed turbomachinery flows is very recent. This paper validates one of the first LBM simulations of a high-subsonic high-pressure compressor stage.

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.

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.

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.

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