Analysis of double diffusion natural convection in an enclosure filled with alumina water nanofluid using Buongioro's two phase model

2019 ◽  
Vol 29 (10) ◽  
pp. 3707-3729
Author(s):  
Saritha Natesan ◽  
Senthil Kumar Arumugam
Keyword(s):  
Natural Convection ◽  
Design Methodology ◽  
Simple Algorithm ◽  
Double Diffusion ◽  
Phase Model ◽  
Governing Equations ◽  
Two Phase ◽  
Content Type ◽  
Square Enclosure ◽  
Volume Method

Purpose The purpose of this study is to apply Buongiorno’s two phase model to analyse double diffusion natural convection in a square enclosure filled with nanofluids. Design/methodology/approach A computational code based on the SIMPLE algorithm and finite volume method is used to solve the non-dimensional governing equations. Findings The nanoparticle plays a crucial role when thermal and solutal buoyancy forces are equal and opposing. Originality/value This is the first paper to apply Buongiorno’s two phase model for double diffusion natural convection in enclosures filled with nanofluids.

Laminar Natural Convection Inside a Wavy Enclosure Heated From Top and Uniformly Cooled From the Bottom and Both Sides

2005 ◽  
Author(s):  
Amaresh Dalal ◽  
Manab Kumar Das
Keyword(s):  
Natural Convection ◽  
Simple Algorithm ◽  
Governing Equations ◽  
Square Cavity ◽  
Integral Forms ◽  
Nusselt Number Distribution ◽  
Laminar Natural Convection ◽  
Lower Temperature ◽  
Volume Method ◽  
Spatially Varying

In the present paper, natural convection inside a square cavity with one and three undulations on the top wall has been carried out. The top wall is heated by a spatially varying temperature and other three walls are kept constant lower temperature. The integral forms of the governing equations are solved numerically using finite-volume method in non-orthogonal body-fitted coordinate system. SIMPLE algorithm with higher-order up-winding scheme are used. The streamlines and isothermal lines are presented for different Rayleigh number (103-106) and a fluid having Prandtl number 0.71. Results are presented in the form of local and average Nusselt number distribution for two different undulations (1 and 3) with wave amplitude of 0.05.

Effects of two-phase nanofluid model on natural convection in a square cavity in the presence of an adiabatic inner block and magnetic field

2018 ◽  
Vol 28 (7) ◽  
pp. 1613-1647 ◽  
Author(s):  
Ammar I. Alsabery ◽  
Tahar Tayebi ◽  
Ali J. Chamkha ◽  
Ishak Hashim
Keyword(s):  
Magnetic Field ◽  
Natural Convection ◽  
Boussinesq Approximation ◽  
Phase Model ◽  
Square Cavity ◽  
Two Phase ◽  
Left Wall ◽  
Content Type ◽  
Conjugate Natural Convection ◽  
The Right

Purpose The purpose of this paper is to study problem of conjugate MHD natural convection of Al2O3-water nanofluid in a square cavity with conductive inner block using Buongiorno’s two-phase model numerically. Design/methodology/approach An isothermal heater is placed on the left wall of the square cavity, while the right wall is maintained at a constant cold temperature. The horizontal top and bottom walls are kept adiabatic. The boundaries of the annulus are assumed to be impermeable, the fluid within the cavity is a water-based nanofluid having Al2O3 nanoparticles. The Boussinesq approximation is applicable. The governing equations subject to the boundary conditions are solved using the finite difference method. Findings Numerical results are presented graphically in the form of streamlines, isotherms and nanoparticles distributions as well as the local and average Nusselt numbers. The results show that the effect of the nanoparticles addition on the average Nusselt number is essential for low Rayleigh, high Hartmann and high values of length ratio when attenuated the convective flow. Originality/value According to exist studies and to the authors’ best knowledge, so far, there have been no studies of conjugate natural convection of Al2O3-water nanofluid in a square cavity with a conductive inner block using Buongiorno’s two-phase model with the effect of the magnetic field. Thus, the authors believe that this work is new and valuable. The aim of this study is to investigate the MHD natural convection of Al2O3-water nanofluid in a square cavity with conductive inner block using Buongiorno’s two-phase model.

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.

Electro-thermo-convection in dielectric liquid subjected to partial unipolar injection between two eccentric cylinders

2019 ◽  
Vol 29 (1) ◽  
pp. 78-93
Author(s):  
Mohamed Issam Elkhazen ◽  
Walid Hassen ◽  
Hakan F. Öztop ◽  
Lioua Kolsi ◽  
Abdullah A.A.A. Al-Rashed ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Rayleigh Number ◽  
Design Methodology ◽  
Dielectric Liquid ◽  
Eccentricity Ratio ◽  
Governing Equations ◽  
Content Type ◽  
Eccentric Cylinders ◽  
Volume Method ◽  
Unipolar Injection

Purpose The purpose of this work is to highlight the effects of partial unipolar injection on electro-thermo-convection (ETC) in dielectric liquid contained between two eccentric cylinders. Design/methodology/approach A finite volume method was used to solve governing equations. The study is performed for different parameters, such as radius ratio (0.2 ≤ Γ ≤ 0.6), dimensionless electric Rayleigh number (0 ≤ T ≤ 900), eccentricity (−0.4 ≤ e ≤ 0.4) and thermal Rayleigh number (10 ≤ Ra ≤ 5.105). Findings It is found that heat transfer increases with increase in dimensionless electric Rayleigh number and eccentricity ratio. Originality/value The originality of this work is to analyze the ETC in dielectric liquid subjected to partial unipolar injection between two eccentric cylinders

Effect of position and height of a shield on convective heat transfer performances of plate fin heat sink

2015 ◽  
Vol 25 (5) ◽  
pp. 1047-1063 ◽  
Author(s):  
Rachid Bouchenafa ◽  
Rachid Saim ◽  
Said Abboudi ◽  
Hakan F. Öztop
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Sink ◽  
Dynamic Performance ◽  
Simple Algorithm ◽  
Governing Equations ◽  
Enhancement Of Heat Transfer ◽  
Content Type ◽  
The One ◽  
Volume Method

Purpose – The purpose of this paper is to examine the thermal and dynamic performance of the plate-fin heat sink fitted with a shield in the bypass. Design/methodology/approach – The governing equations were solved using the finite volume method based on the SIMPLE algorithm. The k-ω Shear Stress Transport was used to model turbulence. The thermal and dynamic results were presented in term of average Nusselt number and friction factor, respectively. The effect of the height (Hs=6, 10 and 13) and the position (X=0, 1/3, 1/2, 2/3 and 3/4) of the shield was studied for a Reynolds number ranging from 2×103 to 12×103 and compared with a heat sink without shield. To evaluate the performance of different heat sink geometries, the efficiency was presented and discussed. Findings – By adding a shield in the bypass, a greater amount of air is injected between the heat sink fins, which improves the heat transfer (advantage) of the one part, and increases the friction on the other hand (disadvantage). The efficiency of the heat sink varies inversely proportional with the Reynolds number. Originality/value – The originality of this work is the method for enhancement of heat transfer.

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.

scholarly journals Natural Convection of Dusty Hybrid Nanofluids in an Enclosure Including Two Oriented Heated Fins

2019 ◽  
Vol 9 (13) ◽  
pp. 2673 ◽  
Author(s):  
Raizah
Keyword(s):  
Natural Convection ◽  
Volume Fraction ◽  
Simple Algorithm ◽  
Systems Of Equations ◽  
Nusselt Numbers ◽  
Pressure Distributions ◽  
Nanoparticles Volume Fraction ◽  
Hybrid Nanofluids ◽  
Volume Method ◽  
Present Simulation

In the current work, the natural convection of dusty hybrid nanofluids in an enclosure including two inclined heated fins has been studied via mathematical simulation. The inclined heated fins are arranged near to the enclosure center with variations on their orientations and lengths. The present simulation is represented by two systems of equations for the hybrid nanofluids that are dusty. The pressure distributions for the dusty phase and hybrid nanofluids phase are evaluated using a SIMPLE algorithm based on the finite volume method. The numerical results are examined using contours of the streamlines, isotherms for the hybrid nanofluids and velocity components for the dusty phase. In addition, the graphical illustrations for profiles of the local and average Nusselt numbers are presented. The main results reveal that an increase in the mixture densities ratio and dusty parameter reduces the rate of the heat transfer. Both the local and average Nusselt numbers are supported as the fins lengths increase regardless of the fins’ rotation. In addition, the nanoparticles volume fraction enhances the thermal boundary layer near the top wall.

Numerical Survey of the Melting Driven Natural Convection Using Generation Heat Source: Application to the Passive Cooling of Electronics Using Nano-Enhanced Phase Change Material

2019 ◽  
Vol 12 (2) ◽  
Author(s):  
Hamza Faraji ◽  
Mustapha Faraji ◽  
Mustapha El Alami
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Source ◽  
Phase Change ◽  
Phase Change Material ◽  
Metallic Nanoparticles ◽  
Simple Algorithm ◽  
Bottom Side ◽  
Volume Method ◽  
Change Material

Abstract The present paper reports numerical results of the melting driven natural convection in an inclined rectangular enclosure filled with nano-enhanced phase change material (NePCM). The enclosure is heated from the bottom side by a flush-mounted heat source (microprocessor) that generates heat at a constant and uniform volumetric rate and mounted on a substrate (motherboard). All the walls are considered adiabatic. The purpose of the investigation is analyzing the effect of nanoparticles insertion by quantifying their contribution to the overall heat transfer. Combined effects of the PCM type, the inclination angle and the nanoparticles fraction on the structure of the fluid flow and heat transfer are investigated. A 2D mathematical model based on the conservation equations of mass, momentum, and energy was developed. The governing equations were integrated and discretized using the finite volume method. The SIMPLE algorithm was adopted for velocity–pressure coupling. The obtained results show that the nanoparticles insertion has an important quantitative effect on the overall heat transfer. The insertion of metallic nanoparticles with different concentrations affects the thermal behavior of the heat sink. They contribute to an efficient cooling of the heat source. The effect of nanoparticles insertion is also shown at the temperature distribution along the substrate.

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