Viscous Dissipation Effects on Heat Transfer for Nanofluid Flow Over a Backward-Facing Step Through Porous Medium Using Lattice Boltzmann Method

2018 ◽  
Vol 7 (4) ◽  
pp. 668-682
Author(s):  
Sihem Hammouda ◽  
Bayssain Amami ◽  
H. Dhahri
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Lattice Boltzmann Method ◽  
Viscous Dissipation ◽  
Lattice Boltzmann ◽  
Backward Facing Step ◽  
Nanofluid Flow ◽  
Boltzmann Method

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.

scholarly journals Influence of magnetohydrodynamic viscous flow on entropy generation within porous micro duct using the Lattice Boltzmann Method

RSC Advances ◽  
2017 ◽  
Vol 7 (49) ◽  
pp. 30673-30686
Author(s):  
Raja Rabhi ◽  
Abir Yahya ◽  
Bayssain Amami ◽  
Hacen Dhahri
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Viscous Flow ◽  
Lattice Boltzmann Method ◽  
Forced Convection ◽  
Entropy Generation ◽  
Lattice Boltzmann ◽  
Convection Flow ◽  
Forced Convection Flow ◽  
Boltzmann Method

In this work entropy generation and heat transfer for magnetohydrodynamic (MHD) forced convection flow in a micro duct filled with a porous medium are investigated using a modified axisymmetric Lattice Boltzmann Method.

Numerical Analysis of Flow and Heat Transfer at a Backward-Facing Step With an Obstacle Based on Lattice Boltzmann Method

2016 ◽  
Author(s):  
Insaf Mehrez ◽  
Ramla Gheith ◽  
Fethi Aloui ◽  
Sassi Ben Nasrallah
Keyword(s):  
Heat Transfer ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Expansion Ratio ◽  
Physical Parameters ◽  
Backward Facing Step ◽  
Flow Problems ◽  
Flow And Heat Transfer ◽  
Recirculation Length ◽  
Boltzmann Method

The Lattice Boltzmann method is actually considered as one of the simplest approach. The flow and heat transfer distribution in a duct containing a backward and an obstacle are studied for different geometric and physical parameters. The LBM is applied to solve the backward-facing step flow problems for an expansion ratio H/h = 2 in rectangular duct and to determine the effect of the obstacle on flow and heat transfer distribution. The obstacle is situated in the bottom wall of the duct. The effect of various obstacle lengths (0.5<h/S<1.5) will be also considered. All this results were observed for a Prandtl number of 0.71 and different range of Reynolds number (1–200). This study showed the instabilities of velocity, recirculation length, temperature and Nusselt number with the obstacle downstream the step. These results were compared to with published experimental.

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