LBM simulation of MHD nanofluid heat transfer in a square cavity with a cooled porous obstacle: effects of various temperature boundary conditions

This paper contains natural convection of Ag–MgO/water micropolar hybrid nanofluid in a hollow hot square enclosure equipped by four cold obstacles on the walls. The simulations were performed by the lattice Boltzmann method (LBM). The influences of Rayleigh number and volume fraction of nanoparticle on the fluid flow and heat transfer performance were studied. Moreover, the effects of some geometric parameters, such as cold obstacle height and aspect ratio, were also considered in this study. The results showed that when the aspect ratio is not large ([Formula: see text] or 0.4), at low Rayleigh number (103), the two secondary vortices are established in each main vortex and this kind of secondary vortex does not form at high Rayleigh number (106). However, at [Formula: see text], these secondary vortices occur again in the middle two vortices at [Formula: see text], which is similar to that at [Formula: see text]. At [Formula: see text], the critical Rayleigh number, when the dominated mechanism of heat transfer changes from conduction to convection, is 104. However, the critical Rayleigh number becomes 105 at [Formula: see text] or 0.6. When the cold obstacle height increases, the shape of the vortices inside the enclosure changes due to the different spaces. Besides, at [Formula: see text], for different cold obstacle heights, the location of the thermal plume is different, owing to the different shapes of vortices. Accordingly, the average Nusselt number increases by increment of the Rayleigh number, nanoparticle volume fraction, cold obstacle height and aspect ratio.

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Effect of obstacle height on the nanofluid convection patterns inside a hollow square enclosure

Mohebbi

Babamir

Amooei

et al. 2021

Int. J. Mod. Phys. C

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Investigation of Nanofluid Natural Convection Inside a Square Cavity for Two Orientations Using Lattice Boltzmann Method

et al. 2023

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In this study, natural convection heat transfer of a water based nanofluid inside a square cavity is numerically investigated for two different orientations of a wall-heated cavity. The enclosure is heated by applying a constant heat flux while cooled at ambient conditions. Lattice Boltzmann method (LBM) is used to simulate nanofluid natural convection. The Brownian motion of nanoparticles is considered. LBM simulation is validated by comparison with experimental and numerical results of the literature. The effect of Rayleigh number (Ra = 103, 104, 105, 106), Biot number (Bi = 0.1, 1, 10, 100) and volume fraction of nanoparticles (Φ = 0, 1, 3 and 5%) on the isotherms, streamlines, velocity components, local and Nusselt number is analyzed for two oriented cavities. The bottom-heated cavity shows higher heat transfer rate than that of the cavity heated from the sidewall. The average Nusselt number increases by up to 6.81%. Furthermore, Biot number, Rayleigh number, and volume fraction of nanoparticles show significant effects on the heat transfer rate.

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Research Progress of Fluid Convective Heat Transfer in Rectangular Enclosures Based on Numerical Simulation

胡¹

2021

APP

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LBM simulation of MHD nanofluid heat transfer in a square cavity with a cooled porous obstacle: effects of various temperature boundary conditions

Cited by 3 publications

References 55 publications

Effect of obstacle height on the nanofluid convection patterns inside a hollow square enclosure

Effect of obstacle height on the nanofluid convection patterns inside a hollow square enclosure

Investigation of Nanofluid Natural Convection Inside a Square Cavity for Two Orientations Using Lattice Boltzmann Method

Research Progress of Fluid Convective Heat Transfer in Rectangular Enclosures Based on Numerical Simulation

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