Natural convection in circular enclosures heated from below for various central angles

Mirabedin, Seyed Milad; Farhadi, Fatola

doi:10.1016/j.csite.2016.08.007

Cited by 28 publications

(3 citation statements)

References 10 publications

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“…Therefore, many researchers have explored the impact of various factors, such as the use of modern HTF, external or internal modulation, the influence of magnetic fields, geometrical shape and so on, for enhancing thermal performance and controlling transport phenomena. In this regard, the thermo-fluid phenomena in a confined passage are rather complex, especially in the presence of multiphysical scenarios such as nanofluid/hybrid nanofluid, porous substances and magnetic fields (Maxwell, 1904;Ozoe, 2005;Khaled and Vafai, 2003;Nield and Bejan, 2013;Kabeel et al, 2015;Manna et al, 2021). Kabeel et al (2015) provided a detailed overview of the role of these factors in enhancing thermal performance.…”

Section: Introductionmentioning

confidence: 99%

“…Further research works on the effect of various geometric shapes/curved boundaries on thermal convection could be found in Refs. (Sheikholeslami and Rashidi, 2015;Mirabedin and Farhadi, 2016;Salari et al, 2017;Sheikholeslami and Shehzad, 2018;Sheikholeslami et al, 2019;Molana et al, 2020;Mandal et al, 2021;Biswas et al, 2021Biswas et al, , 2022Saha et al, 2022). In fact, Lukose and Basak (2020) reported on the flow visualization of various-shaped geometries.…”

Section: Introductionmentioning

confidence: 99%

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Hybridized nanofluidic convection in umbrella-shaped porous thermal systems with identical heating and cooling surfaces

Biswas

Mandal²,

Manna

et al. 2023

HFF

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Purpose This study aims to investigate the impact of different heater geometries (flat, rectangular, semi-elliptical and triangular) on hybrid nanofluidic (Cu–Al2O3–H2O) convection in novel umbrella-shaped porous thermal systems. The system is top-cooled, and the identical heater surfaces are provided centrally at the bottom to identify the most enhanced configuration. Design/methodology/approach The thermal-fluid flow analysis is performed using a finite volume-based indigenous code, solving the nonlinear coupled transport equations with the Darcy number (10–5 ≤ Da ≤ 10–1), modified Rayleigh number (10 ≤ Ram ≤ 104) and Hartmann number (0 ≤ Ha ≤ 70) as the dimensionless operating parameters. The semi-implicit method for pressure linked equations algorithm is used to solve the discretized transport equations over staggered nonuniform meshes. Findings The study demonstrates that altering the heater surface geometry improves heat transfer by up to 224% compared with a flat surface configuration. The triangular-shaped heating surface is the most effective in enhancing both heat transfer and flow strength. In general, flow strength and heat transfer increase with rising Ram and decrease with increasing Da and Ha. The study also proposes a mathematical correlation to predict thermal characteristics by integrating all geometric and flow control variables. Research limitations/implications The present concept can be extended to further explore thermal performance with different curvature effects, orientations, boundary conditions, etc., numerically or experimentally. Practical implications The present geometry configurations can be applied in various engineering applications such as heat exchangers, crystallization, micro-electronic devices, energy storage systems, mixing processes, food processing and different biomedical systems (blood flow control, cancer treatment, medical equipment, targeted drug delivery, etc.). Originality/value This investigation contributes by exploring the effect of various geometric shapes of the heated bottom on the hydromagnetic convection of Cu–Al2O3–H2O hybrid nanofluid flow in a complex umbrella-shaped porous thermal system involving curved surfaces and multiphysical conditions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hybridized nanofluidic convection in umbrella-shaped porous thermal systems with identical heating and cooling surfaces

Biswas

Mandal²,

Manna

et al. 2023

HFF

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“…They found an equivalent conductivity coefficient for different values of solid-fluid conductivity ratios for the case of eccentricity. Mirabedin and Farhadi (2016) investigated the effect of different central angles in circular enclosures using two-dimensional numerical simulation. They found that decreasing central angles results in enhancing the overall heat transfer.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the effects of geometrical parameters, eccentricity and perforated fins on natural convection heat transfer in a finned horizontal annulus using three dimensional lattice Boltzmann flux solver

Ashouri

Zarei

Moosavi

2021

HFF

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Purpose The purpose of this paper is to investigate the effects of geometrical parameters, eccentricity and perforated fins on natural convection heat transfer in a finned horizontal annulus using three-dimensional lattice Boltzmann flux solver. Design/methodology/approach Three-dimensional lattice Boltzmann flux solver is used in the present study for simulating conjugate heat transfer within an annulus. D3Q15 and D3Q7 models are used to solve the fluid flow and temperature field, respectively. The finite volume method is used to discretize mass, momentum and energy equations. The Chapman–Enskog expansion analysis is used to establish the connection between the lattice Boltzmann equation local solution and macroscopic fluxes. To improve the accuracy of the lattice Boltzmann method for curved boundaries, lattice Boltzmann equation local solution at each cell interface is considered to be independent of each other. Findings It is found that the maximum heat transfer rate occurs at low fin spacing especially by increasing the fin height and decreasing the internal-cylindrical distance. The effect of inner cylinder eccentricity is not much considerable (up to 5.2% enhancement) while the impact of fin eccentricity is more remarkable. Negative fin eccentricity further enhances the heat transfer rate compared to a positive fin eccentricity and the maximum heat transfer enhancement of 91.7% is obtained. The influence of using perforated fins is more considerable at low fin spacing although some heat transfer enhancements are observed at higher fin spacing. Originality/value The originality of this paper is to study three-dimensional natural convection in a finned-horizontal annulus using three-dimensional lattice Boltzmann flux solver, as well as to apply symmetry and periodic boundary conditions and to analyze the effect of eccentric annular fins (for the first time for air) and perforated annular fins (for the first time so far) on the heat transfer rate.

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Comparative Study between Step and Sinusoidal Temperature Profiles During Natural Convection Inside a Square Enclosure Heated from Bottom

Mullick

Ghosh

DasGupta

et al. 2023

Lecture Notes in Mechanical Engineering

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Natural convection in circular enclosures heated from below for various central angles

Cited by 28 publications

References 10 publications

Hybridized nanofluidic convection in umbrella-shaped porous thermal systems with identical heating and cooling surfaces

Hybridized nanofluidic convection in umbrella-shaped porous thermal systems with identical heating and cooling surfaces

Investigation of the effects of geometrical parameters, eccentricity and perforated fins on natural convection heat transfer in a finned horizontal annulus using three dimensional lattice Boltzmann flux solver

Comparative Study between Step and Sinusoidal Temperature Profiles During Natural Convection Inside a Square Enclosure Heated from Bottom

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