Using of Bejan's Heatline Technique for Analysis of Natural Convection in a Divided Cavity with Differentially Changing Conductive Partition

Koca, Ahmet; Öztop, Hakan F.; Varol, Yasin; Mobedi, Moghtada

doi:10.1080/10407782.2013.773791

Cited by 12 publications

(4 citation statements)

References 27 publications

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“…Heatlines are useful means for understanding mechanism of heat and fluid flows during the convective transport process. The result of conduction and convection heat equations first derivatives give the heat function, which, satisfies the steady energy balance equation [Equation ( 4)], is expressed as (Mobedi and Oztop, 2008;Koca et al, 2013):…”

Section: Dimensionless Heat Function and Boundary Conditionsmentioning

confidence: 99%

Appraising conjugate heat transfer, heatlines visualization and entropy generation of Ag-MgO/H₂O hybrid nanofluid in a partitioned medium

Ferhi

Djebali

2020

HFF

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Purpose This paper aims to perform the lattice Boltzmann simulation of conjugate natural convection heat transfer, heat flow visualization via heatlines approach and entropy generation in a partitioned medium filled with Ag-MgO (15-85%)/water. Design/methodology/approach The lattice Boltzmann method (LBM) is used to predict the dynamic and thermal behaviors. Experimental correlations for dynamic viscosity and thermal conductivity versus solid volume fraction are used. The study is conducted for the ranges of Rayleigh number 103 ≤ Ra ≤ 106, the partitioner thickness 0.01 ≤ δ ≤ 0.9, its position 0.15 ≤ Xs ≤ 0.85 and the hybrid nano-suspensions volume fraction 0% ≤ ϕ ≤ 2%. Findings The effects of varying of controlling parameters on the convective flow patterns, temperature contours, heat transfers, the heatlines and the entropy generation are presented. It has been found that the maximum rate of heat transfer enhancement occurs for low Ra numbers (103) and is close to 13.52%. The solid thickness d and its horizontal position Xs have a substantial influence on the heat transfer rate, flow structure, heatline, total entropy generation and Bejan number. Besides, the maximum heat transfer is detected for high Ra and δ ≈ 1 and the percentage of augmentation is equal to 65.55% for ϕ = 2%. According to the horizontal position, the heat transfer remains invariant for Ra = 103 and takes a maximum value near the active walls for Ra ≥ 104. The total entropy generation increases with Ra and decreases with ϕ for Ra = 106. The increase of ϕ from 0 to 2% leads to a reduction in close to 40.76%. For this value of Ra, the entropy is the maximum for δ = 0.4 and Xs = 0.35 and Xs = 0.65%. Moreover, as the Ra increases the Bejan number undergoes a decrease. The Bejan number is the maximum for Ra = 103 independently to δ and Xs. The superior thermal performance manifests at low Ra and high value of δ independently to the positions of the conducting body. Originality/value The originality of this paper is to analyze the hybrid nano-additive effects on the two-dimensional conjugate natural convection in a partitioned medium using the LBM. The experimental correlations used for the effective thermal conductivity and dynamic viscosity give credibility to our study. Different approaches such as heatlines and entropy generation are used.

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Section: Dimensionless Heat Function and Boundary Conditionsmentioning

confidence: 99%

Appraising conjugate heat transfer, heatlines visualization and entropy generation of Ag-MgO/H₂O hybrid nanofluid in a partitioned medium

Ferhi

Djebali

2020

HFF

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“…Ahmet Koca et al [10] studied the natural convection with partition of varying width and concluded that thickness is important for high value of Ra. Bennet and Hsueh [11] presented the benchmark solutions and concluded that local Nusselt number is identical for both 2-dimensional and 3-dimensional analyses when Ra ≤ 10 5 .…”

Section: Introductionmentioning

confidence: 99%

Buoyancy enhanced natural convection inside the ventilated square enclosure with a partition and an overhanging transverse baffle

Kalidasan

Velkennedy

Kanna

2014

International Communications in Heat and Mass Transfer

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“…Yousefi et al [11] have studied the effect of the partition inclination on the natural convection in a square enclosure, it found that the maximum and minimum heat transfer occurs at the partition angle of 45° and 15°, respectively. Koca et al [12] have studied the effect of the thermal conductivity and the thickness of the partition in a square enclosure, It is found that both heat transfer and flow strength strongly depend on the thermal conductivity ratio of the solid material of partition and Rayleigh numbers. Also, thickness ratio is important for higher Rayleigh numbers.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of heat transfer in a flat plat thermal solar collector with partitions attached to its glazing

Laaraba¹

2019

THERM SCI

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Heat transfer in the air-gap of a horizontal flat plat thermal solar collector contain partitions attached to its glazing has been studied numerically. The absorber and the glazing are kept at constant and different temperatures, while the vertical walls (insulation) were kept adiabatically. A conjugate formulation was used for mathematical formulation of the problem and a computer program based on the control volume approach and the SIMPLER algorithm was used. The main aim of the current paper is to study numerically the effects of number of fins and their length on the air pattern and heat transfer. It was observed that the heat transfer rate through the air-gap is affected greatly and hence can be controlled by the number of attached fins to the glazing of the solar collector as well as the fin lengths, and the addition of partitions reduces the heat losses by convection by 90%.

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Using of Bejan's Heatline Technique for Analysis of Natural Convection in a Divided Cavity with Differentially Changing Conductive Partition

Cited by 12 publications

References 27 publications

Appraising conjugate heat transfer, heatlines visualization and entropy generation of Ag-MgO/H₂O hybrid nanofluid in a partitioned medium

Appraising conjugate heat transfer, heatlines visualization and entropy generation of Ag-MgO/H₂O hybrid nanofluid in a partitioned medium

Buoyancy enhanced natural convection inside the ventilated square enclosure with a partition and an overhanging transverse baffle

Numerical study of heat transfer in a flat plat thermal solar collector with partitions attached to its glazing

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Using of Bejan's Heatline Technique for Analysis of Natural Convection in a Divided Cavity with Differentially Changing Conductive Partition

Cited by 12 publications

References 27 publications

Appraising conjugate heat transfer, heatlines visualization and entropy generation of Ag-MgO/H2O hybrid nanofluid in a partitioned medium

Appraising conjugate heat transfer, heatlines visualization and entropy generation of Ag-MgO/H2O hybrid nanofluid in a partitioned medium

Buoyancy enhanced natural convection inside the ventilated square enclosure with a partition and an overhanging transverse baffle

Numerical study of heat transfer in a flat plat thermal solar collector with partitions attached to its glazing

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Appraising conjugate heat transfer, heatlines visualization and entropy generation of Ag-MgO/H₂O hybrid nanofluid in a partitioned medium

Appraising conjugate heat transfer, heatlines visualization and entropy generation of Ag-MgO/H₂O hybrid nanofluid in a partitioned medium