Fluid flow and heat transfer maximization of elliptic cross- section tubes exposed to forced convection: A numerical approach motivated by Bejan's theory

Razera, A.L.; Quezada, L.A.; Fagundes, T. M.; Isoldi, Liércio André; Santos, Elizaldo Domingues dos; Biserni, Cesare; Rocha, Luíz Alberto Oliveira

doi:10.1016/j.icheatmasstransfer.2019.104366

Cited by 14 publications

(12 citation statements)

References 35 publications

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“…For the purpose of the validation of the present numerical code, the heat transfer density obtained in this study under fixed pressure drop (Bejan number) is compared with that obtained in Razera et al 26 The comparison is conducted for a single row of circular cylinders placed under fixed pressure drop at spacing (

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= 3) for Bejan numbers ( Be = 10 2 , 10 3 , 5 × 10 3 , and 10 4 ) as shown in Table 2. The agreement between the two compared heat transfer densities is good as illustrated in Table 2.…”

Section: Numerical Methods and Validationmentioning

confidence: 99%

Maximization of heat transfer density from a single‐row cross‐flow heat exchanger with wing‐shaped tubes using constructal design

Anas

Mussa

2021

Heat Trans

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A single‐row cross‐flow heat exchanger with wing‐shaped tubes is designed in this paper using the constructal design method. The wing‐to‐wing spacing and the wing thickness are free to morph while the chord of the wings remains constant. Wing‐to‐wing spacing optimization or heat transfer density maximization from the wings is the objective function in this design. Two directions of the free‐stream (incoming) flow are considered. The right‐ and left‐flow directions are considered with a constant drop in pressure. All wings are heated at a uniform temperature, and the air is used to cool these wings. The two‐dimensional conservation of mass, conservation of momentum, and the conservation of energy equations are solved by means of the finite volume method for steady and incompressible flow. The ratio of the wing thickness to the chord (dimensionless wing thickness) is changed from 0.2 to 1. For each wing thickness, three Bejan numbers (Be = 103, 104, and 105) are used in the numerical simulation. The results revealed that in the case of the flow direction to the left, the maximum heat transfer density is higher than that in the case of the flow direction to the right for all wing thicknesses and all Bejan numbers.

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\overset{S}{true}

= 3) for Bejan numbers ( Be = 10 2 , 10 3 , 5 × 10 3 , and 10 4 ) as shown in Table 2. The agreement between the two compared heat transfer densities is good as illustrated in Table 2.…”

Section: Numerical Methods and Validationmentioning

confidence: 99%

Maximization of heat transfer density from a single‐row cross‐flow heat exchanger with wing‐shaped tubes using constructal design

Anas

Mussa

2021

Heat Trans

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“…Furthermore, they presented a three-dimensional ENFHT 303-2 numerical and experimental optimization for staggered arrangements of finned circular and elliptic tubes in forced convection, which showed a significant 19% gain in heat transfer. Razera et al [10] explored a study on the impact of spacing between elliptical cylinders to enhance the heat transfer rate in forced convection for Newtonian fluid at a fixed Prandtl number. Suffice it to say that adequate information is now available on most aspects of optimization of heat transfer from the staggered or bundle of circular and elliptical tubes in Newtonian fluids.…”

Section: Introductionmentioning

confidence: 99%

Thermal Analysis of the Effect of Non-Newtonian Fluid on the Optimally Spaced Elliptical Cylinder

Kumar,

Suri,

Dutt

et al. 2024

Proceedings of the 9th World Congress on Momentum, Heat and Mass Transfer

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The transfer of heat between bluff bodies and working fluids is a critical factor in various industrial applications, such as the design of heat exchangers and chemical reactors that can significantly impact the efficiency and performance of the system. This study aims to explore the heat transfer density between two aligned elliptical cylinders and a power-law fluid under external forced convection.The study investigates the influence of the Bejan number (100 ≤ Be ≤ 10000) and Prandtl number (1 ≤ Pr ≤ 100) for different aspect ratios (r = 0.1, 1, 5) of elliptical cylinders. Extensive results of streamlines and isothermal contours are discussed to delineate the influence of range of parameters on the flow and thermal field around the elliptical cylinders. The study also examines the heat transfer densities as a function of the Be, Pr, n and r. The results reveal that the heat transfer densities have a complex dependency on Be and Pr, particularly for shear-thinning fluid (n < 1). However, for shear-thickening and Newtonian fluids (n ≥ 1), the heat transfer densities increase with the increase in both Prandtl and Bejan number.

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“…This result was for three Bejan numbers ( Be = 10 3 , 10 4 , and 10 5 ). Razera et al 6 studied the maximization of the heat transfer density from a row of elliptical tubes under fixed pressure difference. The dimensionless pressure differences were ( Be = 10 2 , 10 3 , 5 × 10 3 , and 10 4 ).…”

Section: Introductionmentioning

confidence: 99%

Maximization of heat transfer density from radially finned tubes in cross‐flow using the constructal design method

2022

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The maximization of volumetric heat transfer density from radially finned tubes in cross‐flow is investigated in this study based on the constructal design method. A row of radially finned tubes is placed in cross‐air flow. The tubes and the radial fins are heated at uniform temperatures and cooled by the air cross‐flow. The cross‐air flow is generated by a finite pressure difference. Two dimensionless pressure differences (Bejan number) are considered (Be = 103 and Be = 105). The objective function, the degrees of freedom, and the constraints in the constructal design method should be identified. The objective function is the maximization of the heat transfer density from the finned tubes. The degrees of freedom are; the fin tip‐to‐fin tip spacing, the number of fins, the tube diameter, the fin thickness, and the angle between the fins. The constraints are the length and height of the space occupied by the finned tubes. The pressure‐driven flow and energy equations (steady, two‐dimensional, and incompressible) are solved by means of the finite volume method. The ranges of the dimensionless fin tip‐to‐fin tip spacing are (0.2 ≤ S ≤ 1 for Be = 103 and 0.05≤ S ≤ 0.3 for Be = 105). The number of fins is changed as (N = 2, 4, 6, 8, 10, and 12). The dimensionless tube diameter is changed as (D = 0.25, 0.5, and 0.75). The dimensionless fin thickness is changed as (T = 0.001, 0.01, and 0.05). The results showed that for both (Be = 103) and (Be = 105), the highest value of the maximum volumetric heat transfer density is for (N = 2) and decreases as the number of fins increases. In addition, the minimum values of the maximum volumetric heat transfer density occur when the vertical fins exist at (N = 4, 8, and 12).

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Fluid flow and heat transfer maximization of elliptic cross- section tubes exposed to forced convection: A numerical approach motivated by Bejan's theory

Cited by 14 publications

References 35 publications

Maximization of heat transfer density from a single‐row cross‐flow heat exchanger with wing‐shaped tubes using constructal design

Maximization of heat transfer density from a single‐row cross‐flow heat exchanger with wing‐shaped tubes using constructal design

Thermal Analysis of the Effect of Non-Newtonian Fluid on the Optimally Spaced Elliptical Cylinder

Maximization of heat transfer density from radially finned tubes in cross‐flow using the constructal design method

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