Maximization of heat transfer density rate from a single row of rhombic tubes cooled by forced convection based on constructal design

Mustafa, Ahmed Waheed

doi:10.1002/htj.21398

Cited by 11 publications

(17 citation statements)

References 31 publications

(42 reference statements)

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“…This is due to the fact that the change in heat densities is less than 0.5% when these lengths are doubled. The validation of the present code is conducted in the previous studies 9,14,16 . For briefness purpose, this validation is not mentioned in the present study.…”

Section: Grid Independence Test and Validationmentioning

confidence: 99%

“…Also, the dimensionless temperature in the energy equation can be expressed by using the temperature difference ( t w − t ∞ ). Based on these scales, the dimensionless equations of mass, momentum, and energy are 14,16 as follows:

\frac{\partial U}{\partial X} + \frac{\partial V}{\partial Y} = 0,

\frac{\partial U^{2}}{\partial X} + \frac{\partial UV}{\partial Y} = - \frac{\partial P}{\partial X} + {(\Pr / Be)}^{1 / 2} true(\frac{\partial^{2} U}{\partial X^{2}} + \frac{\partial^{2} U}{\partial Y^{2}} true),

\frac{\partial VU}{\partial X} + \frac{\partial V^{2}}{\partial Y} = - \frac{\partial P}{\partial Y} + {(\Pr / Be)}^{1 / 2} true(\frac{\partial^{2} V}{\partial X^{2}} + \frac{\partial^{2} V}{\partial Y^{2}} true),

\frac{\partial TU}{\partial X} + \frac{\partial TV}{\partial Y} = {(italicPr italicBe)}^{- 1 / 2} true(\frac{\partial^{2} T}{\partial X^{2}} + \frac{\partial^{2} T}{\partial Y^{2}} true),

…”

Section: Mathematical Modelmentioning

confidence: 99%

“…They showed that the elliptic tubes give better performance as compared with the circular one. Mustafa 14 found the optimal arrangement of diamond‐shaped tubes in crossflow using the constructal design. It was shown that the heat transfer rate decreased with the increase in the tube bluntness.…”

Section: Introductionmentioning

confidence: 99%

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Constructal design of multiscale elliptic tubes in crossflow

Mustafa

Elqadir

2020

Heat Trans

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The optimal configuration of two-scale elliptic tubes in crossflow is found on the basis of the constructal design. The larger tubes are installed inside a domain of fixed length and height. In the same domain, smaller tubes are inserted between the larger tubes in the entrance region at the mid leading edge to leading edge distance of the larger tubes. The spacing between the larger tubes, the semiminor axis of the larger tubes, the major axis of the smaller tubes, and the semiminor axis of the smaller tubes are varied inside the domain freely to find the optimal configuration. There are two optimal configurations: one without the smaller tubes and the other with the presence of the smaller tubes. Both the larger and the smaller tubes are heated at a constant surface temperature. The flow is induced by a fixed pressure difference. The equations for steady, laminar, twodimensional, and incompressible flow are solved by finite volume method. In the absence of the smaller tubes, the range of Bejan number (dimensionless pressure drop) is Be 10 < < 10 3 5 , and in the presence of the smaller tubes, Bejan number is Be = 10 5 . The range of the dimensionless larger tubes semiminor axis is 0.1 ≤ B ≤ 0.4. Air is used to cool the row of the tubes with Prandtl number equal to 0.7. The results show that for different semiminor axes of the larger tubes, the heat transfer rate is enhanced when the smaller tubes are placed between the larger tubes. K E Y W O R D SBejan number, constructal design, crossflow, elliptic tubes

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Section: Grid Independence Test and Validationmentioning

confidence: 99%

\frac{\partial U}{\partial X} + \frac{\partial V}{\partial Y} = 0,

\frac{\partial U^{2}}{\partial X} + \frac{\partial UV}{\partial Y} = - \frac{\partial P}{\partial X} + {(\Pr / Be)}^{1 / 2} true(\frac{\partial^{2} U}{\partial X^{2}} + \frac{\partial^{2} U}{\partial Y^{2}} true),

\frac{\partial VU}{\partial X} + \frac{\partial V^{2}}{\partial Y} = - \frac{\partial P}{\partial Y} + {(\Pr / Be)}^{1 / 2} true(\frac{\partial^{2} V}{\partial X^{2}} + \frac{\partial^{2} V}{\partial Y^{2}} true),

\frac{\partial TU}{\partial X} + \frac{\partial TV}{\partial Y} = {(italicPr italicBe)}^{- 1 / 2} true(\frac{\partial^{2} T}{\partial X^{2}} + \frac{\partial^{2} T}{\partial Y^{2}} true),

…”

Section: Mathematical Modelmentioning

confidence: 99%

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Constructal design of multiscale elliptic tubes in crossflow

Mustafa

Elqadir

2020

Heat Trans

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“…Significant research has been carried out to improve the efficiency of heat exchangers. These efforts are needed because, in addition to domestic applications, heat exchangers are widely used in industries such as thermal power plants, transport, heating and air conditioning systems, electronic equipment, and space vehicles . Increased efficiency of heat exchangers would consequently reduce cost, space, and material.…”

Section: Introductionmentioning

confidence: 99%

“…These efforts are needed because, in addition to domestic applications, heat exchangers are widely used in industries such as thermal power plants, transport, heating and air conditioning systems, electronic equipment, and space vehicles. [1][2][3][4][5] Increased efficiency of heat exchangers would consequently reduce cost, space, and material. For designing a heat exchanger and identifying optimal parameters and operational performance requirements, both the pressure drop and heat transfer between a fluid flow and the heat exchanger need to be known previously.…”

Section: Introductionmentioning

confidence: 99%

An experimental investigation in forced convective heat transfer and friction factor of air flow over aligned round and flattened tube banks

Jassim

Tahseen

Mustafa

et al. 2019

Heat Trans. Asian Res.

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Heat transfer coefficients and pressure drop are studied experimentally for airflow over aligned round and flattened tube configurations. The Reynolds number is based on the outer diameter of the round tube or the outside transverse diameter of the flattened tube, which is used for various flows, ranging from 133 to 800 with a constant input heat flux. In the present work, a total of 30 samples of round and flattened tubes heat exchangers with three transverse pitches, 2.0, 3.0, and 4.5, were studied to investigate their thermal performance. The results indicate that the relative gain in the overall Nusselt number is about 32.5 to 60.6% in flattened tubes, while the reduction range in the friction factor is about 11 to 30.6%. Correlations are proposed for the overall Nusselt number, friction factor, and Colburn j–factor for both round and flattened tube banks. A higher value means that a deviation error of 9.9% in the round tube banks and 10.1% in the flattened tube banks are expected. In addition, the best value for thermal performance for the flattened tube bundle was found to be coincident with a smaller Reynolds number.

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