Effects of inlet velocity profile on flow and heat transfer in the entrance region of a ribbed channel

Kim, Dae Hyun; Lee, Byung Ju; Park, Jung Shin; Kwak, Jae Su; Chung, Jin Taek

doi:10.1016/j.ijheatmasstransfer.2015.05.077

Cited by 23 publications

(6 citation statements)

References 13 publications

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“…Based on comparison observation on the various models, the error is within 5% 7 and the deficiency does not affect the main observation in their study. The persistent error is also reported by Liu et al 18 and Kim et al 19 using various turbulence models. However to conclude which model is more accurate is immaterial in this case due to different rib surfaces produce varying form of flow characteristics, which no single model may cater an accurate solution.…”

Section: Methodssupporting

confidence: 76%

“…The distribution of the local heat transfer coefficient also changed as a result of the relocation of flow reattachments. 19 Viswanathan and Tafti 12 also observed that the rotation of the channel with internal ribs could improve the heat transfer augmentation on the channel walls, where the corner of the rib shows high heat transfer caused by impingement of secondary flow, which is generated from Coriolis effect on mean shear or flow under exertion of system rotation.…”

Section: Introductionmentioning

confidence: 99%

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Spatial effect of a vertical multi-faceted rib on thermal performance and flow characteristics in a square channel

Amir

Ir.

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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A multi-faceted vertical rib has been numerically investigated using the internal flow of rib in a rectangular channel method under turbulent flow for 17,000 < Re < 27,000. The vertical rib that can be encountered inside porous media design often creates a persisting issue of high-pressure drop. The challenge frequently intensifies, mainly when a two-phase state heat transfer is introduced inside the porous media. The vertical multi-faceted rib models the various surfaces often encountered inside the porous media. The effect of blockage ratio on the flow characteristics and thermal performance is observed. The results are compared to the more conventional circular rib, equal in surface area to the multi-faceted rib. The multi-faceted rib yields a higher average Nusselt number of approximately 33% and contributes to the higher average Nusselt number of the channel. The multi-faceted rib channel has a better thermal performance factor, in average of approximately 13% higher and lower pressure drop than the circular rib channel. The advantage of the multi-faceted rib is attributed to, surprisingly, the poor flow attachment on the rib surface, which results in a low Cf/ f ratio. Consequently, the multi-faceted rib suffers from very low velocity on the downstream rib surface. Ultimately, the spatial effect of the rib inside the square channel can be evaluated using the Cf/ f ratio, which takes into account the rib surface and channel walls. In the quasi two-phase state, the circular rib is observed to provide a more favorable condition for latent heat transfer under extreme condition investigated.

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Section: Methodssupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Spatial effect of a vertical multi-faceted rib on thermal performance and flow characteristics in a square channel

Amir

Ir.

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…Bhattacharyya et al, (2018) experimentally and numerically investigated the characteristics of convection heat transfer in a circular pipe supplied with twisted tape with Re ranging from (100 to 2000), the entrance angle of pipe (140º to 180º), and the twisted ratio (18 to 30). Kim et al, (2016) performed numerical investigation to determine the effects of entrance velocity of coolant flow on the characteristics of flow and convection heat transfer Frontiers in Heat and Mass Transfer 2 in a ribbed duct. Eiamsa-Ard and Promvonge ( 2009) studied the effects of rib-grooved compound tabulator on the forced heat transfer coefficient within a rectangular ribbed duct under a regular heat flux condition.…”

Section: Introductionmentioning

confidence: 99%

Effect of Semi-Circle Rib on Heat Transfer Coefficient in a Rectangular Channel

Fadhil¹,

Al-Turaihi²,

Abed³

2020

Frontiers in Heat and Mass Transfer

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In this paper an experimental and numerical analysis has been conducted to study the effect of heat transfer and filed flow of two-phase flow (water and air) through a rectangular ribbed channel. The study has involved the several values of heat flux (120,140,160 Watts), air and water superficial velocity (1.096, 1.425, 1.644, 1.864, and 2.193 m/s) and (0.0421, 0.0842, and 0.1474 m/s), respectively. The distribution of temperature along the channel was photographed using thermal camera and compared with numerical results . The experimental test system was fabricated of vertical rectangular channel with cross section of (0.08m × 0.03m) and a length (0.7 m) to analyze the behavior of the mixture (water-air) over the heated plate (semi-circle ribs ). The computational fluid dynamics CFD software was utilized to simulate the governing equations with initial and boundary conditions. Results found that the ribbed channel give the high heat transfer rate compared to the smooth channel. The percentage deviation between the experimental and numerical data is (1.0% -6.0% ). The results proved that the flow is growing to become turbulent, eddies develop about the heated plate (rib), the temperature at the outlet decreases and heat transfer coefficient improved by adding ribs, it also improved when the velocities of the flow increased.

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“…Fifi et al, and Salman [18,19], conducted a numerical analysis for studying the impacts of various shapes of ribs like (triangular, trapezoidal, and rectangular), on forced heat transfer of the convection and friction factor in the rectangular duct. Kim et al, [20], performed numerical study for determining the impacts of entrance velocity of coolant flow on the flow and convection heat transfer features in ribbed ducts. Eiamsa and Promvonge [21], studied the impacts of ribs-grooved compound tabulator on the forced heat transfer coefficient within a rectangular ribbed duct under regular heat flux conditions.…”

Section: Introductionmentioning

confidence: 99%

Experimental and CFD Analysis of Two-Phase Forced Convection Flow in Channels of Various Rib Shapes

Abed

Kareem

Majdi³

et al. 2020

ARFMTS

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This paper investigates numerically and experimentally heat transfer forced convective two-phase flow (i.e. air and water) over a rectangular ribbed channel with a vertical orientation. Three distinct rib–groove shapes have been examined. Ribs - groove shapes are; Triangle, Trapezoid, and Semi-Trapezoid ribs-groove. The present study has been performed with continuous heat flux through range of water and air superficial inlet velocity values between 0.105 – 0.316m/s, and 0.263 – 1.320 m/s, respectively. Continuity, momentum and energy calculations have been formulated using the Finite Volume Approach (FVM). Results indicate that the triangle rib-groove has the high heat transfer coefficient and lower temperature difference than other cases against a different number of Reynolds. The experimental data has been compared to numerical results for ribs –grooved channel with deviation of about 1.0% - 7.5%. The channel fitted with triangle ribs shows the highest heat transfer, which is about 59% higher than the smooth channel; 56% for trapezoidal rib, and 44% for channel fitted by semi-trapezoidal rib. Finally, the triangle rib-groove gives a better heat transfer improvement value in comparison with trapezoidal and semi trapezoidal rib-groove channel at constant pumping power.

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Effects of inlet velocity profile on flow and heat transfer in the entrance region of a ribbed channel

Cited by 23 publications

References 13 publications

Spatial effect of a vertical multi-faceted rib on thermal performance and flow characteristics in a square channel

Spatial effect of a vertical multi-faceted rib on thermal performance and flow characteristics in a square channel

Effect of Semi-Circle Rib on Heat Transfer Coefficient in a Rectangular Channel

Experimental and CFD Analysis of Two-Phase Forced Convection Flow in Channels of Various Rib Shapes

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