Experimental Study on Heat Transfer Augmentation for High Heat Flux Removal in Rib-Roughened Narrow Channels

Islam, Mohammed Saiful; Hino, Ryutaro; Haga, Katsuhiro; Monde, Masanori; Sudo, Yukio

doi:10.1080/18811248.1998.9733923

Cited by 14 publications

(16 citation statements)

References 9 publications

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“…(11) h= q/∆T (11) The temperature difference that used in this equation is (Ts-Tb), Ts is the temperature of the heat plate which is measured by thermocouples. The bulk temperature (Tb) at location Y along the streamwise direction, and It was calculated assuming a linear working fluid temperature rise along the rectangular channel and is defined as (Islam et al, 1998;Ghorbani-Tari 2014) Tb = Ts + (Tout-Tin) Y/L (12) Where Ts, Tin and Tout were read from thermocouple output.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

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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“…The coefficients of the local heat transfer are assessed from heat inputs and measured temperatures. With uniformly adding heat into the fluid (Q) and the difference of the temperature between the wall and the fluid (Ts-Tb), the coefficient of the local heat transfer is going to be assessed from experimental data through the use of the equations below [25,26]…”

Section: The Processing Of Datamentioning

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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“…Han et al [2] conducted study on heat transfer augmentation on rectangular narrow channels with rib turbulators. Islam et al [3] conducted a similar study on rectangular narrow channels with square microribs. He later extended the work to analyze the influence of turbulence flow structure on the enhancement of heat transfer in those channels [4,5].…”

Section: Introductionmentioning

confidence: 99%

“…In many cases, it is observed that the results from a specific turbulence model do not agree well with experimental results. In this field of interest, there are no such studies available in the literature except for a few, such as of Islam et al [3].…”

Section: Introductionmentioning

confidence: 99%

Calibration of κ-ε turbulence model for thermal–hydraulic analyses in rib-roughened narrow rectangular channels using genetic algorithm

2021

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Nowadays, applications of turbulent fluid flow in removing high heat flux in rib-roughened narrow channels are drawing much interest. In this work, an improved version of the κ-ε turbulence model is proposed for better prediction of thermal–hydraulic characteristics of flow inside rib-roughened (pitch-to-rib height (p/k) ratio = 10 and 20) narrow channels (channel height, H = 1.2 mm and 3.2 mm). For this, the four turbulence model parameters, Cμ, Cε1, Cε2, and σk, are calibrated. These parameters are adjustable empirical constants provided for controlling the accuracy of the turbulence model results when needed. The simulated data are used to develop correlations between the relative errors in predicting the friction factor (f), Nusselt number (Nu), and the model parameters using a multivariate nonlinear regression method. These correlations are used to optimize the errors using genetic algorithm. Results reveal that the calibrated parameters are not the same for all the narrow channel configurations. After calibration, the overall predictive improvements are up to 35.83% and 27.30% for p/k = 10 and p/k = 20 respectively when H = 1.2 mm. Also, up to 15.48% and 18.05% improvements are obtained for p/k = 10 and p/k = 20 respectively when H = 3.2 mm. The role of the two parameters Cε1 and Cε2 are found to be of primary importance. Furthermore, three types of nanofluids i.e. Al2O3-water, CuO-water, and TiO2-water are studied using the calibrated model to check the potentiality of heat transfer enhancement. Among them, CuO-water nanofluid is predicted to have around 1.32 times higher value of Nu than pure water for the same narrow channel configuration. Article Highlights κ-ε turbulence model is calibrated for rib-roughened narrow rectangular channels using genetic algorithm. Cε1 and Cε2 are the most influential parameters on the performance of the model inside rib-roughened narrow channel. Suggested calibration process is more effective for channel height of 1.2 mm than 3.2 mm.

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Experimental Study on Heat Transfer Augmentation for High Heat Flux Removal in Rib-Roughened Narrow Channels

Cited by 14 publications

References 9 publications

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

Calibration of κ-ε turbulence model for thermal–hydraulic analyses in rib-roughened narrow rectangular channels using genetic algorithm

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