Heat transfer in a twin-blow narrow channel with two opposite walls roughened by skewed ribs arranged in staggered manner

Chang, Shyy Woei; Chiang, Kuei Feng; Yang, Tsun Lirng; Chen, Ping‐Hei

doi:10.1016/j.ijthermalsci.2004.05.005

Cited by 5 publications

(3 citation statements)

References 11 publications

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“…A major source attributing the experimental uncertainties was the temperature measurement as the fluid properties and the convective heat fluxes were evaluated using the temperature measurements. The maximum uncertainty of the present infrared thermal image system was estimated as + 0.7 0 C from the calibration runs and the repetitiveness tests [7]. The maximum uncertainties associated with the local Nusselt and Reynolds numbers and the Fanning friction factor were estimated as 10.2, 5.8 and 6.7% respectively [14].…”

Section: Program and Data Processingmentioning

confidence: 99%

“…The thickness, gap, pitch and height of fins along with their arrangements were examined in order to study their impacts on the convective capabilities of the fin arrays [2][3][4][5][6]. Augmentations of heat convection for each individual fin channel in a fin array were recently explored using surface ribs [7][8]. Heat transfer rates in the fin channels roughened by 45 0 ribs were about 10~50% higher than those in the smooth-walled channels [8].…”

Section: Introductionmentioning

confidence: 99%

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Forced Heat Convection of Wavy Fin Channel

Yang

Chiang

Chang

et al. 2008

JTST

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This experimental study measures the detailed heat transfer distributions over the wavy fin channel with twin flow exits that simulates an elongated flow passage in a fin array. Heat transfer results acquired from the wavy and flat fin channels are compared. Impacts of Reynolds number (Re) and the undulant surface on heat transfer distributions over the wavy fin surface in the Re range of 500-11000 are examined. The spatially averaged Nusselt numbers ( Nu ) over the flat and wavy fin surfaces are analyzed with the empirical Nu correlations derived. Within the Re range tested, the lack of traversing flow momentum over the undulant fin surface prohibits the overall heat transfer elevations from the flat fin levels. Increments of cooling power available from the wavy fin surface due to the surface enlargement only develop at the test conditions of Re>6000 for the present test configuration.

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Section: Program and Data Processingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Forced Heat Convection of Wavy Fin Channel

Yang

Chiang

Chang

et al. 2008

JTST

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“…Chang, Liou and Lu [6] studied heat transfer enhancement in narrow rectangular channel with two opposite rib-roughened walls. The work was extended to observe the effect for skewed ribs [7]. Esmaili, Ranjbar and Porkhail [8] conducted experimental analysis on heat transfer in ribbed microchannels.…”

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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Heat transfer of rectangular narrow channel with two opposite scale-roughened walls

Chang

Liou

2005

International Journal of Heat and Mass Transfer

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Heat transfer in a twin-blow narrow channel with two opposite walls roughened by skewed ribs arranged in staggered manner

Cited by 5 publications

References 11 publications

Forced Heat Convection of Wavy Fin Channel

Forced Heat Convection of Wavy Fin Channel

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

Heat transfer of rectangular narrow channel with two opposite scale-roughened walls

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