Flowfield Investigation of the Effect of Rib Open Area Ratio in a Rectangular Duct

Liou, Tong‐Miin; Kao, Chih-Wen; Chen, Shih-Hui

doi:10.1115/1.2820691

Cited by 10 publications

(3 citation statements)

References 15 publications

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“…The results also showed that slit ribs with larger void fractions in a lower flow Reynolds number range provide better thermal performance under a constant friction power constraint. Liou et al [14] focused on the flow characteristics in a channel containing perforated ribs. The fixed parameters were rib height to duct hydraulic diameter ratio of 0.106, rib width to height ratio of 0.76, rib pitch to height ratio of 10 and Reynolds number of 20,000, while the main parameter investigated was the rib open-area ratio with values of 0, 10, 22, 38 and 44 percent.…”

Section: Nomenclaturementioning

confidence: 99%

Heat Transfer Enhancement in a Rectangular Duct With Perforated Ribs on One Principal Wall

El-Shamy

2001

International Conference on Aerospace Sciences and Aviation Tec

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Experiments were carried out to investigate the thermal performance of a rectangular duct with permeable ribs mounted on one of the principal walls. A horizontal rectangular duct with an aspect ratio (width/height) of 4:1 was examined. Multiple permeable ribs were attached to the bottom base surface of the channel. Constant heat flux was the boundary condition for the ribbed wall. The perforated ribs were placed periodically and transversely to the stream wise direction. The parameters investigated in the present work are rib open-area ratio (0, 10 and 20 percent), rib pitch to height ratio (5, 10 and 20) and Reynolds number ranged from 15,000 to 75,000. It was found that the perforated ribs provide a substantially lower drag force in comparison with the solid type ribs and still provide enhanced heat transfer coefficient in comparison with the smooth wall duct. The results indicated that the perforated ribs with open-area ratio of 20% in a lower flow Reynolds number range provide better thermal performance under a constant power constraint. New correlations were obtained for the effects of rib pitch to height ratio, rib open-area ratio and Reynolds number on both the heat transfer and friction similarity factors.

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Section: Nomenclaturementioning

confidence: 99%

Heat Transfer Enhancement in a Rectangular Duct With Perforated Ribs on One Principal Wall

El-Shamy

2001

International Conference on Aerospace Sciences and Aviation Tec

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“…Comparing both studies, no Reynolds number dependency of reattachment distance was found. The flow in a straight, rectangular channel with ribs on the two opposite walls was investigated by Liou et al [5,6], and the flow in a rectangular channel with a 180-degree bend was investigated by Schabacker et al [7] and Servouze et al [8]. Iacovides et al [9] conducted a Laser Doppler Anemometry (LDA) investigation of the flow at a Reynolds number of 100,000 in a ribbed channel with a 180-degree turn.…”

Section: Introductionmentioning

confidence: 99%

Computational Investigation of Flow and Heat Transfer in a Rectangular Duct with Ribs Mounted in a Staggered Arrangement

Alhajeri¹

2012

IJTEE

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Fluid Flow and heat transfer results are presented from a ribbed U-tube, which models passages used to cool the blades in gas turbine engines. Computational fluid dynamics is used here to predict the air flow behavior and the surface Nusselt number distributions. The model of the coolant passage consists of two square legs that are connected by a sharp, 180-degree bend with a rectangular outer wall. Four ribs are placed in each side of the leg and mounted in a staggered arrangement. The height and width of the rib are equal to 0.1 duct width, and the rib spacing is 10 times the rib height. Based on inlet flow conditions, the Reynolds number (Re) is 95000. It was found that, after the flow resettles from the disturbances created by the obstacle of the first rib or the effect of the bend, the flow forms two re-circulations, a large one behind the rib and a small one ahead of the rib. The maximum values of the Nusselt numbers are located at a distance of almost one rib height h ahead of the flow reattachment point.

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“…The perforated roughness geometry will yield desired heat transfer augmentation with a minimum friction factor. The effect of the perforated ribs on the heat transfer and friction factor have been studied by several investigators [8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Heat Transfer Enhancement With a Single Inclined Perforated Obstacle in a Rectangular Channel

Afify

2003

International Conference on Aerospace Sciences and Aviation Tec

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Measurements were carried out to investigate the enhancemen and the influence of flow friction in a rectangular channel usi perforated obstacle (baffle) affixed on the bottom surface whit uniform heat flux. A horizontal rectangular channel with an aspe of 1:5 was examined. The obstacle was attached to the heated aligned in the favorable direction of the flow. Both solid (wit perforated obstacles were used. The effects of perforation, obs between obstacle and upper surface were studied. The ope 0.023, 0.038, 0.115, and 0.167 were investigated and Reynolds 15000 to 45000. The experiments covered a range of obsta height ratio (UH) from 2.0 to 6.0, and gap to channel height r 0.7. Inclined perforated obstacle combines three major heat tra boundary layer separation, internal flow swirls, and jet impi showed that the maximum heat transfer enhancement and frict 3.7 and 11.0 times more than that smooth channel, respectivel were achieved using obstacle with (3 = 0.023, UH = 2.0, and B/ efficiency index was found for the obstacle with 13 = 0.167, L/H where, a maximum efficiency index of about 1.6 was found. N obtained for the influence of the parameters on both Nusselt and flow friction factor ratios.

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Flowfield Investigation of the Effect of Rib Open Area Ratio in a Rectangular Duct

Cited by 10 publications

References 15 publications

Heat Transfer Enhancement in a Rectangular Duct With Perforated Ribs on One Principal Wall

Heat Transfer Enhancement in a Rectangular Duct With Perforated Ribs on One Principal Wall

Computational Investigation of Flow and Heat Transfer in a Rectangular Duct with Ribs Mounted in a Staggered Arrangement

Experimental Study of Heat Transfer Enhancement With a Single Inclined Perforated Obstacle in a Rectangular Channel

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