Experimental and numerical investigation of turbulent heat transfer in a channel with periodically arranged rib roughness elements

Braun, H.; Neumann, H. E.; Mitra, N. K.

doi:10.1016/s0894-1777(99)00015-1

Cited by 13 publications

(6 citation statements)

References 16 publications

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“…Simulations of turbulent heat transfer and flow through a channel with attached-rib arrays (c/a = 0.0) and detached-rib arrays (c/a = 0.1, 0.2, 0.3, and 0.4) using the shear stress transport k-ω (SST k-ω) turbulence model and the Renormalized Group (RNG) k-ε turbulence model, are presented and validated with measurement data [3]. The results of these computations for different clearance ratios (c/a) are shown in Figs.…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

“…Therefore, selecting the turbulence model, to accommodate the flow behavior of each application, is very important. To attain an accurate aerodynamic prediction in the channel with attached-rib arrays, the predictive reliability of two different turbulence models, including, the RNG k-ε turbulence model and the SST k-ω turbulence model, are evaluated by comparing the predicted local Nusselt number with those reported previously [3], under similar conditions. More details of the models can be found elsewhere [25].…”

Section: Mathematical Formulationmentioning

confidence: 99%

“…The distributions of axial local Nusselt number of attached-rib (c/a = 0.0) predicted by the SST k-ω turbulence model and the RNG k-ε turbulence model are compared with the measured data of Braun et al [3] in Fig. 2.…”

Section: Effect Of Turbulence Modelsmentioning

confidence: 99%

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Numerical investigation of turbulent heat transfer in channels with detached rib‐arrays

Changcharoen

Eiamsa-ard

2011

Heat Trans. Asian Res.

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A numerical investigation is conducted to analyze the flow-field and heat transfer characteristics in a rectangular passage of width-to-height ratio of 6:1 with detached ribs on one wall, where constant wall temperature condition is applied. The effect of detached-rib geometry on heat transfer coefficient, friction factor, and thermal enhancement factor is investigated covering the range of the detached-clearance ratios (c/a) of 0.1, 0.2, 0.3, and 0.4, the Reynolds number based on the channel hydraulic diameter ranges from 8000 to 24,000. The numerical results show that the flow-field, temperature pattern, local Nusselt number distribution, average Nusselt number, and friction factor are strongly dependent on the detached-clearance ratios. The thermal enhancement factor (TEF) under the same pumping power constraint is calculated in order to examine the overall effect of the detached-clearance ratio. For the present range investigated, the maximum TEF of 1.22 is achieved by the use of the ribs with c/a of 0.1 at Reynolds number of 8000.

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Section: Numerical Results and Discussionmentioning

confidence: 99%

Section: Mathematical Formulationmentioning

confidence: 99%

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Numerical investigation of turbulent heat transfer in channels with detached rib‐arrays

Changcharoen

Eiamsa-ard

2011

Heat Trans. Asian Res.

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“…Han et al [3] showed that ribs at a 45°angle of attack increased heat transfer performance at a given friction power compared to ribs at a 90°angle of attack. Braun et al [6] experimentally and numerically studied turbulent heat transfer in a channel with periodically arranged rib roughness elements. Han and Zhang [5] found that a 60°p arallel broken rib or a 60°V-shaped broken rib provides a higher heat transfer augmentation than a 45°parallel broken rib or a 45°V-shaped broken rib and it is higher than that produced by 90°broken ribs as well.…”

Section: Introductionmentioning

confidence: 99%

Computational study on effects of rib height and thickness on heat transfer enhancement in a rib roughened square channel

Shukla

Dewan

2016

Sādhanā

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A computational study was carried out for the heat transfer augmentation in a three-dimensional square channel fitted with different types of ribs. The standard k-e model and its two variants (RNG and realizable) were used for turbulence modeling. The predictions were compared with available experimental and computational results. Three rib configurations were used in the present study: 90°continuous attached ribs, 60°V -shaped broken attached thick and thin ribs. It was observed that the maximum heat transfer occurs at the normalized rib spacing (p/e) = 10 in the case of 90°attached ribs. The effects of the blockage ratio and rib thickness were investigated for 60°V-shaped broken ribs with Re = 10,000-30,000 and p/e = 10. It was observed that the average Nusselt number decreases with an increase in the Reynolds number for almost all configurations studied in the present study. For the 60°V-shaped broken ribs, increasing the blockage ratio had an adverse effect on the heat transfer. It was also observed that thin ribs perform better than thick ribs.

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“…Effects of the Reynolds number, relative roughness height, relative roughness pitch, and rib chamfer angle, on the heat transfer were described. Braun et al [5] studied the local heat transfer coefficients on the rib-roughened wall of a channel with turbulent flow numerically and experimentally using large eddy simulation (LES) and ammonia absorption technique, respectively. In spite of different in the experimental condition (non-periodic flow) and numerical condition (periodic flow), both experimental and numerical results were in good agreement.…”

Section: Introductionmentioning

confidence: 99%

Analysis of turbulent heat transfer and fluid flow in channels with various ribbed internal surfaces

Eiamsa-ard

Changcharoen

2011

J. Therm. Sci.

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This paper presents results of a numerical investigation of heat transfer and flow pattern characteristics of a channel with repeated ribs on one broad wall. Numerical computations are performed for seven ribs placed on the bottom wall of a channel for Reynolds numbers ranging from 10,000 to 30,000. The newly modified ribs (the ones with convex pointing upstream/downstream rib, wedge pointing upstream/downstream rib, concave pointing upstream/downstream rib and also concave-concave rib as well as convex-concave rib), are proposed for simulation with prospect to reduce flow separation and extend reattachment area compared to the unmodified square rib.The numerical results are reported in forms of flow structure, temperature field, turbulent kinetic energy, Nusselt number, friction factor and thermal enhancement factor. The results indicate the rib with concave-concave surfaces efficiently suppresses flow separation bubble in the corner of the rib and induces large recirculation zone over those of the others, hence giving the highest Nusselt number and friction factor. On the other hand, the one with convex-concave surface provides the lowest friction factor with moderate Nusselt number. Due to the prominent effect of its low friction factor, the rib with convex-concave surface offers the highest thermal enhancement factor of 1.19.

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Experimental and numerical investigation of turbulent heat transfer in a channel with periodically arranged rib roughness elements

Cited by 13 publications

References 16 publications

Numerical investigation of turbulent heat transfer in channels with detached rib‐arrays

Numerical investigation of turbulent heat transfer in channels with detached rib‐arrays

Computational study on effects of rib height and thickness on heat transfer enhancement in a rib roughened square channel

Analysis of turbulent heat transfer and fluid flow in channels with various ribbed internal surfaces

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