Heat transfer and friction in an asymmetrically heated rectangular duct with half and fully perforated baffles at different pitches

Karwa, Rajendra; Maheshwari, B. K.

doi:10.1016/j.icheatmasstransfer.2008.11.005

Cited by 125 publications

(48 citation statements)

References 4 publications

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“…Tall height tabulators, such as baffles, are generally used for increasing heat transfer rates due to the turbulence in the flow field. Typical shapes of baffles are transverse, angled shaped, V-shaped, perforated, and have multiple blockages that can be fitted and bent away from the heated wall to produce turbulence in the flow field that results in an improvement of Nu ave [6][7][8][9][10][11][12]. Furthermore, these baffles are modified to improve the thermo-hydraulic performance.…”

Section: Introductionmentioning

confidence: 99%

“…They showed that the blockage-grooved with an upper wall at e/H = 0.5 yielded the highest overall performance. Furthermore, Karwa and Maheshwari [11] performed an experimental study on the thermo-hydraulic performance for half and fully perforated blockage with Re values ranging from 2700 to 11,150. They reported that half-perforated blockage with P/e of 7.2 showed the maximum performance that is approximately 68.66% higher than the smooth wall with the same pumping power.…”

Section: Introductionmentioning

confidence: 99%

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Thermal Hydraulic Performance in a Solar Air Heater Channel with Multi V-Type Perforated Baffles

Kumar

Kim

2016

Energies

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This article presents heat transfer and fluid flow characteristics in a solar air heater (SAH) channel with multi V-type perforated baffles. The flow passage has an aspect ratio of 10. The relative baffle height, relative pitch, relative baffle hole position, flow attack angle, and baffle open area ratio are 0.6, 8.0, 0.42, 60˝, and 12%, respectively. The Reynolds numbers considered in the study was in the range of 3000-10,000. The re-normalization group (RNG) k-ε turbulence model has been used for numerical analysis, and the optimum relative baffle width has been investigated considering relative baffle widths of 1.0-7.0.The numerical results are in good agreement with the experimental data for the range considered in the study. Multi V-type perforated baffles are shown to have better thermal performance as compared to other baffle shapes in a rectangular passage. The overall thermal hydraulic performance shows the maximum value at the relative baffle width of 5.0.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermal Hydraulic Performance in a Solar Air Heater Channel with Multi V-Type Perforated Baffles

Kumar

Kim

2016

Energies

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“…It therefore attained utmost at an angle of attack of about 60°. In order to elaborate the effect of angle of attack on h = (Nu b =Nu s )=(f b =f s ) 0:33 , Figure 11 has been replotted as Figure 10 The data of h = (Nu b =Nu s )=(f b =f s ) 0:33 determined for the shape of discrete V-pattern baffle have been compared with the data determined for angled baffle, 13 continuous V-pattern baffle, 15 perforated baffle, 22 transverse perforated baffle, 25 delta shaped baffle 27 and V-pattern perforated baffle. 35 It can be observed that from Figure 12.…”

Section: Thermohydraulic Performancementioning

confidence: 99%

Experimental investigation of effect of flow attack angle on thermohydraulic performance of air flow in a rectangular channel with discrete V-pattern baffle on the heated plate

Kumar

Chauhan

Sethi

et al. 2016

Advances in Mechanical Engineering

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In this work, the effect of angle of attack (a a ) of the discrete V-pattern baffle on thermohydraulic performance of rectangular channel has been studied experimentally. The baffle wall was constantly heated and the other three walls of the channel were kept insulated. The experimentations were conducted to collect the data on Nusselt number (Nu b ) and friction factor (f b ) by varying the Reynolds number (Re) = 3000-21,000 and angle of attack (a a ) from 30°to 70°, for the kept values of relative baffle height (H b =H) = 0:50, relative pitch ratio (P b =H) = 1:0, relative discrete width (g w =H b ) = 1:5 and relative discrete distance (D d =L v ) = 0:67. As compared to the smooth wall, the V-pattern baffle roughened channel enhances the Nusselt number (Nu b ) and friction factor (f b ) by 4.2 and 5.9 times, respectively. The present discrete V-pattern baffle shapes with angle of attack (a a ) of 60°equivalent to flow Reynolds number of 3000 yields the greatest thermohydraulic performance. Discrete V-pattern baffle has improved thermal performance as compared to other baffle shapes' rectangular channel.

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“…This leads to a high operating temperature of the collector, especially the absorber plate, resulting in greater heat loss from the collector. Hence, the researchers have directed their efforts towards enhancement of heat transfer coefficient by creating turbulence near the heat transferring surface using artificial roughness in various forms, such as solid roughness elements of various shapes and in different arrangements and perforated or detached roughness elements [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

“…The detached elements or elements with perforations allow a part of the flow to pass through the perforations or gap, and thus, the adverse effects of the hot zone and form drag are reduced [12][13][14][15][16][17][18]. Hwang and Liou in [14] studied the effect of the half-perforated turbulence promoters symmetrically mounted on two opposite walls on the heat transfer and friction in a rectangular channel.…”

Section: Introductionmentioning

confidence: 99%

Performance Study of Solar Air Heater Having Absorber Plate with Half-Perforated Baffles

Maheshwari

Karwa

Gharai

2011

ISRN Renewable Energy

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The paper presents a detailed mathematical model for performance prediction of a smooth duct solar air heater validated against the experimental results. Experimental study on a solar air heater having absorber plate with half-perforated baffles on the air flow side shows thermal efficiency enhancement of 28%-45% over that of the smooth duct solar air heater, which is attributed to the heat transfer enhancement (of the order of 180%-235%) due to the perforated baffles attached to the absorber plate and reduction in the mean temperature of the absorber plate by 20• C-25• C as compared to the temperature of absorber plate of smooth duct air heater. Using the mathematical model, the performance plot for the baffled duct air heater has been presented, and the effect of the variation of ambient parameters on the predicted thermal efficiency has been studied.

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Heat transfer and friction in an asymmetrically heated rectangular duct with half and fully perforated baffles at different pitches

Cited by 125 publications

References 4 publications

Thermal Hydraulic Performance in a Solar Air Heater Channel with Multi V-Type Perforated Baffles

Thermal Hydraulic Performance in a Solar Air Heater Channel with Multi V-Type Perforated Baffles

Experimental investigation of effect of flow attack angle on thermohydraulic performance of air flow in a rectangular channel with discrete V-pattern baffle on the heated plate

Performance Study of Solar Air Heater Having Absorber Plate with Half-Perforated Baffles

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