Augmentation of heat transfer coefficient by using 90° broken transverse ribs on absorber plate of solar air heater

Sahu, Madhusmita; Bhagoria, J.L.

doi:10.1016/j.renene.2004.10.016

Cited by 224 publications

(57 citation statements)

References 6 publications

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“…For mass flow rate of 0.035 kg/s, it is observed that the air temperature increasing along the air stream dynamics length with a mean of (316.3 K) in the smooth case and with an average of (324.3 K, 329.5 K, 330.7 K and 332.1 K) in the case (without inclined part, 0°, 45° and 60°) with a rise of (2.52%, 4.17%, 4.55% and 4.99%)respectively. This is due to the secondary flow when it is trapped between two chicanes and the main flow where powered with a brewing phenomenon which provokes a heat transfer from the hot flow to the cold one, therefore the chicanes provide a delaying aspect for more and more time to the heat transfer process which is confirmed by Moummi et al [4][5][6][7][8][9][10][11][12][13]. …”

Section: Reynolds Number Effect On the Heat Transfer Coefficientmentioning

confidence: 98%

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The Air Solar Collectors: Introduction of Chicanes to Favour the Heat Transfer and Temperature in the Air Stream Dynamics

Mahfoud

Moummi

2015

MATEC Web of Conferences

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Abstract.The thermal performance of a single pass solar air heater with chicanes attached was investigated numerically using a 2D model of solar air stream dynamics collectors where the turbulence standard − model has been implemented. The chicane is formed with two parts: the first is perpendicular to the air flow and the second part is titled (α), they are mounted in successive rows, oriented perpendicular to the air flow and soldered to the back plate. The predicted results are validated by comparing with the literatures semi-empirical and experimental data and shown a reasonable agreement. Effects of relevant parameters as the (Reynolds number, chicanes upper parts tilts angles and air mass flow rates) on the heat transfer coefficient and temperature development are discussed. It is apparent that the turbulence created by the chicanes resulting in greater increase in heat transfer inside the air stream dynamics.

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Section: Reynolds Number Effect On the Heat Transfer Coefficientmentioning

confidence: 98%

“…General arrangement of different types of roughness geometries reported by various investigators, they studied heat transfer enhancement and friction loss by fixing protruding wires of different shapes, size and orientations as an artificial roughness element on absorber plate as in Sahu and Bhagoria [6], Karmare and Tikekar [7].…”

Section: Introductionmentioning

confidence: 99%

The Air Solar Collectors: Introduction of Chicanes to Favour the Heat Transfer and Temperature in the Air Stream Dynamics

Mahfoud

Moummi

2015

MATEC Web of Conferences

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“…The boundary conditions for the V-shaped ribs combined with dimple ribs are applied as experimental conditions. [7][8][9][10][11][12][13][14][15][16][17][18] Fi g. It is therefore, RNG k-ε model has been employed for the present CFD study. Fig.4 shows the velocity profiles for the V-down shaped ribs combined with dimple ribs with different values of α = 35°-70°, and kept other rib parameters used to roughened an air duct with a fixed value of Re=8000.…”

Section: Governing Equationsmentioning

confidence: 99%

“…[12][13][14][15][16][17][18][19][20][21][22][23] Taslim et al 20) presented the effect of V-shaped rib roughness with variation of relative rib height, relative rib pitch and flow attack angle on heat transfer and friction factor in a flow through SAH duct. They reported that the V-shaped rib showed higher performance compared to the angled rib.…”

Section: Introductionmentioning

confidence: 99%

Numerical study on overall thermal performance in SAH duct with compound roughness of V-shaped ribs and dimples

Kumar¹,

Kim²

2015

Journal of the Korean Solar Energy Society

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: This paper presents the thermal hydraulic performance of a three dimensional rib-roughened solar air heater (SAH) duct with the one principal wall subjected to uniform heat flux. The SAH duct has aspect ratio of 12.0 and the Reynolds number ranges from 2000 to 12000. The roughness has relative rib height of 0.045, ratio of dimple depth to print diameter of 0.5 and rib pitch ratio of 8.0. The flow attack angle is varied from 35°to 70°. Various turbulent flow models are used for the heat transfer and fluid flow analysis and their results are compared with the experimental results for smooth surfaces. The computational fluid dynamics (CFD) results based on the renormalization k-epsilon model are in better outcomes compared with the experimental data. This model is used to calculate heat transfer and fluid flow in SAH duct with the compound roughness of V-shaped ribs and dimples. The overall thermal performance based on equal pumping power is found to be the highest (2.18) for flow attack angle of 55°. The thermo-hydraulic performance for V-pattern shaped ribs combined with dimple ribs is higher than that for dimple rib shape and V-pattern rib shape air duct.

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“…While minimum value of friction factor has been found correspond to relative roughness height (e/Dh) of 0.0289 and relative pitch (p/e) of 10. It is therefore suggested that, roughness parameters of the geometry are to be selected by considering the net heat gain and corresponding power required to force the air through the duct Sahu and Bhagoria [5] have investigated the effect of 90° broken wire ribs on heat transfer coefficient of a solar air heater duct. A pitch of 20 mm gives the highest thermal efficiency of 83.5% for and element height of 1.5 mm and reported heat transfer coefficient of roughened duct is 1.25 to 1.4 times compared to smooth duct under similar operating conditions at higher Reynolds number.…”

Section: Literature Viewmentioning

confidence: 99%

'Enhancement of Heat Transfer Rate and Thermal Efficiency of Solar Air Heater by Using Artificial Roughness'-A Review

B¹

2015

IJIRSET

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ABSTRACT:Heat energy plays most important role in the field of power generation which involves the heat transfer in domestic as well as industrial purposes. Literature shows the heat transfer coefficient between heat transferring surface and air is low which leads to lower thermal efficiency of the system. Therefore it is important to increase heat transfer coefficient between heat transferring surface and air. The most promising technique to enhance heat transfer coefficient is artificial roughness on heat transfer field. Artificial roughness applied on the absorber plate is the most acclaimed method to improve thermal performance of solar air heaters at the cost of low to moderate friction penalty. Experimental investigations pertinent to distinct roughness geometries unfolds that the enhancement in heat transfer is accompanied by considerable rise in pumping power. In view of the fact, a designer needs to carefully examine shape and orientation of roughness elements in order to choose the best fit roughness geometry for intended application. This dissertation work will cover the types of technique used in enhancing the heat transfer coefficient in field of heat transfer and thermal efficiency.

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Augmentation of heat transfer coefficient by using 90° broken transverse ribs on absorber plate of solar air heater

Cited by 224 publications

References 6 publications

The Air Solar Collectors: Introduction of Chicanes to Favour the Heat Transfer and Temperature in the Air Stream Dynamics

The Air Solar Collectors: Introduction of Chicanes to Favour the Heat Transfer and Temperature in the Air Stream Dynamics

Numerical study on overall thermal performance in SAH duct with compound roughness of V-shaped ribs and dimples

'Enhancement of Heat Transfer Rate and Thermal Efficiency of Solar Air Heater by Using Artificial Roughness'-A Review

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