Analysis of heat transfer augmentation and flow characteristics due to rib roughness over absorber plate of a solar air heater

Chaube, Alok; Sahoo, Prasanta Kumar; Solanki, S.C.

doi:10.1016/j.renene.2005.01.012

Cited by 217 publications

(73 citation statements)

References 7 publications

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“…For transverse ribs, growth in the friction factor is almost twice the increase in heat transfer. The best performance was recorded for ribs with rectangular section in the range of the studied parameters [11,19,26]. Another important criterion, which has not been investigated enough, is that the rib height should not a ect the ow out of the laminar sublayer [6,19].…”

Section: E Ect Of the Cross Section Of The Roughnessmentioning

confidence: 99%

“…The choice of a two-dimensional geometry is based on the results of a numerical analysis by Chaube [19], who conducted two 2D and 3D analyses and compared the results with the experimental results of Karwa [11]. 3D analysis was performed with 1,203 million cells and the 2D one was carried out with 113, 006 cells.…”

Section: Geometry Descriptionmentioning

confidence: 99%

“…Studies using CFD techniques were fewer in the last decade [19,20], but their number is in constant growth because of the computer technology development and several numerical codes available [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

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Comparative Study of the Effect of Two Type of Ribs on Thermal Performance of Solar Air Heaters

2017

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Abstract. This paper aims to analyze uid ow characteristics and heat transfer augmentation in the air duct of a solar air heater using CFD techniques. The air duct has a rectangular section, the top wall is the glazing and the bottom one is the absorber provided with transverse rectangular or squared ribs. The simulations are performed in the turbulent regime and RANS formulation is used to model the ow and resolve mass, momentum, and energy equations using Finite Volumes method. The air ow analysis shows that the velocity pro le is not disturbed by the ribs outside the laminar sublayer. Heat transfer analysis based on the calculation of Nusselt Number, friction factor, and thermo-hydraulic performance highlights the heat transfer enhancement and no big friction losses are recorded. A comparative study between two rib shapes (square and rectangular) is performed, which shows better thermohydraulic performance of the rectangular ribs.

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Section: E Ect Of the Cross Section Of The Roughnessmentioning

confidence: 99%

Section: Geometry Descriptionmentioning

confidence: 99%

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Comparative Study of the Effect of Two Type of Ribs on Thermal Performance of Solar Air Heaters

2017

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“…These equations for incompressible streams can be written as follows. [24][25][26][27][28][29][30] :…”

Section: Governing Equationsmentioning

confidence: 99%

“…A critical review of literatures on rib roughened air duct reveals that very few studies are used CFD. 6,[24][25][26][27][28][29][30] To the best of our knowledge, no such type of CFD study has been reported on an artificially roughened air duct with V-shaped ribs combined with dimple ribs. The purpose of this work was to investigate fluid flow and heat transfer characteristics of a three-dimensional rectangular duct of an air duct with V with dimpled ribs by adopting the CFD approach.…”

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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Optimizing of heat transfer and flow characteristics within a roughened solar air heater duct with compound turbulators

Al‐Chlaihawi,

Alyas,

Abdullah

2024

Asia-Pacific J Chem Eng

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Thermal systems for solar air heating have been widely used in both industrial and residential contexts, and are essential for converting and recovering solar energy. Thermal performance in solar air heaters (SAHs) can be improved through the repetitive application of artificial roughness to the surfaces. This research work includes a numerical evaluation of SAH performance with artificial rough surfaces made up of combined transverse trapezoidal ribs and chamfered grooves. The ANSYS Fluent software version 2023 R1 was used to simulate SAH with varying relative roughness pitch (), relative roughness heights (), and Reynolds number (). The RNG model was chosen to forecast an enhancement in Nusselt number (), friction factor (), and thermohydraulic performance factor (TPF) for the proposed roughness. Out of multiple roughness parameters analyzed, it was determined that the compound turbulator with and , were the most effective. The TPF for this scenario was determined to be 2.12 at . Finally, a numerical based empirical correlations for and in terms of Re, , and were developed.

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Analysis of heat transfer augmentation and flow characteristics due to rib roughness over absorber plate of a solar air heater

Cited by 217 publications

References 7 publications

Comparative Study of the Effect of Two Type of Ribs on Thermal Performance of Solar Air Heaters

Comparative Study of the Effect of Two Type of Ribs on Thermal Performance of Solar Air Heaters

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

Optimizing of heat transfer and flow characteristics within a roughened solar air heater duct with compound turbulators

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