Impact of Angle of Attack and Relative width of V-Shaped Ribs on the Thermo-Hydraulic Performance of a Solar Air Heater

Document Type : Research Article

Authors

1 Department of Chemical Engineering, Amirkabir University of Technology, Tehran, Iran.

2 Department of Chemical Engineering, Amirkabir University of Technology, Tehran, Iran

Abstract

Solar air heaters offer a low-cost way to convert solar energy into usable heat, but their efficiency is limited by the inherently low heat transfer coefficient of air. To address this limitation, artificial roughness elements such as V-shaped ribs are commonly added to the absorber plate to boost turbulent mixing and improve thermal performance. This study numerically investigates the thermo-hydraulic characteristics of a solar air heater duct equipped with V-shaped ribs by analyzing the combined effects of angle of attack and relative rib width using computational fluid dynamics. The results demonstrate that both thermal performance and flow characteristics are influenced by rib geometry. The Nusselt number reaches its maximum enhancement of 2.8 times that of a smooth duct when using a single V-rib with a relative width of 1 and a 30° angle of attack. However, reducing the relative width results in progressively diminished heat transfer effectiveness. The thermo-hydraulic performance parameter peaks at 1.63 for the optimal relative width of 1 at a 30° angle of attack, indicating the most favorable ratio of Nusselt number enhancement to friction factor increase. These results offer essential guidance for optimizing roughened solar air heater designs, suggesting that a single, properly oriented V-rib offers the most favorable compromise between thermal enhancement and energy efficiency.

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References

[1] R. Chauhan, N.S. Thakur, Investigation of the thermohydraulic performance of impinging jet solar air heater, Energy, 68 (2014) 255-261.
[2] S. Yadav, R.P. Saini, Numerical investigation on the performance of a solar air heater using jet impingement with absorber plate, Solar Energy, 208 (2020) 236-248.
[3] S. Yadav, R.P. Saini, K.M. Pandey, Effect of jet angle and jet pitch on the Thermo-Hydraulic performance of solar air heater having absorber plate with jet impingement, Thermal Science and Engineering Progress, 45 (2023) 102146.
[4] L.N. Azadani, N. Gharouni, Multi objective optimization of cylindrical shape roughness parameters in a solar air heater, Renewable Energy, 179 (2021) 1156-1168.
[5] H. Singh, C. Kishore, S. Chamoli, A. Joshi, Enhancing heat transfer in rectangular solar air heater channels: a numerical exploration of multiple Boomerang-shaped roughness elements with variable gaps, Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 46(1) (2024) 6696-6712.
[6] S.L. Sharma, K. Kishor, V.S. Bisht, A. Debbarma, A. Gaur, CFD analysis of artificially roughened solar air heater: a comparative study of C-Shape, reverse C-Shape, and reverse R-Shape roughness element, International Journal of Ambient Energy, 45(1) (2024) 2331240.
[7] A. Taghavi, A.H. Aghdam, Thermo-hydrodynamic analysis of various curved solar air-heaters with boot-shaped ribs: CFD simulations coupled with an optimized Artificial Neural Network model, Applied Thermal Engineering, 267 (2025) 125750.
[8] A.M.E Momin, J.S. Saini, S.C. Solanki, Heat transfer and friction in solar air heater duct with V-shaped rib roughness on absorber plate, International Journal of Heat and Mass Transfer, 45(16) (2002) 3383–3396.
[9] A. Lanjewar, J.L. Bhagoria, R.M. Sarviya, Heat transfer and friction in solar air heater duct with W-shaped rib roughness on absorber plate, Energy, 36(7) (2011) 4531-4541.
[10] A. Lanjewar, J.L. Bhagoria, R.M. Sarviya, Experimental study of augmented heat transfer and friction in solar air heater with different orientations of W-Rib roughness, Experimental Thermal and Fluid Science, 35(6) (2011) 986-995.
[11] A. Sharma, V. Goel, P. Kumar, G. Bharadwaj, Heat transfer and friction characteristics of double pass solar air heater having V-shaped roughness on the absorber plate, Journal of Renewable and Sustainable Energy, 5(2) (2013) 023109.
[12] D. Jin, M. Zhang, P. Wang, S. Xu, Numerical investigation of heat transfer and fluid flow in a solar air heater duct with multi V-shaped ribs on the absorber plate, Energy, 89 (2015) 178-190.
[13] D. Jin, S. Quan, J. Zuo, S. Xu, Numerical investigation of heat transfer enhancement in a solar air heater roughened by multiple V-shaped ribs, Renewable Energy, 134 (2019) 78-88.
[14] M. Sharma, M. Bhargva, CFD based performance analysis of solar air heater provided with artificial roughness in the form of V – Shaped ribs, Materials Today: Proceedings, 63 (2022) 595-601.
[15] O. Nouri Kadijani, H. Kazemi Moghadam, S. Mousavi Ajarostaghi, A. Asadi, M. Saffari Pour, Hydrothermal performance of humid air flow in a rectangular solar air heater equipped with V‐shaped ribs, Energy Science & Engineering, 10 (2022) 2276-2289.
[16] N. Salarpour, L.N. Azadani, Optimization and evaluation of thermo-hydraulic performance of solar air heaters equipped with different roughness geometries, Case Studies in Thermal Engineering, 61 (2024) 105037.
[17] H. Pachori, T. Choudhary, T. Sheorey, A. Kumar Shukla, V. Verma, A novel energy, exergy and sustainability analysis of a decentralized solar air heater integrated with V-shaped artificial roughness for solar thermal application, Sustainable Energy Technologies and Assessments, 66 (2024) 103816.
[18] S.G. Noureini, L.N. Azadani, Thermal performance enhancement of a solar air heater with different roughness layouts, Case Studies in Thermal Engineering, 74 (2025) 106776.
[19] R. Kumar, A. Kumar, R. Chauhan, M. Sethi, Heat transfer enhancement in solar air channel with broken multiple V-type baffle, Case Studies in Thermal Engineering, 8 (2016) 187-197.
[20] R. Kumar, R. Chauhan, M. Sethi, A. Kumar, Experimental study and correlation development for Nusselt number and friction factor for discretized broken V-pattern baffle solar air channel, Experimental Thermal and Fluid Science, 81 (2017) 56-75.
[21] R. Agrawal, R. Prasad, Thermal performance analysis of triangular solar air heater duct having broken V-shaped ribs, International Journal of Ambient Energy, 45(1) (2024) 2260814.
[22] D. Jin, J. Zuo, S. Quan, S. Xu, H. Gao, Thermohydraulic performance of solar air heater with staggered multiple V-shaped ribs on the absorber plate, Energy, 127 (2017) 68-77.
[23] A.K. Hegde, R. Pai, K.V. Karanth, Influence of solar insolation on energy and exergy efficiency of a rectangular duct solar air heater with various types of V rib roughness: An analytical approach, International Communications in Heat and Mass Transfer, 153 (2024) 107397.
[24] D. Wilcox, Turbulence Modeling for CFD (Third Edition), DCW industries, 2006.
[25] A.S. Yadav, J.L. Bhagoria, A CFD (computational fluid dynamics) based heat transfer and fluid flow analysis of a solar air heater provided with circular transverse wire rib roughness on the absorber plate, Energy, 55 (2013) 1127-1142.
[26] ASHRAE, Methods of testing to determine the thermal performance of solar collectors, (2010).
[27] B.R. Munson, T.H. Okiishi, W.W. Huebsch, A. P. Rothmayer, Fundamentals Of Fluid Mechanics 7th Edition, John Wiley and Sons, 2012.
[28] F.W. Dittus, L.M.K. Boelter, Heat transfer in automobile radiators of the tubular type, International Communications in Heat and Mass Transfer, 12 (1) (1985) 3-22.
AUT Journal of Mechanical Engineering
Volume 10, Issue 2
April 2026
Pages 199-210

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