Correlations for solar air heater duct with V-shaped perforated baffles as roughness elements on absorber plate |
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Authors: | Sunil Chamoli N.S. Thakur |
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Affiliation: | Centre for Energy and Environment, National Institute of Technology, Hamirpur 177005, India |
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Abstract: | An experimental investigation has been carried out to study the effect of heat transfer and friction characteristics of air passing through a rectangular duct which is roughened by V-down perforated baffles. The experiment encompassed Reynolds number (Re) from 3800 to 19,000, relative roughness height (e/H) values of 0.285–0.6, relative roughness pitch (P/e) range of 1–4 and open area ratio values from 12% to 44%. The effect of roughness parameters on Nusselt number (Nu) and friction factor (f) has been determined and increase in heat transfer and friction loss has been observed for ducts having a roughened test plate. Maximum Nusselt number is observed for the relative roughness pitch ranging from 1.5 to 3 for flow and geometrical parameters under consideration. The experimental data have been used to develop Nusselt number and friction factor correlations as a function of roughness and flow parameters. |
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Keywords: | perforated baffles V-down open area ratio Nusselt number friction factor |
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