Influences of Pentagonal Ribs on the Performance of Rectangular Solar Air Collector

In the present study, 2-D fluid flow and heat transfer characteristic in a roughened rectangular duct with pentagonal ribs are being numerically investigated. The influences of the Reynolds number, non-dimensional relative height, non-dimensional relative pitch on the thermal performance factor and hydraulic performance factor are discussed. The numerical analysis is carried out using commercial available CFD code ANSYS FLUENT 14.0 finite-volume version to simulate turbulent fluid flow through pentagon roughened solar air collector. The Renormalization-group k-e model is used, and for that forecasted results are nearly very close to the experimental results. The range of parameters that have been used are Reynolds number = 12633-62842 (5 steps), non-dimensional roughness height of e/D = 0.045, 0.066, and 0.084, and non-dimensional roughness pitch of P/e = 6.43, 7.27, and 8. As compared to the smooth duct pentagonal ribs shows better enhancement in terms of thermal performance. The best configuration that has been found is e/D = 0.045 and P/e = 8 for Re = 38414 in which enhancement of the Nusselt number and friction factor by 70% and 67.2% respectively have been done. (C) 2019 The Authors. Published by Elsevier Ltd.