Effect of roughness width ratios in discrete multi V-rib with staggered rib roughness on overall thermal performance of solar air channel

This work presents the outcomes of a computational fluid dynamics (CFD) analysis of thermal-fluid flow characteristics in solar air channel having discrete multi V-rib with staggered rib roughness. Four different turbulence models (RNG k-epsilon model, realizable k-epsilon model, standard k-epsilon model and SST k-omega model) were tested for smooth solar air channel. The RNG k-epsilon model was finally selected as the most suitable one. The effect of relative width ratios of discrete multi V-rib with staggered rib shape on the average Nusselt number, average friction factor and overall thermal performance have been studied. The average Nusselt number has the maximum value in the discrete multi V-rib with staggered rib shape for a relative width ratio of 6.0. The heat transfer enhancement parameter shows also the highest value for the relative width ratio of 6.0 and the lowest value for the relative with ratio of 1.0. The present study shows that the overall thermal performance of discrete multi V-rib with staggered rib shape is around 6% higher as compared to other rib shapes. (C) 2015 Elsevier Ltd. All rights reserved.