Analysis of the effect of variation in open area ratio in perforated multi-V rib roughened single pass solar air heater- Part A

The effect of variation in open area ratio (beta) in multi-V rib roughened single pass solar air heater (SPSAH) is computed in this study. Different perforated plastic ribs are used to develop variations in perforation. Four values of the open area ratio (beta) ranged from 0 to 0.31, six values of relative roughness width (W/w) ranged from 2 to 10, and nine values of the Reynolds number (Re) ranged from 2000 to 18,000. These values were under consideration, along with fixed values of other parameters. Optimum values of performance parameters achieved at an open area ratio beta = 0.27 with W/w = 6. The optimum range of improvement in Nusselt number ratio (Nu/Nus) and thermo-hydraulic performance parameter (THPP) was 6.33-8.19 and 3.78-5.41, while duct friction ratio (f/fs) was recorded within the range of 3.68-4.78 when compared to the flat channel, respectively. A correlation for Nusselt number and friction factor with varying parameters was also established with +/- 12% and +/- 7.5% accuracy, respectively.