Experimental assessment of variation in open area ratio on thermohydraulic performance of parallel flow solar air heater

Abstract

This experimental study explains the phenomena of secondary flow development due to change in rib perforation and the effect on improvement in THPP values due to variation in β and W/w values of a perforated multi-V rib roughness applied in double-pass parallel flow solar air heater (DPPFSAH). The fixed parameters are e/D = 0.043, p/e = 10, α = 60° and W/H = 12, and the range of variable parameters includes β = 0.0–0.31, W/w = 2–10 and Re = 2000–18,000. The optimum values of Nu/Nus, f/fs, THPP and TEIF are observed as 9.66, 12.31, 3.96 and 1.33, respectively, at β = 0.27 and W/w = 6. The maximum improvement in THPP values was 3.96 times and 1.90 times in DPPFSAH with perforation and continuous rib with a smooth plate, respectively. Double-pass SAH outperforms the single-pass SAH. Correlations for Nu and f are also developed for DPPFSAH with ± 14% and ± 7% accuracy.