Numerical analysis of roughened solar air heater with arc and fan shape roughness to understand heat transfer and fluid flow characteristics

Abstract

The computational model of rectangular solar air heater is analyzed by using computational fluid dynamics (CFD). In this work, we investigate the heat transfer, friction factor, and fluid flow characteristics in the SAH channel with mounted fan and arc shape roughness along the total length (L = 1200 mm), and these results are carried out from the RNG k-ɛ model for flowing fluid with 3000 ≤ Re ≤ 21,000. The combination of fan and arc shape roughness are mounted on SAH channel to improve heat transfer rate with parameters radius of fan shape Rf = 8.5 mm, the radius of arc shape roughness Ra = 14 mm, Gaps between fan and arc shape roughness G = 1.5, 3, 4.5 and 6 mm, angle of combine shape roughness ϕ = 115°, 120°, and 125°. The relative gaps and angle parameters are discussed for heat transfer, friction factor, the thermal-hydraulic performance of the SAH channel. The maximum thermal performance factor of 2.869946 and also an increase of 4.842202696 times heat transfer rate as compared to the smooth channel has been observed.