Improved Performance Evaluation of a Solar Air Heater with Staggered Vortex Generators

This study explores the impact of staggered vortex generators on heat transfer enhancement in internal cooling channels, particularly relevant to solar air heaters. Using a ۲D outward flow passage model with staggered ribs, the investigation spanned Reynolds numbers from ۱۰,۰۰۰ to ۳۰,۰۰۰. The ribs were configured with a height-to-hydraulic diameter ratio (e/Dh) of ۰.۵ and a pitch-to-height ratio (p/e) of ۲۰. Computational fluid dynamics (CFD) modeling, validated against the Dittus-Boelter equation, revealed that the Nusselt numbers in ribbed ducts were ۳ to ۴ times higher than in smooth ducts, depending on the Reynolds number. This enhancement is attributed to increased turbulence mixing induced by the rib turbulators. The k-ω turbulence model was found to more accurately capture fine gradients in velocity and temperature fields compared to the k-ε model. The results highlight the potential of staggered vortex generators in optimizing thermal performance across various applications.

کلیدواژه ها:

Solar ، Air Heater ، Vortex generators