Augmentation of solar air heater effectiveness with flapped triangular-wings

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dc.contributor.authorPromvonge, Pongjet
dc.contributor.authorSripattanapipat, Somchai
dc.contributor.authorJayranaiwachira, Nuthvipa
dc.contributor.authorNakhchi, Mahdi Erfanian
dc.contributor.authorSkullong, Sompol
dc.date.accessioned2026-08-06T10:53:10Z
dc.date.available2026-08-06T10:53:10Z
dc.date.issued2025-12-01
dc.description.abstractAn experiment was conducted to identify the optimal method for enhancing the thermal effectiveness of a solar air heater duct utilizing flapped triangular-wing (FTW) vortex generators affixed to the absorber. The wings are structured in two configurations: backward FTW (B-FTW) and forward FTW (F-FTW), each incorporating a louver-flapped opening for lowering frictional loss. This study seeks to improve the Nusselt number ratio (Nu<inf>R</inf>) while lowering friction loss to optimize thermal effectiveness, hence minimizing the overall dimensions of thermal energy systems. The research findings focus on heat transmission (Nu) and frictional loss (f), encompassing thermal effectiveness across the entire range of Reynolds numbers (Re) from 5280 to 22,510. The FTW elements are configured in B-FTW and F-FTW forms, employing three relative pitches (P<inf>R</inf> = 0.75, 1.25, and 1.75) and five flap angles (θ = 0°, 35°, 45°, 65°, and 90°), while maintaining a constant attack angle (α = 45°) and a wing height ratio (B<inf>R</inf> = 1). The research findings demonstrate that the FTWs produce a significant increase in Nu contrasted to the smooth duct, which varies from 4.72 to 8.05 times, while the increase in f is approximately 13 to 68.1 times. For P<inf>R</inf> = 1.25, θ = 45°, and lower Re, the greatest thermal effectiveness factor (TEF) is roughly 2.87 for the F-FTW and 2.64 for the B-FTW, while Nu<inf>R</inf> is approximately 6.98 for the F-FTW and 6.29 for the B-FTW. This implies that the largest TEF is exclusively associated with the F-FTW, and therefore, the B-FTW should be averted in practice. Additionally, correlations are established and documented for the key quantities (Nu, f, and TEF).
dc.identifier.citationInternational Journal of Heat and Mass Transfer, 252, 2025
dc.identifier.doi10.1016/j.ijheatmasstransfer.2025.127436
dc.identifier.issn00179310
dc.identifier.other2-s2.0-105009272682
dc.identifier.urihttps://dspace.kmitl.ac.th/handle/123456789/17486
dc.sourceInternational Journal of Heat and Mass Transfer
dc.subjectHeat transfer
dc.subjectSolar air duct
dc.subjectThermal effectiveness
dc.subjectTriangular wing
dc.subjectVortex generator
dc.titleAugmentation of solar air heater effectiveness with flapped triangular-wings
dc.typeArticle

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