Akademik Veri Yönetim Sistemi
Journal of Thermal Analysis and Calorimetry, cilt.151, sa.1, ss.523-550, 2026 (SCI-Expanded, Scopus)
Solar drying systems often suffer from low thermal efficiency due to poor heat transfer in the solar air heater (SAH). To address this limitation, this study numerically investigates the effect of incorporating rectangular ribs, both perforated and non-perforated ribs, placed beneath the absorber plate of a solar air heater used in an indirect solar dryer. 2D-CFD simulations were performed using ANSYS Fluent 17.1, employing the RNG k–ε turbulence model with enhanced wall treatment to accurately resolve near-wall flow behavior. The analysis considered a constant heat flux of 1000 W m−2, Reynolds numbers between 4000 and 18,000, a rib blockage height ratio of 0.23–0.7, and a rib spacing ratio of 3.33–10. Results showed that the incorporation of rectangular ribs as roughness elements significantly improves the heat transfer and friction characteristics. The average Nusselt number increased by up to 2.05 times for non-perforated ribs and 1.89 times for perforated ribs compared with a smooth duct. However, this enhancement was accompanied by an increase in the friction factor of 64.54 times and 5.17 times, respectively. The optimal thermo-hydraulic performance parameter of 1.12 was achieved for perforated ribs at BR = 0.7, PR = 3.33, and Re = 4000. Additionally, roughened configurations raised the drying air temperature by 13.25 K for non-perforated ribs and 5.62 K for perforated ribs, improving the drying chamber heat gain by 39.38 and 16.33%, respectively. Upgrading to a roughened SAH, particularly the perforated ribs configuration, significantly enhances heat transfer, airflow mixing, and energy utilization. This improvement offers a practical and efficient approach to increasing the thermal performance of solar drying systems.