NUMERICAL FRAMEWORK FOR ANALYZING COUPLED HEAT TRANSFER AND FLOW LOSSES IN FIN-MODIFIED SOLAR AIR HEATING SYSTEMS

Abstract

This study presents a numerical investigation into the thermo-hydraulic performance of a solar air heater (SAH) duct enhanced with inclined fins. The analysis explores a wide range of fin tilt angles (α = 15° to 135°) and Reynolds numbers (Re = 2,000 to 22,000), emphasizing a novel geometric configuration with bottom-mounted fins and heat supplied from the top absorber plate. The fin geometry includes a protrusion of 1.00 mm, length of 5.00 mm, and pitch of 10.00 mm, while the duct height is reduced to 9.00 mm to intensify flow interaction. Computational Fluid Dynamics (CFD) simulations using the RNG k-ε turbulence model are conducted to evaluate the Nusselt number (Nu), friction factor (f), and thermo-hydraulic performance parameter (THPP). Results predict enhanced turbulence and heat transfer due to the aggressive fin design, with a corresponding increase in pressure drop. Extreme fin angles are expected to cause complex vortex dynamics and recirculation. The findings offer valuable insights into performance optimization and support future validation studies through experimental and 3D CFD approaches.