Güneş hava ısıtıcısının verimlilik artırımında geometrik ve yapısal tasarımın araştırılması

This study aims to enhance the thermo-hydraulic performance of solar air heaters (SAHs) by employing various broken V-shaped artificial roughness configurations on the absorber plate, with and without incorporating grooves of triangular, semi-circular, and trapezoidal cross-sections. A three-dimensional numerical analysis was conducted using ANSYS Fluent software to examine the fluid flow and the heat transfer characteristics within a solar air heater duct with an aspect ratio of 12 and a hydraulic diameter of 0.046 m, across Reynolds numbers ranging from 3*103 to 15*103. Geometrical parameters of roughness are set to the optimized and best performance of related experimental validated set of parameters. The results indicate that there is significant increase of both heat transfer rates and friction losses of V-shaped ribs attributed to enhanced turbulence and vortex formation. Applying gaps in the V-ribs yield further enhancement in Nusselt numbers, accompanied by slight increase in friction factors. The maximum improvement in the Nusselt number reaches three times greater than that of a smooth duct, with an increase of THPP ranging from 2 to 2.15. Furthermore, the addition of grooves to the broken V-ribs configurations increases both Nusselt numbers and friction factors. For the semi-circular grooves, which provide the most favourable results, the Nusselt number reaches up to 1.25 times that of the corresponding arrangement without grooves, with only a slight increase in friction factors. THPP of the combined V-rib and groove arrangements significantly exceed those of other configurations, with maximum values observed for V-ribs combined with semi-circular grooves, ranging from 6.3 to 2.4, depending on the Reynolds number.