Heat transmission and air flow friction in a solar air heater with a ribbed absorber plate: A computational study

The influence of geometrical parameters of V-symmetry ribs on heat flow and fluid flow characteristics of solar air heater (SAH) rectangular duct with ribbed absorber is investigated theoretically. Fabrication of ribs in repeated artificial protrusions pattern on the absorber surface appears as a simple approach for increasing the solar collectors radiation harnessing capacity. The various characteristics of artificial roughness protrusions include relative roughness height (e/Dh), relative roughness pitch (p/e), and angle of attack of flow (α), and the span of these parameters is determined based on experimental considerations of the device and working circumstances. To measure the improvement in the coefficient of heat transfer and friction factor, the outcomes were correlated to those of a smooth conduit under identical flow characteristics. The greatest increase in Stanton number and friction factor is 1.13 and 1.19 folds that of the smooth SAH duct, correspondingly.