In the present paper, CFD analysis of the effect of providing an artificial roughness on the absorber plate of solar air heater has been studied. A transverse rib roughness with isosceles right triangle cross-section has been used. The roughness has been placed in such way that the hypotenuse faces against the flow direction. The design parameters chosen for study are Reynolds number, roughness height and roughness pitch. The turbulence model used in CFD solutions is renormalization group (RNG) k-e. The roughness height (e) is chosen as 0.5mm, 1.0mm and 1.5mm at roughness pitch (P) of 5mm, 10mm, 15mm and 20mm. Each of this case is simulated at Reynolds number of 3593, 5000, 7500, 10000, 12500 and 15000. To get a sense of the variation of performance due to the introduction of artificial roughness, the obtained results are compared with that of a smooth plate by calculating the ratio of Nusselt number and friction factor. Thermo-hydraulic performance is also calculated to get a combined effect for change in pump work and heat transfer.

solar air heater, thermo-hydraulic performance, artificial roughness, CFD, heat transfer enhancement.