Impact of trapezoidal ribs on the performance of solar air collector: A numerical solution with optimized rib dimensions for better performance

Abstract

In the present study, a 2D numerical analysis of the solar air collector (SAC) of an indirect solar dryer having trapezoidal corrugations on the absorber plate was performed. Corrugation pitch, p (twelve values ranged from 20 to 160 mm) and height, e (six values ranged from 1 to 10 mm) were varied and analyzed for six values of Reynolds numbers (Re). The output characteristics such as Nusselt number (Nu), friction factor (f) and thermo-hydraulic performance index (T_hp) were calculated for different p, e and Re. The total work was categorized into two parts (part-I for optimizing p and part-II for optimizing e). 18 domains (twelve for part-I and six for part-II simulations) were generated and 108 simulations were executed to find the optimum dimensions (p, e and corrugation angle, α) of the corrugation. ANSYS Fluent-v15 was used to solve the problem. The maximum Nu for the corrugated sheet was 2.663 times greater than the flat absorber plate. The maximum T_hp range was from 1.435 to 1.699 and obtained at the optimal values of p = 140 mm, e = 4 mm and α = 38.66° The numerical results were compared with the existing literature.