Numerical Analysis to Optimize the Corrugation Angle of Pentagonal Corrugated Absorber Plate of Solar Air Collector in an Indirect Solar Dryer for Enhanced Heat Transfer Characteristics

A two-dimensional numerical analysis was conducted to optimize the corrugation angle of a pentagonal corrugated absorber plate in the solar air collector of an indirect solar dryer for maximizing thermo-hydraulic performance parameter (Thpp) to obtain enhanced heat transfer characteristics. A total of 60 simulations were performed in ANSYS FLUENT 2023 R1 using the SIMPLE algorithm and RNG k–ε model for evaluating the governing equations. Design parameters considered for the analysis were corrugation angle (α), height (e), pitch (p), and Reynolds number (Re). The corrugation angle (α) was varied from 10 to 37.5° with an interval of 2.5° for a fixed corrugation pitch, p = 150 mm and corrugation height, e = 10 mm. Reynolds number (Re) was varied from 1800 to 15,000 for all values of α and performance parameters such as Nusselt number (Nu), friction factor (f), Nusselt number ratio (Nu ratio), friction factor ratio (f ratio), and thermo-hydraulic performance parameter (Thpp) were estimated and an optimum value of α was proposed for the specified range of Re. It was found that the Nu ratio varied from 1.997 to 3.126 which implies that the heat transfer was enhanced up to 3.126 times as compared to flat absorber plate. Maximum Thpp was found for α = 35° (Thpp = 1.827) at Re = 1800, however, the maximum Thpp occurred at α = 35° only for Re = 1800 and 4440, whereas for Re = 7080, 12,360, and 15,000, maximum Thpp was found at α = 15°. Wind speed varies significantly in everyday use, and thus an α that provides maximum Thpp for a wider range of Re would be more beneficial. Hence, the optimum corrugation angle (α) is proposed as α = 15° as it provides better overall performance for the ISD.