Computational analysis of modified solar air heater having combination of ribs and protrusion in S-shaped configuration

Use of different roughness in solar air heater can effectively influence the thermo-hydraulic performance. In present work, solar air heater was roughened with ribs and protrusion in S-shaped. The average Nusselt number, friction factor, velocity contour, turbulent kinetic energy contour, and thermal performance factor for solar air heater systems with varied operating and design parameters are illustrated to provide comparative numerical results. In operating parameter, air flow was varied while in design parameters, relative pitch roughness (P/E = 12 to 24), gap between ribs and protrusion (G_R−P = 0.5 mm and 1.5 mm) and protrusion diameter (D_P = 0.3 mm and 0.5 mm) was studied. The simulation was carried under uniform heat flux of 1200 W/m². Based on comparison of various parameters, it was found that P/E = 20, G_R−P = 0.5 mm and D_P = 0.3 mm has shown maximum thermo performance factor value from 2.5 to 3.1. While, P/E = 12, G_R−P = 0.5 mm and D_P = 0.5 mm has depicted minimum thermo performance factor value ranging from 1.4 to 1.7.