Effect of Subducting Baffle Structure in Solar Air Heaters: A CFD Insight into Thermo-Hydraulic Performance

Numerical analysis is an economically viable method for improving the performance of a thermal system without many trials. The numerical analysis reported in this paper serves to clarify the extent to which a newly designed subducting baffling structure impacts the performance of a solar air heater (SAH). The performance of different baffle shapes is evaluated through a two-dimensional Computational Fluid Dynamics (CFD) simulation in terms of the thermal (Nu), hydraulic (f), and thermo-hydraulic (THP) performances of the SAH. Moreover, the study is performed with different Reynolds numbers (Re) varying from 3000 to 18,000. The study investigates the parameters arm length (k), arm height (l), pitch (p), pitch angle (α), and arm angle (β) within the ranges of 40–60°, 140–160°, 0.03–0.07 m, 0.03–0.05 m, and 0.05–0.15 m, respectively. The results demonstrate that the assistance of a subducting baffle structure is more effective than a smooth arrangement. The SAH shows a maximum Nu and f of 101.23 and 0.97, respectively. The system with the best performance has revealed the highest THP of 0.798. The greatest intensification of heat transfer (Nu/Nus) and friction loss (f/fs) are 2.58 and 87.76, respectively.