A computational study for enhancement in thermal performance of plus (+)-shaped ribbed solar air heater duct

This article uses the CFD approach to present heat transfer augmentation and flow characteristics in solar air heater duct (SAHD) plus(+)-shaped rib turbulators. In this study, a two-dimensional domain is considered for simulation, and the collector plate of SAHD is made from aluminum, which is exposed to a consistent heat flux of 1000 W/m2. The numerical exercise uses ANSYS-Fluent R22 code to analyze the consequence of different dimensionless parameters crucial in characterizing fluid flow and heat transfer dynamics. The parameters of interest include Reynolds number (Re), relative roughness pitch (P/e), and relative roughness height (e/Dh). The investigation gives rise to noteworthy results that put up in terms of average Nusselt number enhancement factor, average enhancement friction factor, thermo-geometric performance parameter (TGPP), solar air heater performance index (SAHPI), pumping power, and visualization of different fluid properties for the SAHD. The study was done by varying P/e and Re from 7.14 to 17.85 and 4000 to 22,000, respectively, at a constant e/Dh of 0.042. The analysis reveals that a solar air heater performance index (SAHPI) of 2.54 is achieved as heat removal is augmented for the SAHD. The RNG k- epsilon model with enhanced wall treatment is chosen as the best model to simulate the governing equations. The average Nusselt number and the friction factor correlations, based on Re and P/e, have been determined through a non-linear regression analysis.