Experimental and Numerical Investigation of Implementing a Novel Vortex Generator: A Perforated Delta Wing Vortex Generator (PDWVG) on the Performance of Solar Air Collector

Experiments were carried out for the numerical investigation of heat transfer enhancement in a solar air collector using different types of baffles and vortex generators. In this study, the vortex generator was implemented to increase the efficiency of the solar air collector. The variations in Nusselt number, pressure drop, friction coefficient, and thermal and exergy efficiency in four collectors with different baffles arrangement (type A, B, C, D) were investigated. Type A was chosen as the optimum collector for implementing the vortex generator on the absorber surface. In the solar air collector the effects of using a novel vortex generator - the Perforated Delta Wing Vortex Generator (PDWVG), in comparison with a flat one - the Flat Delta Wing Vortex Generator (FDWVG), were considered. In order to determine the maximum efficiency of the solar air collector, four different pitch ratios of vortex generators were studied. The Nusselt number and pressure drop increased with the Reynolds number but the friction coefficient decreased with Reynolds; the experimental and numerical results revealed that the thermal and exergy efficiency decreased from a specific range. The comparison of PDWVG and FDWVG showed that the presence of holes on the novel vortex generator led to reduced pressure drop and increased heat transfer between the airflow and the absorber surface. Increasing the number of vortex generator rows had a slight effect on increasing the studied parameters. The results showed that collector type A with ep=0.55 of PDWVG improves the energy and exergy efficiency 4.43% and 5.29% respectively.