Utilizing circular jet impingement to enhance thermal performance of solar air heater

In the present work, the thermal performance of impinging jet double pass solar air heater is investigated experimentally. A corrugated wavy plate consists of circular holes, each of 7.66 mm in diameter on the crest region are used to provide the impinging jets of air that provide 1.4%-0.48% plate perforation. While, the double pass is provided by circulating the air first through the channel formed between back and lower corrugated plates and then through another wavy channel formed between two corrugated plates. To provide thermal backup and increase heat transfer to air, two design configurations are investigated i.e. Design-I without porous media (100% porosity) and Design-II with porous media (95% -98% porosity) in the wavy channel. Moreover, the deep insight on physics of fluid using CFD tool is presented in the extent of this work. It is recommended to operate the present solar air heater designs at the mass flow rate of 0.04 kg/s, bed porosity of 98% and impinging plate perforation of 0.48% to have the best thermal performance. Whereas, the maximum thermal efficiency and thermohydraulic efficiency of 94% and 84% is obtained for Design-I, which is about 7.5% and 19%, respectively high compared to Design- II. (C) 2020 Elsevier Ltd. All rights reserved.