Innovative impinging jet methods for performance enhancement: a review

Abstract

This paper explores diverse techniques aimed at enhancing the heat transfer performance of solar air heaters, with a primary emphasis on impinging jet arrays. The discussion includes an examination of available standards governing the manufacturing, evaluation, and certification of solar air heaters. Traditional approaches, such as the use of turbulators (ribs, baffles, and dimples), improve thermo-hydraulic performance but often lead to thermal stress due to nonuniform cooling. In contrast, jet impingement heat transfer has gained attention for its ability to provide enhanced and consistent cooling even in confined spaces. The study examines key geometric and operational parameters that influence jet impingement heat transfer, such as nozzle-to-target plate spacing, jet diameters, jet arrangement, and jet angle. Among these, the nozzle-to-target spacing and jet diameters are identified as critical factors in optimizing heat transfer. The paper also highlights the superior performance of pipe jets over orifice jets, as pipe jets generate higher fluid velocity on the target plate, resulting in enhanced heat transfer and more uniform cooling. This research underscores the growing importance of jet impingement technology in improving the efficiency of SAH and opens avenues for its application in other thermal management systems, including concentrated solar power and electric vehicle cooling systems.