Convective heat transfer by a row of tab-excited impinging jets on a wedge-shaped concave surface

摘要

A Computational study was conducted to investigate the convective heat transfer characteristics by a row of tab-excited air jets impingement on a wedge-shaped concave surface having larger curvature than semi-circular concave surface. The geometric effects, including the tab number and tab penetration ratio, as well as the offset-jets arrangement, on the impinging jet flow and heat transfer behaviors are analyzed under several non-dimensional jet-to-leading edge distances (6, 9, 12) and the jet Reynolds numbers ranging from 6900 to 26,100. The results show that both the jet offset-arrangement and tab-excitation are proved to be capable of improving the convective heat transfer in the vicinity of jet impingement region. Either for the conventional round jet or tab-excited jet, it appears that an optimum non-dimensional jet-offset distance is about 1.5. The heat transfer enhancement is improved as the increase of tab number (ranging from 4 to 8), as well as tab penetration ratio (ranging from 0.13 to 0.25). The influence intensity of non-dimensional jet-offset distance on the convective heat transfer inside a concave cavity is more significant for the tab-excited jet impingement than that for the conventional round jet impingement. In general, the effects of jet offset-arrangement and tab-excitation on the jet impingement heat transfer enhancement behave more significant under larger jet Reynolds number as well as smaller impingement distance. (C) 2015 Elsevier Masson SAS. All rights reserved.