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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Dynamic and Heat Transfer of Lobed Impinging Jets

Get access (open in a dialog) DOI: 10.1615/IHTC15.hte.008554
pages 4229-4238

Résumé

Heat transfer of an impinging lobed jet is studied experimentally. The six lobes distributed uniformly around the exit nozzle can be seen as a passive control in order to enhance heat transfer. The canonical case of a jet impacting orthogonally to a flat plat was considered. Several impact distances was studied at a fixed constant flow rate. The plate is uniformly heated by Joule effect and the jet is maintained at ambient temperature. Temperature fields are determined by infrared thermography of the impacting area and compared to the reference case, e.g. an axisymmetric straight cylinder. In conjunction with the heat transfer measurements, particle image velocimetry was performed in order to quantify the dynamics of these impinging jets. Preliminary results show a great influence of the impacting distances H/D on the temperature distribution. For the lobed jet around H/D ? 1, the temperature field has the distinct nozzle geometry pattern with the associated high spatial gradient.With increasing impacting distance this characteristic pattern is gradually smoothed to an almost circular shape. Of prime interest lobed jet shows Nusselt numbers greater than circular jet on an average field distribution.