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Affiliation of Author(s):能源与动力学院

Journal:INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER

Key Words:Conjugated convective heat transfer Hot jet impingement Conical surface Chevron nozzle

Abstract:Experimental investigations were carried out to study the conjugated convective heat transfer on the leading edge of a conical wall subjected to external cold flow and internal hot jet impingement by a single chevron nozzle. The geometric effects, including the chevron penetration depth (p/d ranging from 0.1 to 0.2) and chevron length (I/d ranging from 0.1 to 0.3) on the conjugated convective heat transfer performances were experimentally analyzed for a typical 6-chevrons nozzle under non-dimensional jet-to-leading edge distance (H/d) of 2-4 and jet Reynolds number (Re-j) of 7800-39,400. The results show that the chevron jet is proved to be capable of improving the heating effectiveness in the vicinity of the conical surface leading edge, especially under a small jet Reynolds number. For the specified zone with a chordwise length of 5d apart from the leading edge, the area-averaged heat effectiveness could be increased approximately 20% by the chevron nozzle in relative to the conventional nozzle. The heat transfer enhancement is improved with the increase of chevron penetration length for a fixed chevron length or the decrease of chevron length for a fixed chevron penetration length. The influence of chevron penetration depth or the chevron length on the specified area-averaged heating effectiveness becomes weaker gradually as the jet Reynolds number increases. For the current conditions, the non dimensional jet-to-leading edge distance seems to have little influence on the specified area-averaged heating effectiveness. (C) 2016 Elsevier Ltd. All rights reserved.

ISSN No.:0017-9310

Translation or Not:no

Date of Publication:2017-03-01

Co-author:Guan, Tao,Shan Yong,Hang, Jin

Correspondence Author:zjz