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Affiliation of Author(s):能源与动力学院

Journal:APPLIED THERMAL ENGINEERING

Key Words:Conjugated heat transfer Confined jet impingement Wedge-shaped concave surface Offset-jets arrangement Heating effectiveness

Abstract:An experimental investigation is conducted to study the effect of offset-jets arrangement on the conjugated heat transfer performance for a specifically wedge-shaped concave surface subjected to external cold flow and internal hot jet impingement. The external flow Reynolds number (Re-c) defined on the base width of wedge-shaped concave surface is fixed as 54,000. The jet Reynolds number (Re-j) is varied in the range of 7900-31,700. Four non-dimensional jet-bole offset distances (L/d) ranging from 0 to 2.5 and four non-dimensional jet-to-leading edge distances (H/d) ranging from 6 to 15 are considered respectively. In order to illustrate the effect of offset-jets arrangement on the flow and heat transfer features inside the wedge-shaped concave cavity, numerical simulations are also performed. The results show that the offset-jets arrangement generally has a significant impact on improving the overall heating effectiveness in the vicinity of concave wall leading edge due to the reduction of normal jet impinging distance and the formation of recirculation flow structure inside the concave cavity. In current study, L/d = 1.5 is confirmed to be a superior offset-jets arrangement for achieving the highest specified area-averaged heating effectiveness. It is also noted that the effect of offset-jets arrangement on the leading edge hot-air heating effectiveness is tightly dependent on the normal jet-to-leading edge distance. Under Hid = 15, the offset-jets distance has a weak effect of on the internal hot-jet impingement heat transfer. In this situation, the offset-jets arrangement has nearly no effect on improving the hot-jet heating effectiveness. (C) 2017 Elsevier Ltd. All rights reserved.

ISSN No.:1359-4311

Translation or Not:no

Date of Publication:2018-01-05

Co-author:Guan, Tao,Shan, Yong

Correspondence Author:zjz