Effects of Air-Induced Duct Diameter on Flow and Heat Transfer Characteristics of Multiple Impinging Jets

Kirttayoth Yeranee; Makatar Wae-hayee; Yu Rao; Chayut Nuntadusit

Authors

Kirttayoth Yeranee Department of MechanicalEngineering, Faculty of Engineering, Prince of SongklaUniversity, 90112Hat Yai, Songkhla, Thailand
Makatar Wae-hayee Department of MechanicalEngineering, Faculty of Engineering, Prince of SongklaUniversity, 90112Hat Yai, Songkhla, Thailand
Yu Rao School of Mechanical Engineering, Shanghai Jiao Tong University, 200240, Shanghai, China
Chayut Nuntadusit Department of MechanicalEngineering, Faculty of Engineering, Prince of SongklaUniversity, 90112Hat Yai, Songkhla, Thailand

Keywords:

Multiple impinging jets, Heat transfer enhancement, Air-induce duct, CFD

Abstract

The objective of this study is to investigate effects of air-induced duct diameter on flow and heat transfer of multiple impingement jet, experimentally and numerically. 5 columns x 5 rows of pipe nozzles, which have diameter of d=17.2 mm, was arranged with inline configuration. The diameter of air-induced duct (D) were varied at D/d=2, 4 and 6, and Reynolds numbers was fixed at Re=30,000. Moreover, the jet-to-plate distances (H) were studied at H/d=6 and H/d=8, respectively. Nusselt number was calculated by measuring temperature distributions on the surface using infrared camera. Numerical study was performed to visualize the flow characteristics and to elucidate the heat transfer mechanism. The results showed that the highest average Nusselt number was found at D/d=4 with short jet-to-plate distance, H/d=6.