Experimental study of single-row chevron-jet impingement heat transfer on concave surfaces with different curvatures  

作　　者：Yuanwei LYU Jingzhou ZHANG Xichen LIU Yong SHAN 

机构地区：[1]Jiangsu Province Key Laboratory of Aerospace Power System, College of Energy and Power Engineering, Nanjing University of Aeronautics and Astronautics

出　　处：《Chinese Journal of Aeronautics》2019年第10期2275-2285,共11页中国航空学报（英文版）

基　　金：the financial supports for this project from the National Natural Science Foundation of China(No.51776097);the Open Fund of Jiangsu Province Key Laboratory of Aerospace Power System(No.APS20A7002);the Postgraduate Research and Practice Innovation Project of Jiangsu Province(No.KYCX17 0280)

摘　　要：To address the curvature effect on single-row chevron-nozzle jet impingement heat transfer on concave surface,a series of experiments are conducted in the present investigation.Four concave surfaces including one semi-cylindrical concave surface and three parabolic concave surfaces with different width-to-depth ratios are tested under three typical Reynolds numbers(Re=5000,10000 and 15000)and several dimensionless nozzle-to-surface distances ranging from 1 to 8.The results show that the concave curvature has a clear impact on chevron-nozzle jet impingement heat transfer,tightly dependent on jet Reynolds number and impinging distance.In general,the semicylindrical concave surface produces the highest longitudinally-averaged Nusselt number at the leading line of concave surface.Under a low jet Reynolds number,the parabolic concave surface with a highly curved curvature produces higher longitudinally-averaged Nusselt number at the leading line and more uniform longitudinally-averaged Nusselt number distribution along the curvilinear direction.However,the longitudinally-averaged Nusselt number at the leading line of concave surface is the lowest for the highly curved surface under a high jet Reynolds number and large impinging distance.In comparison with the round-nozzle,chevron nozzle plays a more significant role on improving jet impingement heat transfer at small impinging distances.To address the curvature effect on single-row chevron-nozzle jet impingement heat transfer on concave surface, a series of experiments are conducted in the present investigation.Four concave surfaces including one semi-cylindrical concave surface and three parabolic concave surfaces with different width-to-depth ratios are tested under three typical Reynolds numbers(Re = 5000,10000 and 15000) and several dimensionless nozzle-to-surface distances ranging from 1 to 8.The results show that the concave curvature has a clear impact on chevron-nozzle jet impingement heat transfer, tightly dependent on jet Reynolds number and impinging distance.In general, the semicylindrical concave surface produces the highest longitudinally-averaged Nusselt number at the leading line of concave surface.Under a low jet Reynolds number, the parabolic concave surface with a highly curved curvature produces higher longitudinally-averaged Nusselt number at the leading line and more uniform longitudinally-averaged Nusselt number distribution along the curvilinear direction.However, the longitudinally-averaged Nusselt number at the leading line of concave surface is the lowest for the highly curved surface under a high jet Reynolds number and large impinging distance.In comparison with the round-nozzle, chevron nozzle plays a more significant role on improving jet impingement heat transfer at small impinging distances.

关 键 词：CHEVRON NOZZLE CONCAVE surface Experimental test Heat transfer Jet IMPINGEMENT 

分 类 号：O17[理学—数学]