摘要
对半圆柱形凹形靶面单排圆形喷管和冠齿形喷管射流冲击换热进行了实验研究。凹形靶面直径与喷管直径之比D/d为10,射流孔节距与直径之比W/d为5,射流雷诺数分别为5000、10000和20000,冲击间距比H/d分别为2、4、6和8。实验结果表明:两种形状喷管均在冲击间距比H/d=4时获得最强的驻点对流换热,但凹靶面前缘附近纵向平均努塞尔数基本呈现随射流冲击间距增加而减小的单调变换趋势;相对于圆形喷管,冠齿喷管射流冲击使得凹形靶面前缘线上的纵向平均努塞尔数最大提高幅度约为16%,凹形靶面前缘±2d区域的面积平均努塞尔数最大提高幅度约为18%。
Experimental investigations are performed on the single⁃row jet impingement heat transfer onto a semi⁃cylindrical concave surface.Two kinds of nozzle shapes are taken into consideration.They are circular nozzle and chevron nozzle.The semi⁃cylindrical concave surface has a diameter ratio(D/d)of 10.The jet⁃to⁃jet pitch is 5d.The experiments are conducted under three Reynolds numbers(Re=5000,10000,and 20000)and four dimensionless nozzle⁃to⁃surface distances(H/d=2,4,6,and 8).The results show that both nozzles achieve their respective maximum stagnation Nusselt numbers at H/d=4.However,the longitudinally⁃averaged Nusselt number in the vicinity of concave leading is monotonously reduced with the increase of nozzle⁃to⁃surface distance in general.The chevron nozzle is confirmed to produce higher convective heat transfer than that of circular nozzle.In comparison with the circular nozzle jet impingement,the maximum increase of longitudinally⁃averaged Nusselt number at the concave leading is about 16%and the maximum increase of the locally area⁃averaged Nusselt number in the vicinity of concave leading(within±2d)is about 18%,produced by the chevron⁃nozzle jet impingement.
作者
刘锡晨
吕元伟
张靖周
LIU Xichen;LYU Yuanwei;ZHANG Jingzhou(College of Energy and Power Engineering,Nanjing University of Aeronautics&Astronautics,Aero-engine Thermal Environment and Structure Key Laboratory of Ministry of Industry and Information Technology,Nanjing,210016,China;Collaborative Innovation Center for Advanced Aero-engine,Beijing,100191,China)
出处
《南京航空航天大学学报》
EI
CAS
CSCD
北大核心
2020年第5期808-816,共9页
Journal of Nanjing University of Aeronautics & Astronautics
基金
国家自然科学基金(51776097)资助项目。
关键词
射流冲击
冠齿喷管
凹形靶面
对流换热
jet impingement
chevron nozzle
concave surface
convective heat transfer
