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利用红外热像仪测试了脉冲频率为10 Hz和占空比为50％的脉冲射流冲击平直表面的对流换热特性,在射流雷诺数为5 000～20 000、冲击间距比为2～8的范围内,与连续射流冲击换热进行了对比分析.研究结果表明,脉冲射流冲击对流换热系数依然具有随射流雷诺数增加而提高、沿径向急剧降低等基本特征,但是与连续射流相比,脉冲射流冲击引起的射流驻点和壁面射流区的对流换热存在差异,其影响与射流雷诺数和射流冲击间距密切相关;一般而言,在较大的射流冲击间距比下,脉冲射流体现出传热增强的效果,随着射流雷诺数的增加,脉冲射流较连续射流的优势更为明显;而在小射流冲击间距比下,连续射流则更具优势,在Re=20 000下仅当以3倍以上射流管直径作为区域半径进行平均时,脉冲射流才具有略高于连续射流冲击换热的作用效果.“,”Experimental tests of jet impingement heat transfer on a flat surface were performed by using the infrared camera for the pulsed jets with a constant operating frequency of 10 Hz and duty cycle of 50％.Comparisons with continuous jets were made at the jet Reynolds numbers ranging from 5 000 to 20 000 and the dimensionless nozzle-to-surface distances ranging from 2 to 8.The results show that the pulsed jet possesses the same basic heat transfer features as the continuous jet impingement,such as increase of the convective heat transfer coefficient with the increase of jet Reynolds numbers and rapid decrease of the local convective heat transfer coefficient along the radial direction.However,different from the continuous jet,the pulsed jet produces some differences in heat transfer either at the stagnation point or the wall jet zone.This is tightly associated with the jet Reynolds number and nozzle-to-surface distance.In general,the pulsed jet impingement exhibits its advantage over the continuous jet at larger dimensionless nozzle-to-surface distances,especially at a high jet Reynolds number.At a small dimensionless nozzle-to-surface distance,the continuous jet is demonstrated to achieve better heat transfer than the pulsed jet.For Re =20 000,the pulsed jet produces a slight improvement of the region-averaged convective heat transfer relative to the continuous jet only when the specified region for average use has a large radius beyond three times of the jet-nozzle diameter.