PIV tests for flow characteristics of impinging jet in a semi-closed circular pipe
CHEN Ming1,2, HUANG Haijin1, WANG Duoyin1,2, L Senpeng1, CHEN Yanji1
1. Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education, Chongqing Jiaotong University,
Chongqing 400074, China; 2. National Engineering Research Center for Inland Waterway Regulation,
Chongqing Jiaotong University, Chongqing 400074, China
Abstract：Here, to study effects of a closure plate on flow characteristics of impinging jet in a long straight circular pipe, the particle image velocimetry (PIV) tests were conducted to measure the flow field under different Reynolds number of 5 084-13 926 and impingement distance H/D of 2-6. Motion law of recirculation zone, change of potential flow core length, entrainment characteristics before jet impingement, wall jet expansion rate and velocity attenuation index were statistically analyzed. The test results showed that effect laws of Reynolds number and impingement distance on motion characteristics of recirculation zone are consistent with those of a semi-closed orifice plate impinging jet; flow characteristics before impingement reveal that effects of impingement distance is larger than those of Reynolds number on length of potential flow core and expansion rate of entrainment coefficient, length of potential flow core and expansion rate of entrainment coefficient increase with increase in impingement distance; flow characteristics of wall jet region reveal that expansion rate decreases with increase in Reynolds number, attenuation index increases with increase in Reynolds number when impingement distance is smaller (H/d=2), and then effects of Reynolds number on attenuation index gradually decrease with increase in impingement distance; compared with free impinging jet, existence of closure plate makes velocity attenuation of wall jet zone speed up, but its effects on expansion rate of wall jet zone are not significant, this result is significantly different from the existing study results about effects of closure plate on flow characteristics of orifice plate impinging jet.
陈明，黄海津，王多银，吕森鹏，陈沿吉. 半封闭圆管冲击射流流动特性PIV试验研究[J]. 振动与冲击, 2021, 40(15): 90-97.
CHEN Ming HUANG Haijin, WANG Duoyin, L Senpeng, CHEN Yanji. PIV tests for flow characteristics of impinging jet in a semi-closed circular pipe. JOURNAL OF VIBRATION AND SHOCK, 2021, 40(15): 90-97.
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