An experimental investigation of chevron nozzle jet impingement heat transfer on a flat surface was performed by using the infrared camera. The tests were conducted with typical Reynolds numbers ranging from 5 000 to 20 000 and dimensionless nozzle-to-surface distances ranging from 1 to 8. A comparison with the round nozzle jet was made, and the geometric effects of the chevron nozzle were analyzed. The results show that the chevron nozzle plays a significant role in improving jet impingement heat transfer. At small impinging distances, the distribution of local convective heat transfer produced by the chevron-jet shows an obvious lobe-shaped feature in the vicinity of the impinging stagnation point. When the dimensionless nozzle-to-surface distance is beyond 4, distribution of local convective heat transfer produced by the chevron-jet is similar to that by the round jet. The averaged Nusselt number of the chevron nozzle jet area of either 2 or 4 times of the nozzle diameter for average achieves 15%-30% increase compared to that of the round nozzle jet, and the increase depends on the jet Reynolds number and dimensionless nozzle-to-surface distance. For the current geometric parameters of the chevron nozzle, it is found that the 6-chevron nozzle with a chevron length-to-nozzle diameter of 0.6 can produce more favorable heat transfer enhancement.
LYU Yuanwei
,
ZHANG Jingzhou
,
WANG Boyan
,
TAN Xiaoming
. Experimental of chevron nozzle jet impingement heat transfer on flat targeting surface[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2018
, 39(3)
: 121694
-121694
.
DOI: 10.7527/S1000-6893.2017.21694
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