Effects of impingement parameters on impinging-film cooling performance

Impinging-film cooling is a kind of hybrid cooling, in which the cooling effectiveness would be influenced by the impingement characteristics. Thus, this paper investigates the effects of impinging parameter variations on the performance of impinging-film cooling. The impinging parameters include jet inclination (30o, 45o, 60o, and 90o), jet-to-slab spacing (1 mm, 1.5 mm, and 2 mm), and jet hole diameter (d = 1 mm, 1.2 mm, and 1.6 mm). In addition, numerical simulation was employed to help in understanding the flow field changes caused by different impinging parameters. The results show that the jet inclination of 90o has higher cooling effectiveness compared to other ones due to the lower turbulent intensities. A smaller jet-to-plate spacing is conducive to the liner cooling attributed to its higher slot velocity. The jet diameter of 1.2 mm shows a great capacity for liner cooling estimated by the cooling effectiveness. An optimal collocation of jet diameter and spanwise hole-to-hole spacing may exist with fixed total jet area according to the cooling effectiveness. The changes of velocity and turbulence intensity distribution due to different impinging parameters account for the difference of cooling effectiveness. © 2020 by Begell House, Inc. www.begellhouse.com