湍流
绝热过程
动量(技术分析)
物理
喷射(流体)
机械
热流密度
热的
焊剂(冶金)
航程(航空)
湍流动能
光学
材料科学
传热
热力学
复合材料
经济
冶金
财务
作者
Atul Kohli,David G. Bogard
出处
期刊:Journal of turbomachinery
[ASME International]
日期:1997-04-01
卷期号:119 (2): 352-358
被引量:124
摘要
The film cooling performance and velocity field were investigated for discrete round holes inclined at an injection angle of 55 deg. Results are compared to typical round film cooling holes, with an injection angle of 35 deg. All experiments in this study were performed at a density ratio of DR = 1.6, using cryogenic cooling of the injected air. Centerline and lateral distributions of effectiveness were obtained for a range of momentum flux ratios. Thermal field and two component mean velocity and turbulence intensity measurements were made at a momentum flux ratio that was within the range of maximum spatially averaged effectiveness. Compared to round holes with 35 deg injection angle, the 55 deg holes showed only a slight degradation in centerline effectiveness for low momentum flux ratios, while a significant reduction in effectiveness was seen at high momentum flux ratios. The thermal field for the 55 deg round holes indicated a faster decay of cooling capacity for the 55 deg round holes. The high turbulence levels for the 55 deg round hole coincided with the sharp velocity gradients between the jet and free stream, and the decay of turbulence levels with downstream distance was found to be similar to those for a 35 deg hole.
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