Experimental study on film cooling effectiveness of shallow hole with upstream sister holes
This paper deals with effects of sister hole on cylindrical shape film cooling performance. The objective of introducing sister holes is aiming for further enhancement of film cooling effectiveness of conventional film cooling. The performance of sister holes, installed upstream of primary holes wit...
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| Main Authors: | , , |
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| Format: | Conference or Workshop Item |
| Published: |
2014
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/6339/ http://eprints.uthm.edu.my/6339/1/115.pdf |
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| Summary: | This paper deals with effects of sister hole on cylindrical shape film cooling performance. The objective of introducing sister holes is aiming for further enhancement of film cooling effectiveness of conventional film cooling. The performance of sister holes, installed upstream of primary holes with shallow inclination angle 20°, is thoroughly investigated and reported in this study. Effects of blowing ratio (M) are examined. Three different blowing ratios, 1.0,1.5 and 2.0 are examined in this study to explore the capability of sister holes to suppressing the growth of counter-rotating vortex pair (CRVP) associated with the ejected cooling air, then enhancing the cooling air attachment to the flat plate surface. In order to investigate the film effectiveness, a steady-state method using a high-resolution infrared camera is adopted. Mainstream temperature and secondary air temperature is measured by K-type thermocouple. The result showed significant improvement compared to shallow hole of 35°. The optimum blowing ratio is 1.5. Smaller shallow angle and upstream sister holes reduce the jet lifting effect of the secondary air flow. Future study can be done on shallow hole of shallow angle and blowing ratio around 1.5 in order to further improve the film cooling effectiveness |
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