Film cooling with primary and secondary hole injection is numerically investigated. Effects of primary hole shape and secondary hole injection angle are documented. Each primary hole, either cylindrical or laterally diffused, has two secondary, cylindrical holes located symmetrically about it. Adding secondary holes improves cooling performance. Five cases of different secondary hole injection configuration are analyzed. With a cylindrical primary hole, increasing secondary hole inclination angle provides better cooling; outwardly inclining the secondary holes shows continued improvement. With horn-shaped primary holes, smaller secondary hole inclination angles provide higher cooling at lower blowing ratios; larger secondary hole inclination angles provide higher cooling at higher blowing ratios, and compound-angle secondary hole injection shows no improvement over parallel hole injection.
Bibliographical noteFunding Information:
This work was supported by National Natural Science Foundation of China , by the Fundamental Research Funds of Shaanxi Province [2015KJXX-12], and by the Fundamental Research Funds of Shenzhen City of China [JCYJ20170306155153048].
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