Abstract

To study the effect of blockage on the film cooling performance, film cooling plate models with cylindrical hole, compound hole, and fan-shaped hole under the all-round blockage, leading-edge blockage, and trailing-edge blockage were established respectively. The anti-blockage performance of three kinds of the hole was compared. The result shows that the cooling performance of cylindrical holes is the worst due to the appearance of counter-rotating vortex pair (CRVP) under blockage. The cooling effectiveness decreases with the increase of the blockage ratio. With the re-attachment effect, the cooling effectiveness of downstream increases by 11% on the contrary. The cooling effectiveness of the compound hole decreases obviously with the all-round and trailing-edge blockages, meanwhile, the peak cooling effectiveness and the coolant coverage area decrease. However, the cooling effectiveness increases by 15% when the leading-edge is blocked. For fan-shaped hole, the change of velocity gradient affects the development of the anti-CRVP, which disappears under the all-round blockage and reduces the cooling effectiveness greatly. The change of cooling performance of leading-edge and trailing-edge is very slight no more than 5%. In conclusion, the fan-shaped hole shows the best anti-blockage capability under the trailing-edge blockage condition and the all-round blockage condition with a high blow ratio, while the compound hole performs better in other conditions.

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