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International Journal of Heat and Mass Transfer
Agency for Defense Development, Aerospace Technology Research Institute
Choi, S., Choi, S. M., Rhee, D. H., Moon, H. K., & Cho, H. H.
Department of Mechanical Engineering, Yonsei University
The blade tip is one of the most susceptible parts of gas turbine blade due to the thermally induced failure caused by a hot gas tip leakage flow through tip clearance. A highly sophisticated and efficient blade tip cooling scheme plays a crucial role in reliable operation of a gas turbine blade. In the present study, we adopted a special slot cooling scheme in turbine blade tip. The film cooling effectiveness (FCE) and flow characteristics of turbine blade tip were investigated according to the cooling flow through the slot gap in blade tip rim. A linear cascade was fabricated to measure and evaluate the cooling performance of the blade tip with the film cooling through a slotted rim versus the blade tip with cooling holes. The local FCE values of the blade tip floor and rim upper surface were measured using the pressure-sensitive paint (PSP) method. The Reynolds number based on the axial chord length and the inlet velocity in the experiment was set at 192,000. The tip clearance was varied from 1 to 3% of the blade span and the coolant mass flow rate ranged from 0.3 to 0.7% of the main flow. The slot cooling in the blade tip, which can be incorporated through an additive manufacturing, showed highly enhanced cooling performance ranging from 53 to 116% compared to that of the blade tip with film cooling holes for various tip gaps and coolant mass flow rates. The slot cooling in the blade tip is expected to improve the thermal durability and reliability of blade tip with better coolant coverage and additional convective cooling through the internal cooling passage in the narrow squealer rim.
- Gas Turbine
- Hot Components
- Blade tip
- Additive manufacturing
- Slot cooling