Effect of Turbine Blade Tip Cooling Configuration on Tip Leakage Flow and Heat Transfer

Date

2019-06-21

Author

Sakaoğlu, Sergen
Kahveci, Harika Senem

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The pressure difference between suction and pressure sides of a turbine blade leads to the so-called phenomenon, the tip leakage flow, which most adversely affects the first-stage high-pressure (HP) turbine blade tip aerodynamics. In modern gas turbines, HP turbine blade tips are also exposed to extreme thermal conditions requiring the use of tip cooling. If the coolant jet directed into the blade tip gap cannot counter the leakage flow, it will simply add up to the pressure losses due to this leakage flow. Therefore, it is necessary to handle the design of tip cooling in such a way that the compromise between the aerodynamic loss and the gain in the tip cooling effectiveness is optimized. In this paper, the effect of tip cooling configuration on the turbine blade tip is investigated numerically both from the aerodynamics and thermal aspects in order to determine the optimum tip cooling configuration. The studies are carried out using the tip cross-section of General Electric E3 (Energy Efficient Engine) HP turbine first-stage blade for two different tip geometries, squealer tip and flat tip, where the number, location, and diameter of the cooling holes are varied. The study presents a discussion on the overall loss coefficient, the total pressure loss across the tip clearance, and the variation of heat transfer on the blade tip. The aerodynamic and heat transfer results are compared with the experimental data from literature. It is observed that increasing the coolant mass flow rate by using more holes or by increasing the hole diameter results in a decrease in the area-averaged Nusselt number on the tip floor, as expected. The findings show that both aerodynamic and thermal response of the squealer tips to the implementation of cooling holes is superior to their flat counterparts. Among the studied configurations, the squealer tip with larger number of cooling holes located towards the pressure side is highlighted as the configuration having the best cooling performance.

Subject Keywords

Squealer Tip

URI

https://hdl.handle.net/11511/39016

DOI

https://doi.org/10.1115/gt2019-90130

Collections

Department of Aerospace Engineering, Conference / Seminar

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Effect of Turbine Blade Tip Cooling Configuration on Tip Leakage Flow and Heat Transfer Sakaoglu, Sergen; Kahveci, Harika Senem (ASME International, 2020-02-01) The pressure difference between suction and pressure sides of a turbine blade leads to tip leakage flow, which adversely affects the first-stage high-pressure (HP) turbine blade tip aerodynamics. In modern gas turbines, HP turbine blade tips are exposed to extreme thermal conditions requiring cooling. If the coolant jet directed into the blade tip gap cannot counter the leakage flow, it will simply add up to the pressure losses due to leakage. Therefore, the compromise between the aerodynamic loss and the g...
EFFECT OF TURBINE BLADE TIP COOLING CONFIGURATION ON TIP LEAKAGE FLOW AND HEAT TRANSFER Kahveci, Harika Senem; Sakaoğlu, Sergen (2019-06-17) The pressure difference between suction and pressure sides of a turbine blade leads to the so-called phenomenon, the tip leakage flow, which most adversely affects the first-stage high- pressure (HP) turbine blade tip aerodynamics. In modern gas turbines, HP turbine blade tips are also exposed to extreme thermal conditions requiring the use of tip cooling. If the coolant jet directed into the blade tip gap cannot counter the leakage flow, it will simply add up to the pressure losses due to this leak...
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Citation Formats

S. Sakaoğlu and H. S. Kahveci, “Effect of Turbine Blade Tip Cooling Configuration on Tip Leakage Flow and Heat Transfer,” 2019, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/39016.