Gas Turbine Airfoil Tip Cooling via Serpentine Shelf
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Solution Overview
Problem
Existing cooling schemes for gas turbine engine components, such as turbine blades and vanes, face challenges in efficiently cooling the tip regions due to exposure to hot combustion gases, leading to potential thermal mechanical fatigue and reduced durability.
Innovation Solution
The proposed solution involves an airfoil design for a gas turbine engine that incorporates a tip arrangement with a tip pocket and a tip shelf, coupled with a double wall cooling arrangement and serpentine cooling passages, which enhance cooling effectiveness and reduce thermal mass at the tip region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling schemes are used for turbine blades, then cooling is provided to the blade, but cooling effectiveness at the tip region is insufficient due to exposure to hot combustion gases
Solution Approach 1:
The cooling system is segmented into multiple independent cooling passages (first and second cooling passages) with different flow paths and functions. The first cooling passage provides cooling to the pressure side while the second cooling passage cools the suction side, allowing targeted temperature control at the tip region without compromising overall blade durability
Solution Approach 2:
Different cooling strategies are applied to different regions of the blade tip. The pressure side and suction side receive customized cooling through respective dedicated passages, with varying hole distributions and flow directions optimized for local thermal conditions and stress patterns at each surface
2Stress or pressure
If thermal mass at the tip region is reduced to manage heat transfer, then thermal transient strains are reduced, but structural strength may be compromised
Solution Approach 1:
The thermal mass parameter is locally modified by creating a tip pocket cavity and tip shelf structure that reduces material volume at the tip region. This parameter change decreases thermal transient strains by reducing the thermal inertia, while the strategic placement of cooling passages compensates for the reduced structural mass
Solution Approach 2:
The tip pocket cavity is nested within the blade structure, creating a hollow space that reduces thermal mass. The tip shelf extends from this nested cavity to provide structural support, effectively nesting the cooling feature within the overall blade geometry to maintain strength while reducing thermal strain
3Temperature
If a tip pocket and tip shelf arrangement is implemented, then cooling augmentation is improved at the tip region, but device complexity increases
Solution Approach 1:
The tip pocket and tip shelf features are merged with the existing blade casting process, allowing these complex geometric features to be integrated into the manufacturing workflow without requiring separate assembly steps. The cooling passages are also integrated into the tip pocket structure, combining multiple cooling functions in a unified geometric arrangement
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design improves cooling augmentation at the tip region, reduces thermal transient strains, and enhances the durability of gas turbine engine components by effectively managing heat transfer and maintaining a robust thermal response.
Implementation Method 1
Thermal energy is transferred from the component to the airflow as the airflow circulates through the cooling scheme to cool the component
Implementation Method 2
The blade may include a tip pocket that receives airflow to cool the tip and establish a sealing relationship with an adjacent blade outer air seal
Data Source
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AI summary
An airfoil (162) for a gas turbine engine includes a platform section (162B) and an airfoil section (162A) extending in a spanwise direction from the platform section (162B) to a tip portion (162TP) establishing a tip (162T). The airfoil section (162A) has an external wall (166) defining pressure and suction sides (162P, 162S) extending in a chordwise direction (X) between a leading edge (162LE) and a trailing edge (162TE), and the pressure and suction sides (162P, 162S) are spaced apart in a thickness direction (T) between the leading edge (162LE) and the trailing edge (162TE). The tip portion (162TP) includes a tip pocket (174) and a tip shelf (176) extending inwardly from the tip (162T). The tip pocket (174) and tip shelf (176) are on opposite sides of a shelf wall (178), and the shelf wall (178) has a serpentine profile.