Airfoil Cooling Circuit Tip Flag Chamber Design
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Solution Overview
Problem
Conventional cooling circuit designs in airfoils of gas turbine engines suffer from aerodynamic mixing losses due to the way cooling circuit air is purged, which affects the efficiency and capacity of cooling the airfoils.
Innovation Solution
The airfoil design incorporates a skin chamber and a tip flag chamber with outlet openings on the trailing edge or pressure side, allowing a majority of cooling circuit air to exit through these routes instead of traditional suction side film holes or radially outward outlets, creating a more efficient pathway for purging cooling circuit air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If cooling circuit air is purged through traditional suction side film holes or radially outward outlets, then the cooling circuit can function, but aerodynamic mixing losses occur that reduce cooling efficiency
Solution Approach 1:
The cooling circuit is segmented into distinct chambers (skin chamber and tip flag chamber) with separate outlet pathways. This segmentation allows different portions of cooling air to be directed through different routes - some through the skin chamber outlet opening and others through the tip flag chamber and outlet hole - optimizing the purge location to reduce aerodynamic mixing losses while maintaining adequate cooling capacity
Solution Approach 2:
The patent introduces a new spatial dimension for cooling air egress by adding the tip flag chamber that extends to the airfoil tip region. This creates an additional exit pathway at the tip end of the airfoil, moving the purge location from the traditional suction side to the tip region, thereby reducing interference with the main airflow and minimizing aerodynamic mixing losses
2Temperature
If cooling air exits through the suction side, then cooling is provided, but aerodynamic mixing losses reduce the efficiency
Solution Approach 1:
Instead of expelling cooling air through the traditional suction side outlets, the patent inverts the approach by directing cooling air through the tip flag chamber and outlet hole located at the airfoil tip. This reversal of the purge direction moves the cooling air exit away from the suction side boundary layer, reducing aerodynamic mixing losses while still achieving effective cooling of the airfoil surface
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 configuration reduces aerodynamic mixing losses and enhances the ability to cool the airfoil, improving its efficiency and capacity by directing cooling air away from the suction side, thereby mitigating conventional purging inefficiencies.
Implementation Method 1
Cooling air may be extracted from the compressor section and used to cool the gas path components. One mechanism used to cool turbine airfoils includes utilizing internal cooling circuits
Data Source
AI summary
An airfoil may include an airfoil body that defines a skin chamber, a skin chamber outlet opening, and a tip flag chamber. In various embodiments, the skin chamber is in fluidic communication with the tip flag chamber via the skin chamber outlet opening. In various embodiments, the airfoil body further defines an outlet hole disposed on at least one of a trailing edge and a pressure side of the airfoil. The tip flag chamber may be in fluidic communication with the outlet hole (e.g., cooling circuit air in the tip flag chamber may exit the airfoil via the outlet hole). In various embodiments, the tip flag chamber extends parallel and directly adjacent to the outermost tip of the airfoil.