Airfoil Dead-End Tip Flag Cavity Cooling Design
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Solution Overview
Problem
Current gas turbine engine rotor blade cooling designs face inefficiencies due to varying thermal loads and operational conditions, necessitating improved cooling schemes for both external and internal surfaces.
Innovation Solution
The design incorporates a dead-end tip flag cavity fluidly connected to a serpentine cavity through bleed holes, with the tip flag cavity aligned with the serpentine cavity and a squealer pocket for enhanced cooling, utilizing stand-offs to form bleed holes and maintain cooling airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional cooling cavities are used in airfoils, then cooling is provided for the airfoil body, but thermal stress on tip cap materials increases and cooling efficiency is insufficient
Solution Approach 1:
The cooling system is segmented into multiple distinct cavities: a tip flag cavity located at the tip region and a serpentine cavity extending through the airfoil body. This segmentation allows targeted cooling of the high-stress tip region separate from the main airfoil body, directly addressing the thermal stress concentration problem at the tip cap materials while improving overall thermal mechanical fatigue life
Solution Approach 2:
The tip flag cavity is specifically positioned and dimensioned to provide localized cooling quality where thermal stress is highest. The cavity extends radially outward to align with the squealer pocket, creating a dedicated cooling zone at the tip region with different thermal management characteristics than the main airfoil body, thereby reducing thermal stress on tip cap materials
2Temperature
If cooling cavities are added to airfoils, then cooling portions of airfoil bodies is achieved, but device complexity increases
Solution Approach 1:
The tip flag cavity and serpentine cavity are merged into a single integrated cooling system with fluid communication between them. The tip flag cavity connects to the serpentine cavity through their respective walls, allowing cooling airflow to traverse both cavities sequentially. This merging provides enhanced cooling efficiency while avoiding the complexity of entirely separate cooling systems
Solution Approach 2:
The serpentine cavity serves multiple functions: it cools the main airfoil body and simultaneously provides a fluid communication pathway to the tip flag cavity. This multi-functionality allows a single cavity structure to contribute to both general airfoil cooling and specialized tip region cooling, improving overall cooling efficiency without proportionally increasing device complexity
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 thermal stress on tip cap materials, improves cooling efficiency, and provides additional protection to the serpentine cavity, enhancing thermal mechanical fatigue life and maintaining airflow even if the outer wall is breached.
Implementation Method 1
at least one bleed hole arranged to fluidly connect the dead-end tip flag cavity and the serpentine cavity
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Airfoils for gas turbine engines are described. The airfoils (320) include an airfoil body extending between a platform (348) and a tip (322), the airfoil body having a leading edge (322), a trailing edge (324), a pressure side (326), and a suction side (328), a serpentine cavity formed within the airfoil body and having an up-pass serpentine cavity (340), a down-pass serpentine cavity (342), and a trailing edge cavity (344), and a dead-end tip flag cavity (338) extending in a direction between the leading edge and the trailing edge, the dead-end tip flag cavity arranged between the serpentine cavity and the tip, wherein the dead-end tip flag cavity ends at a dead-end wall (366) located at a position between the leading edge and the trailing edge of the airfoil body. A corresponding core assembly for the formation of the airfoil is also provided.