Gas Turbine Airfoil Cooling Circuit Segmentation
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Solution Overview
Problem
Gas turbine engine airfoils face challenges in efficiently cooling internal and external surfaces due to repetitive thermal cycling under extreme temperatures and pressures, requiring effective internal cooling circuits that minimize dedicated cooling airflow.
Innovation Solution
The cooling circuit design includes a first and second core cavity radially extending inside the airfoil, with axial skin cores in fluid communication, and a leading edge cavity, allowing for efficient distribution and reuse of cooling airflow to cool the airfoil's tip and edge portions, enhancing heat transfer through features like pedestals and trip strips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional internal cooling circuits are used in airfoils, then cooling coverage is provided, but dedicated cooling airflow consumption is high
Solution Approach 1:
The cooling circuit is segmented into multiple independent cavities (leading edge cavity, first core cavity, second core cavity, tip flag cavity) that can be separately configured and optimized. Each cavity serves specific cooling zones, allowing targeted cooling where needed rather than uniform cooling throughout, thereby reducing overall cooling airflow requirements while maintaining effective temperature control in critical areas.
Solution Approach 2:
The cooling cavities are nested within the airfoil structure, with core cavities positioned between skin cores and internal structures. The first and second core cavities are nested between pressure side and suction side skin cores, while the tip flag cavity is nested within the tip structure. This nested arrangement maximizes cooling surface area within the limited airfoil volume without increasing external dimensions or cooling airflow consumption.
2Reliability
If cooling circuits are added to cool airfoil surfaces, then thermal protection is improved, but device complexity increases
Solution Approach 1:
The skin cores serving as structural elements of the airfoil also function as walls defining the cooling cavities. The leading edge structure serves both aerodynamic purposes and houses the leading edge cooling cavity. The tip structure serves both structural integrity and contains the tip flag cooling cavity. This multi-functionality reduces the need for separate cooling components, thereby improving thermal durability without proportionally increasing device complexity.
Solution Approach 2:
The cooling circuit is merged with the airfoil's structural framework. The first and second skin cores that provide structural support to the airfoil also form the boundaries of the core cooling cavities. The pedestals and trip strips that are part of the airfoil's internal structure also serve as heat transfer enhancement features within the cooling cavities. This merging of cooling and structural functions achieves thermal protection without adding separate complex cooling systems.
3Temperature
If cooling airflow is increased to improve heat transfer, then cooling effectiveness increases, but energy consumption increases
Solution Approach 1:
Trip strips are positioned within the core cavities to preliminarily disturb the cooling airflow before it reaches the airfoil cooling surfaces. This preliminary action creates turbulence and enhances mixing, improving heat transfer coefficients without requiring increased cooling airflow volume. The pedestals similarly prepare the flow structure to maximize heat extraction from the airfoil surfaces, achieving better cooling effectiveness with the same or reduced cooling airflow energy input.
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 effectively cools the airfoil with minimal dedicated airflow, accommodating various shapes and sizes, and increases the heat transfer coefficient, thereby improving the operational efficiency and durability of gas turbine engine components.
Implementation Method 1
Airfoil cooling systems are taught in WO 99/06672 and US 7,717,675 as well as in GB-2111604-A and EP-1882820-A1
Implementation Method 2
a first axial skin core in fluid communication with the first core cavity at a first location of the first axial skin core, and a second core cavity in fluid communication with the first axial skin core at a second location of the first axial skin core
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
A component for a gas turbine engine according to an exemplary aspect of the present disclosure includes, among other things, an airfoil that extends between a leading edge, a trailing edge, a pressure side wall and a suction side wall. A cooling circuit is disposed inside of the airfoil. The cooling circuit includes a first core cavity that radially extends inside of the airfoil. A first axial skin core is in fluid communication with the first core cavity at a first location of the first axial skin core and a second core cavity is in fluid communication with the first axial skin core at a second location of the first axial skin core.