Airfoil Leading Edge Cooling Pin Structures
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Solution Overview
Problem
Gas turbine engines face challenges in cooling the leading edges of airfoils due to high temperature gases, which increases the risk of oxidation, especially as higher turbine inlet temperatures and speeds are required for efficiency.
Innovation Solution
An airfoil with a leading edge convective cooling system that utilizes pin structures within a cavity to enhance convective heat transfer between the leading edge and a low-temperature cooling fluid, reducing oxidation risks and allowing for increased turbine inlet temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If higher turbine inlet temperatures are used to improve gas turbine engine efficiency, then power output and efficiency are improved, but the risk of oxidation of the leading edge increases
Solution Approach 1:
The leading edge is segmented into multiple cavities (first cavity and second cavity) that are separated by a rib. Each cavity contains pin structures that create turbulence independently. This segmentation allows for more effective cooling coverage and better heat transfer distribution across the leading edge surface, enabling the airfoil to withstand higher turbine inlet temperatures without oxidation.
Solution Approach 2:
The cooling approach transitions from a two-dimensional smooth surface to a three-dimensional structured surface with pin structures extending into the cavities. This adds vertical dimensionality to the cooling system, creating turbulence and enhancing convective heat transfer in the fluid passage, thereby improving cooling effectiveness at higher temperatures.
2Device complexity
If conventional cooling systems are used with smooth leading edges, then the structure is simple, but the cooling effectiveness is insufficient and requires high cooling flow
Solution Approach 1:
The pin structures are pre-positioned within the cavities before the cooling fluid flows through the passage. These structures create turbulence and enhance heat transfer immediately as the cooling fluid enters, preparing the flow conditions for maximum cooling effectiveness before the fluid contacts the heated leading edge surface.
Solution Approach 2:
The pin structures act as intermediaries between the cooling fluid and the leading edge surface. They transfer heat from the leading edge to the cooling fluid more effectively by creating turbulence and increasing the heat transfer surface area, thereby improving cooling effectiveness without requiring excessive cooling flow.
3Reliability
If pin structures are added to create turbulence and enhance heat transfer, then cooling effectiveness is improved, but the device complexity increases
Solution Approach 1:
The pin structures are integrated with the rib that divides the cavities. The rib serves dual purposes: separating the cavities and supporting the pin structures. This merging of functions reduces the number of separate components and simplifies the overall manufacturing process while maintaining the turbulence-enhancing cooling effectiveness.
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
The cooling system effectively reduces the risk of oxidation by improving heat transfer, allowing for higher turbine inlet temperatures and reducing the required cooling flow by approximately half compared to smooth leading edges.
Implementation Method 1
pin structures disposed within the leading edge cavity and providing convective cooling between the leading edge and a cooling fluid
Data Source
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AI summary
An airfoil includes a leading edge and an opposing trailing edge. The airfoil includes a pressure sidewall and an opposing suction sidewall. A leading edge cavity (240) is defined between the pressure sidewall and the suction sidewall. The leading edge cavity has a first end opposite the leading edge and a second end defined at a rib. The airfoil includes at least one pin structure (250) defined in the leading edge cavity between the first end and the second end. The at least one pin structure includes a main body (260) and a first branch (262). The main body is coupled to the second end and extends toward the first end. The first branch extends from the main body toward the first end. Alternatively, the airfoil includes at least one pin set defined in the leading edge cavity between the first end and the second end, the at least one pin set including a first pin and a second pin, the first pin coupled to the second end and extending to an inner surface of the suction sidewall, the second pin coupled to the second end and extending toward the first end, the first pin overlapping the second pin.