CMC Airfoil Vane Baffle Assembly for Trailing-Edge Cooling
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Solution Overview
Problem
Existing airfoil baffles in gas turbine engines often lack cooling holes near the trailing edge, leading to reduced cooling efficiency due to manufacturing limitations, resulting in inadequate impingement cooling at this critical area.
Innovation Solution
The airfoil vane incorporates a baffle with a leading edge portion formed via additive manufacturing and a trailing edge portion made of sheet metal, both featuring cooling holes, with a joint design that includes a neck and step configuration to enhance cooling air distribution and structural integrity, allowing for improved cooling efficiency at the trailing edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a baffle is made entirely by additive manufacturing, then manufacturing flexibility and cooling hole placement are improved, but manufacturing precision and structural integrity at thin sections deteriorate
Solution Approach 1:
The baffle is divided into two distinct portions: a leading edge portion manufactured by additive manufacturing that provides cooling holes and geometric flexibility, and a trailing edge portion made by conventional methods that ensures precision at thin sections. This segmentation allows each portion to be optimized for its specific manufacturing requirements while working together as an integrated component.
2Reliability
If cooling holes are added to the trailing edge portion, then cooling efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The baffle manufacturing is segmented into two portions with different fabrication methods. The trailing edge portion is manufactured separately using conventional precision methods that can accommodate cooling holes, while the leading edge portion uses additive manufacturing. This segmentation resolves the complexity issue by applying the appropriate manufacturing method to each section rather than attempting to manufacture the entire baffle by one method.
3Length of moving object
If the trailing edge width is reduced to accommodate size constraints, then fit to airfoil section is improved, but structural strength deteriorates
Solution Approach 1:
The baffle employs a composite construction with two different material portions: the leading edge portion made by additive manufacturing and the trailing edge portion made by conventional methods. This composite approach allows the trailing edge to be precisely sized to fit the airfoil section while maintaining adequate strength through the use of appropriate materials and manufacturing methods for that specific section.
4Ease of manufacture
If the baffle is manufactured as a single piece, then assembly simplicity is improved, but manufacturing flexibility and cooling performance deteriorate
Solution Approach 1:
The baffle is segmented into a leading edge portion and a trailing edge portion that can be manufactured separately using optimized methods for each section. The leading edge portion incorporates cooling holes and complex geometry through additive manufacturing, while the trailing edge portion is manufactured with precision conventional methods. These portions are then joined to form the complete baffle, combining the advantages of both manufacturing approaches.
5Reliability
If cooling air flow is increased to the trailing edge, then cooling efficiency is improved, but pressure loss in the cooling system increases
Solution Approach 1:
The baffle implements local quality by providing different cooling configurations in different sections. The trailing edge portion is specifically equipped with cooling holes to deliver cooling air precisely where needed, while the leading edge portion has its own cooling hole pattern. This localized cooling approach ensures efficient cooling at the trailing edge without requiring excessive overall cooling air flow, thereby minimizing pressure loss in the cooling system.
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 provides enhanced cooling efficiency at the trailing edge of the airfoil vane by ensuring cooling air impingement through strategically placed cooling holes, addressing the inefficiencies of baffles without such features and accommodating manufacturing tolerances and size constraints.
Implementation Method 1
Both the leading edge portion and the trailing edge portion include a plurality of cooling holes which are configured to provide cooling air to the airfoil outer wall
Implementation Method 2
The joint includes a step formed on the leading edge portion. A forward edge of the leading edge of the trailing edge portion is disposed in the step.
Data Source
Figure 1
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Figure 4~5
AI summary
An airfoil vane (100) includes an airfoil section (106) which includes an outer wall (108) that defines an internal cavity (110). A baffle (200) is situated in the internal cavity (110). The baffle (200) includes a leading edge portion (202) and a trailing edge portion (204) which is bonded to the leading edge portion (202) at a joint (206). The leading edge portion (202) and the trailing edge portion (204) define an internal cavity (110) therewithin. Both the leading edge portion (202) and the trailing edge portion (204) include a plurality of cooling holes (210) which are configured to provide cooling air to the airfoil outer wall (108). The trailing edge portion (204) is formed of sheet metal and the leading edge portion (202) is formed of non-sheet-metal. A method of making a baffle (200) for a vane arc segment and a method of assembling a ceramic matrix composite (CMC) airfoil vane (100) are also disclosed.