Two-Panel Gas Turbine Transition Duct Cooling
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Solution Overview
Problem
The transition ducts in gas turbine engines face stress concentration and poor cooling in corner regions due to manufacturing processes and design constraints, particularly with four-panel designs where welds preclude corner cooling channels, leading to inefficiencies in thermal management and increased stress.
Innovation Solution
A two-panel transition duct design with subsurface cooling channels located directly in the corners, featuring increased corner radii and reduced curvature, allowing effective cooling and reduced stress concentrations, along with thinner panels and optimized welding to maintain cooling channel integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If four-panel construction with welds in corners is used, then manufacturing complexity is reduced, but cooling effectiveness in corner regions deteriorates
Solution Approach 1:
The transition duct is divided into multiple panels (first, second, third, and fourth panels) that are joined together to form the complete duct structure. This segmentation allows for modular manufacturing while enabling cooling channels to be positioned in corner regions through strategic placement of welds along non-corner edges.
Solution Approach 2:
Cooling channels are specifically positioned in corner regions where thermal loads are highest, creating local quality enhancement in critical areas. The corner regions receive dedicated cooling attention through channels located at corners of the panels, ensuring optimal cooling effectiveness where it is most needed.
2Manufacturing precision
If welds are placed in corner regions, then manufacturing strain is reduced, but cooling channel placement is precluded
Solution Approach 1:
The duct is segmented into multiple panels where welds are strategically placed along edges that are not corner regions. This segmentation allows welds to be positioned in locations that minimize forming strain while preserving corner regions for cooling channel placement.
Solution Approach 2:
The problem is resolved by considering the three-dimensional arrangement of panels and welds. Welds are placed on panel edges rather than in corner regions, utilizing the dimensional space available in the panel assembly to separate weld locations from corner regions where cooling channels are needed.
3Strength
If corner cooling channels are excluded, then welding integrity is maintained, but thermal management in high-stress regions deteriorates
Solution Approach 1:
The transition duct is divided into multiple panels with welds positioned along non-corner edges. This segmentation maintains welding integrity away from corner regions while enabling dedicated cooling channels to be installed in corner regions for effective thermal management.
Solution Approach 2:
Cooling channels are specifically positioned in corner regions where thermal loads and stresses are highest, providing localized quality enhancement for thermal management in these critical areas while maintaining overall welding integrity.
4Stress or pressure
If highly engineered specific duct profile is used, then stress concentration is reduced, but design flexibility is reduced
Solution Approach 1:
Instead of requiring a highly engineered specific duct profile throughout, the invention applies local quality enhancement by positioning cooling channels specifically in corner regions where stress concentration occurs. This targeted approach reduces stress concentration without compromising overall design flexibility.
Solution Approach 2:
The invention modifies specific parameters (cooling channel placement in corner regions) rather than requiring changes to the overall duct profile geometry. This allows stress concentration to be addressed through parameter optimization in critical areas while maintaining design flexibility for the overall duct configuration.
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 two-panel design reduces stress concentration, enhances cooling effectiveness, decreases thermal growth, and lowers fabrication costs while maintaining or improving flow efficiency and fatigue life, with reduced gap requirements between adjacent ducts.
Implementation Method 1
a first cooling channel (32) extending along a first corner (34) of the first panel (36) generally parallel to a direction of flow of hot combustion gas
Implementation Method 2
subsurface cooling channels located directly in the corners, featuring increased corner radii and reduced curvature, allowing effective cooling
Data Source
AI summary
A transition duct (30) for a gas turbine engine (2) having improved cooling and reduced stress levels. The transition duct may be formed of two panels ((36, 38) joined together with welds (40) disposed remote from the bent corner regions (34) of the panels. Cooling channels (32) extending longitudinally in the direction of flow of the hot combustion gas carried by the duct are formed within each panel, including the corner regions. Because the entire annular width (W) of the transition duct is cooled, the gap (G) separating adjacent ducts around the inlet to the turbine (4) may be reduced when compared to prior art designs. Two-panel construction with welds remote from the corner regions is facilitated by maintaining the minimum bend radius in the corners (R2) and in the direction of flow (R4) to be greater than in prior art designs.