Turbine Trailing Edge Coating Discontinuous Transition
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Solution Overview
Problem
Ceramic matrix composite components in gas turbines face issues with hot gas flow along curved trailing edges due to the lack of adherence of environmental barrier coatings (EBC) and thermal barrier coatings (TBC), leading to undesirable stresses and failure, especially with sharp-edged features and tight radii.
Innovation Solution
A coated turbine component with a discontinuous transition feature formed from an additional portion of the coating extending outward from the curved trailing edge face, discouraging hot gas flow and using thermal or environmental barrier coatings to prevent stress and failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sharp-edged features or tight radii are used on turbine components, then manufacturing precision and aerodynamic performance are improved, but coating adherence deteriorates and stress concentration increases leading to coating failure
Solution Approach 1:
The trailing edge is segmented into multiple zones with different radius values. A first radius is applied at the leading portion of the trailing edge, while a second, larger radius is applied at the trailing portion. This segmentation allows the coating to adhere properly to the substrate by providing adequate transition zones, while still maintaining precise aerodynamic features in the leading portion where tight radii are critical for performance.
2Productivity
If tight radii are used to control leakage, then aerodynamic efficiency is improved, but coating stress increases leading to coating failure
Solution Approach 1:
Different radius values are applied to different local zones of the trailing edge. The leading portion maintains tight radii for effective leakage control, while the trailing portion uses larger radii to reduce coating stress. This local differentiation allows tight leakage control to be maintained where aerodynamic efficiency is most sensitive, while coating stress is relieved in regions where it would otherwise cause failure.
3Ease of manufacture
If uniform coating is applied across the trailing edge, then manufacturing simplicity is maintained, but coating performance deteriorates due to stress concentration at sharp features
Solution Approach 1:
The trailing edge features curved transitions with specific radius values instead of sharp edges or uniform geometry. A first curved transition with a first radius connects the hot gas path surface to the curved trailing edge face, while a second curved transition with a second radius connects the curved trailing edge face to the cooling air path surface. These curved transitions eliminate stress concentration points, allowing the coating to remain stable and adherent across the entire trailing edge structure.
Data Source
AI summary
A method for forming a coated turbine component and a coated turbine component is provided. The method includes a step of providing a component having a substrate including a trailing edge face. The method further includes a step of applying a thermal barrier coating or environmental barrier coating selectively to the substrate to form a discontinuous transition from a hot gas path surface at the trailing edge face to discourage hot gas flow along the trailing edge face.