Gas Turbine Airfoil Diffuser Hole Linear Ridge Thermal Barrier Coating
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Solution Overview
Problem
Existing gas turbine engine cooling systems face challenges due to linear ridges forming at the exit portion of diffuser holes connected to minicores, which disrupt air flow and require additional fabrication steps to remove, increasing time and cost.
Innovation Solution
A component for a gas turbine engine is designed with a minicore exit aperture featuring a linear ridge on its downstream end, which is covered by a thermal barrier coating. The linear ridge's height is within a specific range relative to the cooling passage depth, and the thermal barrier coating transitions smoothly to ensure uninterrupted air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If linear ridges are removed from the diffuser hole exit portion, then air flow disruption is prevented, but manufacturing time and cost increase due to additional fabrication steps
Solution Approach 1:
The linear ridge, originally considered a harmful defect disrupting air flow, is reinterpreted as a beneficial feature that enhances thermal barrier coating adherence. The ridge structure provides anchoring points for the coating material, improving its bonding to the component surface while maintaining acceptable air flow characteristics.
Solution Approach 2:
The invention accepts the linear ridge as an inherent feature of the investment casting process rather than attempting to eliminate it through additional expensive fabrication steps. The ridge is retained and utilized for its coating adherence benefit, eliminating the need for costly removal operations.
2Ease of operation
If linear ridges are removed from the diffuser hole exit portion, then air flow disruption is prevented, but manufacturing cost increases
Solution Approach 1:
The linear ridge defect is converted into a beneficial feature that improves thermal barrier coating adherence. This eliminates the need for additional fabrication steps to remove the ridge, thereby reducing manufacturing costs while maintaining component performance.
Solution Approach 2:
The linear ridge structure serves dual purposes: it is both a byproduct of the investment casting process and a functional feature that enhances coating adherence. The manufacturing process inherently creates a feature that serves a useful function, eliminating the need for separate corrective operations.
3Productivity
If linear ridges are retained on the diffuser hole exit portion, then manufacturing time and cost are reduced, but air flow disruption occurs
Solution Approach 1:
The linear ridge, initially seen as causing air flow disruption, is reinterpreted as providing beneficial anchoring for thermal barrier coating. The coating adheres more effectively to the ridged surface, and the overall aerodynamic impact is minimized through proper coating application.
Solution Approach 2:
The invention changes the functional interpretation of the linear ridge from a harmful geometric feature to a beneficial surface structure for coating adherence. By focusing on coating application parameters rather than ridge removal, the system achieves both manufacturing efficiency and acceptable air flow performance.
4Ease of manufacture
If linear ridges are retained on the diffuser hole exit portion, then manufacturing cost is reduced, but cooling efficiency deteriorates
Solution Approach 1:
The linear ridge structure is converted from a potential cooling efficiency detriment into a coating adherence enhancement feature. The improved coating bonding ensures better thermal protection and maintains cooling system reliability while avoiding additional manufacturing costs.
Solution Approach 2:
The invention utilizes the composite structure of the thermal barrier coating applied over the ridged surface. The combination of the ridged metal substrate and the coating material creates a synergistic structure that maintains cooling efficiency while providing enhanced coating adherence and cost-effective manufacturing.
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 solution enhances manufacturability by eliminating the need to remove linear ridges, reduces manufacturing costs, and improves the adherence of cooling fluid to the component surface, thereby enhancing the cooling efficiency of gas turbine engine components.
Implementation Method 1
a thermal barrier coating covering the outer wall and the linear ridge
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
An airfoil for a gas turbine engine (100) is disclosed. In various embodiments, the airfoil includes a cooling passage (354); an outer wall (202; 302) separating a core flow path from the cooling passage (354); a diffuser in fluid communication with the cooling passage (354) and opening into the core flow path, the diffuser being characterized by a linear ridge (262; 362) on a downstream end of the diffuser; and a thermal barrier (260; 360) coating covering the outer wall (202; 302) and the linear ridge (262; 363).