Segmented Effusion Cooling Holes for Thermal Barrier Coating Flow
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Solution Overview
Problem
Thermal barrier coatings can inadvertently occlude or plug effusion cooling holes in gas turbine engine components, compromising their cooling effectiveness and durability.
Innovation Solution
The design of coating occlusion resistant effusion cooling holes with specific geometric features, including an inlet section, metering section, and outlet section, that allow for uniform application of thermal barrier coatings while maintaining efficient cooling fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal barrier coating is applied to protect combustor liner, then component protection from hot combustive gas flow is improved, but cooling features may be occluded or plugged
Solution Approach 1:
The effusion cooling hole is divided into multiple functional sections: an inlet section with larger cross-sectional area, a metering section with reduced cross-sectional area, and an outlet section. This segmentation allows the coating to be applied uniformly without completely blocking the cooling flow path, as the metering section maintains a controlled opening for cooling fluid passage.
Solution Approach 2:
Different sections of the effusion cooling hole have different geometric properties tailored to specific functions. The inlet section has a larger area for fluid intake, the metering section has a reduced area for flow control, and the outlet section has specific geometry for film formation. This local differentiation ensures coating applicability while maintaining cooling effectiveness.
2Manufacturing precision
If uniform thermal barrier coating application is desired, then coating quality is improved, but cooling hole functionality may be compromised
Solution Approach 1:
By segmenting the cooling hole into inlet, metering, and outlet sections with distinct geometries, the design allows uniform coating application across the surface while the internal segmentation maintains functional flow paths that are not completely blocked by the coating.
Solution Approach 2:
The effusion cooling hole geometry is pre-designed with the metering section having a reduced cross-sectional area before coating application. This preliminary geometric configuration ensures that even after uniform coating is applied, sufficient flow area remains for effective cooling fluid passage.
3Ease of manufacture
If effusion cooling hole cross-sectional area is reduced to prevent coating occlusion, then coating application is improved, but cooling fluid flow may be insufficient
Solution Approach 1:
The cooling hole is segmented into an inlet section with larger area for sufficient fluid intake and a metering section with reduced area for coating compatibility. This segmentation allows the system to maintain adequate cooling flow while being manufacturable with uniform thermal barrier coating application.
Solution Approach 2:
The cross-sectional area parameter is changed along the length of the effusion cooling hole, with the inlet section having a larger area for flow supply and the metering section having a reduced area. This parameter variation optimizes both cooling fluid flow and coating application characteristics.
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
Ensures effective cooling of gas turbine engine components by preventing plugging of cooling holes and enabling uniform coating application, thereby enhancing component life and reducing maintenance costs.
Implementation Method 1
The outlet section is configured to form the film of the cooling fluid on the surface
Implementation Method 2
a thermal barrier coating may be applied to the combustor liner to provide further protection from the hot combustive gas flow
Data Source
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AI summary
A coating occlusion resistant effusion cooling hole (300) to form a film of a cooling fluid on a surface of a wall (308). The cooling hole extends along a longitudinal axis (LA). The cooling hole includes an inlet section (310) defined so as to be spaced apart from the surface. The inlet section is to receive the cooling fluid. The cooling hole includes a metering section (316) fluidly coupled downstream of the inlet section. The cooling hole includes an outlet section (318) fluidly coupled downstream of the metering section. The outlet section includes an overhang portion (348) , a recessed portion (350,352), a first sidewall (354) and a second sidewall (356). The first sidewall and the second sidewall interconnect the overhang portion with the recessed portion along a portion of the outlet section, and the first sidewall and the second sidewall converge and diverge in a plane transverse to the longitudinal axis.