Microchannel Trailing-Edge Cooling for Thin Turbine Components
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Solution Overview
Problem
Conventional cooling methods for gas turbine engine components, particularly the trailing edge region of airfoils, result in non-uniform temperature profiles and require thicker profiles or compromise casting yields, necessitating an improved cooling strategy that maintains thinness and efficiency.
Innovation Solution
The implementation of micro-channel cooling systems with re-entrant shaped grooves and channels on both pressure and suction side walls, utilizing abrasive liquid jet machining and structural coatings to enhance heat transfer without increasing the trailing edge thickness, allowing for thinner profiles and improved cooling effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling circuits with internal passages are used, then cooling coverage is provided, but heat transfer rates are low and temperature profiles are non-uniform
Solution Approach 1:
The invention changes the geometric parameters of the cooling channels by transitioning from conventional large-diameter passages to micro-scale channels with dimensions in the range of 0.1-1.0 mm. This parameter change increases the surface area to volume ratio, thereby enhancing heat transfer rates and improving temperature profile uniformity across the component.
Solution Approach 2:
The invention introduces micro-scale dimensional characteristics (10-1000 times smaller than conventional channels) to the cooling system. This dimensional transformation enables significantly increased surface area for heat transfer within the same component volume, resolving the contradiction between heat transfer rate and temperature uniformity.
2Temperature
If cooling holes are drilled through the trailing edge base, then cooling is provided to the trailing edge region, but the trailing edge thickness must be increased
Solution Approach 1:
The invention applies local quality by concentrating multiple micro-scale cooling channels within the existing trailing edge thickness rather than requiring additional thickness. The local region (trailing edge) is enhanced with dense micro-channel networks that provide adequate cooling without modifying the overall component geometry.
Solution Approach 2:
By transitioning to micro-scale channel dimensions, the invention enables multiple cooling pathways to be packed into the available trailing edge thickness, eliminating the need to increase thickness while still providing sufficient cooling coverage to the trailing edge region.
3Temperature
If pressure side bleed slot configuration is used, then trailing edge cooling is achieved, but ceramic core issues arise and casting yields decrease
Solution Approach 1:
The invention changes the geometric parameters from large bleed slots to micro-scale channels, which can be integrated into the casting process without creating the ceramic core support issues associated with conventional slot configurations. This parameter change maintains cooling effectiveness while improving manufacturing yield.
4Weight of moving object
If thin walls of superalloy metals are used, then component weight is reduced, but cooling requirements increase
Solution Approach 1:
The invention applies parameter changes by implementing micro-scale cooling channels that provide enhanced heat transfer coefficients, enabling thin-walled components to be adequately cooled. The increased surface area to volume ratio in micro-channels compensates for the reduced mass and thermal capacity of thin walls.
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 approach provides enhanced cooling effectiveness, reduces specific fuel consumption, and increases the service lifetime of gas turbine components by maintaining thin trailing edges while improving aerodynamic efficiency and combined cycle efficiency.
Implementation Method 1
A cooling fluid may be provided to the channels from a plenum, and the cooling fluid may flow through the channels, cooling the hot gas path component substrate and any associated coatings
Data Source
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AI summary
A component includes a substrate 110 having an outer surface 112 and an inner surface 116, where the inner surface 116 defines at least one hollow, interior space 114. The outer surface of the substrate 110 defines a pressure side wall 24 and a suction side wall 26. The pressure and suction side walls 24, 26 are joined together at a leading edge 28 and at a trailing edge 30 of the component. The outer surface 112 defines one or more grooves 132 that extend at least partially along the pressure or suction side walls in a vicinity of the trailing edge 30 of the component. Each groove 132 is in fluid communication with a respective hollow, interior space 14. The component further includes a coating 50 disposed over at least a portion of the outer surface 112 of the substrate 110. The coating 50 comprises at least a structural coating, where the structural coating extends over the groove(s) 132, such that the groove(s) 132 and the structural coating together define one or more channels for cooling the trailing edge 30 of the component. A method of forming cooling channels 130 in the vicinity of the trailing edge 30 of a component is also provided.