Combustor Wall Metallic Coating for Thermal Transfer
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Solution Overview
Problem
Gas turbine combustors face challenges in managing high thermal loads, leading to potential burn-through and oxidation issues due to prolonged exposure to hot combustion gases, which existing cooling methods and coatings do not adequately address.
Innovation Solution
A combustor wall with geometric surface features, such as pins or dimples, coated with an oxidation-resistant MCrAlY metallic coating, which covers at least a portion of the surface and includes a ceramic thermal barrier coating on the opposite side, effectively resisting burn-through and oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thermal barrier coating is applied on the hot side of the combustor wall, then thermal insulation is improved, but thermal transfer on the cold side deteriorates
Solution Approach 1:
The coating system is segmented into two distinct parts: a ceramic thermal barrier coating on the hot side for insulation, and a metallic coating on the cold side for thermal transfer. This segmentation allows each coating to optimize its specific function without interfering with the other.
Solution Approach 2:
Different coatings are applied to different sides of the combustor wall based on local requirements. The hot side receives a ceramic coating for maximum thermal insulation, while the cold side receives a metallic coating to maintain thermal transfer efficiency, creating local quality optimization.
2Productivity
If the combustor wall is exposed to hot combustion gases for prolonged periods, then power generation is maintained, but burn-through and oxidation occur
Solution Approach 1:
The combustor wall employs a composite coating system combining ceramic and metallic materials. The ceramic thermal barrier coating provides primary protection against heat, while the metallic coating on the cold side provides oxidation resistance and structural integrity, creating a composite protective system that addresses multiple failure modes simultaneously.
Solution Approach 2:
The dual-coating system acts as a beforehand cushioning mechanism, providing multiple layers of protection before burn-through or oxidation can occur. The ceramic layer absorbs thermal stress, while the metallic layer prevents oxidation and structural degradation, cushioning the wall against prolonged thermal exposure.
3Temperature
If geometric surface features are added to enhance thermal transfer, then heat dissipation is improved, but surface area for oxidation increases
Solution Approach 1:
The metallic coating acts as an intermediary layer between the geometric surface features and the oxidizing environment. It allows the surface features to maintain their heat dissipation function while protecting them from direct oxidation exposure, mediating between thermal management requirements and chemical resistance needs.
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 solution significantly enhances thermal transfer and oxidation resistance, preventing complete burn-through of the combustor wall while maintaining thermal conductivity, even when the thermal barrier coating spalls or oxidizes.
Implementation Method 1
The geometric surface features are either pins that extend outwards from the substrate or dimples that extend into the substrate
Implementation Method 2
A metallic coating is disposed on at least a portion of the second side of the combustor wall... the metallic coating is more resistant to oxidation than at least one material that forms the combustor wall
Implementation Method 3
there is a ceramic thermal barrier coating disposed on the first side
Data Source
Figure 1~2
Figure 3~5
AI summary
A combustor (56) includes a combustion chamber (56a) and a combustor wall (60) that at least partially bounds the combustion chamber. The combustor wall includes a first side (60a) that faces the combustion chamber and a second side (60 b) that faces away from the combustion chamber. The second side includes an array of geometric surface features (62) for thermal transfer. A metallic coating (64) is disposed on at least a portion of the second side of the combustor wall.