Ceramic-to-Metal Turbine Volute Attachment via Radial Recessed Faces
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Solution Overview
Problem
Current ceramic-to-metal attachment methods in gas turbine engines face challenges with differential thermal expansion, leading to friction, wear, and potential failure due to stress concentrations and uneven motion between ceramic and metallic components, limiting operating temperatures and efficiency.
Innovation Solution
A new attachment method using radial recessed faces on both ceramic and metallic surfaces allows for differential thermal growth while maintaining alignment and reducing stress concentrations, providing a larger bearing surface and minimizing friction, enabling operation at higher temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional ceramic-to-metal attachment methods are used, then the components can be assembled, but differential thermal expansion causes friction, wear, and stress concentrations that limit operating temperature and reliability
Solution Approach 1:
The attachment surface features localized recessed regions that concentrate the thermal expansion accommodation function in specific areas, while other areas maintain rigid support. This local differentiation allows the joint to handle differential expansion without compromising overall structural integrity, enabling higher operating temperatures while maintaining reliability.
Solution Approach 2:
The design explicitly incorporates features that accommodate differential thermal expansion between ceramic and metal components. The recessed attachment surfaces and compliant elements allow each material to expand at its own rate without generating excessive stress, directly addressing the thermal expansion contradiction.
2Stability of the object's composition
If rigid attachment methods are used to maintain alignment, then component alignment is preserved, but thermal cycling causes wear and degradation of clearances due to differential expansion
Solution Approach 1:
The attachment design transitions from a purely rigid connection to a dynamic system that can adapt during thermal cycling. The recessed features and compliant elements allow controlled movement and adjustment as temperatures change, maintaining alignment while accommodating differential expansion, thereby extending service life.
Solution Approach 2:
The design incorporates compliant elements and recessed regions that act as cushions before excessive stresses can develop. These features absorb the shocks of differential expansion during thermal cycling, preventing wear and degradation that would otherwise occur in rigid attachments, thus extending component service life.
3Stress or pressure
If larger attachment surfaces are used to reduce stress concentrations, then stress distribution improves, but friction and wear increase due to greater contact area during thermal cycling
Solution Approach 1:
The attachment surface is segmented into multiple recessed regions rather than a single large continuous surface. This segmentation distributes the contact areas, reducing stress concentrations while also reducing the total friction surface area. Each recessed region handles a portion of the load and thermal expansion independently, minimizing overall friction and wear.
Solution Approach 2:
The attachment interface has differentiated local zones: recessed regions for stress distribution and compliant element engagement, and non-recessed regions for minimal contact. This local quality differentiation allows stress concentration reduction without proportionally increasing friction and wear, as the high-stress areas are concentrated in controlled recessed zones.
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 design enhances the durability and efficiency of gas turbine engines by maintaining component alignment and reducing wear, allowing for increased operating temperatures and improved thermal cycling performance.
Implementation Method 1
differential thermal expansion, leading to friction, wear, and potential failure due to stress concentrations and uneven motion between ceramic and metallic components
Data Source
AI summary
A means of attachment applicable to mating parts which have substantially different coefficients of thermal expansion is disclosed. The means of attachment substantially reduces the friction between the mating surfaces while still keeping the mating parts centered with respect to one another. The approach is based on radial recessed faces wherein the radial faces slide relative to each other. There may be three or more recessed/raised faces on each mating component, which when mated, maintain the alignment between the mating parts while allowing differential growth of the mating parts. This approach also the provides a much larger bearing surface for the attachment than a radial pin/slot approach, for example, and substantially eliminates areas of high stress concentration. It is thus a more robust design for components that undergo many thousands of thermal cycles.