Ceramic Matrix Composite Nozzle Guide Vane Passage with Integral Attachment Lugs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current ceramic matrix composite (CMC) materials for gas turbine nozzle guide vanes face challenges in forming annular arrays due to the required lay-up of fibers, which prevents acute transitions from vanes to platforms, and joining separate components is difficult, limiting their mechanical robustness and compatibility with existing architectures.
Innovation Solution
A nozzle guide vane assembly comprising a plurality of layers of ceramic fibers held in a ceramic matrix, with integral attachment lugs that continue uninterrupted between the vanes and platforms, allowing for secure coupling of adjacent passages in an annular array, and a method of forming these passages using a mandrel and braided tubes of interwoven fibers, enabling the creation of a continuous ceramic structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If CMC materials are used to form nozzle guide vanes with acute transitions from vanes to platforms, then the mechanical robustness and temperature tolerance are improved, but the manufacturing complexity increases due to the required fiber lay-up patterns
Solution Approach 1:
The nozzle guide vane is divided into separate components: the vane body and the attachment lug. This segmentation allows the fiber lay-up to be optimized for each component's specific structural requirements, with the vane body using patterns suitable for aerodynamic loads and the attachment lug using patterns optimized for mechanical coupling, thereby achieving high mechanical robustness without excessive manufacturing complexity
Solution Approach 2:
The attachment lug is extracted as a separate functional element from the main vane body. This extraction allows the acute transition geometry to be concentrated in the lug portion where it is most needed for mechanical robustness, while the main vane body can use simpler fiber lay-up patterns, reducing overall manufacturing complexity while maintaining the required strength
2Adaptability or versatility
If separate CMC components are joined together to form annular arrays, then the adaptability to existing engine architectures is improved, but the joining difficulty increases
Solution Approach 1:
The attachment lug merges the functions of mechanical attachment and structural support into a single integrated component. The lug is designed to attach adjacent nozzle guide vanes together while also providing the acute transition geometry needed for mechanical robustness, thereby reducing the number of separate joining operations required and simplifying the assembly process for annular arrays
Solution Approach 2:
The attachment lug acts as an intermediary element between adjacent vane bodies. It provides a standardized interface for joining vanes in annular configurations, making the components compatible with existing engine architectures while managing the joining complexity through a dedicated coupling mechanism rather than direct vane-to-vane joining
3Strength
If continuous long fibers are used in CMC materials, then the mechanical robustness is improved, but the difficulty of forming acute transitions from vanes to platforms increases
Solution Approach 1:
By segmenting the structure into vane body and attachment lug, the continuous long fibers can be oriented optimally in each segment. The vane body uses fiber orientations suited for aerodynamic loads, while the attachment lug uses orientations optimized for acute transitions and mechanical coupling, maintaining mechanical robustness without requiring complex fiber routing across the entire component
Solution Approach 2:
Extracting the attachment lug as a separate element concentrates the acute transition requirements in a dedicated component where continuous fibers can be efficiently routed. This allows the main vane body to use simpler, more manufacturable fiber lay-up patterns while the lug portion handles the complex acute transitions, reducing overall manufacturing precision difficulties
Data Source
Figure 1~4
Figure 2a~2b
Figure 3a~3e
AI summary
Described is a nozzle guide vane assembly may comprise: a plurality of nozzle guide vane passages (236) arranged in an annular array, each nozzle guide passage comprising inner (216) and outer (218) radial platforms, a suction surface (230) of a first vane, and a pressure surface (228) of a second vane, wherein the nozzle guide passages are made from a plurality of layers of ceramic fibres held in a ceramic matrix, wherein a first nozzle guide passage includes at least one attachment lug (252) attaching the nozzle guide passage to either or both of an engine casing and an adjacent second nozzle guide passage, the attachment lug being integral with the first nozzle guide passage.