Ceramic Matrix Composite Turbine Bucket Dovetail Insert
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Solution Overview
Problem
The production of large ceramic matrix composite turbine buckets is hindered by excessive variation in root shank geometry, increased ply lay-up time, and difficulty in inspecting or monitoring interior portions, leading to higher production costs and weight issues.
Innovation Solution
A process involving a bucket preform with a dovetail cavity, where an insert is positioned within the cavity, allowing for uniform thickness formation and inspection, and using a ceramic matrix composite turbine bucket arranged for receiving an insert in a dovetail cavity, facilitating melt infiltration and reducing material costs and ply lay-up time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional melt infiltration processes are used for large turbine buckets, then production can proceed with conventional methods, but excessive variation in root shank geometry occurs and inspection of interior portions is difficult
Solution Approach 1:
The root shank is divided into two parts: an exterior portion and an interior portion. The interior portion is further segmented into multiple preform segments (first preform segment, second preform segment, etc.) that can be separately fabricated and then assembled. This segmentation allows each segment to be inspected individually before assembly, solving the inspection difficulty while maintaining geometric uniformity through controlled fabrication of each segment.
2Manufacturing precision
If a large number of plies are used to produce large blades/buckets, then coverage and completeness can be improved, but ply lay-up time increases and production costs increase
Solution Approach 1:
Multiple preform segments are fabricated in advance before the final assembly step. Each preform segment is prepared separately with the required ply structures already in place, then these pre-fabricated segments are assembled into the final blade/bucket structure. This preliminary fabrication of segments eliminates the need for time-consuming on-site ply lay-up of the entire structure, significantly reducing production time while maintaining completeness.
3Ease of manufacture
If conventional production methods are used, then existing processes can be maintained, but weight increases due to use of a large number of plies
Solution Approach 1:
The invention changes the fabrication parameters from traditional multi-pley sequential lay-up to a segmented preform assembly approach. By fabricating separate preform segments and assembling them, the structure achieves the required completeness with fewer total plies, thereby reducing weight while maintaining ease of manufacture through standardized segment fabrication and assembly procedures.
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 enables the fabrication of larger components with uniform thickness, reduces production costs, simplifies manufacturing of thick sections, and allows for effective monitoring and inspection of pre-fabricated portions within the dovetail cavity.
Implementation Method 1
forming the ceramic matrix composite turbine bucket in a furnace
Data Source
AI summary
A process of producing a ceramic matrix composite turbine bucket, an insert for a ceramic matrix composite turbine bucket, and a ceramic matrix composite turbine bucket are disclosed. The process includes providing a bucket preform having a dovetail cavity, the dovetail cavity being enclosed within a dovetail shank of the bucket preform, positioning an insert within the dovetail cavity, then forming the ceramic matrix composite turbine bucket in a furnace. The insert includes a geometry configured to be fit within a dovetail cavity of the ceramic matrix composite turbine bucket, a bucket preform, or both. The insert is foam material or a plurality of ceramic matrix composite plies. The ceramic matrix composite turbine bucket includes a dovetail shank and a dovetail cavity enclosed within the dovetail shank. The dovetail cavity is arranged and disposed for receiving an insert.