Pinned Platform for Gas Turbine Blade Attachment
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Solution Overview
Problem
Gas turbine engine turbine wheels face design challenges in coupling composite blades with metallic disks due to heat from combustion products, requiring innovative solutions to enhance durability and stress distribution.
Innovation Solution
A multi-piece disk assembly with a blade and platform system, featuring a dovetail-shaped root and airfoil, and a pin system that couples platforms with the disk for rotation, providing a secure and stress-reduced attachment mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If composite blades are coupled with metallic disks in turbine wheels, then the turbine can withstand heat from combustion products, but stress concentration occurs at the blade attachment points
Solution Approach 1:
The disk is divided into multiple segments (first disk segment, second disk segment, third disk segment) that are arranged circumferentially to form a circumferential attachment feature. This segmentation allows the blade root to be distributed across multiple disk segments, reducing stress concentration at any single attachment point while maintaining the ability to withstand high temperatures through the metallic disk structure.
Solution Approach 2:
The attachment feature extends in the circumferential direction rather than only axially, creating a three-dimensional attachment structure. The circumferential attachment feature includes multiple disk segments arranged around the circumference, which distributes the blade attachment stresses across a larger circumferential area, reducing stress concentration while maintaining thermal resistance.
2Reliability
If larger attachment features are used to reduce stress, then durability improves, but device complexity increases
Solution Approach 1:
The complex attachment structure is achieved through segmentation of the disk into multiple segments that can be manufactured separately and then assembled. The circumferential attachment feature is formed by arranging first, second, and third disk segments circumferentially, which allows for modular manufacturing and assembly while achieving the desired stress distribution and durability.
Solution Approach 2:
The circumferential attachment feature serves multiple functions: it provides stress distribution across multiple disk segments, maintains structural integrity under centrifugal loads, and enables thermal resistance through the metallic disk material. This multi-functional design achieves durability without proportionally increasing complexity.
3Strength
If a multi-piece disk structure is used with circumferential attachment, then stress distribution improves, but manufacturing complexity increases
Solution Approach 1:
The disk is segmented into multiple manufacturable components (first disk segment, second disk segment, third disk segment) that can be produced using standard manufacturing processes. These segments are then assembled to form the complete circumferential attachment feature, allowing for specialized manufacturing of each segment while achieving superior stress distribution in the final assembly.
Solution Approach 2:
The disk segments are prepared in advance with specific geometries and attachment features that facilitate their circumferential arrangement. The blade root is designed with a dovetail shape that can be preliminarily fitted into the circumferential attachment feature, simplifying the final assembly process while ensuring proper stress distribution.
Data Source
AI summary
A wheel assembly for a gas turbine engine includes a disk, a plurality of blades, and a platform system that includes a plurality of platforms and pins. The disk is configured to rotate about an axis during operation of the gas turbine engine. The blades each include a circumferentially extending root received in the disk and an airfoil that extends radially away from the root. The platforms are arranged around the wheel to define a flow path of the gas turbine engine and the pins extend into the platforms and the disk to couple the platforms with the disk.