Turbomachine Rotor Assembly with Segmented Dovetail Platform
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Solution Overview
Problem
In turbomachines, the one-piece airfoil and platform configuration leads to over-engineering of the platform area due to material choices for stress resistance, resulting in increased cost and weight, and thermal mismatch between the airfoil and platform, causing stress increments.
Innovation Solution
A rotor assembly design featuring a disk with circumferential and axial dovetails allows for separate installation of blades and platforms, enabling the use of different materials for each component and reducing thermal stresses, with the last blade locking the positions of both, facilitating lighter and more cost-effective construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a one-piece airfoil and platform configuration is used, then structural integrity is improved, but the platform area becomes over-robust, increasing cost and weight
Solution Approach 1:
The invention divides the previously integrated airfoil and platform into separate components. The platform is now a distinct component that can be attached to the airfoil, allowing each part to be optimized independently. This segmentation enables the platform to use lighter materials or thinner sections since it no longer needs to be over-engineered for the same reasons as the airfoil.
2Strength
If a one-piece airfoil and platform configuration is used, then structural integrity is improved, but manufacturing cost increases due to over-engineering
Solution Approach 1:
By separating the platform from the airfoil into distinct components, each can be manufactured independently using materials and processes optimized for their specific requirements. This reduces the need for expensive, over-engineered monolithic construction and allows for more cost-effective manufacturing approaches for each component.
3Device complexity
If an integral platform and airfoil are used, then structural simplicity is maintained, but thermal stresses increase due to thermal mismatch
Solution Approach 1:
Separating the platform and airfoil into distinct components allows each to be made from materials optimized for their specific thermal environments. The attachment interface between components can accommodate thermal expansion differences, reducing thermal stress compared to a constrained monolithic structure where different regions experience mismatched thermal behavior.
Data Source
AI summary
Disclosed is a rotor assembly for a turbomachine includes a disk having a first axial face and a second axial face. The disk includes at least one circumferential dovetail extending around an outer surface of the disk and a plurality of axial dovetails extending from the first axial face to the second axial face. Each blade of a plurality of blades is installed into an axial dovetail of the plurality of axial dovetails and each platform of a plurality of platforms is installed adjacent to a blade of the plurality of blades via the at least one circumferential dovetail. Further disclosed is a method of assembly of a rotor for a turbomachine.