Segmented Gas Turbine Rotor Blade Attachment Design
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Solution Overview
Problem
Gas turbine engine designers face challenges in increasing turbine rotational speed while maintaining reduced weights, as larger rotor disk bores require complex heat treating and are impacted by rim pull and airfoil attachments, necessitating improved rotor blades and cooling schemes.
Innovation Solution
The development of a rotor assembly with cantilevered projections and a unique attachment geometry, using materials like ceramic matrix composites, and internal cooling passages to reduce weight and enhance cooling efficiency, along with a manufacturing method involving layered sheets of material to form the rotor blades and attachments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If turbine rotational speed is increased to improve performance, then power output is improved, but rotor disk bore size increases making heat treating challenging
Solution Approach 1:
The rotor disk is divided into multiple segments separated by radial slots, allowing each segment to be manufactured and heat treated independently before assembly. This segmentation enables conventional heat treating processes to be applied to smaller individual segments rather than a large monolithic disk, resolving the heat treating difficulty while maintaining the overall rotor disk structure needed for high power output.
2Adaptability or versatility
If separate airfoils with mechanical attachments are used, then rotor blade flexibility is improved, but device complexity increases due to live rims and cover plates
Solution Approach 1:
The attachment features are extracted from the traditional live rim structure and integrated directly into the rotor disk segments. The radial slots that previously required cover plates to seal are now designed to accommodate the attachment features directly, eliminating the need for separate cover plates and simplifying the overall structure while maintaining airfoil attachment capability.
Solution Approach 2:
The attachment features and rotor disk segments are merged into an integrated structure where the attachments are formed as part of the disk segments themselves. This merging eliminates the need for separate live rims and cover plates, reducing device complexity while preserving the flexibility benefits of separate airfoil attachments.
3Strength
If traditional rotor disk sizing is used, then structural integrity is maintained, but weight increases due to rim pull and attachment features
Solution Approach 1:
By segmenting the rotor disk with radial slots, the overall weight is reduced by removing material in the slot regions. The segmented structure maintains structural integrity through the careful design of slot geometries and attachment features that distribute loads appropriately across the segments, achieving weight reduction without sacrificing strength.
Data Source
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AI summary
An apparatus is provided for a rotor assembly with a rotational axis. This apparatus includes a rotor blade (104) including an airfoil (110), a neck (114) and an attachment (116). The neck radially connects the airfoil and the attachment. The attachment extends axially between an attachment first axial side (146) and an attachment second axial side (148). A first end portion (162) of the attachment projects axially out from the neck to the attachment first axial side. A second end portion (166) of the attachment projects axially out from the neck to the attachment second axial side.