Turbomachine Blade Retention via External Retaining Ring
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Solution Overview
Problem
There is a need for improved retention features in turbomachines, such as gas turbine engines, to balance conflicting design criteria like fuel efficiency, operational efficiency, power output, weight, part count, and packaging, while securely retaining rotating and counter-rotating blades.
Innovation Solution
A turbomachine design featuring a rotatable annular outer drum rotor with segmented drum segments and a retaining ring that radially secures blade root portions, utilizing structural radial retention features like dovetails and mating features for torque transmission, and a contact zone for axial retention, to enhance blade retention and assembly efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blades are retained using conventional internal disk retention methods, then blade retention is achieved, but the engine weight and part count increase
Solution Approach 1:
The patent extracts the blade retention function from the internal disk structure and relocates it to an external retaining ring. This separates the retention function from the rotating mass, reducing the weight of moving parts while maintaining reliable blade retention through the external ring structure that engages with blade roots from the outside.
Solution Approach 2:
The patent introduces a retaining ring as an intermediary component between the blades and the drum rotor. This intermediary element provides the retention function without requiring the blades to be directly integrated into the drum or requiring heavy internal disk structures, thus reducing overall engine weight while ensuring secure blade retention.
2Reliability
If complex retention features are used to secure blades, then blade retention reliability improves, but device complexity increases
Solution Approach 1:
The retaining ring serves multiple functions simultaneously: it retains blades radially, provides axial positioning through contact zones, and enables torque transmission through mating features. This multi-functionality consolidates what would otherwise require multiple separate retention mechanisms into a single component, reducing device complexity while improving retention reliability.
Solution Approach 2:
The patent merges radial retention, axial retention, and torque transmission functions into a single retaining ring structure. By combining these functions that would traditionally require separate components into one integrated ring, the design reduces the number of parts and simplifies the overall retention system while maintaining high reliability.
3Ease of manufacture
If segmented drum structure is used, then assembly efficiency and manufacturing ease improve, but the number of parts increases
Solution Approach 1:
The drum rotor is divided into multiple segmented sections that can be manufactured separately and then assembled together with the retaining ring in between. This segmentation allows each section to be optimized for manufacturing and assembly, improving ease of manufacture while the modular nature actually reduces overall complexity compared to a monolithic drum structure.
Data Source
AI summary
A turbomachine includes a rotatable annular outer drum rotor connected to a first plurality of blades. The rotatable annular outer drum rotor is constructed of, at least, a first drum segment and a second drum segment. The turbomachine further includes a retaining ring arranged and secured between the first and second drum segments of the rotatable annular outer drum rotor for radially retaining each of the first plurality of blades via their respective blade root portions within the rotatable annular outer drum rotor.