Solid Bore Turbine Disc for Geared Turbofan Engine
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Geared turbofan aero gas turbine engines face increased mechanical stress in airfoils and discs due to high rotational speeds, which traditional designs struggle to manage effectively, particularly in the aft turbine stage where disc stresses are exacerbated by the use of center tie bolts and outboard fasteners.
Innovation Solution
A solid bore turbine disc design is implemented, featuring a center tie bolt attached to the upstream face of the disc, eliminating the need for outboard fasteners and reducing disc stress, with a stub shaft for bearing mounting, allowing for easier assembly, reduced weight, and lower costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If outboard fasteners are used to attach the turbine disc, then the disc can be secured to the shaft, but the disc experiences high stresses and increased mechanical complexity
Solution Approach 1:
The patent removes the outboard fasteners from the turbine disc assembly, extracting the source of stress concentration and mechanical complexity while maintaining disc attachment through alternative means that reduce overall system stress
Solution Approach 2:
The attachment function is segmented from the outboard region to the inboard region, where the center tie bolt and inboard fasteners provide attachment without creating the same stress concentration issues as outboard fasteners
2Strength
If outboard fasteners are used to attach the turbine disc, then the disc can be secured to the shaft, but the assembly complexity and part count increase
Solution Approach 1:
The patent extracts the outboard fasteners from the assembly, reducing the total part count and simplifying the assembly process while maintaining secure disc attachment through the center tie bolt and inboard fastener configuration
Solution Approach 2:
The attachment function is merged into a more integrated configuration where the center tie bolt and inboard fasteners work together as a unified attachment system, reducing the need for separate outboard fastener components
3Strength
If outboard fasteners are used to attach the turbine disc, then the disc can be secured to the shaft, but the overall weight of the assembly increases
Solution Approach 1:
The patent removes the outboard fasteners, directly reducing the weight of the moving assembly while maintaining secure disc attachment through the simplified center tie bolt and inboard fastener system
Data Source
AI summary
An aero gas turbine engine with a last stage turbine disc of a solid bore design. The solid bore turbine disc includes a center tie bolt that attaches to an upstream face of the solid bore disc. The attachment location is under the bore of the upstream stage. The aft side of the solid disc creates a stub shaft upon which a bearing is directly mounted. No fasteners pass through the solid bore disc. Omission of outboard fasteners allow for ease of assembly, reduced cost, reduced weight, and a reduced part count.