Asymmetric Rotor Disk Load Path for Gas Turbine Preload
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Solution Overview
Problem
Gas turbine rotor systems require higher preload forces and associated hardware due to non-straight, tortuous rotor stack load paths, which can be inefficient and costly.
Innovation Solution
The use of axially asymmetric rotor disks and contoured rotor rings to create a smooth rotor stack load path, reducing the need for excessive preload forces and allowing for the use of different materials for blades and disks to manage thermal and mechanical stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a non-straight, tortuous rotor stack load path is used, then the rotor stack preload can be effectively carried through the structure, but relatively greater rotor stack preload forces and associated hardware are required
Solution Approach 1:
The rotor disk employs a curved load path design where the load transitions smoothly through contoured surfaces rather than sharp angles or straight lines. The load path curves through the disk thickness and radial directions, distributing stresses more evenly and reducing peak forces required to achieve the same preload capacity.
Solution Approach 2:
The rotor disk features an asymmetric thickness distribution and asymmetric load path geometry, with varying disk thickness strategically positioned to optimize load carrying capacity. The asymmetric design allows the load path to follow the most efficient stress flow pattern rather than a uniform symmetric path, reducing overall preload requirements.
2Reliability
If higher rotor stack preload forces are used, then the rotor stack can be assembled and maintained, but weight increases and manufacturing costs increase
Solution Approach 1:
The invention changes geometric parameters of the rotor disk including thickness distribution, radius variations, and load path curvature to optimize the structure. By adjusting these parameters, the disk achieves higher stiffness and load carrying capacity with less material, reducing weight while maintaining assembly integrity.
Solution Approach 2:
The rotor disk employs local quality variations where disk thickness and material properties are optimized at different locations. Thicker sections are placed where stresses are highest, while thinner sections are used where stresses are lower, achieving optimal weight-strength ratio throughout the rotor stack assembly.
3Ease of manufacture
If uniform rotor disk design is used, then manufacturing is simplified, but thermal and mechanical stresses cannot be effectively managed in high-temperature areas
Solution Approach 1:
The rotor disk features locally optimized properties where thickness, material composition, and thermal barrier coating are varied to match local stress and temperature conditions. High-temperature regions receive enhanced thermal protection and structural reinforcement, while cooler regions use lighter constructions, effectively managing thermal and mechanical stresses throughout the component.
Data Source
AI summary
A spool for a gas turbine engine includes at least one rotor disk defined along an axis of rotation and at least one rotor ring defined along the axis of rotation, with the rotor ring being in contact with the rotor disk. The rotor disk and rotor ring are contoured to define a smooth rotor stack load path.