Gas Turbine Rotor Balancing via Segmented Weight Placement
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Solution Overview
Problem
Gas turbine engine rotors face challenges in balancing without increasing weight, as existing methods like oversizing and material removal can lead to increased weight and stress concentrations, which are critical for vibration acceptance tests.
Innovation Solution
A rotor assembly with a disk and circumferentially spaced blades, featuring regularly spaced balancing weights positioned at specific angular offsets relative to the blades to minimize stress concentrations and reduce weight, allowing for the use of more temperature-resistant materials like nickel-based superalloys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If material is removed from selected portions of the rotor disk to alleviate eccentricities, then rotor balancing is improved, but rotor weight increases
Solution Approach 1:
The rotor disk is segmented into multiple sectors, with balancing weights positioned in specific sectors rather than uniformly distributed. This segmentation allows precise control over the balancing function while minimizing overall weight addition.
Solution Approach 2:
Balancing weights are placed only in specific local regions (sectors) of the rotor disk where they are most effective for counteracting eccentricities, rather than distributing mass uniformly. This localized approach optimizes balancing while minimizing weight increase.
2Reliability
If an additional removable ring is provided for material removal to balance the rotor, then rotor balancing is improved, but rotor weight increases
Solution Approach 1:
The balancing function is segmented into discrete weights positioned in specific sectors, replacing the continuous mass modification approach of removable rings. This allows precise balancing control with minimal weight addition.
Solution Approach 2:
Instead of adding a complete removable ring, only specific discrete weights are extracted and positioned in selected sectors where they provide maximum balancing effect, reducing unnecessary weight.
3Ease of manufacture
If features are positioned at standard angular locations on the rotor disk, then manufacturing is simplified, but stress concentrations increase
Solution Approach 1:
The balancing weights are positioned asymmetrically in specific sectors rather than at symmetric standard angular locations. This asymmetric positioning optimizes stress distribution while maintaining manufacturing feasibility through precise angular specification.
Solution Approach 2:
Features are positioned at specific local angular locations optimized to minimize stress concentrations in critical blade root regions, rather than using uniform standard angular spacing throughout.
Data Source
AI summary
A rotor assembly for a gas turbine engine including a circumferential array of regularly spaced apart features provided on the disk which are each configured for receiving a balancing weight. The circumferential array of features has an angular orientation relative to the circumferential array of blades such that the features are each located at an at least substantially same offset angle from a stacking line of a respective adjacent blade.