Partially Bladed Rotor Balancing for Stable Test Operation
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Solution Overview
Problem
Gas turbine engines face instability during rotor testing due to mass centroid offset and asymmetrical mass moments of inertia in partially bladed rotors, which is exacerbated by the limited availability and high cost of new blades.
Innovation Solution
A rotor module with a blade cluster and counter weights is designed to zero out the center of gravity and equalize the moments of inertia about the X and Y axes, achieving a tri-lobe configuration that stabilizes the rotor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a partially bladed rotor is used for testing new blades, then blade availability requirements are reduced and testing cost is decreased, but mass centroid offset and asymmetrical mass moments of inertia are introduced causing rotor instability
Solution Approach 1:
Counterweights are added to the rotor disk to compensate for the mass imbalance created by the partial blade configuration. The counterweights are positioned and sized to create a balanced mass distribution that eliminates mass centroid offset and equalizes mass moments of inertia about principal axes, thereby stabilizing the rotor while maintaining the partial blade configuration for cost-effective testing
Solution Approach 2:
The patent intentionally introduces asymmetry through counterweights to compensate for the asymmetry of the partial blade configuration. By strategically placing counterweights at specific locations on the rotor disk, the overall mass distribution is adjusted to achieve symmetrical mass moments of inertia, resolving the instability caused by the asymmetric blade arrangement
2Stability of the object's composition
If counterweights are added to balance the rotor, then rotor stability is improved, but device complexity increases
Solution Approach 1:
The counterweights are integrated with the existing rotor disk structure rather than being separate components. This merging approach allows the counterweights to be manufactured as part of the rotor assembly, reducing the number of discrete parts and simplifying the overall structure while still achieving the necessary balance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively eliminates potential vibrations and instability during rotor testing by ensuring a zero nominal imbalance and axi-symmetrical moment of inertia, allowing for reliable testing of new blades.
Implementation Method 1
the counter weights cause a moment of inertia Jx about an X axis of the rotor disk is equal to a moment of inertia Jy about a Y axis of the rotor disk
Data Source
AI summary
A rotor module, including: a blade cluster of a plurality of blades secured to a rotor disk of the rotor module; and counter weights secured to the rotor disk, wherein the counter weights cause a center of gravity of the plurality of blades to be zeroed out with respect to an axis “O” of the rotor disk and wherein the counter weights cause a moment of inertia Jx about an X axis of the rotor disk is equal to a moment of inertia Jy about a Y axis of the rotor disk when the rotor module is rotated about the axis “O”.