Engine Shaft Active Damping for Torsional Resonance Control
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Solution Overview
Problem
Gas turbine engines face challenges in controlling unforeseen interactions that can lead to torsional resonance, potentially causing shaft failure due to significant resonance amplitudes, especially in lightly damped low and intermediate pressure spools.
Innovation Solution
Active damping of shafts is implemented by measuring rotational velocity at frequencies higher than torsional resonance, extracting oscillatory terms, and applying torque components to counteract resonances, thereby reducing or eliminating torsional resonances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active damping control is implemented to reduce torsional resonances, then shaft life and engine integrity are improved, but device complexity and control system requirements increase
Solution Approach 1:
The control system continuously measures rotational velocity, extracts oscillatory components representing torsional resonance, and applies counteracting torque through fuel flow modulation. This closed-loop feedback mechanism actively suppresses resonance while adapting to varying engine conditions, thereby extending shaft life without requiring fundamental redesign of the engine architecture.
Solution Approach 2:
Instead of using passive mechanical damping elements or redesigning shaft structures to avoid resonance, the invention substitutes an active control system that uses sensor measurements, signal processing, and actuated torque application. This replaces complex mechanical design constraints with a more flexible control-based solution.
2Reliability
If design-out rules are applied to avoid resonance-inducing interactions, then shaft failure risk is reduced, but adaptability to unforeseen interactions decreases
Solution Approach 1:
The control system dynamically adjusts torque application based on real-time measurement of actual shaft oscillations. Rather than relying on fixed design constraints that cannot anticipate unforeseen resonance sources, the system adapts its damping action to counteract any resonance condition that arises, whether foreseen or unexpected, thereby maintaining reliability while improving adaptability.
Solution Approach 2:
The system changes operational parameters (fuel flow rate) in response to measured resonance conditions. By continuously monitoring rotational velocity and adjusting the damping torque accordingly, the system can respond to varying resonance frequencies and amplitudes, making the engine adaptable to different operating conditions and unforeseen interactions.
3Measurement precision
If measurement frequency is increased to accurately capture torsional resonance, then resonance detection precision is improved, but energy consumption and processing requirements increase
Solution Approach 1:
The system uses measurement frequencies that exceed the minimum required to capture torsional resonance (at least twice the resonance frequency, preferably ten times or more). This excessive measurement rate ensures accurate capture of high-frequency oscillations while the signal processing extracts only the relevant oscillatory components, balancing measurement precision with manageable processing requirements.
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
This approach effectively reduces the need to design-out resonance-inducing interactions, enhancing shaft life by actively canceling torsional resonances and ensuring engine integrity.
Implementation Method 1
measuring a rotational velocity of the shaft
Implementation Method 2
applying a torque component to the shaft so as to counteract the torsional resonance
Implementation Method 3
Active damping of shafts is implemented by measuring rotational velocity at frequencies higher than torsional resonance, extracting oscillatory terms, and applying torque components to counteract resonances
Data Source
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AI summary
A method of actively controlling torsional resonance of a rotating shaft of an engine is provided. The shaft has a rotational velocity characterised by a low frequency, rotational velocity term and a high frequency, oscillatory term superimposed on the low frequency term, the oscillatory term being caused by torsional resonance. The method including: measuring the rotational velocity of the shaft; extracting the oscillatory term from the measured rotational velocity; and on the basis of the extracted oscillatory term, applying a torque component to the shaft, the torque component being modulated at the same frequency as the torsional resonance to counteract the torsional resonance.