Rotor Vibration Control Using Multi-Position Modal Sensing
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Solution Overview
Problem
Rotating machinery, such as gas turbine engines, face challenges in controlling vibration levels due to imbalances and external forces, leading to resonance and cross-shaft vibrations, which current damping systems inadequately address, requiring operational adjustments and thrust reduction.
Innovation Solution
A system comprising a stator, rotor, active devices, sensors, and a controller that applies linear forces and moments based on vibration parameter measurements from multiple positions, allowing precise identification of oscillation modes and efficient control to reduce vibrations by activating devices at optimal locations and modifying stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional damping systems are used to reduce vibrations, then vibration levels are partially controlled, but the system cannot effectively address multiple vibration modes and cross-shaft vibrations, requiring operational adjustments and thrust reduction
Solution Approach 1:
The system divides vibration control into multiple independent control zones along the rotational axis, with sensors and active devices positioned at different locations to address specific vibration modes independently. This segmentation allows simultaneous control of multiple vibration modes without requiring operational adjustments.
Solution Approach 2:
The system dynamically changes the stiffness parameter of the rotor-stator system using active devices (such as magnetic bearings or adjustable springs) to shift resonant frequencies and avoid resonance conditions. This allows the system to maintain optimal performance across varying operating conditions without thrust reduction.
2Measurement precision
If sensors are positioned at multiple locations to identify vibration modes, then mode identification precision improves, but system complexity increases
Solution Approach 1:
The sensor system is designed to perform multiple functions: detecting vibration amplitude, frequency, and phase at different locations, as well as identifying the overall vibration mode pattern. This multi-functionality allows accurate mode identification without proportionally increasing system complexity.
Solution Approach 2:
The system uses feedback from multiple sensors to continuously monitor vibration parameters and automatically adjust active devices to counteract detected vibration modes. This closed-loop feedback mechanism simplifies the control strategy by letting the system self-regulate based on real-time measurements.
3Reliability
If active devices are activated at optimal locations based on mode identification, then vibration reduction efficiency improves, but control system complexity increases
Solution Approach 1:
The system pre-identifies optimal sensor and actuator locations during the design phase based on expected vibration modes. This preliminary positioning ensures that active devices are strategically placed to maximize their effectiveness, reducing the complexity of real-time control decisions.
Solution Approach 2:
The control system dynamically adjusts the activation and positioning of active devices based on real-time vibration mode identification. This dynamic adaptation allows the system to maintain high efficiency across varying operating conditions while using a relatively simple control algorithm that selects from pre-defined actuator configurations.
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 system effectively manages vibrations by identifying and compensating for multiple modes simultaneously, improving operational characteristics and reducing resonance, even in complex modes, while allowing the machinery to operate efficiently across various speed and power conditions.
Implementation Method 1
Each of the one or more active devices is configured to apply linear forces and/or moments on the rotor and/or on the stator
Implementation Method 2
The at least two sensors are adapted for measuring vibrational parameter values with respect to two or more different positions along the rotational axis, around the rotational axis and/or radial distances to the rotational axis
Implementation Method 3
By determining not just one single amplitude of vibration, but location-dependent vibration parameter values, it becomes possible to determine in which of a plurality of normal modes the rotor is oscillating
Data Source
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AI summary
A system (1) for vibration management comprises a stator (24, 45); a rotor (26) being mounted rotatably with respect to the stator (24, 45) about a rotational axis (9); one or more active devices (41A-41C) adapted to apply forces and/or moments on the rotor (26) and/or on the stator (24, 45); at least two sensors (42) for measuring vibrational parameter values with respect to two or more different positions, particularly along the rotational axis (9); and a controller (44) adapted to provide control signals to the one or more active devices (41A-41C) based on the vibrational parameter values of the at least two sensors (42) and on the respective position.