Rotor Vibration Control Using Distributed Sensors and Active Forces
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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 improved operational characteristics.
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 for precise identification of normal 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 adequately address multiple vibration modes and resonance conditions
Solution Approach 1:
The system divides the rotor into multiple segments by placing sensors and active devices at different axial positions, allowing independent measurement and control of vibration modes at each location. This segmentation enables the system to address multiple vibration modes simultaneously that a single damping system cannot handle
Solution Approach 2:
The system uses active devices with controllable stiffness characteristics that can dynamically adjust to different operating conditions and vibration modes. The controllable stiffness elements can adapt their properties in real-time to effectively counteract varying resonance conditions and multiple vibration modes
2Adaptability or versatility
If multiple sensors and active devices are deployed at different positions to identify and control multiple vibration modes, then vibration management capability is improved, but system complexity increases
Solution Approach 1:
Each sensor and active device in the distributed system is designed to perform multiple functions: sensors measure both amplitude and phase information, while active devices provide both stiffness control and damping effects. This multi-functionality reduces the overall system complexity compared to having specialized components for each function
Solution Approach 2:
The system implements closed-loop feedback control where sensors continuously monitor vibration parameters and feed this information to the controller, which adjusts the active devices in real-time. This feedback mechanism enables coordinated control of multiple vibration modes without requiring overly complex open-loop control systems
3Measurement precision
If active devices are positioned at nodes of oscillating modes where deflection is zero, then device activation becomes ineffective, but selecting optimal positions requires precise mode identification
Solution Approach 1:
The system uses real-time feedback from sensors to continuously identify the current vibration mode and its nodal positions. Based on this feedback, the controller dynamically adjusts the activation and positioning of active devices to ensure they operate at anti-nodes where they are most effective, avoiding nodes where deflection is zero
Solution Approach 2:
The system employs dynamic positioning and activation of active devices based on the identified vibration mode characteristics. The active devices can be selectively activated or repositioned according to the current operating conditions and mode shapes, ensuring optimal placement effectiveness without requiring fixed pre-determined positions
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 counteracting multiple modes simultaneously, improving operational characteristics and reducing resonance, even in complex modes, while allowing for weight optimization and emergency operation.
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
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.