Active Stiffness Control for Rotating Machinery Vibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rotating machinery, such as gas turbine engines, face challenges in controlling vibration levels due to imbalances and external forces, which can be exacerbated by excessive clearance between components leading to impaired operational characteristics.
Innovation Solution
A system with a first component rotatably mounted relative to a second component, featuring a clearance for relative displacement, and an active device applying non-contact forces to modify stiffness and displacement, controlled by a controller based on target values for optimal performance across varying operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If clearance is increased to allow thermal expansion and assembly, then ease of manufacture is improved, but vibration levels increase and operational characteristics are impaired
Solution Approach 1:
The patent applies active stiffness control to dynamically adjust the mechanical properties of the bearing support structure. By varying the stiffness in real-time based on operating conditions, the system optimizes the balance between clearance requirements for thermal expansion and vibration control, transforming a static design compromise into a dynamic optimization solution.
Solution Approach 2:
The patent changes the stiffness parameter of the bearing support structure actively. By controlling the stiffness of the support structure, the system can adjust the effective clearance characteristics dynamically, allowing optimal performance across different operating conditions without sacrificing ease of manufacture or increasing vibration.
2Object-affected harmful factors
If clearance is decreased to reduce vibration, then vibration levels are reduced, but operational characteristics are impaired due to inability to accommodate thermal expansion
Solution Approach 1:
The system dynamically adjusts stiffness based on real-time operating conditions. When thermal expansion is expected, the control system reduces stiffness to accommodate the expansion; when vibration is the primary concern, stiffness is increased to minimize vibration, thereby achieving both adaptability and vibration control.
Solution Approach 2:
The patent employs a control system that monitors operating conditions and adjusts stiffness accordingly. This feedback mechanism ensures that the stiffness is optimized for current conditions, accommodating thermal expansion when necessary while minimizing vibration when operating within normal parameters.
3Adaptability or versatility
If active stiffness control is implemented to dynamically adjust clearance, then adaptability to different operating conditions is improved, but device complexity increases
Solution Approach 1:
The patent integrates the active stiffness control functionality into existing bearing support structures, allowing the same system to serve multiple functions: structural support, vibration control, and thermal expansion accommodation. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in overall system complexity.
4Reliability
If non-contact forces are used to apply stiffness control, then wear on movable parts is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent replaces mechanical contact-based stiffness control with non-contact electromagnetic forces. This substitution eliminates wear associated with mechanical contacts while using the magnetic bearing's electromagnetic field to apply the necessary stiffness control forces, thereby achieving wear resistance without excessive manufacturing precision 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 solution dynamically adjusts clearance and stiffness to reduce vibrations and improve operational characteristics by applying non-contact forces, enhancing the system's adaptability to different conditions and reducing wear on movable parts.
Implementation Method 1
The force that the active device is adapted to apply may be a non-contact force, e.g., a magnetic force or an electric force
Implementation Method 2
The controller may regulate the non-contact force (in particular by regulating the magnetic flux) to set the target value
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A system (1A-1F) comprises a first component (26) being rotatably mounted with respect to a second component (24), wherein a clearance (Ca, Cr, θa) is provided that allows relative displacement of the first component (26) with respect to the second component (24); an active device (41; 48A, 48B; 70) configured to apply a force on the first component (26), on the second component (24) and/or on a part (64) supporting the first component (26) against the second component (24); and a controller (44) controlling the active device (41; 48A, 48B; 70) based on a target value indicative for a range of a displacement of the first component (26) with respect to the second component (24) and/or on a target value indicative for a stiffness of at least one of the first and second components (26, 24).