Floating Ring Seal with Permeable Damping for Shaft Whirl
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sealing devices for high-speed rotating shafts, such as those in cryogenic liquid fuel turbopumps, fail to effectively reduce shaft vibration and prevent leakage while maintaining alignment and lubrication.
Innovation Solution
A sealing device featuring a floating ring with a permeable damping member, such as a wire mesh damper, around its outer peripheral portion, which imparts radial restoring forces to correct eccentricity and tangential damping forces to reduce whirling, while maintaining a lubricated sealing face through an introduction recess.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a floating ring sealing device is used for high-speed rotating shafts, then sealing performance is improved, but shaft vibration increases due to lack of vibration reduction mechanism
Solution Approach 1:
A permeable damping member is introduced as an intermediary component between the floating ring and the shaft. This damping member acts as a mediator that provides both radial restoring force to correct eccentricity and tangential damping force to reduce whirling vibration, thereby solving the vibration problem while maintaining the sealing function of the floating ring.
Solution Approach 2:
The damping characteristics of the system are changed by introducing the permeable damping member with specific permeability and damping properties. This changes the force characteristics between the floating ring and shaft, providing both restoring and damping forces that reduce vibration while maintaining sealing performance.
2Stability of the object's composition
If leaf springs are added to dampen floating ring vibration, then floating ring stability is improved, but the rotating shaft vibration is not reduced
Solution Approach 1:
The permeable damping member serves as an intermediary that transmits and transforms forces between the floating ring and shaft. Unlike leaf springs that only support the floating ring, the damping member provides tangential damping force that directly reduces shaft whirling vibration while maintaining floating ring stability through radial restoring force.
Solution Approach 2:
The conventional mechanical support system (leaf springs) is supplemented with a permeable damping member that utilizes fluid permeation and viscous damping mechanisms. This substitution introduces a new force generation mechanism that provides both radial and tangential force components, effectively reducing shaft vibration while maintaining floating ring stability.
3Stability of the object's composition
If support means are added to prevent alignment loss, then floating ring alignment is improved, but frictional resistance increases and shaft vibration is not reduced
Solution Approach 1:
Traditional mechanical support means that cause high frictional resistance are replaced with a permeable damping member system. This new system maintains floating ring alignment through controlled fluid permeation and viscous forces rather than high-friction mechanical contact, thereby reducing shaft vibration while preserving alignment stability.
Solution Approach 2:
The permeable damping member utilizes hydraulic principles where sealed fluid flows through the permeable structure to provide damping forces. This fluid-based mechanism replaces solid-to-solid mechanical support, reducing frictional resistance while maintaining alignment and reducing vibration through viscous damping effects.
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 reduces shaft vibration, prevents leakage, and maintains alignment by providing radial and tangential damping forces, while ensuring a good lubrication state, thus enhancing the operational stability of high-speed rotating machinery.
Implementation Method 1
a permeable damping member provided around an outer peripheral portion of the floating ring
Implementation Method 2
the permeable damping member is provided around an outer peripheral portion of the floating ring
Implementation Method 3
maintain a constant clearance between the inner peripheral surface of the floating ring and the rotating shaft by the wedge effect generated between the inner peripheral surface of the floating ring and the rotating shaft
Implementation Method 4
the Lomakin effect (the aligning effect due to inflow losses between the surfaces of the seal ring and the shaft when seal differential pressure develops)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
To impart a radial restoring force against the eccentricity of a rotating shaft to restore it to its axis position, and a tangential damping force to reduce the whirling of the rotating shaft. A sealing device includes a floating ring 5 in a space 4 between the outer circumference of a rotating shaft 3 and the inner circumference of a housing 2, and a permeable damping member 10 provided around an outer peripheral portion of the floating ring 5.