Fluid Damping Disc for Long Shaft Bending Vibration
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Solution Overview
Problem
Conventional radial SFDs are ineffective in damping rotor vibration in the bending direction, leading to rotor instability and performance degradation in turbine engines, particularly affecting long rotor shafts.
Innovation Solution
A damping device is introduced that includes a housing with a chamber for damping fluid and a damping disc operatively coupled with the shaft, allowing the disc to wobble within the chamber to move the fluid and absorb bending vibrations, thereby effectively damping shaft vibrations in both radial and bending directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If SFDs are placed at rotor bearing locations, then structural support is provided, but damping effectiveness is reduced due to low relative radial motion at nodal points
Solution Approach 1:
The invention transitions from purely radial damping (single dimension) to include axial dimension damping through the bending damping assembly. The damping disc chamber is positioned to accommodate axial/bending vibrations while the bearing provides radial support, effectively adding another dimension of damping capability to the system without compromising structural support
2Productivity
If long rotor shafts are used to achieve desired engine architecture, then engine performance is improved, but rotor instability increases due to vulnerability to bending vibrations
Solution Approach 1:
The damping disc serves as an intermediary that couples the shaft to the damping fluid chamber. When the long rotor shaft experiences bending vibrations, the damping disc wobbles within the chamber, transferring the vibration energy to the damping fluid which absorbs it. This intermediary mechanism provides the necessary damping for long shafts without affecting the engine's performance-critical architecture
Solution Approach 2:
The invention employs hydraulic damping by utilizing a damping fluid within the chamber. The damping disc moves the damping fluid during bending vibrations, and the fluid's viscosity and compressibility provide energy dissipation. This hydraulic mechanism effectively dampens bending vibrations in long rotor shafts, enhancing stability while maintaining the engine's performance 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
The solution effectively mitigates bending and radial vibrations, enhancing rotor stability and engine performance by transferring vibration energy into the damping fluid, thus preventing instability and component damage.
Implementation Method 1
the damping disc is movable within the chamber to move the damping fluid such that the damping fluid absorbs bending vibration emitted by the shaft
Implementation Method 2
the damping disc is configured to wobble within the chamber to move the damping fluid along a direction substantially parallel to the axis of rotation for damping bending vibration of the shaft
Data Source
AI summary
A damping device that includes features for damping bending vibration of a shaft rotating about its axis of rotation and methods for damping bending vibration utilizing the damping device are provided. In one exemplary aspect, the damping device includes a damping disc operatively coupled with a shaft, e.g., of a turbine engine or shaft system. The damping disc is at least partially received within a chamber defined by a housing. The chamber of the housing is configured to receive a damping fluid. When the shaft is rotated about its axis of rotation, the damping disc is movable within the chamber to move the damping fluid such that the damping fluid absorbs bending vibration emitted by the shaft. The damping fluid moved by the damping disc dampens bending vibration emitted by the shaft.