Squeeze Film Damper Seal Structure for Pressure-Adaptive Leakage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircraft engine squeeze film dampers vary in behavior with operating conditions, affecting their ability to effectively dampen vibrations, and existing sealing solutions fail to prevent air ingestion and fluid leakage efficiently.
Innovation Solution
The design incorporates a sealing ring with a monolithic or distinct ring body configuration, featuring a U-shape or annular space with a biasing member, that axially displaces to prevent air ingestion and fluid leakage by adjusting its position relative to the groove walls based on pressure differentials, ensuring effective sealing and damping fluid containment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional sealing ring is used in the squeeze film damper, then the structure is simple, but air ingestion and fluid leakage occur under varying pressure conditions
Solution Approach 1:
The sealing ring is designed with an axially movable inner ring face that can dynamically adjust its position relative to the damping fluid pressure. When pressure differential exceeds a threshold, the inner ring face moves axially to open communication between the annulus and bearing cavity, allowing controlled air ingestion and fluid leakage to prevent damage from excessive pressure buildup.
Solution Approach 2:
The sealing ring structure changes its effective sealing parameter (axial position of inner ring face) in response to changing pressure conditions. The seal transitions between a closed configuration (preventing air ingestion and fluid leakage) and an open configuration (allowing controlled communication), thereby adapting to varying operating conditions.
2Reliability
If the sealing ring prevents air ingestion completely, then damping fluid purity is maintained, but pressure buildup damages the damper under high pressure conditions
Solution Approach 1:
The sealing ring design accepts that some fluid leakage and air ingestion are inevitable and potentially harmful, but converts this harm into a benefit by controlling it through the movable inner ring face. The controlled leakage acts as a pressure relief mechanism that prevents catastrophic damage from pressure buildup, while the biasing member minimizes unnecessary leakage during normal operation.
Solution Approach 2:
The sealing ring dynamically adjusts its sealing effectiveness based on pressure conditions. Under normal operating pressures, the biasing member maintains the inner ring face in a position that prevents leakage. When pressure differential exceeds the threshold, the inner ring face moves axially to open a controlled leakage path, transforming the sealing function from static to dynamic pressure-dependent behavior.
3Reliability
If the sealing ring allows controlled air ingestion, then pressure relief is achieved, but damping fluid purity deteriorates
Solution Approach 1:
The movable inner ring face acts as an intermediary mechanism between the sealed annulus and the bearing cavity. It mediates the interaction between damping fluid pressure and external air pressure, allowing controlled communication only when necessary for pressure relief, while minimizing contamination during normal operation through the biasing member's holding force.
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 configuration enhances the sealing efficiency of the squeeze film damper by mitigating air ingestion and fluid leakage, maintaining optimal damping performance across varying operating conditions, thereby improving the overall vibration damping capability of the aircraft engine.
Implementation Method 1
the sealing ring having an outer ring face axially facing the outer groove wall and an inner ring face axially facing the inner groove wall, the inner ring face being axially movable relative to the outer ring face
Implementation Method 2
mitigating leakage of a damping fluid out of an annulus defined radially between a bearing and a bearing housing by pushing a sealing ring of one of seals disposed at axial ends of the annulus axially outward, away from the annulus and into abutment with an outer groove wall of a groove receiving the sealing ring, when a pressure of the damping fluid contained in the annulus is greater than an air pressure outside the annulus
Implementation Method 3
squeeze film dampers are fed with oil and at least partially dampen vibrations of the shaft
Implementation Method 4
an annulus defined axially between the first seal and the second seal, the annulus defined radially between the bearing and the bearing housing, the annulus having a damping fluid in the annulus
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An aircraft engine, comprising: a shaft (16, 18); a bearing housing (25) extending around the shaft (16, 18) and defining a bearing cavity; a bearing (21) in the bearing cavity and rotatably supporting the shaft (16, 18); a squeeze film damper (26) including: a first seal (28) proximate a first end of the bearing (21), and a second seal (28) proximate a second end of the bearing (21); an annulus (27) between the first seal (28) and the second seal (28), the annulus (27) having a damping fluid in the annulus (27); and wherein at least the first seal (28) includes a sealing ring (50, 150, 250, 350) received within a groove (23A) extending axially from an outer groove wall (23B) to an inner groove wall (23C), the inner groove wall (23C) located axially between the outer groove wall (23B) and the annulus (27), the sealing ring (50, 150, 250, 350) having an outer ring face (56, 153, 253, 352) facing the outer groove wall (23B) and an inner ring face (27, 154, 254, 353) facing the inner groove wall (23C), the inner ring face (27, 154, 254, 353) being movable relative to the outer ring face (56, 153, 253, 352).