Circumferential Plenum Oil Damper Seal Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Squeeze-film dampers in gas turbine engines face degradation in damping ability due to mixing of oil with surrounding fluid medium, leading to compromised performance under pressure differentials.
Innovation Solution
Incorporation of an oil-filled buffer region between the damper film and the atmosphere, utilizing seals to create a radial thickness difference that prevents air or atmospheric gases from entering the thin film of oil, thereby maintaining damping effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the squeeze-film damper uses a thin annulus of oil retained between the outer race and bearing housing, then the damper can provide damping function, but the oil may mix with the surrounding fluid medium under pressure differentials, degrading damping ability
Solution Approach 1:
The bearing assembly is segmented into distinct regions: the oil film region containing the squeeze-film damper, and the surrounding fluid medium region. Seals are positioned at the boundary to prevent mixing between these segmented regions, allowing the damper to maintain its damping ability without contamination from the surrounding fluid.
Solution Approach 2:
Seals act as intermediary elements positioned between the oil film region and the surrounding fluid medium. These seals prevent direct contact and mixing between the two fluids while allowing the damper to function independently, thus protecting the oil film from contamination and maintaining reliable damping performance.
2Reliability
If the bearing compartment is surrounded by fluid medium that can back-flow into the oil film region, then the compartment can be sealed, but the pressure differentials cause fluid back-flow that compromises damper performance
Solution Approach 1:
Seals serve as intermediary barriers that isolate the oil film region from the surrounding fluid medium. This intermediary structure prevents pressure-driven back-flow of the surrounding fluid into the oil film region, allowing the damper to maintain consistent performance regardless of pressure differentials in the bearing compartment.
Solution Approach 2:
The seals are positioned to preemptively prevent fluid back-flow before pressure differentials can cause contamination. By establishing the sealing barrier in advance, the system prevents the harmful effect of fluid mixing under various pressure conditions, ensuring the damper maintains its damping ability throughout operation.
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 buffer region effectively restricts air leakage into the oil film, maintaining the damping ability of the squeeze-film damper and preventing fluid backflow, ensuring consistent performance.
Implementation Method 1
The buffer region may reduce the likelihood of the fluid within the thin-film region to cavitate. Seals may define a boundary between the thin-film region and the buffer region.
Implementation Method 2
Oil may be fed into the annulus to form the squeeze-film damper which damps whirling of the shaft.
Implementation Method 3
Seals may define a boundary between the thin-film region and the buffer region.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A bearing assembly includes an inner race configured to couple to a shaft, an outer race disposed around the inner race, and a housing (406) disposed around the outer race. The housing (406) and the outer race define an annulus (402) and a buffer region (410), and the buffer region (410) defines an axial boundary of the annulus (402).