Multi-Film Oil Damper Ring Spacing for Continuous Oil Films
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Solution Overview
Problem
Existing multi-film oil dampers in gas turbine engines face challenges in maintaining a continuous supply of pressurized oil during start-up, leading to difficulties in forming and maintaining oil films between damper rings due to imbalanced rotation and surface tension issues.
Innovation Solution
A multi-film oil damper system with a housing containing nested damper rings and spacer rings, where the damper rings are spaced apart to create oil-filled gaps and a radial oil channel connects the oil inlet to the damper rings, ensuring consistent oil distribution and film formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If damper rings are placed in coaxial nested series to provide damping, then vibration reduction is improved, but oil supply to maintain continuous oil films becomes difficult during start-up
Solution Approach 1:
The damper system is segmented into multiple nested damper rings (first, second, third damper rings) that create separate squeeze film annuli. Each annulus can be independently supplied with oil through dedicated flow paths, allowing continuous oil film formation even during start-up when rotation is imbalanced. This segmentation enables each ring interface to maintain its oil film independently.
Solution Approach 2:
A spacer ring is introduced as an intermediary component between the nested damper rings. The spacer ring includes a central bore that serves as an intermediary oil distribution channel, receiving pressurized oil and distributing it to multiple squeeze film annuli simultaneously. This intermediary structure ensures continuous oil supply to all damper interfaces without relying on rotational balance.
2Reliability
If multiple nested damper rings are used to increase damping capacity, then vibration control is improved, but the complexity of ensuring continuous oil supply to all films increases
Solution Approach 1:
The oil supply system merges multiple oil delivery functions into a single spacer ring component. The central bore of the spacer ring consolidates what would otherwise require multiple separate oil channels or injection points, simplifying the overall oil supply architecture while maintaining the ability to supply multiple squeeze film annuli simultaneously.
Solution Approach 2:
The spacer ring performs multiple functions: it provides mechanical spacing between damper rings to maintain gap geometry, acts as a structural support element, and serves as an oil distribution manifold through its central bore. This multi-functionality reduces the number of separate components needed and simplifies the oil supply system.
3Reliability
If damper rings are positioned close together to maximize damping effect, then damping efficiency is improved, but oil films may not form properly due to insufficient spacing
Solution Approach 1:
The spacer ring pre-establishes the correct gap geometry between nested damper rings before operation begins. By mechanically maintaining the specified spacing, the spacer ring ensures that sufficient oil film thickness can be achieved and maintained during start-up and operation, eliminating the need for precise operational conditions to achieve proper film formation.
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 ensures effective damping of rotor shaft vibrations by maintaining continuous oil supply and film formation, even during start-up conditions, by preventing oil rings from sticking together and ensuring consistent oil distribution across the damper rings.
Implementation Method 1
a radial oil channel in fluid communication between the oil inlet and the plurality of nested damper rings
Implementation Method 2
multi-film oil dampers may be placed in a coaxial nested series with the rotor system bearing supports to provide damping to a rotor system
Implementation Method 3
it might be challenging to provide for a continuous supply flow of pressurized oil so as to ensure that oil films are maintained
Data Source
AI summary
A multi-film oil damper for accommodating radial movement of a rotary shaft bearing relative to a bearing housing, the multi-film oil damper comprising: an annular damper cavity defined within the bearing housing between a radially outward wall, a first radially extending side wall and a second radially extending side wall, the annular damper cavity having an oil inlet in the radially outward wall, the oil inlet being in communication with a source of pressurized oil; an inner damper ring having axial ends abutting the first and second radially extending side walls of the annular damper cavity; a plurality of outer damper rings coaxially nested between the inner damper ring and the radially outward wall, each outer damper ring having axial ends adjacent the first and second radially outward walls of the annular damper cavity, each outer damper ring having a first cylindrical surface and a second cylindrical surface; a spacer ring disposed at each axial end of the plurality of outer damper rings, a contact surface of the spacer ring extending radially beyond the first surface of an associated outer damper ring and engaging the second surface of an adjacent outer damper ring defining an oil filled gap there between; and a radial oil channel through a central portion of the plurality of outer damper rings in fluid communication with the oil inlet.