Check-Valve Damper Ring for Gas Turbine Bearing Vibration
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Solution Overview
Problem
Gas turbine engine spool shafts experience undesirable vibrations due to cyclical orbital motion caused by thermal gradients, leading to increased stress on bearing components, and existing fluid damping structures often require lubricant fluid boost pumps and suffer from performance issues.
Innovation Solution
A damper ring with check valve passages and fluid-impedance check valves, which are designed to provide effective damping without moving components, and are integrated into the gas turbine engine's lubrication system to manage fluid flow and pressure variations during imbalanced conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If fluid damping structures are used to reduce lateral forces on bearings, then bearing stress is reduced, but the structures require lubricant fluid boost pump mechanisms and suffer from performance issues
Solution Approach 1:
The patent extracts and eliminates the boost pump mechanism from the fluid damping structure, using the existing engine lubrication system instead. The damper ring integrates check valve passages directly into its structure, allowing fluid to be supplied from the main lubrication system without requiring a separate boost pump, thereby reducing device complexity while maintaining force reduction capability
Solution Approach 2:
The damper ring serves multiple functions: it provides fluid damping to reduce lateral bearing forces, incorporates check valve passages to control fluid flow direction, and integrates with the existing lubrication system. This multi-functionality eliminates the need for dedicated boost pump mechanisms while achieving the desired force reduction
2Reliability
If check valve passages are integrated into the damper ring, then fluid flow control is improved, but manufacturing complexity increases
Solution Approach 1:
The damper ring incorporates check valve passages that can be manufactured using porous material techniques or integral forming methods. The passages are designed with specific geometric configurations (different diameters at different sections) that can be achieved through modern manufacturing processes, balancing fluid flow control requirements with manufacturing feasibility
Solution Approach 2:
The check valve passages are nested within the damper ring structure itself, with the valve components positioned inside the passages. This nested configuration allows the check valve functionality to be integrated into the existing damper ring geometry without requiring separate external components, thereby managing manufacturing complexity while improving fluid flow control
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 lateral forces and stresses on bearings by maintaining consistent lubricant fluid distribution and pressure within the damping chamber, even during imbalanced conditions, enhancing the durability and performance of the fluid damping structure.
Implementation Method 1
each check valve passage may include a check valve configured to permit flow through the check valve passage in a first direction, and not permit flow through the check valve passage in a second direction, opposite to the first direction
Implementation Method 2
Fluid damper structures are known in the prior art, but many suffer from performance issues and/or require lubricant fluid boost pump mechanisms
Implementation Method 3
Gas turbine engine lubrication systems and methods for use with fluid damping structures
Data Source
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AI summary
A fluid damping structure is provided that includes a damper ring. The damper ring includes an annular body, a plurality of fluid check valves (122), and at least one fluid stop (124). The annular body extends circumferentially around an axial centerline, and is defined by a first end surface (88), a second end surface (90), an outer radial surface (92), and an inner radial surface (94). The outer radial surface (92) and the inner radial surface (94) extend axially from the first end surface (88) toward the second end surface (90). The body includes one or more check valve passages (104). Each check valve passage (104) extends axially from an open end (106) disposed at the first end surface (88) inwardly toward the second end surface (90), and is disposed between the inner radial surface (94) and the outer radial surface (92). An inlet aperture (112) extends between each check valve passage (104) and the outer radial surface (92), and an outlet aperture (114) extends between each check valve passage (104) and the inner radial surface (94). Each fluid check valve (122) is disposed in a check valve passage (104). The at least one fluid stop (124) is configured to prevent fluid exit from the open end (106) of each check valve passage (104).