Gas Turbine Damper Ring With Pressure Relief Dimples
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional friction dampers in gas turbine engines tend to lock by friction at high speeds, leading to reduced effectiveness and increased rotor vibratory stress, which can result in premature engine failure due to the inability to maintain relative sliding under centrifugal loads.
Innovation Solution
A damper ring with circumferentially spaced pressure relief dimples is designed to reduce contact pressure below the threshold that causes locking, allowing for relative movement by distributing centrifugal forces through lands and dimples, preventing frictional locking and ensuring energy dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the damper ring is subjected to high centrifugal load at high rotation speeds, then the reaction force between the damper and rotor increases, but the friction force locks the damper ring against movement and damper effectiveness is lost
Solution Approach 1:
The invention introduces pressure relief dimples at specific locations on the outer circumferential surface of the damper ring. These dimples create localized regions where contact pressure is reduced, allowing the damper ring to maintain relative sliding capability even under high centrifugal loads. The lands between dimples provide structural strength while the dimples themselves prevent complete frictional locking by creating zones of reduced contact pressure.
2Reliability
If the contact pressure between the damper ring and rotor is increased to maintain frictional damping, then the damping effectiveness improves, but the damper ring locks against circumferential movement at high speeds
Solution Approach 1:
The invention modifies the contact pressure distribution by introducing pressure relief dimples that change the local contact parameters. The dimples create a non-uniform contact pressure profile where certain regions have reduced pressure, preventing the threshold for frictional locking from being reached while maintaining adequate damping in other regions. This parameter change allows the system to operate effectively across a wider range of rotation speeds.
3Strength
If the damper ring is designed with a continuous outer surface for uniform contact, then the structural strength is maximized, but the friction forces lock the damper at high rotation speeds
Solution Approach 1:
The invention segments the continuous outer circumferential surface of the damper ring by introducing pressure relief dimples. This segmentation divides the contact surface into lands (elevated portions) and dimples (depressed portions). The lands maintain structural strength and provide primary contact areas, while the dimples create localized stress relief zones that prevent frictional locking. This segmentation allows the damper to maintain both strength and anti-locking capability simultaneously.
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 maintains vibratory damping at high rotation speeds by reducing contact pressure, preventing damper lock by friction and extending the service life of gas turbine engines by ensuring continuous energy dissipation and relative slippage between the damper ring and rotor.
Implementation Method 1
the damper ring being displaceable under a centrifugal load from a first position, in which the lands are in contact with the radially inwardly facing surface of the circumferential groove while the pressure relief dimples are spaced radially inwardly therefrom, to a second position, in which the pressure relief dimples are deformed under the centrifugal load in contact with the radially inwardly facing surface of the circumferential groove
Implementation Method 2
this force could be enough to stick the damper to the rotor by friction so that no relative sliding is maintained and damper effectiveness is lost
Data Source
AI summary
A damper ring is mounted in frictional engagement with a radially inwardly facing surface of a circumferential groove defined in a rotary part of a gas turbine engine. Energy dissipation is provided via sliding friction of the ring in the groove. Pressure relief dimples are provided around the outer diameter of the ring for locally reducing contact pressure at the outer diameter below a value at which the damper ring locks in the groove by friction forces when subject to centrifugal loads.