Turbine Blade Platform Spacer for Friction Vibration Damping
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Solution Overview
Problem
Current vibration-damping systems for turbomachine blades face challenges such as corrosion in harsh environments, complexity in installation and repair, and reduced effectiveness due to lack of grounding for vibrations, particularly during in-phase vibratory responses.
Innovation Solution
A vibration-damping system that includes a spacer axially adjacent to the platform of a turbomachine blade, featuring a damping element coupler and a vibration-damping element configured to engage the radially inner surface of the blade, providing frictional damping and grounding to reduce vibrations without altering the blade configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dampers are attached to external surfaces of blades, then vibration damping is provided, but the dampers are exposed to harsh corrosive environment and may corrode or separate
Solution Approach 1:
The patent introduces an intermediary damping structure located in the annulus space between adjacent blades, rather than attaching dampers directly to blade surfaces. This intermediary positioning protects the damping elements from direct exposure to the harsh corrosive environment while still enabling vibration damping through engagement with blade platforms.
2Reliability
If blade structure is altered to reinforce against vibrations, then vibration resistance is improved, but aerodynamic performance changes and weight/length increase
Solution Approach 1:
The patent segments the vibration damping function from the blade's primary aerodynamic structure. Instead of modifying the blade itself, separate damping elements are introduced that engage with the blade platforms, allowing vibration control without altering the blade's aerodynamic shape or adding significant weight.
Solution Approach 2:
The damping elements serve as intermediary components between adjacent blades, providing vibration resistance without requiring modifications to the blades themselves. This maintains the original aerodynamic performance while achieving the desired vibration control.
3Reliability
If damping elements engage platforms of adjacent blades, then vibration damping is achieved, but the installation and repair become very complicated
Solution Approach 1:
The patent extracts the damping function from complex integrated structures and provides it through separate, removable damping elements. These elements can be independently installed and removed from the annulus space, significantly simplifying maintenance and repair operations compared to modifying blade structures themselves.
4Reliability
If damping elements are positioned in the annulus, then grounding for vibrations is provided, but the device complexity increases
Solution Approach 1:
The damping elements in the annulus serve multiple functions: they provide vibration grounding, dampen vibrations between adjacent blades, and can be positioned to address both in-phase and out-of-phase vibratory responses. This multi-functionality achieves comprehensive vibration control without requiring multiple separate systems.
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 system effectively reduces blade vibrations through frictional damping, both between blades and to the rotor disk, enhancing damage tolerance and simplifying assembly, while avoiding the drawbacks of existing methods.
Implementation Method 1
The vibration-damping element frictionally damps vibration of the turbomachine blade(s)
Implementation Method 2
The vibration-damping element and the damping element coupler are disposed to cause the vibration-damping element to engage the radially inner surface of the platform of the turbomachine blade(s) to dampen vibration of the turbomachine blade(s)
Data Source
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AI summary
A vibration-damping system (128) for turbine blade(s) (114) in a turbine (108) is provided. Each turbine blade (114) includes a platform (136, 136A, 136B) having a radially inner surface (137, 184). The system (128) includes a spacer (150) axially adjacent the platform (136, 136A, 136B) of the at least one turbine blade (114) in the turbine (108), e.g., adjacent a turbine blade (114) stage. The spacer (150) includes a body (154) having a gaspath facing surface (156) forming a portion of an annulus for a working fluid flowpath. A damping element coupler (162) is on the body (154) of the spacer (150), and a vibration-damping element (164) is configured to couple to the damping element coupler (162). The vibration-damping element (164) and the damping element coupler (162) are disposed to cause the vibration-damping element (164) to engage the radially inner surface (137, 184) of the platform (136, 136A, 136B) of the turbine blade(s) (114) to dampen vibration of the turbine blade(s) (114) during operation of the turbine (108).