Turbine Blade Internal Wire Damper Vibration Control
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Solution Overview
Problem
Turbine rotor blades in gas turbine engines experience significant vibration due to aerodynamic, thermal, and centrifugal loads, which affects their high cycle fatigue life, and existing damping solutions like frictional dampers increase weight and complexity, while internal dampers complicate design and impact cooling performance.
Innovation Solution
A turbine rotor blade design incorporating a wire damper mounted within the airfoil, using a plurality of damper ribs and pads to minimize obstruction of coolant flow and maximize damping effectiveness, while maintaining structural integrity and aerodynamic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a discrete damper is used for frictionally damping vibration of the blades, then vibration is reduced and blade life is enhanced, but weight increases and the number of parts increases
Solution Approach 1:
The damper is merged with the blade structure itself, forming an integrated unit rather than a separate component. The damper ribs are formed as integral parts of the blade airfoil structure, eliminating the need for separate damper components and their associated mounting hardware, thus reducing weight while maintaining vibration damping functionality
Solution Approach 2:
The blade structure serves multiple functions: it provides aerodynamic surfaces for energy extraction, structural support for centrifugal loads, and incorporates damping functionality through the integrated damper ribs. This multi-functionality eliminates the need for dedicated separate dampers, reducing part count and weight
2Reliability
If an internal damper is used to dampen vibratory modes, then damping effectiveness is improved, but design difficulty substantially increases
Solution Approach 1:
The internal damping structure is segmented into discrete damper ribs positioned at specific locations within the blade airfoil. These ribs are spaced apart longitudinally and positioned to effectively dampen specific vibratory modes without requiring a complex continuous damping structure, thereby reducing design complexity while maintaining effectiveness
Solution Approach 2:
Damping functionality is localized to specific regions within the blade where damper ribs are strategically positioned to address critical vibratory modes. The damper ribs are chordally positioned intermediate the partitions at locations that provide effective damping without complicating the overall blade design or interfering with other critical functions
3Reliability
If damper ribs and pads are added inside the airfoil, then vibration damping is achieved, but cooling performance may be compromised
Solution Approach 1:
The damper ribs and pads occupy only a portion of the airfoil internal volume, strategically positioned to provide effective damping while leaving sufficient space for coolant flow. The ribs are spaced longitudinally apart and positioned chordally intermediate the partitions, creating a balanced configuration that achieves damping without excessively blocking cooling passages
Solution Approach 2:
The damping structure utilizes the chordal dimension (positioned intermediate the partitions) rather than blocking the longitudinal cooling flow path. By positioning damper ribs and pads chordally between the partitions rather than filling the entire cross-section, coolant flow is maintained in the longitudinal direction while damping functionality is provided in the chordal direction
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 internal wire damper effectively reduces vibration without compromising the blade's cooling performance or increasing weight, thereby enhancing the high cycle fatigue life of the rotor blades.
Implementation Method 1
A frictional damper introduces an interface centrifugally loaded during operation for effecting frictional damping as the adjacent components experience relative motion during vibration. The energy of vibration is dissipated by the friction, which therefore reduces the magnitude of the vibration.
Implementation Method 2
A main flow channel extends longitudinally in span through the blade and is bound chordally by opposite partitions transversely bridging opposite sidewalls of the airfoil
Data Source
AI summary
A turbine rotor blade includes a hollow airfoil joined to a platform and dovetail. A main flow channel extends longitudinally in span through the blade and is bound chordally by opposite partitions transversely bridging opposite sidewalls of the airfoil. A damper rib and transversely opposite damper pad are arranged together in a plurality of pairs spaced longitudinally apart in the airfoil and chordally positioned intermediate to the partitions to provide unobstructed forward and aft portions of the flow channel for channeling a coolant therethrough. The damper ribs and pads are configured to receive a wire damper through the channel to locally dampen vibration while minimizing obstruction of the coolant flow therethrough.