Segmented Damper Pin for Turbine Blade Resonant Mode Tuning
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Solution Overview
Problem
Existing vibration dampers in turbomachines are not effectively tunable for resonant mode excitation avoidance, often requiring costly tooling rework if they do not perform as expected, and lack independent mode tuning options without modifying the turbine blade design.
Innovation Solution
A damper pin with a plurality of rings coaxially aligned along a retention pin, providing a generally arcuate outer surface to contact the groove between turbine blades, allowing for natural frequency tuning and independent mode tuning without altering the existing turbine blade design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional vibration dampers (round damper pins, sheet metal flat dampers, or complex wedge shaped dampers) are used, then the damper structure is simple to manufacture, but the damper effectiveness for vibration damping is insufficient and cannot be tuned for resonant mode excitation avoidance
Solution Approach 1:
The damper pin is segmented into multiple cylindrical segments (rings) of different diameters arranged coaxially along the retention pin. This segmentation allows each segment to contribute differently to the damping characteristics, enabling tuning of natural frequencies for resonant mode avoidance while maintaining a manageable structural complexity through modular design.
Solution Approach 2:
The damper pin transitions from a static, uniform structure to a dynamic, multi-dimensional structure with varying diameters along its length. The non-uniform cylindrical segments create different stiffness characteristics at different locations, allowing the damper to dynamically respond to and tune multiple vibrational modes simultaneously.
2Ease of manufacture
If the damper pocket geometry in turbine blades is locked in by hard tooling, then the turbine blade design is fixed and manufacturing is simplified, but costly tooling rework is required if the damper does not perform as expected
Solution Approach 1:
The damper pin allows for parameter changes in the form of varying segment diameters and configurations without requiring changes to the turbine blade tooling. By adjusting the dimensions and arrangement of the cylindrical segments, different damping characteristics can be achieved while maintaining the same blade pocket geometry, thus avoiding costly tooling rework.
3Adaptability or versatility
If existing damper designs are used, then the turbine blade design remains unchanged, but independent mode tuning options are not available
Solution Approach 1:
The damper pin adds a dimensional aspect to the damping solution by varying the diameter along the axial length of the retention pin. This creates a gradient of stiffness properties that enables independent tuning of different vibrational modes, transforming a one-dimensional damping approach into a multi-dimensional tuning capability.
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 damper pin effectively dissipates vibrational energy, reduces vibration amplitude, and enables tuning of resonant modes without requiring changes to the turbine blade design, enhancing damper performance and avoiding costly rework.
Implementation Method 1
vibration dampers are typically provided below and/or between the platforms to frictionally dissipate vibratory energy and reduce the corresponding amplitude of vibration during operation
Data Source
AI summary
A damper pin for damping adjacent turbine blades coupled to a rotor shaft includes a first end portion that is axially aligned with and axially spaced from a second end portion and a retention pin that is coaxially aligned with and disposed between the first end portion and the second end portion. The retention pin couples the first end portion to the second end portion. The damper pin further includes a plurality of rings coaxially aligned with and disposed along the retention pin between the first end portion and the second end portion. The first end portion, the second end portion and the plurality of rings define a generally arcuate outer surface of the damper pin that is configured to contact with a groove defined between the adjacent turbine blades.