Variable Depth Damper Pocket for Turbine Bucket Vibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing turbine bucket vibration dampers are inadequate during transient operations, such as startups and shutdowns, and fail to ensure proper installation without compromising system efficiency.
Innovation Solution
A damping system featuring a damper with a variable tangential depth and a damper pin positioned within a cast or machined damper pocket, which includes angled surfaces for proper alignment and engagement, effectively restraining the damper and minimizing stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vibration damper is added to the turbine bucket, then bucket vibration is reduced, but device complexity increases
Solution Approach 1:
The damper pin is integrated directly into the bucket structure through a damper pocket, merging the damper function with the bucket itself rather than adding a separate complex damping system. This reduces overall device complexity while maintaining vibration protection.
Solution Approach 2:
The damper pin automatically engages and disengages based on vibration conditions without requiring external control mechanisms. The system self-regulates damping activation, eliminating the need for complex control systems while maintaining reliable vibration protection.
2Reliability
If the damper pocket depth is increased to improve damping effectiveness, then vibration damping improves, but stress concentration increases
Solution Approach 1:
The damper pocket depth varies locally around the bucket circumference - deeper in regions where vibration damping is most needed and shallower where stress concentration would be problematic. This localized variation optimizes both damping effectiveness and stress distribution.
Solution Approach 2:
The damper pocket geometry parameters (depth, width, orientation) are optimized to achieve the desired damping effect while maintaining acceptable stress levels. By carefully selecting these geometric parameters, the design balances damping performance with structural integrity.
3Reliability
If the damper pin is fully enclosed to ensure proper installation, then installation reliability improves, but manufacturing complexity increases
Solution Approach 1:
The damper pocket is divided into enclosed portions and open portions, allowing the damper pin to be partially visible for installation verification while maintaining sufficient enclosure for reliability. This segmentation approach balances installation reliability with manufacturing simplicity.
Solution Approach 2:
Angled surfaces act as intermediaries that guide the damper pin into proper alignment during installation. These surfaces facilitate correct positioning without requiring full enclosure, simplifying both installation verification and manufacturing.
4Reliability
If the damper is restrained axially and radially to prevent rotation, then damping effectiveness during transient operations improves, but device complexity increases
Solution Approach 1:
The restraint function is merged with the bucket structure itself through integrated restraint surfaces and geometric features, rather than adding separate restraint mechanisms. This maintains effective damping during transient operations while minimizing added complexity.
Solution Approach 2:
The damper pin's geometric features (angled surfaces, bosses) automatically engage with corresponding features in the bucket to prevent rotation and ensure proper orientation. The system self-restrains without requiring external control mechanisms, maintaining effectiveness during transient operations while keeping the design simple.
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 enhances damping effectiveness during transient operations, ensures proper installation, and maintains system efficiency by radially and axially restraining the damper pin, thereby reducing bucket vibrations and stress concentrations.
Implementation Method 1
The damper pin includes a pin angled surface. The damper pocket is machined or cast into the bucket.
Implementation Method 2
The present application relates to gas turbines and more particularly relates to turbine buckets having a bucket damping system for minimizing bucket vibration.
Data Source
AI summary
A damping system for a turbine bucket. The damping system includes a damper pocket with a variable tangential depth and a damper pin positional within the damper pocket.