Turbine Bucket Mode Shape Identification via Segmented Trigger Patterns
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing systems for monitoring vibrations in gas turbine buckets struggle to accurately discern mode shapes due to the complexity of natural resonant frequencies and rotational harmonics, particularly in shrouded bucket structures where multiple targets are needed for discrimination among mode shapes.
Innovation Solution
A system and method for mode shape identification in turbine buckets, featuring rotating trigger patterns on the tip shroud of the bucket, which are detected by a sensor to identify at least one mode shape, with the trigger patterns designed to provide varying probe sensitivity and distinguish between different mode shapes based on their configuration and orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple targets are placed on the shroud segment to discriminate among mode shapes, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The trigger pattern is segmented into multiple distinct trigger locations (first trigger, second trigger, third trigger) arranged in specific spatial configurations. Each trigger segment responds to different vibrational modes, allowing mode shape discrimination through the combined response of segmented trigger elements rather than requiring a single complex sensor array
Solution Approach 2:
The trigger pattern utilizes spatial arrangement in multiple dimensions (radial, tangential, and axial positions) to encode vibrational mode information. By positioning triggers at different locations and orientations around the shroud segment, the system captures multi-dimensional vibrational characteristics that enable mode shape identification without increasing sensor count
2Reliability
If triggers are placed in the shroud to monitor vibrations of each bucket, then monitoring capability is improved, but difficulty of detecting and measuring mode shapes increases
Solution Approach 1:
Each trigger location is strategically positioned to be sensitive to specific vibrational modes. The first trigger may be optimized for radial vibrations, the second for tangential, and the third for axial modes. This local specialization of trigger functions allows the system to capture comprehensive vibrational information while maintaining simple individual trigger designs
Solution Approach 2:
The trigger pattern acts as an intermediary element that translates complex multi-axis vibrational motions into distinguishable trigger responses. By placing triggers at specific locations on the shroud segment, the system mediates between the bucket's complex vibration and the sensor's measurement capability, making mode shapes discernible through the trigger response pattern
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
Enables precise identification of mode shapes by amplifying deflection sensitivity and distinguishing between operating deflection shapes, allowing for improved vibration analysis and measurement capability of turbine buckets.
Implementation Method 1
natural resonant mechanical frequencies of the buckets may coincide with or be excited by certain bucket rotational speeds and rotational harmonics thereof. Each natural frequency is associated with a particular mode shape, each of which is a different combination of vibrational deflections
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Embodiments of the present application can provide systems and methods for mode shape identification of turbine buckets. According to one embodiment, a system is provided including a turbine bucket (55) having numerous trigger patterns (100) disposed at a distal end of the turbine bucket (55). A sensor (105) is disposed adjacent to the distal end of the turbine bucket (55) for detecting the trigger patterns (100). The trigger patterns (100) are patterned to identify at least one mode shape of the turbine bucket (55).