Multi-Probe Turbine Blade Vibration Sensor Matching
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Solution Overview
Problem
In turbine blade vibration monitoring, multiple sensors often become misaligned axially, leading to errors and spectral noise in vibration measurements due to varying electrical performance and positional discrepancies.
Innovation Solution
A method is developed to match sensors by analyzing signals from probes mounted adjacent to the blade structure, generating sets of harmonics characteristic of each sensor's position, and adjusting their placement to ensure matching harmonics, indicating aligned axial locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sensors are used to provide multiple blade pass signals, then frequency foldover is removed and synchronous vibration measurement is enabled, but sensor misalignment axially introduces errors and spectral noise in measurements
Solution Approach 1:
The patent applies preliminary action by performing sensor alignment using harmonic matching before actual vibration measurement. The system analyzes blade pass signals to generate harmonic sets, compares these harmonics to determine axial misalignment, and adjusts sensor positions accordingly before conducting the measurement, thereby eliminating alignment errors in advance
Solution Approach 2:
The patent implements feedback by using the harmonic content of blade pass signals to detect sensor misalignment and providing corrective feedback for sensor repositioning. The system continuously monitors the harmonic matching between multiple sensors and adjusts their positions to maintain optimal alignment, creating a closed-loop control system
2Productivity
If sensors are positioned at different axial locations, then each sensor captures blade pass events, but positional discrepancies create errors in vibration measurement
Solution Approach 1:
The patent applies parameter changes by utilizing the harmonic frequency content of blade pass signals as a diagnostic parameter for sensor alignment. By analyzing changes in harmonic matching between sensors, the system determines axial position discrepancies and adjusts sensor locations to optimize measurement precision
Data Source
AI summary
A method of matching sensors in a multi-probe blade vibration monitor for a turbine. The method includes providing at least two probes mounted in a casing of the turbine adjacent to a rotating blade structure of the turbine. Targets are provided on radially outer portions of the blade structure. Each of the probes includes a sensor generating signals corresponding to target passing events, and a set of synchronous harmonics of the rotational speed of the rotor are produced for each sensor. The position of the sensors is adjusted such that the sets of harmonics of the sensors are substantially matched, indicating that the positions of the sensors are matched.