Vibration Signal Phase Error Compensation in Turbomachines
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Solution Overview
Problem
Gas turbine engines experience vibrations due to rotor imbalances, which reduce efficiency and service life, and existing vibration signal processing methods fail to accurately identify and correct phase errors in vibration signals, leading to ineffective trim balancing.
Innovation Solution
A vibration system comprising a sensor, signal conditioner, and processor that uses a test signal with a base frequency modulated at a specific frequency to introduce a phase shift, allowing for harmonic analysis and compensation of phase errors in the vibration signals, thereby improving trim balance solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vibration sensors are used to detect rotor imbalances, then rotor imbalance detection is enabled, but phase errors are introduced in the vibration signals
Solution Approach 1:
The system uses a test signal generator to inject known test signals through the signal conditioner, measures the phase shift introduced by the conditioner, and uses this feedback information to compensate for phase errors in the vibration signals from the vibration sensor. This closed-loop feedback mechanism allows the system to detect and correct the phase errors introduced during signal conditioning.
Solution Approach 2:
A test signal acts as an intermediary to characterize the signal conditioner's phase error. By analyzing how the test signal transforms through the conditioner, the system can determine the phase shift introduced by the conditioner and use this information to correct the vibration signals, effectively using the test signal as a mediator to uncover and compensate for the phase error.
2Ease of operation
If signal conditioning is applied to vibration signals, then signal processing capability is improved, but phase errors are introduced
Solution Approach 1:
The system implements feedback by continuously monitoring the phase shift introduced by the signal conditioner through test signals and using this information to compensate for phase errors in the actual vibration signals, thereby maintaining signal processing capability while correcting the introduced phase errors.
Solution Approach 2:
The system changes the parameter of phase shift by introducing a known phase shift through the test signal and then applying compensatory phase adjustment to the vibration signals. This parameter change approach allows the system to characterize and correct the phase error introduced by the signal conditioner.
3Productivity
If existing vibration signal processing methods are used, then basic vibration detection is achieved, but trim balancing effectiveness is reduced
Solution Approach 1:
The system enhances the basic vibration detection function by adding a feedback mechanism that uses test signals to characterize phase errors in the signal conditioner and then compensates for these errors in the vibration signals. This feedback enhancement improves the reliability of trim balancing effectiveness while maintaining the basic vibration detection capability.
Solution Approach 2:
The system replaces the mechanical imbalance correction approach with a signal processing-based approach. Instead of relying solely on mechanical trim balancing, the system uses digital signal processing to compensate for phase errors and improve the accuracy of imbalance detection, thereby enhancing trim balancing effectiveness.
Data Source
AI summary
A system comprises a vibration sensor for generating a vibration signal on a turbomachine, a signal conditioner for conditioning the vibration signal, and a test signal generator for calibrating the signal conditioner. The test signal generator calibrates the signal conditioner with a test signal having a base frequency and a modulation frequency. The signal conditioner introduces a phase error into the vibration signal, and the signal conditioner introduces a phase shift into the test signal. A processor compensates for the phase error in the vibration signal by correcting the vibration signal based on the phase shift in the test signal, where the processor determines the phase shift in the test signal based on harmonic analysis of the modulation frequency.