Blade Tip Timing Full-Frequency Vibration Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional displacement-based blade tip timing measurement methods struggle to accurately measure medium-frequency, high-frequency, and super-high-frequency blade vibrations in turbomachinery, which are crucial for comprehensive vibration analysis and fault diagnosis.
Innovation Solution
A method and system that perform prestress modal analysis to determine sensor placement and use blade tip timing sensors to measure vibration displacement, velocity, acceleration, and jerk across different frequency ranges, enabling full-frequency-domain vibration measurement by calculating vibration parameters using a least squares method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If displacement-based blade tip timing measurement method is used, then low-frequency blade bending vibration parameter can be obtained, but medium-frequency, high-frequency, and super-high-frequency blade vibration cannot be accurately measured
Solution Approach 1:
The patent segments the frequency measurement range into four distinct bands (low-frequency <500Hz, medium-frequency 500-2000Hz, high-frequency 2000-5000Hz, super-high-frequency >5000Hz) and applies different measurement methods optimized for each band. This segmentation allows the system to achieve accurate measurements across the entire frequency spectrum by tailoring the measurement approach to each specific frequency range's characteristics.
Solution Approach 2:
The patent changes the measurement parameter from displacement-only to multiple physical quantities (displacement, velocity, acceleration, jerk) depending on the frequency band. By selecting appropriate physical quantities for each frequency range and using corresponding differentiation orders, the system overcomes the limitations of displacement-based methods and achieves accurate measurement across all frequency bands.
2Adaptability or versatility
If conventional displacement-based measurement is used, then measurement system is simple, but it cannot provide comprehensive blade vibration information across all frequency bands
Solution Approach 1:
The patent creates a universal measurement system that can handle all frequency bands using a single integrated approach. The system uses blade tip timing sensors combined with signal differentiation to achieve multi-functionality across low-frequency, medium-frequency, high-frequency, and super-high-frequency ranges, eliminating the need for separate measurement systems for each band.
Solution Approach 2:
The patent introduces dynamic signal processing through time-differentiation to adapt the measurement system to different frequency characteristics. By dynamically selecting the differentiation order (0 for displacement, 1 for velocity, 2 for acceleration, 3 for jerk) based on frequency band, the system maintains simplicity while achieving comprehensive frequency coverage.
3Measurement precision
If blade tip timing sensors are mounted to measure all frequency bands, then full-frequency-domain vibration information can be obtained, but sensor mounting requirements become complex
Solution Approach 1:
The patent performs preliminary modal analysis to determine the optimal number and circumferential mounting angles of blade tip timing sensors before actual measurement. This preliminary action ensures that the sensor layout is optimized for capturing vibration modes across all frequency bands, simplifying the manufacturing and installation process while guaranteeing measurement accuracy.
Solution Approach 2:
The patent uses prestress modal analysis to create a virtual model of blade vibration characteristics, which guides the sensor layout design. By copying the vibration mode information from the modal analysis into the sensor placement strategy, the system achieves accurate full-frequency measurement without requiring complex trial-and-error sensor arrangements.
Data Source
AI summary
Disclosed are a method and system for blade tip timing measurement of full-frequency-domain vibration of a rotor blade. The method includes: identifying low-frequency, medium-frequency, high-frequency, and super-high-frequency mode parameters of the rotor blade to determine the number and mounting angles of sensors; identifying low-frequency vibration parameters based on blade tip timing according to blade tip vibration displacement; identifying medium-frequency vibration parameters based on blade tip timing according to blade tip vibration velocity; and identifying high-frequency vibration parameters based on blade tip timing according to blade tip acceleration and identifying super-high-frequency vibration parameters based on blade tip timing according to blade tip jerk. The present disclosure also provides a system for implementing the method for full-frequency-domain vibration measurement based on blade tip timing. The method for blade tip timing measurement of full-frequency-domain vibration extends the range of blade vibration frequency effectively measured by the blade tip timing technology.