Rotating Machine Rubbing Localization Using AE and Shaft Vibration Phase
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Solution Overview
Problem
Existing rubbing detection methods in rotating machines using multiple AE sensors are costly and prone to noise interference, and fail to detect axial direction rubbing accurately.
Innovation Solution
A rubbing position identification device and method utilizing a single AE sensor and shaft vibration sensor to identify the circumferential position of rubbing by analyzing the phase difference between AE and shaft vibration signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple AE sensors are installed along the circumferential direction to identify rubbing occurrence position, then the rubbing position identification capability is improved, but the number of sensors increases and the cost increases
Solution Approach 1:
The patent combines AE signal detection with shaft vibration signal detection to achieve rubbing position identification. Instead of using multiple AE sensors, the system uses one AE sensor together with shaft vibration sensors, merging the functionality of multiple sensors into a combined detection approach that reduces sensor quantity while maintaining position identification capability.
Solution Approach 2:
The shaft vibration sensor serves multiple functions: it detects shaft vibration signals for monitoring and provides reference signals for determining rubbing position when combined with AE signals. This multi-functionality allows the system to achieve position identification without requiring dedicated multiple AE sensors at different circumferential positions.
2Reliability
If multiple AE sensors are disposed at the same cross section to detect rubbing, then the rubbing detection coverage in that cross section is improved, but it becomes difficult to detect rubbing at positions different from the sensor cross section in the axial direction
Solution Approach 1:
The patent transitions from a single cross-sectional detection plane to three-dimensional rubbing detection by combining AE signal timing with shaft vibration signals from sensors positioned at different axial locations. This allows the system to identify rubbing positions not only in the circumferential direction but also to detect rubbing at different axial positions, expanding the detection coverage to multiple dimensions.
3Measurement precision
If rubbing detection is performed based on minute phase difference between multiple AE sensors, then the rubbing position can be identified, but the detection becomes susceptible to noise influence and may fail to detect rubbing
Solution Approach 1:
The patent introduces shaft vibration signals as an intermediary reference to determine rubbing position. Instead of relying solely on minute phase differences between multiple AE sensors which are susceptible to noise, the system uses the shaft vibration signal as a stable reference that correlates with the rubbing event, providing a more robust method for position identification that is less affected by noise.
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 accurate and reliable identification of rubbing positions in the circumferential direction with a simple configuration, reducing sensor costs and noise interference.
Implementation Method 1
a rubbing detection technique using an acoustic emission (AE) sensor capable of detecting an AE signal
Implementation Method 2
The shaft vibration in the rotary shaft may be generated by rubbing (scraping) between a seal or the like and the rotary shaft due to thermal deformation of a casing and by causing thermal bending of the rotary shaft due to heat generated by the rubbing
Data Source
AI summary
The present invention relates to a rubbing position identification device for a rotating machine provided with a fixed part and a rotating part. This device is provided with an AE sensor, an axial vibration sensor and a rubbing position identification unit. In the case of rubbing occurring in the rotating machine, the rubbing position identification unit calculates the AE phase, which corresponds to the peak of an envelope determined on the base of change over time in the AE signal detected by the AE sensor, and the axial vibration phase, which corresponds to the high spot position of the rotating part specified on the basis of the change over time in the axial vibration signal detected by the axial vibration sensor, and, on the basis of the phase difference between these, identifies the circumferential-direction position of where rubbing has occurred in the rotating machine.