Microwave Probe Rotor Blade Vibration Monitoring
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Solution Overview
Problem
Existing methods for monitoring rotor blade vibration in gas turbine engines face challenges due to high temperatures, requiring offline testing and multiple probes for accurate data, and fail to provide comprehensive twisting and flutter analysis during engine operation.
Innovation Solution
A microwave-based system using a probe to direct and detect microwave signals reflected from rotating rotor blades, allowing for real-time measurement of arrival time, thickness, and vibration modes, including twisting and flutter, by analyzing energy levels and signal patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensors or eddy current sensors are used to measure vibration modes, then measurement precision is improved, but the system cannot withstand high temperatures and requires offline testing
Solution Approach 1:
The patent replaces optical sensors and eddy current sensors with a microwave-based measurement system. The microwave probe transmits electromagnetic waves that reflect off the rotor blades, allowing vibration mode measurement without physical contact. This substitution enables the system to withstand high temperatures while maintaining measurement precision, eliminating the need for offline testing.
Solution Approach 2:
The patent introduces microwave waves as an intermediary medium to transfer measurement information from the high-temperature turbine blade environment to the external monitoring system. The microwave probe acts as a mediator that can operate in the harsh thermal environment while delivering vibration data, solving the contradiction between temperature resistance and measurement capability.
2Measurement precision
If multiple probes are placed along the chord of the blade to detect twisting, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the single microwave probe multi-functional by enabling it to detect multiple vibration modes including flutter, twisting, and blade passage characteristics. The probe can measure arrival time, thickness, and twisting information from a single location, eliminating the need for multiple probes along the blade chord while maintaining comprehensive measurement precision.
Solution Approach 2:
The patent transitions from spatial distribution of multiple probes along the blade chord to a single probe measuring in the temporal domain. By analyzing the time-domain characteristics of the microwave reflection signal, the system extracts twisting information without needing multiple spatial probes, reducing device complexity while maintaining measurement precision.
3Reliability
If routine testing is scheduled by operators, then safety is improved, but loss of time increases due to scheduled downtime
Solution Approach 1:
The patent enables continuous monitoring of rotor blade vibration modes during engine operation rather than requiring periodic offline testing. The microwave measurement system operates continuously throughout engine run-time, providing ongoing reliability data without interrupting engine operation. This eliminates scheduled downtime while maintaining comprehensive blade monitoring reliability.
Solution Approach 2:
The system performs self-monitoring during normal engine operation without requiring external intervention or scheduled maintenance downtime. The microwave probe continuously captures vibration data automatically, allowing the system to service itself by providing ongoing health assessments during operational periods rather than requiring separate maintenance windows.
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 continuous, accurate monitoring of rotor blade vibrations and twisting within high-temperature environments, providing detailed data on blade stress and vibration patterns without the need for multiple probes, enhancing operational reliability and maintenance scheduling.
Implementation Method 1
The probe directs a microwave signal toward a rotor such that during rotation the rotor blade will pass through the path of the microwave signal. As the rotor blade passes, the microwave signal is reflected back to the probe.
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A rotor blade measurement system includes a microwave source (26) and a probe (28). A directional coupler (34) is attached to the source (26) and the probe (28). A detector (36) is attached to the directional coupler (34). The probe directs a microwave signal (30) toward a rotor (20) such that during rotation the rotor blade (22) will pass through the path of the microwave signal (30). As the rotor blade (22) passes, the microwave signal (30) is reflected back to the probe (28). The directional coupler (34) separates the original microwave signal (30) and the reflected signal (32). The detector (36) then determines the energy level of the reflected signal (32). As each rotor blade (22) passes the microwave signal (30) it generates a reflected signal that can be analyzed over time. From the length and shape of the waveform of the reflected signal (32) the amount of twisting and flutter in a rotor blade can be determined.