Reduction Gearbox Thermal Monitoring for Early Degradation Detection
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Solution Overview
Problem
Current monitoring methods for gas turbine reduction gears are inadequate for precise and fine-state assessment, often leading to delayed maintenance or replacement, as they rely on vibration analysis with limited threshold setting and detection of existing failures rather than predictive maintenance.
Innovation Solution
A method involving the collection and analysis of multiple parameters such as lubricating oil temperatures and gas turbine speed over specific operating phases, with normalization and comparison to reference signatures to evaluate thermal efficiency, allowing for timely detection of reducer degradation and maintenance needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vibration analysis with amplitude ratio comparison is used to monitor gearbox condition, then the monitoring method is simple to implement, but the measurement precision and ability to detect early degradation is insufficient
Solution Approach 1:
The patent changes the monitored parameter from vibration amplitude ratio to thermal efficiency, which is calculated from temperature measurements. This parameter change enables early detection of gearbox degradation through thermal changes before mechanical failure occurs, significantly improving measurement precision while using standard temperature sensors already present in the system.
Solution Approach 2:
The patent replaces the mechanical vibration analysis approach with a thermal-based monitoring approach. By substituting vibration sensors and complex signal processing with temperature measurements and thermal efficiency calculation, the system achieves higher precision in detecting early degradation while simplifying the overall monitoring system architecture.
2Loss of information
If vibration-based Boolean determination is used to detect gearbox faults, then the monitoring method is easy to operate, but the loss of information occurs due to inability to detect early-stage degradation
Solution Approach 1:
The patent performs preliminary detection of degradation through thermal efficiency monitoring before mechanical failure occurs. By continuously tracking thermal changes and comparing against reference signatures, the system captures early-stage degradation information that would be lost in traditional vibration-based Boolean determination, enabling proactive maintenance planning.
Solution Approach 2:
The patent introduces thermal efficiency as an intermediary parameter between normal operation and catastrophic failure. This intermediary metric provides gradual information about degradation progression, allowing operators to understand the gearbox's health state without the abrupt binary classification of traditional vibration analysis, thus preserving information while maintaining operational simplicity.
3Reliability
If traditional vibration monitoring thresholds are used, then the monitoring approach is straightforward, but the reliability of maintenance timing determination is insufficient leading to delayed maintenance
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring thermal efficiency, comparing it with reference signatures from healthy and degraded gearboxes, and adjusting maintenance decisions based on the detected deviations. This feedback loop significantly improves the reliability of maintenance timing determination by providing objective, data-driven indicators of actual gearbox condition rather than relying on fixed vibration thresholds.
Solution Approach 2:
The patent performs preliminary assessment of gearbox health through thermal efficiency monitoring, allowing maintenance to be scheduled at the optimal time before failure occurs. By detecting degradation trends early and comparing them against reference data, the system enables proactive maintenance planning, eliminating the delays associated with waiting for vibration thresholds to be exceeded or catastrophic failure to occur.
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
This approach enables more precise monitoring of gas turbine reduction gear health by analyzing thermal efficiency over multiple cycles, allowing for early detection of drifts and predictive maintenance, reducing the risk of malfunction and extending equipment lifespan.
Implementation Method 1
temperatures of a gearbox lubricating oil at the gearbox inlet and outlet
Implementation Method 2
a physical model defining the thermal efficiency from a difference between the temperature of the lubricating oil at the outlet of the gearbox and the temperature of the lubricating oil at the inlet of the gearbox
Data Source
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Figure 2
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AI summary
This method for monitoring a status of a reducer of a gas turbine comprises the following steps: - obtaining (F10) measurements of parameters realised during an operating phase of the gas turbine, said parameters comprising temperatures of a lubrication oil of the reducer at the inlet and at the outlet of the reducer, a parameter representing a gas turbine speed, as well as at least one context parameter; - selecting (F20) stable measurements with respect to a predetermined stability criterion; - normalising (F30) temperatures of the lubrication oil at the inlet and at the outlet of the reducer using the measurements of context parameters; - assessing (F40) a thermal efficiency of the reducer using a physical model defining the thermal efficiency from a difference between the temperature of the lubrication oil at the outlet and at the inlet of the reducer; - and determining (F60) a status of the reducer as a function of a step of comparing (F50) the assessed thermal efficiency with a reference signature.