Gas Turbine Shaft Shear Detection Using Axial Force Sensors
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Solution Overview
Problem
Conventional systems for detecting shaft shear events in gas turbine engines are slow to identify the event, which can lead to potential damage if not addressed promptly.
Innovation Solution
A system comprising a sensor configured to detect a shaft shear force exerted by the shaft on a support structure, indicative of shearing, and a controller to initiate a shutdown of the engine upon detection, using load cells or strain gauges to quickly identify a predetermined change in axial force, such as a 50% increase in axial force over a short period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rotational speed change or position change detection methods are used, then the system can identify shaft shear events, but the detection time is significantly delayed
Solution Approach 1:
The patent applies preliminary action by installing force sensors (load cells) in the load path between the shaft and support structure before a shaft shear event occurs. These sensors continuously monitor axial force, so when shearing happens, the change is detected immediately rather than waiting for rotational speed or position changes to manifest. This pre-positioned detection capability eliminates the time delay inherent in conventional methods.
Solution Approach 2:
The patent replaces the conventional mechanical detection approach (monitoring rotational speed or position changes) with a force-based detection system. By using load cells to measure axial force changes directly at the shaft-support interface, the system substitutes indirect mechanical observations with direct force measurement, enabling immediate detection of shaft shear events.
2Speed
If force sensors are installed to detect axial force changes, then detection speed improves, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the force sensor system to serve multiple functions: it detects shaft shear events, monitors operational loads, and provides data for condition-based maintenance. This multi-functionality justifies the added complexity, as the same sensor infrastructure supports both rapid shear detection and ongoing engine health monitoring, reducing the net complexity increase.
Solution Approach 2:
The patent uses the existing support structure as an intermediary element that already provides a natural mounting location for the force sensors. By placing load cells in the existing load path between the shaft and support structure, the system leverages the support structure's inherent geometry and loading characteristics, simplifying sensor installation compared to adding entirely new measurement infrastructure.
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 rapid detection and mitigation of shaft shear events, preventing further engine damage and potential turbine bursts by initiating a shutdown quickly.
Implementation Method 1
The sensor may comprise a load cell disposed in a load path between the shaft of the gas turbine engine and the support structure
Implementation Method 2
The sensor may comprise a strain gauge configured to detect a strain of the support structure in response to the shaft shear force
Data Source
AI summary
A system and a method for detecting a shaft shear event in a gas turbine engine are disclosed. The system comprises a sensor configured to detect a shaft shear force exerted by a shaft on a support structure supporting the shaft where the shaft shear force is indicative of shearing of the shaft. The system also comprises a controller operatively coupled to the sensor and configured to initiate a shutdown of the gas turbine engine in response to the detection of the shaft shear force by the sensor.