Abradable Casing Sensors for Blade Rub and Coating Wear Detection
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Solution Overview
Problem
Current blade tip clearance monitoring technologies fail to account for wear of the abradable layer on the stationary engine casing, which is crucial for determining the actual blade tip clearance and detecting rub events, leading to inefficiencies and safety risks in turbine engines.
Innovation Solution
A sensing system with abradable sensors embedded in the engine casing that measure changes in electrical properties such as resistance, capacitance, or time of flight, correlating these changes to the wear of the abradable layer, using conductive and non-conductive layers and a sensor conditioning unit for temperature compensation and redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional blade tip clearance monitoring sensors are used, then blade tip clearance can be monitored, but wear of the abradable layer is not detected leading to inaccurate clearance measurements
Solution Approach 1:
The patent combines the blade tip clearance monitoring function with the abradable layer wear detection function into a single integrated sensor system. The sensor simultaneously measures both the clearance between the blade tip and engine casing and the thickness/wear of the abradable layer, eliminating the need for separate monitoring systems and providing comprehensive data for accurate clearance measurement.
Solution Approach 2:
The sensor system is designed to perform multiple functions: monitoring blade tip clearance, detecting abradable layer wear, and identifying rub events. This multi-functional approach allows a single system to provide all necessary information for accurate clearance measurement and engine safety monitoring, resolving the information loss problem.
2Reliability
If abradable sensors are embedded in the engine casing to detect wear, then wear detection is enabled, but the sensor must withstand harsh environmental conditions including high temperature and erosion
Solution Approach 1:
The sensor is protected by a sacrificial abradable layer that is deposited over the sensor elements before installation. This protective layer absorbs the harsh environmental conditions including high temperature exposure and erosion from blade rub events, shielding the underlying sensor from damage while still allowing the sensor to detect wear through changes in electrical properties.
Solution Approach 2:
The sensor construction uses composite materials including conductive polymers or coatings that provide both electrical conductivity for sensing and resistance to harsh environmental conditions. The multi-layer structure combines materials with different properties to achieve both sensing capability and environmental durability.
3Productivity
If the sensor measures changes in electrical properties to detect wear, then continuous monitoring is enabled, but temperature changes affect the electrical measurements
Solution Approach 1:
The sensor system incorporates temperature compensation through feedback mechanisms. Temperature sensors monitor the local temperature conditions, and this information is used to adjust or compensate the electrical property measurements in real-time. The system continuously adapts the measurement baseline according to temperature changes, maintaining accurate wear detection despite thermal variations.
Solution Approach 2:
The sensor measures multiple electrical parameters (such as resistance, capacitance, or inductance) and uses changes in these parameters to detect wear. By monitoring how these parameters change relative to each other and to temperature references, the system can distinguish between temperature effects and actual wear, enabling continuous accurate monitoring.
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 and accurate detection of blade rubs and wear of the abradable layer, providing reliable gap information for engine calibration and control, while withstanding harsh environmental conditions.
Implementation Method 1
measuring one of a resistance, a capacitance, or a round-trip time of flight for a reflected electrical signal
Implementation Method 2
measuring one of a resistance, a capacitance, or a round-trip time of flight for a reflected electrical signal
Implementation Method 3
measuring one of a resistance, a capacitance, or a round-trip time of flight for a reflected electrical signal
Data Source
AI summary
A sensing system and method for detecting wear of an abradable layer on a stationary engine casing is provided. The system is capable of measuring the abradable thickness of the abradable layer by embedding abradable sensor in the abradable layer and measuring the changing electrical properties as the abradable sensor wears.