Multi Sensor Clearance Probe for Turbine Blade Tip Measurement
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Solution Overview
Problem
Existing methods for measuring blade tip clearances in gas turbine engines lack accuracy and stability, leading to potential rubs between turbine blade tips and static seals, which can affect engine performance and wear.
Innovation Solution
A multi-sensor clearance probe system with longitudinally and transversely spaced sensors measures distances between rotating rotor blades and stator shrouds, allowing for real-time calibration and adjustment of thermal control air to maintain optimal clearances, preventing rubs and improving engine efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing single sensor probe methods are used to measure blade tip clearances, then the measurement process is simple, but the measurement accuracy and stability are insufficient leading to potential rubs between turbine blade tips and static seals
Solution Approach 1:
The probe is divided into multiple sensors positioned at different locations (first sensor for blade tip clearance, second sensor for reference measurement, third sensor for additional measurement points). Each sensor independently measures clearance at its specific position, and the results are combined to achieve more accurate and stable overall clearance measurement, resolving the contradiction between measurement precision and device complexity.
2Reliability
If thermal control air is used to shrink turbine casings to maintain clearances, then clearance control is achieved, but excessive thermal control air usage reduces engine efficiency
Solution Approach 1:
The multi-sensor probe provides real-time feedback on actual blade tip clearance measurements to the control system. This feedback enables precise modulation of thermal control air flow through the air valve, allowing the system to maintain optimal clearances with minimal air consumption. The feedback loop ensures reliable clearance control while minimizing energy loss by adjusting air flow based on actual measured conditions rather than using excessive air flow.
3Productivity
If blade tip clearance is minimized to improve engine performance, then thrust and fuel consumption improve, but the risk of rubs between blade tips and static seals increases
Solution Approach 1:
The multi-sensor probe continuously measures blade tip clearance before rubs can occur, providing advance warning of clearance degradation. The system uses preliminary measurements from multiple sensors to detect trends and predict potential rub conditions, allowing the control system to adjust thermal control air flow proactively to maintain safe clearances and prevent harmful blade tip rubs while optimizing engine performance.
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
The system provides accurate and stable measurements of blade tip clearances, reducing wear and improving engine performance by minimizing thermal control air usage and preventing unstable rubs, thereby enhancing engine efficiency and longevity.
Implementation Method 1
The probe includes a housing, a first capacitance sensor mounted in the housing, a second capacitance sensor mounted in the housing, and a third capacitance sensor mounted in the housing
Data Source
AI summary
A multi sensor clearance probe with at least longitudinally and transversely spaced apart first and second sensors operable to measure first and second distances respectively between the sensors and a longitudinally spaced apart rotating rotor. The sensors being operable to measure blade tip clearances between radially outer turbine blade tips and an annular stator shroud circumscribing the blade tips. The blade tips may be squealer tips and the sensors operable to measure the distances between the sensors and tops of squealer tip walls and outwardly facing walls within cavities of the squealer tips. The probe may be operably connected to a controller for sending signals to the controller indicating the first and second distances for controlling an air valve used for active clearance control. Two or more of the probe may be used to determine rotor centerline offset.