Phosphor Thermometry for Thermal Barrier Coating Temperature Monitoring
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Solution Overview
Problem
Current thermal barrier coatings for turbine components face challenges in accurate high-temperature measurements, leading to uncertainties in predicting the lifespan of turbine blades and inefficiencies in engine operation due to the limitations of existing temperature measurement techniques, which are either invasive, inaccurate, or lack direct measurement capabilities at the thermally grown oxide layer.
Innovation Solution
A phosphor thermometry device utilizing a laser pulse and rare-earth doped thermal barrier coatings with co-doped Erbium and Europium luminescent dopants, allowing for direct temperature monitoring at the thermally grown oxide layer through luminescence lifetime decay and intensity variations, enabling precise temperature measurements and delamination detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If infrared thermometry is used for temperature measurement, then non-contact measurement is achieved, but measurement precision is limited by variations in emissions from turbine engine operation
Solution Approach 1:
The patent introduces phosphor materials as an intermediary substance that converts thermal energy into optical signals. The phosphor coating on the turbine blade absorbs thermal energy and emits light with characteristics that depend on temperature, providing a reliable intermediary mechanism for non-contact temperature measurement that overcomes the emission variation problem of direct infrared thermometry
Solution Approach 2:
The patent utilizes the temperature-dependent optical properties of phosphor materials, specifically how their emission characteristics change with temperature. By measuring these optical property changes (analogous to color changes), the system achieves precise temperature measurement without being affected by the operational emission variations of the turbine engine
2Measurement precision
If sensor coating is placed in the top coat to enable temperature measurement, then direct temperature measurement capability is achieved, but manufacturing cost increases and mechanical integrity is compromised
Solution Approach 1:
The patent changes the fundamental parameter of the coating material by incorporating phosphor particles into the thermal barrier coating composition. This modifies the optical properties of the coating to enable temperature sensing while maintaining the coating's structural function, avoiding the need for separate sensor coatings that would compromise mechanical integrity
Solution Approach 2:
The patent creates a composite thermal barrier coating material that combines traditional thermal barrier coating components with phosphor particles. This composite structure enables temperature measurement capability while preserving the mechanical and thermal protection functions of the original coating, eliminating the need for additional sensor layers
3Measurement precision
If phosphor thermometry is used for temperature measurement, then measurement precision is improved, but device complexity increases due to requirement for laser excitation and detection systems
Solution Approach 1:
The phosphor coating serves dual functions: it provides thermal barrier protection and generates its own optical signal for temperature measurement. The material itself responds to temperature changes through optical property variations, eliminating the need for separate active sensing components and reducing overall system complexity
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 solution provides accurate, non-invasive, and precise temperature monitoring across a wide range, enhancing the reliability of turbine component lifespan predictions and improving engine efficiency by reducing temperature measurement uncertainties and allowing for real-time thermal barrier coating health assessment.
Implementation Method 1
phosphors, which luminescence is due to rare-earth or transition metal ions that have been illuminated by an ultraviolet lamp or laser source
Implementation Method 2
The thermal barrier coating may include a metallic bond coat layer on the substrate, and a ceramic top coat layer on the bond coat layer that may include an undoped layer and a doped sensing layer having co-doped first and second rare-earth luminescent dopants that emit respective first and second different emission wavelengths upon excitation by the laser pulse
Implementation Method 3
A detector may include first and second photomultiplier devices configured to detect respective first and second different emission wavelengths of the convoluted luminescence signals
Implementation Method 4
phosphor thermometry. This measurement technique uses phosphors, which luminescence is due to rare-earth or transition metal ions that have been illuminated by an ultraviolet lamp or laser source
Data Source
AI summary
A phosphor thermometry device includes a laser that generates a laser pulse onto a thermal barrier coating (TBC) applied onto a substrate. A metallic bond coat layer is on the substrate. A ceramic top coat layer is on the bond coat layer and includes an undoped layer and a doped sensing layer having co-doped first and second rare-earth luminescent dopants that emit respective first and second different emission wavelengths upon excitation by the laser pulse. A detector receives reflected, convoluted luminescence signals from the TBC. First and second photomultiplier devices detect respective first and second different emission wavelengths of the convoluted luminescence signals. A controller receives and processes signals generated from respective first and second photomultiplier devices and determines luminescence lifetime decay and intensity variations for each of the respective first and second rare-earth luminescent dopants for temperature monitoring of the TBC.