Radar-Based REMPI Temperature Measurement Through Ceramic Walls
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Solution Overview
Problem
Conventional methods for measuring high-temperature gas systems are limited by invasive probe-based measurements and optical methods that require significant access, leading to heat loss and spatially integrated measurements, which are not suitable for confined environments like gas turbines and chemical reactors.
Innovation Solution
A radar-based resonance-enhanced multi-photon ionization (REMPI) system that uses microwave radiation to detect temperature through ceramic walls, allowing for non-invasive, spatially localized measurements by probing the electron density of ionized species without the need for optical access, utilizing a small access port and ceramic-insulating materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If probe-based measurement techniques are used, then temperature measurements can be obtained, but the probe materials must survive harsh high-temperature environments and the probe significantly impacts the thermochemical process
Solution Approach 1:
The patent replaces mechanical probe-based measurement systems with an optical measurement system using laser-induced fluorescence. The laser beam passes through the combustion chamber without physical contact, and the fluorescent signal is detected optically, eliminating the mechanical probe that would otherwise interfere with the flow and require high-temperature material survival.
Solution Approach 2:
The patent introduces a fluorescent tracer substance as an intermediary medium. The tracer molecules absorb laser energy and emit fluorescent light whose intensity and spectral characteristics indicate temperature. This intermediary allows indirect temperature measurement without requiring direct physical contact between the measurement device and the high-temperature gas.
2Object-affected harmful factors
If optical-based measurement techniques are used, then non-invasive measurements are achieved, but significant optical access is required leading to heat loss
Solution Approach 1:
The patent uses a focused laser beam to create a localized measurement volume within the combustion chamber. The laser is focused to a specific region where temperature measurement is needed, rather than requiring broad optical access. This localized approach minimizes the optical opening size and reduces heat loss through the optical access port.
Solution Approach 2:
The patent employs pulsed laser excitation rather than continuous illumination. The laser emits short pulses to excite the fluorescent tracer, allowing temperature measurement during brief measurement intervals. This partial action reduces the average optical energy required and minimizes heat input through the optical access compared to continuous optical measurement methods.
3Object-affected harmful factors
If optical probes are used for temperature measurement, then non-invasive measurements are obtained, but spatially integrated measurements are provided rather than localized measurements
Solution Approach 1:
The patent segments the measurement space by using a focused laser beam that creates a distinct, localized excitation volume within the combustion chamber. The fluorescence signal is collected from this specific spatial region, enabling temperature measurement at a defined location rather than providing an integrated average over a large volume. Multiple measurements at different positions can be obtained by moving the laser focus or the detection system.
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 highly accurate, non-invasive temperature measurements with high signal-to-noise ratio and sub-millimeter spatial resolution, suitable for high-temperature applications like gas turbines and chemical reactors, minimizing heat loss and maintaining precision and accuracy.
Implementation Method 1
directing a first electromagnetic energy into the high temperature system so that the first electromagnetic energy may cause multi-photon ionization of a molecular or atomic species within the high temperature system
Implementation Method 2
A radar-based resonance-enhanced multi-photon ionization (REMPI) system that uses microwave radiation to detect temperature through ceramic walls
Implementation Method 3
resonance-enhanced multi-photon ionization (REMPI) system that uses microwave radiation to detect temperature through ceramic walls, allowing for non-invasive, spatially localized measurements by probing the electron density of ionized species
Data Source
AI summary
A method of measuring a temperature of a thermally-insulated, high temperature system. The method includes directing a first electromagnetic energy into the high temperature system so that the first electromagnetic energy may cause multi-photon ionization of a molecular or atomic species within the high temperature system. A second electromagnetic energy resulting from the multi-photon ionization is detected through a thermally-insulating wall of the high temperature system. The detected second electromagnetic energy is related to a temperature within the high temperature system.