Combustor Acoustic Sensing for Turbine Inlet Temperature Estimation
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Solution Overview
Problem
Direct measurement of turbine inlet temperature in gas turbine engines is challenging due to high temperatures that damage temperature sensors, and existing methods for estimating this temperature are not sufficiently accurate or reliable.
Innovation Solution
A method using dynamic pressure sensors to measure acoustic oscillations in the combustor, convert them into signals, and apply a polynomial equation to calculate turbine inlet temperature based on resonant frequencies, with constants determined through actual measurements or heat balance, enabling accurate estimation even in high-temperature environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional thermocouple-based measurement systems are used, then temperature measurement can be obtained, but the system requires physical contact with hot gases, exposure to high temperatures and corrosive environments, and complex installation infrastructure
Solution Approach 1:
The patent replaces the mechanical/physical contact-based thermocouple measurement system with an acoustic measurement system. Microphones positioned in the turbine inlet area detect acoustic signals generated by the hot gas flow, and signal processing algorithms extract temperature information from these acoustic characteristics without requiring physical probes in the hot gas path.
Solution Approach 2:
The patent introduces acoustic waves as an intermediary medium to transfer temperature information from the hot gas to the measurement device. Instead of directly measuring temperature with a probe in contact with hot gases, the system uses acoustic signals propagating through the gas as a carrier of thermal information, which can be detected by remote microphones.
2Measurement precision
If thermocouples are exposed to high temperatures and corrosive environments for direct measurement, then temperature data can be obtained, but the measurement system reliability deteriorates due to probe degradation and contamination
Solution Approach 1:
The patent eliminates the vulnerable mechanical thermocouple probe by substituting it with an acoustic measurement system. Microphones positioned outside the direct hot gas path detect acoustic signals that carry temperature information, avoiding the reliability issues of probe exposure to high temperatures, corrosion, and contamination.
Solution Approach 2:
The acoustic measurement system utilizes the natural acoustic signals already present in the turbine inlet flow. The hot gas flow itself generates acoustic waves that contain temperature information, and the system passively detects these signals without requiring active heating or complex probe structures that would be vulnerable to degradation.
3Measurement precision
If thermocouple probes are installed in the turbine inlet area, then temperature measurement is possible, but the probes are subject to contamination, oxidation, and thermal degradation
Solution Approach 1:
The patent replaces the physical thermocouple probe that is directly exposed to harmful environmental factors with an acoustic measurement system. Microphones positioned in protected locations detect acoustic signals from the hot gas flow, eliminating direct exposure to contamination, oxidation, and thermal degradation.
Solution Approach 2:
The patent uses acoustic waves as an intermediary to transmit temperature information from the hot gas environment to the measurement device. This intermediary approach allows temperature measurement without direct physical contact, protecting the measurement sensors from harmful environmental factors like contamination and oxidation.
4Measurement precision
If physical probes are used for temperature measurement, then direct temperature data can be obtained, but the system requires maintenance and replacement due to probe degradation
Solution Approach 1:
The patent substitutes the mechanical thermocouple probe system with an acoustic measurement system using microphones and signal processing. This eliminates the need for maintenance and replacement of probes exposed to harsh conditions, as the microphones can be positioned in protected locations and the measurement is based on acoustic signal analysis rather than physical exposure.
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
Provides accurate and reliable estimation of turbine inlet temperature, maintaining precision within a few degrees of actual measurements, especially at higher operating loads, thus supporting efficient gas turbine engine control and operation.
Implementation Method 1
an acoustic measurement system and method for measuring the temperature of a fluid stream entering a gas turbine engine compressor
Data Source
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AI summary
A method of determining a turbine inlet temperature for a gas turbine engine includes measuring pressure changes within a combustion section of the gas turbine engine during operation of the gas turbine engine to produce pressure versus time data, extracting a resonant frequency from the pressure versus time data, and calculating the turbine inlet temperature based solely on the resonant frequency.