Gas Turbine Flameout Detection via EGT Second Derivative

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Solution Overview

Problem

Existing gas turbine engine flameout detection methods are inadequate in quickly identifying the extinction of the flame, leading to excess fuel expulsion, which can have negative consequences.

Innovation Solution

A system that determines an engine flameout condition by analyzing the second or first derivative of exhaust gas temperature (EGT) with respect to time and comparing it to a threshold value, allowing for rapid fuel supply cutoff to prevent unburned fuel expulsion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If traditional flameout detection methods are used, then the detection system is simple, but the detection speed is slow leading to excess fuel expulsion

Engineering Contradiction:
Improvedetection speedVSAvoidfuel loss
Core Design Contradiction:
SpeedVSLoss of substance

Solution Approach 1:

The patent changes the detection parameter from direct flame presence to the second derivative of exhaust gas temperature. This parameter transformation enables faster detection because the second derivative captures the acceleration of temperature change, which occurs immediately upon flameout, whereas traditional methods relying on direct temperature measurement or rotor speed detection are slower to respond.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If second derivative of EGT is used for detection, then detection accuracy is improved, but system complexity increases

Engineering Contradiction:
Improveflameout detection accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or optical flame detection systems with a computational approach using temperature derivative analysis. Instead of using additional sensors or complex mechanical mechanisms to detect flameout, the system uses software-based calculation of the second derivative of existing EGT data, achieving high detection accuracy with minimal additional hardware complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If flameout detection is delayed, then the control system has simpler response requirements, but excess fuel is expelled from exhaust

Engineering Contradiction:
Improvefuel cutoff timelinessVSAvoidunburned fuel expulsion
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent implements preliminary detection by monitoring the second derivative of EGT, which changes immediately when flameout occurs. This allows the control system to initiate fuel cutoff action before the engine state deteriorates further, preventing unburned fuel from being expelled through the exhaust. The early detection capability enables proactive rather than reactive fuel management.

Inventive Principle:
Principle #10Preliminary action

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 quick detection and prevention of excess unburned fuel expulsion by determining the engine flameout condition before substantial rotor deceleration, thereby minimizing fuel loss and ensuring timely fuel cutoff.

Implementation Method 1

at least one exhaust gas temperature (EGT) sensor disposed proximate the outlet region of the gas turbine engine and configured to output an EGT signal indicative of a temperature of exhaust gas exiting the outlet region

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP3039270B1Gas turbine flameout detection
Publication Date: 2019.03.06 UNITED TECH CORP
  • EP3039270B1 patent drawingFigure 1
  • EP3039270B1 patent drawingFigure 2
  • EP3039270B1 patent drawingFigure 3

AI summary

A method includes receiving an indication of exhaust gas temperature (EGT) for a gas turbine engine, and determining, by at least one processor, based on the received indication of the EGT, a representation of a second derivative with respect to time of the EGT. The method further includes comparing the representation of the second derivative of the EGT to a threshold value, and determining, based on the comparing, an engine flameout condition of the gas turbine engine. In some embodiments, the at least one processor can determine a representation of a first derivative with respect to time of the EGT. The representation of the first derivative of the EGT can be compared to a threshold value, determined based on the received indication of the EGT, to determine the engine flameout condition.