Gas Turbine Combustion Pressure Gradient Flame Detection

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Solution Overview

Problem

Modern gas turbine systems face challenges in detecting rapid overheating and partial flame extinguishing due to the limitations of conventional thermal and optical sensors, which can lead to reduced service life and safety risks.

Innovation Solution

Measuring the pressure gradient in the combustion chamber, compensated for by correction functions involving pre-guide row position, shaft speed, and ambient conditions, to quickly identify excessive hot gas temperature changes and flame extinguishing, triggering emergency shutdowns when thresholds are exceeded.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional thermal sensors (thermocouples) are used to monitor hot gas temperature, then the system can detect temperature changes, but the response time is too slow (seconds) to prevent abrupt overheating events

Engineering Contradiction:
Improveoverheating protection reliabilityVSAvoidtemperature detection speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent replaces thermal sensors (mechanical/thermal measurement system) with pressure sensors and pressure gradient evaluation (mechanical measurement system). Pressure changes in the combustion chamber respond much faster to temperature changes than thermal sensors, enabling detection of abrupt overheating events within milliseconds rather than seconds. This substitution maintains measurement reliability while dramatically improving response speed.

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

2Reliability

If optical sensors are used to monitor flame parameters, then flame extinction can be detected, but the processing time is too long (1 second) and partial extinguishing cannot be reliably detected

Engineering Contradiction:
Improveflame monitoring reliabilityVSAvoidflame parameter processing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces optical sensors (electromagnetic measurement system) with pressure sensors and pressure gradient evaluation (mechanical measurement system). Pressure gradient measurements respond immediately to combustion changes, enabling detection of both complete and partial flame extinction without the 1-second processing delay of optical systems. The pressure-based method provides continuous real-time monitoring with millisecond response time.

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

3Productivity

If the gas turbine operates at maximum material load limits, then performance is optimized, but the risk of overheating and component damage increases

Engineering Contradiction:
Improvegas turbine performanceVSAvoidcomponent safety
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback control system using pressure gradient measurements to continuously monitor combustion chamber conditions. When the pressure gradient exceeds predetermined thresholds indicating approaching overheating conditions, the system provides early warning signals that allow operators to take preventive action before material limits are exceeded. This feedback mechanism enables the turbine to operate closer to maximum performance while maintaining component safety through real-time monitoring and early intervention.

Inventive Principle:
Principle #23Feedback

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 method enables rapid detection and prevention of overheating and partial flame extinguishing, ensuring the gas turbine system operates within safe temperature limits and preventing potential damage by utilizing pressure gradient measurements that are faster than temperature changes.

Implementation Method 1

the pressure in the combustion chamber is measured by means of a pressure sensor. The change in the measured pressure over time, ie the pressure gradient, is then determined

Methodology Applied
Scientific EffectPressure gradient measurement: Pressure Gradient

Implementation Method 2

air is compressed in a compressor unit and, after being mixed with fuel in the form of a fuel-air mixture, is ignited and burned in a combustion chamber, resulting in a hot gas flow

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP1937950B1Method for protecting the hot gas carrying parts of a gas turbine installation from overheating and for detecting flame extinction in the combustion chamber
Publication Date: 2015.04.08 ALSTOM TECH LTD

AI summary

The invention relates to a method for protecting a gas turbine installation from overheating and for detecting flame extinction in the combustion chamber. According to said method, air is compressed in a compressor unit and is ignited and combusted as a fuel/air mixture in a combustion chamber once fuel is added, thereby producing a hot gas flow that sets a turbine stage rotating downstream of the combustion chamber while doing expansion work. The invention is characterized in that the pressure upstream of the turbine stage, i.e., the pressure pk of the compressed air in the plenum and/or the pressure inside the combustion chamber pcom is measured, a temporal change of the measured pressure, the so-called pressure gradient (p), is determined, at least one threshold value is selected, and the pressure gradient or a variable derived from the pressure gradient is compared with the at least one threshold value, and a signal is generated when the pressure gradient/the variable derived from the pressure gradient exceeds or falls below the threshold value.