Hydrogen Flame Detection via Temperature Model Comparison

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Solution Overview

Problem

Conventional sensor technologies struggle to reliably detect the presence and stability of hydrogen flames in combustion chambers, especially under changing operating conditions, due to the unique characteristics of hydrogen combustion, such as invisible flames and different heat radiation patterns compared to carbon-containing fuels.

Innovation Solution

A method and arrangement using a mathematical model to calculate theoretical temperature curves based on physical operating data, comparing them with actual measured temperatures to determine flame ignition or extinction, ensuring reliable detection across various operating conditions and monitoring sensor integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional temperature sensors are used to monitor hydrogen flames, then the system structure remains simple, but the measurement reliability deteriorates under changing operating conditions

Engineering Contradiction:
Improveflame detection reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A mathematical model serves as an intermediary between the temperature sensor and the flame detection decision. The model processes multiple input parameters (temperature, power output, operating conditions) to calculate expected temperature values, which are then compared with actual measurements to determine flame presence, thereby improving reliability without requiring complex sensor arrays

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system continuously compares measured temperature values with calculated values from the mathematical model and adjusts the flame detection decision based on this feedback. When deviations exceed threshold values, the system concludes flame extinction or ignition, providing reliable real-time monitoring under varying operating conditions

Inventive Principle:
Principle #23Feedback

2Measurement precision

If temperature measurements are used to detect flame ignition or extinction, then the detection capability improves, but false shutdowns occur due to inability to distinguish normal temperature variations from abnormal changes

Engineering Contradiction:
Improvetemperature measurement precisionVSAvoidshutdown decision reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system changes the approach from monitoring absolute temperature values to monitoring temperature deviations from calculated expected values. By comparing measured temperature with temperature calculated from the mathematical model based on current power output and operating conditions, the system can distinguish normal temperature variations from abnormal changes, preventing false shutdowns

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The mathematical model dynamically adapts to changing operating conditions by continuously calculating expected temperature values based on current power output, ambient conditions, and system state. This dynamic comparison allows the system to distinguish between normal temperature fluctuations during load changes and actual flame extinction events

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If simple temperature threshold monitoring is used, then the system remains easy to operate, but it cannot reliably interpret temperatures under modulated power output or after restart

Engineering Contradiction:
Improvesystem operation simplicityVSAvoidtemperature interpretation accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The mathematical model performs preliminary calculations of expected temperature values based on the current operating state and power output before comparing with actual measurements. This preliminary action enables the system to interpret temperature changes correctly under modulated power output or after restart, maintaining both simplicity and accuracy

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

This approach provides a robust flame detection system capable of operating reliably across a wide range of conditions, enhancing safety by accurately distinguishing between normal and abnormal combustion states and detecting sensor errors, thus preventing false shutdowns.

Implementation Method 1

a temperature is measured at at least one measuring point in or on the combustion chamber

Methodology Applied
Scientific EffectTemperature measurement:

Implementation Method 2

the temperature at the measuring point is also measured using a mathematical model

Methodology Applied
Scientific EffectMathematical modeling:

Implementation Method 3

The combustion of hydrogen differs from previously used fuel gases in several ways

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 4

the measured temperature is compared with the calculated one and, in the event of deviations above a threshold value, it is concluded that the flames have gone out

Methodology Applied
Scientific EffectTemperature comparison:

Data Source

PatentEP4071408B1Method and assembly for observing flames in a combustion chamber of a heater operable with hydrogen or hydrogen-containing fuel gas
Publication Date: 2023.09.27 VAILLANT GMBH(DE)
  • EP4071408B1 patent drawingFigure 1
  • EP4071408B1 patent drawingFigure 2

AI summary

The invention relates to a method and an arrangement for observing or monitoring flames (16) in a combustion chamber (15) of a heating appliance (1) which is operated with hydrogen or a hydrogen-containing fuel gas, wherein a temperature (TM) is measured at at least one measuring point (19) in or on the combustion chamber (15), wherein the temperature (TB) at the measuring point (19) is also calculated on the basis of a mathematical model (11) from other physical operating data (PB) measured on or specified at the heating appliance (1), wherein the mathematical model (11) takes into account physical properties of the combustion chamber (15) and parameters essential for combustion.namely the heat capacity of essential components of the combustion chamber (15) as well as the thermal conductivity and heat transfer coefficients of the materials used and a temperature sensor (10) used, wherein the measured temperature (TM) and/or its temporal behavior (TM') is compared with the calculated temperature (TB, TB') and, in the case of deviations above a threshold value, a conclusion is drawn as to whether the flames (16) have ignited or extinguished. The invention makes it possible to reliably monitor the presence of flames (16) in the combustion chamber (15) under a wide range of operating conditions of a heating device (1) with a temperature sensor (10).