In-stream Burner Module Angular Fuel Injection Flame Stability
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Solution Overview
Problem
Current air stream burners face challenges in maintaining flame stability and controlling carbon monoxide emissions due to low oxygen contents and variable temperatures in turbine gases, which require additional components like baffles and result in inefficient combustion and longer flame lengths.
Innovation Solution
The air stream burner module incorporates optimized aerodynamics with angular fuel injection orifices and fins to increase gas mixture speed, create recirculation zones, and staged fuel injection, along with a shield for premixing, to enhance flame stability and reduce CO emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If turbine gas velocity is reduced due to increased duct cross-section, then duct size increases, but flame stability deteriorates and CO emissions increase
Solution Approach 1:
The burner module segments the fuel injection into multiple orifices arranged in diverging planes, creating separate injection streams that enhance mixing and maintain flame stability even at low velocities. The segmentation of injection planes allows each stream to contribute to overall combustion reliability.
Solution Approach 2:
The invention introduces angular injection in three-dimensional space with orifices oriented at angle α to the fuel flow plane. This spatial arrangement creates recirculation zones and enhances mixing in multiple dimensions, maintaining flame stability without requiring high linear velocity.
2Area of stationary object
If turbine gas velocity is reduced, then duct size increases, but CO emission control becomes more difficult
Solution Approach 1:
The angular injection arrangement in diverging planes creates three-dimensional recirculation zones that extend the residence time of gases in the combustion zone. This enhanced mixing in multiple dimensions ensures complete combustion and CO oxidation even at low velocities.
Solution Approach 2:
The recirculation zones created by angular injection maintain continuous mixing and combustion action, ensuring that CO is continuously oxidized to CO2 throughout the extended residence time, preventing CO emission accumulation.
3Loss of energy
If low oxygen content turbine gases are used, then energy efficiency increases, but flame stability deteriorates
Solution Approach 1:
Multiple fuel injection orifices segmented into diverging planes create numerous small combustion zones that collectively maintain stability. Each injection stream contributes to overall flame reliability, compensating for the lower oxygen availability in the turbine gases.
Solution Approach 2:
The angular arrangement of injection orifices in three-dimensional space creates recirculation zones that enhance fuel-oxidizer mixing. This multi-dimensional mixing improves combustion efficiency and flame stability despite the challenging low-oxygen environment.
4Device complexity
If conventional in-line burner modules are used, then device simplicity is maintained, but flame stability and CO control are insufficient
Solution Approach 1:
The burner module is segmented into multiple injection orifices arranged in diverging planes, with each segment contributing to overall flame stability. This segmentation allows complex flow patterns to be achieved while maintaining a relatively simple modular structure.
Solution Approach 2:
The invention adds angular dimensionality to the injection arrangement, with orifices oriented at angle α to the fuel flow plane. This three-dimensional arrangement creates recirculation zones and enhances mixing without requiring additional bulky components.
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 design achieves stable flames, low CO emissions, and reduced need for baffles, allowing for higher linear power operation with shorter flames and lower NOx emissions.
Implementation Method 1
At least two fuel injection orifices are located in a cross-section of the duct, and their axes form an angle α with the fuel flow plane. Thus, the gas is injected through several orifices located in at least two diverging planes. These two planes define a space without fuel or oxidizer input, which promotes internal recirculation of combustion gases within the flame
Implementation Method 2
This also allows for faster mixing of the gas with the TEGs (Total Energy Gases) than with a co-current flow. This angular injection and the induced recirculations ensure flame stability
Implementation Method 3
This angular injection and the induced recirculations ensure flame stability, a short flame, and CO recombustion through increased residence time
Implementation Method 4
a feed duct having a substantially circular cross-section and an axis, fuel injection orifices located on the duct and intended to produce a flame, oxidizer injection orifices
Data Source
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AI summary
The present invention relates to a burner module in an air stream (1) comprising a feed pipe (2) of substantially circular cross section and having an axis, fuel injection orifices (20) situated on the pipe and intended to produce a flame, oxidant injection orifices (34) and fins (3) arranged symmetrically with respect to a plane P of flow of the fuel upstream of the burner module and laterally on the pipe (2) on each side of the fuel injection orifices (20); it is characterized in that there are at least two fuel injection orifices (20) in a section of the pipe (2) and that these have an axis that makes an angle α with the plane of flow P of the oxidant. In this way, gas is injected at several orifices situated in at least two divergent planes. These two planes delimit a space to which fuel is not supplied and to which oxidant is not supplied, thereby encouraging internal recirculation of the combustion gases within the flame and bringing a large proportion of the burnt gases back toward the centre.