Plasma-Assisted Jet Engine Combustion Flame Stabilization
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Solution Overview
Problem
Current jet engine combustion systems face challenges in sustaining combustion due to high air velocity and pressure, leading to inefficiencies and unburnt fuel, as well as NOx emissions, particularly in lean combustion conditions which are unstable and prone to mechanical damage.
Innovation Solution
An apparatus that incorporates a swirler assembly and fuel nozzle with a plasma generator to ionize and dissociate the fuel-air mixture, enhancing combustion efficiency by creating a partially ionized or dissociated air-fuel mixture, which is then introduced into a combustion chamber with a recirculation zone for improved mixing and flame stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high air velocity is used in the combustion chamber, then productivity is improved, but combustion stability deteriorates
Solution Approach 1:
The plasma generator pre-ionizes and pre-heats the fuel-air mixture before it enters the main combustion zone, creating reactive species and elevated temperatures in advance. This preliminary action allows the combustion to be more readily initiated and sustained even at high air velocities, resolving the contradiction between productivity and stability.
Solution Approach 2:
The plasma discharge fundamentally changes the physical and chemical parameters of the fuel-air mixture by creating ionized species, excited states, and elevated local temperatures. These parameter changes enable combustion to occur more readily and sustain itself at higher flow velocities than would otherwise be possible, thereby improving productivity without sacrificing stability.
2Object-generated harmful factors
If lean combustion is used to decrease NOx emissions, then harmful factors are reduced, but combustion stability deteriorates
Solution Approach 1:
The plasma generator changes the chemical parameters of the lean fuel-air mixture by producing active radicals and ionized species. This allows lean combustion to proceed stably by providing alternative reaction pathways that do not require the high temperatures and fuel concentrations that lead to NOx formation, thus maintaining both low emissions and combustion stability.
Solution Approach 2:
The plasma acts as an intermediary that facilitates combustion in lean mixtures by generating reactive species that lower the activation energy barrier. This intermediary mechanism enables stable combustion at lower equivalence ratios, allowing the system to operate lean for reduced NOx emissions while maintaining reliability through plasma-assisted ignition and flame stabilization.
3Productivity
If high temperatures are used for efficient combustion, then productivity is improved, but harmful factors increase
Solution Approach 1:
The plasma generator changes the chemical composition and energy state of the reactants by creating ionized species and excited molecules. This allows combustion to proceed efficiently at lower peak temperatures because the plasma-provided activation energy substitutes for thermal energy, thereby maintaining productivity while reducing NOx emissions that form at high temperatures.
Solution Approach 2:
The plasma discharge replaces the purely thermal-mechanical ignition and combustion process with a chemically-active plasma-assisted process. By substituting thermal energy with plasma-generated reactive species and excited states, the system achieves efficient combustion without requiring the high temperatures that produce harmful NOx emissions.
4Productivity
If plasma generator is added to assist combustion, then combustion efficiency is improved, but device complexity increases
Solution Approach 1:
The plasma generator is designed to perform multiple functions: igniting the fuel-air mixture, stabilizing the flame, enhancing combustion efficiency, and potentially reducing emissions. By consolidating these functions into a single device, the increase in complexity is justified by the multiple benefits achieved, and the system becomes more versatile rather than simply more complex.
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 solution increases combustion efficiency, reduces unburnt fuel, and decreases NOx emissions by stabilizing lean flames, improving fuel flexibility, and reducing mechanical damage risks through enhanced flame stabilization and reaction kinetics.
Implementation Method 1
Plasma is an electronically exited state of matter in which the electrons from individual atoms are stripped via electrical interactions with the energy source and by collisions with other energized particles
Implementation Method 2
at least one plasma generator located at least partially within the lip recirculation zone. The plasma generator at least partially ionizes and/or dissociates the fuel-air mixture
Implementation Method 3
The plasma generator at least partially ionizes and/or dissociates the fuel-air mixture to generate at least one of an at least partially ionized air-fuel mixture and an at least partially dissociated air-fuel mixture
Implementation Method 4
The chamber can be shaped to create an eddy-an area of lower pressure in which combustion is permitted to occur
Implementation Method 5
The area between separate air flows contains a shear layer of increased turbulence for improving at least one of mixing, atomization and/or flame stabilization
Implementation Method 6
Combustion of the at least one of an at least partially ionized air-fuel mixture and an at least partially I/D air-fuel mixture with the plurality of combustion air inputs occurs at least partially within the combustion chamber internal volume
Implementation Method 7
the high temperatures used in the efficient operation of a jet engine also promote the oxidation of atmospheric nitrogen
Data Source
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AI summary
An apparatus for assisting with the combustion of fuel includes a swirler assembly and a fuel nozzle. Fuel from a fuel nozzle fuel reservoir is directed into a fuel nozzle mixing zone and combines with air inside the fuel nozzle mixing zone to form a fuel-air mixture. At least one plasma generator is located at least partially within a lip recirculation zone. The plasma generator provides at least one of an at least partially ionized air-fuel mixture and an at least partially dissociated air-fuel mixture via a plasma generator discharge. A combustion chamber has a combustion chamber internal volume including the lip recirculation zone including a stabilization zone of low velocity air circulation. Combustion of the air-fuel mixture with the plurality of combustion air inputs occurs to responsively produce combustion products.