Coaxial Dihydrogen Injection Device for Turbomachine Flame Stabilization
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Solution Overview
Problem
Current dihydrogen combustion systems in turbomachines face issues with flashback risks, high thermal loads, and excessive nitrogen oxide emissions, leading to complex geometries and high implementation costs, which are not compatible with existing kerosene combustion standards.
Innovation Solution
A longitudinal-axis dihydrogen injection device with an inner channel for dihydrogen circulation and an outer annular channel for air mixture circulation, featuring coaxial swirlers that create a recirculation zone to stabilize the flame aerodynamically, reducing flashback risks and thermal loads, and optimizing the mixture for reduced nitrogen oxide emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If micro-mixing burners are used to combust dihydrogen and air, then combustion efficiency is improved, but device complexity increases and flashback risks remain
Solution Approach 1:
The injection device is segmented into multiple channels: a central channel for dihydrogen injection and surrounding annular channels for air injection. This segmentation allows independent control of fuel and oxidizer flows, enabling efficient combustion while maintaining a relatively simple overall structure that avoids the complexity of micro-mixing burners.
2Power
If dihydrogen and air are mixed and combusted, then energy production is improved, but flashback risks increase damaging the combustion chamber
Solution Approach 1:
Air is injected into the annular channels before the dihydrogen reaches the combustion zone, creating a pre-mixed but spatially separated configuration. The air flow is established in advance in the annular region, and when dihydrogen is injected centrally, the mixture forms in a controlled manner that prevents flashback while enabling complete combustion for high energy production.
Solution Approach 2:
The injection device uses a nested configuration where the central dihydrogen injection channel is surrounded by annular air injection channels. This nested arrangement allows the fuel and oxidizer to be closely positioned for efficient mixing and combustion while maintaining physical separation that prevents flashback from propagating back into the injection system.
3Object-generated harmful factors
If dihydrogen combustion is used, then carbon emissions are reduced, but thermal loads on combustion chamber walls increase reducing lifetime
Solution Approach 1:
The device creates local quality differences in the combustion process by injecting air in annular channels surrounding the central dihydrogen injection. This produces a combustion pattern where the flame stabilizes in the annular region away from the central axis, distributing thermal loads more evenly across the combustion chamber walls and avoiding concentrated hot spots that would reduce component lifetime.
4Power
If dihydrogen and air are combusted at equivalent richness, then energy release is improved, but nitrogen oxide emissions increase exceeding current standards
Solution Approach 1:
The injection device transitions from a conventional single-zone combustion approach to a spatially distributed combustion structure with central fuel injection and annular oxidizer injection. This dimensional arrangement creates extended combustion zones where the flame propagates radially outward, allowing for more complete combustion at lower peak temperatures, thereby reducing nitrogen oxide formation while maintaining high energy release.
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
The device achieves low nitrogen oxide emissions, reduced thermal loads, and simplified geometry, making it cost-effective and adaptable to existing turbomachines, while ensuring flame stability and integrity of the combustion chamber.
Implementation Method 1
Incorporating an inner swirler in the inner channel serves to create a recirculation zone in a dihydrogen flow passing through the inner channel... This recirculation zone is understood to mean a zone generating a centrifugal force with a low pressure inside configured to produce an axial velocity component in the flow on average negative compared to a main direction of the flow.
Implementation Method 2
This recirculation zone is similar to the one generated inside a vortex in which the air is aspirated.
Implementation Method 3
The inner recirculation zone blocks a portion of the dihydrogen flow along the longitudinal axis of the inner channel generating, in an outlet section of this inner channel, significant excess velocities near the walls of the inner channel compared with a flow with a uniform axial discharge velocity.
Data Source
AI summary
A longitudinal-axis (X) dihydrogen injection device is configured to be mounted on an annular bottom of an annular combustion chamber of a turbomachine. The injection device includes an inner channel for dihydrogen circulation and an outer annular channel for circulation of a mixture of at least air. The inner channel and the outer annular channel are coaxial. An inner swirler is housed in the inner channel and an outer swirler is housed in the outer annular channel. A downstream end of the inner channel is arranged upstream, at a distance r, from a downstream end of the outer annular channel. With this dihydrogen combustion, polluting carbon emissions such as carbon monoxide, unburned hydrocarbons or even fine and smoke particles can be eliminated.