Fuel Injector Airflow Layout for Hydrogen Autoignition Control
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Solution Overview
Problem
Turbine engines using hydrogen fuel face challenges with higher flame speeds and reactivity, leading to increased risks of flashback and autoignition, which can damage the fuel injector and surrounding components.
Innovation Solution
A fuel injector design that incorporates non-swirling airflow for fuel supply and additional air supply to introduce swirl or turbulence, enhancing mixing and reducing the risk of flashback and autoignition, while accommodating low-emission fuels like hydrogen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If hydrogen fuel is used in turbine engines, then low-emission operation is achieved, but flashback and autoignition risks increase due to higher flame speeds and reactivity
Solution Approach 1:
The fuel injector divides the fuel supply into multiple separate fuel passages instead of a single passage, allowing different fuel streams to be injected at different locations and angles. This segmentation prevents flashback propagation by creating physical barriers and reduces autoignition risk by distributing fuel injection points throughout the combustion chamber.
Solution Approach 2:
The patent introduces a non-swirling air passage that supplies air as an intermediary medium between the fuel injection point and the combustion zone. This non-swirling airflow acts as a protective barrier that stabilizes the flame front and prevents flashback while maintaining proper fuel-air mixing for complete combustion.
2Productivity
If fuel is injected directly into the combustion chamber, then combustion efficiency is improved, but flashback risk increases due to direct exposure to high-velocity flames
Solution Approach 1:
Different regions of the combustion chamber are provided with different flow characteristics through dedicated passages. The non-swirling air passage provides a calm, low-velocity region for initial fuel mixing, while swirling air passages further downstream provide turbulence for complete combustion. This local differentiation allows efficient combustion without flashback risk.
Solution Approach 2:
Fuel is pre-mixed with air in the non-swirling passage before entering the main combustion zone. This preliminary mixing action ensures proper fuel-air ratio is established before combustion begins, improving combustion efficiency while the controlled mixing environment prevents premature ignition and flashback.
3Stability of the object's composition
If swirling airflow is used for fuel mixing, then combustion stability is improved, but autoignition risk increases due to enhanced turbulence and oxygen availability
Solution Approach 1:
The air supply is segmented into non-swirling and swirling components that operate in sequence. The non-swirling portion provides stable, controlled mixing that prevents autoignition, while the swirling portion further downstream enhances combustion stability without creating conditions for premature ignition.
Solution Approach 2:
The patent adds a spatial dimension to the mixing process by using three-dimensional swirling flow patterns in addition to the axial non-swirling flow. This multi-dimensional approach allows the fuel-air mixture to achieve stable combustion through controlled turbulence in specific regions while maintaining autoignition-free conditions in the injection zone.
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 design ensures stable operation with low-emission fuels by minimizing pressure drop and eliminating flashback and autoignition risks, improving component durability and reducing maintenance costs.
Implementation Method 1
the set of air passages are arranged tangentially relative to the outer wall to impart a swirl to a flow of air provided from the set of air passages to the interior
Implementation Method 2
additional air supply to introduce swirl or turbulence, enhancing mixing
Data Source
AI summary
A turbine engine has a compression section, combustion section, and turbine section in serial flow arrangement. The turbine engine includes a fuel injector for providing fuel and air to the combustion section. The fuel injector includes an outer wall in annular arrangement extending from a forward end to an outlet, surrounding an interior having a non-swirling air passage, and defining a longitudinal axis. A fuel passage fluidly couples to the interior and a set of air passages are in annular arrangement about and extending through the outer wall and fluidly coupled to the interior. The set of air passages are arranged tangentially relative to the outer wall to impart a swirl to a flow of air provided from the set of air passages to the interior.