Staged Fuel Injector Mixing for Hydrogen Flashback Control
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Solution Overview
Problem
Existing fuel injectors struggle with managing high flame speeds and reactivity of low emission fuels like hydrogen, leading to flashback and autoignition issues, and face challenges in mixing different fuel types effectively due to thermal gradients and embrittlement of alloys.
Innovation Solution
A fuel injector design with distinct mixing lengths for liquid and gaseous fuels, incorporating turbulators and specific passage arrangements to enhance mixing efficiency and reduce flashback risk, suitable for low emission fuels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If hydrogen or low emission fuels are used, then emissions are reduced, but flame speed increases causing flashback and autoignition
Solution Approach 1:
The fuel injector is divided into multiple independent fuel outlets (first fuel outlet and second fuel outlet) that can be controlled separately. This segmentation allows different fuel types to be injected at different rates and positions, enabling the system to manage high flame speed fuels like hydrogen without causing flashback or autoignition while maintaining low emissions.
Solution Approach 2:
The fuel injector incorporates variable geometry features including adjustable fuel outlet positions and controllable injection rates. The system dynamically adjusts the injection parameters based on operating conditions, allowing optimal mixing and combustion control for low emission fuels while preventing flashback and autoignition through real-time rate modulation.
2Adaptability or versatility
If multiple fuel types are mixed, then fuel flexibility is improved, but mixing efficiency decreases due to thermal gradients
Solution Approach 1:
The injector separates the injection of different fuel types into distinct outlets with independent control. This allows liquid fuels and gaseous fuels to be introduced at separate locations and rates, enabling effective mixing while managing thermal gradients that would otherwise reduce mixing efficiency.
Solution Approach 2:
Different regions of the fuel injector are optimized for specific fuel types. The first fuel outlet is configured for one fuel type while the second fuel outlet is configured for another, with each region having specific geometric characteristics that enhance mixing for its designated fuel type while accommodating thermal gradient differences.
3Productivity
If high reactivity fuels are used, then combustion efficiency is improved, but structural integrity is compromised due to embrittlement
Solution Approach 1:
The fuel injector uses carefully designed passage geometries and outlet configurations as intermediaries to control the interaction between high reactivity fuels and the structural components. The variable geometry passages act as mediators that allow optimal fuel delivery and mixing while protecting the structure from embrittlement by controlling stress concentration points.
Solution Approach 2:
The system dynamically adjusts fuel injection rates and positions to optimize combustion efficiency while preventing structural damage. The variable geometry features allow real-time modulation of fuel flow patterns, maintaining high reactivity fuel benefits while protecting structural integrity through controlled stress distribution.
4Manufacturing precision
If mixing length is increased, then mixing efficiency is improved, but pressure drop increases
Solution Approach 1:
The fuel injector divides the mixing process into multiple shorter regions rather than one long mixing passage. By segmenting the fuel injection into multiple outlets with controlled mixing zones, the system achieves effective mixing without requiring a single extended mixing length that would cause excessive pressure drop.
Solution Approach 2:
The fuel injector utilizes multi-dimensional mixing by introducing fuels at different positions and orientations rather than relying solely on extended axial mixing length. The variable geometry passages create three-dimensional flow patterns that enhance mixing efficiency while maintaining shorter passage lengths and reducing pressure drop.
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
Ensures effective mixing of hydrogen and other fuels with low pressure drop, minimizing flashback and autoignition, while maintaining structural integrity and ensuring consistent mixing.
Implementation Method 1
A fuel injector for a gas turbine engine comprising a compressor section, combustor section, and turbine section is serial flow arrangement, the fuel injector comprising: an outer wall at least partially defining a mixing passage extending along a stream-wise direction and defining a fuel injector axis, the mixing passage including a first mixing region and a second mixing region in serial arrangement
Data Source
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AI summary
A gas turbine engine (10) includes a compressor section (22), combustion section (28), and turbine section (32) is serial flow arrangement. A fuel injector (102) supplies a mixture of fuel and air for combustion within the combustion section (28). An outer wall (150) defines a mixing passage (154) extending along a stream-wise direction including a first mixing region (240) and a second mixing region (242). A first fuel passage (164) supplies a first fuel (F1) to the first mixing region (240) and an air passage (180) supplies a supply of air (A) to the first mixing region (240). A second fuel passage (166) supplies a second fuel (F2) to the second mixing region (242).