Hydrogen Fuel Injector With Annular Galleries for Uniform Micro-Mix
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydrogen combustion in aircraft gas turbines presents challenges due to fast burning rates and high temperatures, leading to high NOx emissions, and maintaining consistent air/fuel ratios is difficult in micro-mix injectors with complex internal arrangements.
Innovation Solution
A fuel injector design with an axially extending air passage, a fuel manifold, and annular fuel galleries surrounding each air passage, along with a feed plate allowing adjustment of flow characteristics, ensures effective air/fuel mixing and distribution across the injector face, using three separate components that can be easily assembled by diffusion bonding or brazing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If micro-mix injectors with complex internal arrangements are used to achieve fast mixing and reduced residence times, then mixing efficiency is improved, but device complexity increases and maintaining consistent air/fuel ratios becomes difficult
Solution Approach 1:
The injector is divided into multiple independent air/fuel mixing elements, each with its own air aperture and fuel aperture. This segmentation allows each element to function independently, simplifying the internal arrangement while maintaining high mixing efficiency through distributed mixing zones. The complex mixing task is divided into many simple, identical units.
Solution Approach 2:
Each mixing element is designed with specific local characteristics - air apertures and fuel apertures positioned at specific locations and angles. This local optimization ensures consistent air/fuel ratios at each mixing point, while the overall injector maintains simplicity through repetition of these standardized local elements.
2Object-generated harmful factors
If multiple small fuel apertures and air apertures are provided adjacent to each other for micro-mix combustion, then NOx production is reduced, but ease of manufacture decreases
Solution Approach 1:
The injector face is segmented into multiple identical mixing elements, each contributing to the overall micro-mix combustion. This segmentation achieves NOx reduction through distributed small flames while simplifying manufacture, as each element can be designed and manufactured as a standardized unit, making the overall construction more feasible.
Solution Approach 2:
Each mixing element serves multiple functions: it provides fuel injection, air mixing, and flame stabilization. This multi-functionality reduces the need for separate components, easing manufacture while achieving the desired emission reduction through the collective action of all elements.
3Object-generated harmful factors
If a large array of small flames is used to produce similar flame intensity with reduced NOx, then emission performance is improved, but device complexity increases
Solution Approach 1:
The flame array is segmented into multiple identical mixing elements arranged in a systematic pattern. This segmentation achieves the desired emission performance through distributed small flames while reducing complexity by using repetitive, standardized elements rather than a custom complex configuration.
Solution Approach 2:
Multiple identical mixing elements are merged into a single injector assembly, combining their individual small flames into a collective flame array. This merging achieves the desired emission performance and flame intensity while simplifying the overall design through uniformity and repetition of the basic mixing element.
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 achieves reduced NOx emissions by ensuring consistent air/fuel mixing and distribution, preventing blockages, and maintaining even fuel/air ratios, thus improving combustion efficiency and reducing emissions.
Implementation Method 1
the additional feed plate enables adjustment of the feed hole sizes by the designer to adjust flow characteristics
Implementation Method 2
The injector front plate and rear plate may be coupled by diffusion bonding or brazing
Implementation Method 3
The injector front plate and rear plate may be coupled by diffusion bonding or brazing
Implementation Method 4
an annular fuel gallery is provided around each air through passage configured to supply the fuel outlets
Implementation Method 5
Each fuel outlet may be arranged to direct fuel towards air exiting a respective air through passage
Implementation Method 6
The central body may comprise a blunt aft end configured to generate downstream vortices in use. Advantageously, the central body improves mixing of the fuel and air.
Implementation Method 7
Hydrogen combustion in aircraft gas turbines presents a number of challenges. Hydrogen burns very fast and at high temperatures
Data Source
AI summary
A fuel injector for a hydrogen combusting aircraft gas turbine engine has at least one air through-passage extending axially from a front face to a rear face. The injector further comprises a fuel manifold in communication with a hydrogen fuel feed line. A plurality of fuel outlets is provided surrounding the or each air passage and an annular fuel gallery is provided around each air through passage configured to supply the fuel outlets, the annular fuel gallery communicating with the fuel manifold.