Monolithic Gas Turbine Fuel Nozzle for Low-Emission Premixing
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Solution Overview
Problem
Existing fuel nozzle designs for gas turbine engines face challenges in reducing noxious emissions, such as nitrogen oxides (NOx), carbon monoxide (CO), and unburned hydrocarbons (CxHy), while also needing to withstand thermal cycles and control thermally induced deformations for extended life and efficient operation.
Innovation Solution
A fuel nozzle design featuring a monolithic structure with multiple fuel injectors and annular premix chambers, manufactured via additive manufacturing, which allows for complex shapes and improved mixing of air and fuel, reducing emissions and enhancing thermal stability through a single monolithic body construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional fuel nozzle designs are used, then manufacturing is simpler, but emissions control is insufficient
Solution Approach 1:
The fuel nozzle is divided into multiple independent fuel injectors (first and second sets) with separate feed channels and inlet plenums. Each injector can be independently designed and optimized for specific emission control functions, allowing differentiated fuel injection patterns to reduce NOx, CO, and unburned hydrocarbons simultaneously
Solution Approach 2:
Fuel injectors are positioned at angles from the stem rather than aligned axially, creating three-dimensional fuel injection patterns. This angular arrangement enables better mixing of fuel with compressed air from multiple directions, improving combustion completeness and reducing emissions while maintaining compact nozzle geometry
2Object-generated harmful factors
If multiple fuel injectors with complex shapes are manufactured, then emissions control improves, but manufacturing difficulty increases
Solution Approach 1:
Multiple fuel injectors, feed channels, inlet plenums, and premix chambers are integrated into a single monolithic nozzle body manufactured by additive manufacturing. This merging eliminates the need for separate manufacturing and assembly operations, reducing overall manufacturing complexity despite the complex internal geometry of individual components
Solution Approach 2:
The manufacturing method transitions from traditional subtractive or formative processes to additive manufacturing, enabling complex internal geometries like angled injectors and interconnected premix chambers to be created directly as single-piece components. This parameter change in manufacturing approach unlocks design freedom without proportionally increasing manufacturing difficulty
3Duration of action of stationary object
If conventional multi-part nozzles are used, then manufacturing is easier, but thermal stability and lifespan are reduced
Solution Approach 1:
The fuel nozzle is constructed as a single monolithic component with all functional elements (injectors, channels, plenums, chambers) integrated into one piece. This eliminates weak points at joints and interfaces, preventing thermal cracking and deformation under cyclic thermal loading, thereby extending nozzle lifespan and improving thermal stability
Solution Approach 2:
The nozzle is manufactured using additive manufacturing with materials selected for high-temperature resistance and thermal stability. The monolithic structure allows uniform distribution of thermal stresses throughout the single-piece component, improving resistance to thermally induced deformations and extending operational life in high-temperature environments
4Productivity
If fuel injectors are positioned at angles from the stem, then mixing efficiency improves, but device complexity increases
Solution Approach 1:
Fuel injectors are arranged at angles from the stem axis, creating three-dimensional fuel injection patterns that enhance mixing with compressed air. This angular arrangement in multiple dimensions improves combustion efficiency and reduces emissions while the monolithic construction keeps overall device complexity manageable
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 effectively reduces emissions and increases the fuel nozzle's lifespan by optimizing the mixing process and thermal management, thereby improving the efficiency and durability of gas turbine engines.
Implementation Method 1
An annular premix chamber is formed between each outer sleeve and the respective centerbody. At least one air inlet port extends through each outer sleeve, and at least one fuel conduit in each centerbody is in fluid communication with the respective fuel inlet plenum and the respective annular premix chamber.
Data Source
AI summary
A fuel nozzle comprising a stem and a first fuel feed channel extending inside the stem from an inlet end positioned at a proximal end of the stem to a first fuel inlet plenum. The fuel nozzle further comprises a first set of fuel injectors fluidly coupled to the first fuel inlet plenum. The fuel nozzle further includes a second fuel feed channel extending inside the stem from an inlet end, positioned at the proximal end of the stem, to a second fuel inlet plenum. A second set of fuel injectors are fluidly coupled to the second fuel inlet plenum. Each fuel injector comprises a centerbody and an outer sleeve surrounding the centerbody and extending along the axis of the centerbody. An annular premix chamber is provided between each outer sleeve and the respective centerbody.