Annular Concentric Fuel Nozzle Radial Mixing
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Solution Overview
Problem
Gas turbine engine combustors face challenges in achieving high-energy combustion while minimizing emissions and combustion instability at both full power and part power conditions, particularly in forming oxides of nitrogen, unburned hydrocarbons, smoke, carbon monoxide, and carbon dioxide.
Innovation Solution
A fuel nozzle design featuring concentric, nested premixer annuli with specific fuel air mixing passages and radially oriented air inlet ports, which creates shorter, more compact flames at the combustion chamber, mitigating emissions and enabling a longitudinally shorter combustor assembly with similar or greater energy output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional fuel nozzles are used to produce high-energy combustion, then energy output is improved, but emissions (oxides of nitrogen, unburned hydrocarbons, smoke, carbon monoxide, carbon dioxide) increase
Solution Approach 1:
The fuel nozzle is segmented into multiple concentric annular mixing passages (first, second, third passages) with separate fuel injection ports and air inlet ports. This segmentation allows different zones to optimize for either energy output or emission reduction, with each passage controlling specific portions of the fuel-air mixture to balance power and emissions independently
Solution Approach 2:
Different regions of the fuel nozzle are designed with distinct characteristics: the first mixing passage is optimized for high-energy combustion with specific fuel-to-air ratio, while the second and third passages are configured for lower emissions. The annular depression geometry and varying port sizes create local quality differences that enable simultaneous optimization of energy output and emission reduction in different spatial zones
2Reliability
If conventional fuel nozzles are used to achieve stable combustion, then combustion stability is improved, but combustion tones due to pressure oscillations increase
Solution Approach 1:
The combustion process is segmented into multiple stable zones through concentric mixing passages, each with controlled fuel-air mixing. This segmentation distributes the combustion load and prevents large-scale pressure oscillations that cause combustion tones, while maintaining overall combustion stability through the coordinated operation of all passages
Solution Approach 2:
The fuel nozzle incorporates dynamic flow control through the annular depression geometry and multiple adjustable ports that respond to varying operating conditions. This dynamic design allows the system to maintain combustion stability across different power levels while automatically suppressing pressure oscillations that lead to combustion tones
3Stability of the object's composition
If fuel air mixing passages are extended longitudinally to improve mixing, then fuel-air mixing is improved, but combustor assembly length increases
Solution Approach 1:
The patent transitions from longitudinal mixing to radial mixing by implementing concentric annular passages with radially oriented air inlet ports. Fuel and air mix primarily in the radial direction rather than extending longitudinally, allowing effective mixing to occur within a compact axial length. The annular depression creates radial flow patterns that enhance mixing without increasing the combustor assembly length
Solution Approach 2:
Multiple mixing passages are nested concentrically within each other, with the first, second, and third passages arranged in nested annular configurations. This nesting allows multiple mixing zones to occupy the same longitudinal space, achieving thorough fuel-air mixing while maintaining a compact combustor assembly length through efficient spatial utilization
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 combustion instability by producing shorter, more compact flames, allowing for efficient energy output while meeting flow area targets and improving lean blowout margin and combustion dynamics.
Implementation Method 1
fuel air mixing passages
Implementation Method 2
fuel air mixing passages extended substantially along the longitudinal direction
Implementation Method 3
radially oriented air inlet ports
Implementation Method 4
concentric, nested premixer annuli
Data Source
AI summary
A fuel nozzle for a gas turbine engine is generally provided. The fuel nozzle includes an outer sleeve extended circumferentially around a fuel nozzle centerline and extended along a longitudinal direction substantially co-directional to the fuel nozzle centerline. The outer sleeve defines a plurality of first radially oriented air inlet ports through the outer sleeve in circumferential arrangement relative to the fuel nozzle centerline. The fuel nozzle further includes a centerbody positioned radially inward of the outer sleeve. The centerbody is extended along the longitudinal direction substantially co-directional to the fuel nozzle centerline and wherein the centerbody is concentric to the fuel nozzle centerline and the outer sleeve. The centerbody defines a plurality of second radially oriented air inlet ports through the centerbody in circumferential arrangement relative to the fuel nozzle centerline. The centerbody further defines an annular centerbody groove or depression relative to the fuel nozzle centerline at a downstream end directly adjacent to a combustion chamber. The fuel nozzle further includes an inner sleeve extended circumferentially around the fuel nozzle centerline and extended along the longitudinal direction substantially co-directional to the fuel nozzle centerline. The inner sleeve is positioned radially between the outer sleeve and the centerbody. The inner sleeve further defines an annular inner sleeve depression relative to the fuel nozzle centerline at the downstream end directly adjacent to the combustion chamber. The outer sleeve and the inner sleeve together define a first fuel air mixing passage radially therebetween and extended substantially along the longitudinal direction in direct fluid communication with the combustion chamber. The inner sleeve and the centerbody together further define a second fuel air mixing passage radially therebetween and extended substantially along the longitudinal direction in direct fluid communication with the combustion chamber.