Air Diffuser for Combustor Fuel Nozzle
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Solution Overview
Problem
The design and construction of fuel nozzle assemblies in gas turbine engines affect the mixing and combustion of fuel and air, leading to issues with exhaust emissions and power output, as well as increasing the time, cost, and complexity of installation, maintenance, and servicing.
Innovation Solution
A multi-tube fuel nozzle system with an integral air diffuser that redirects air flow radially inward to improve uniformity and distribution across mixing tubes, maintaining axial velocity and reducing flow separation, thereby enhancing the premixing of fuel and air within the combustor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fuel nozzle assembly design is used, then structural simplicity is maintained, but air distribution uniformity and combustion efficiency deteriorate
Solution Approach 1:
The air nozzle assembly is segmented into multiple independent air nozzles (first air nozzle, second air nozzle, third air nozzle, fourth air nozzle) arranged around the fuel nozzle. Each air nozzle has independent adjustment capabilities, allowing precise control of air distribution patterns to achieve uniform air-fuel mixing while maintaining modular simplicity for manufacturing and maintenance.
Solution Approach 2:
The air nozzles incorporate adjustable components that allow dynamic modification of air flow characteristics. The adjustment mechanism enables operators to optimize air distribution uniformity for different operating conditions, improving combustion efficiency without requiring a completely complex fixed structure.
2Productivity
If complex fuel nozzle assembly design is implemented, then combustion efficiency is improved, but installation and maintenance time increases
Solution Approach 1:
The modular segmented structure of multiple independent air nozzles allows individual nozzles to be accessed, adjusted, or replaced without dismantling the entire assembly. This maintains high combustion efficiency through optimized air distribution while significantly reducing installation and maintenance time compared to integrated complex designs.
Solution Approach 2:
Each air nozzle is designed with specific local characteristics optimized for its position around the fuel nozzle. This localized optimization achieves overall high combustion efficiency while keeping each individual component simple and interchangeable, reducing maintenance complexity and time.
3Manufacturing precision
If conventional air flow direction is maintained, then structural simplicity is preserved, but mixing uniformity deteriorates
Solution Approach 1:
The air nozzles are positioned asymmetrically around the fuel nozzle with different orientations and adjustment capabilities. This asymmetric arrangement creates optimized air flow patterns that enhance mixing uniformity, while each individual nozzle remains structurally simple for manufacturing.
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
This solution results in more even air distribution, reduced emissions, lower manufacturing costs, longer equipment lifetime, and improved combustion efficiency, contributing to a durable and reliable gas turbine system.
Implementation Method 1
an air diffuser to redirect an air flow from an axial direction to a radial direction
Implementation Method 2
maintaining axial velocity and reducing flow separation
Implementation Method 3
a plurality of fuel injectors to inject a fuel flow into the plurality of mixing tubes
Implementation Method 4
mixing the air flow and the fuel within the mixing chamber of each mixing tube of the plurality of mixing tubes to create a fuel-air mixture
Data Source
AI summary
A system includes a multi-tube fuel nozzle of a turbine combustor. The multi-tube fuel nozzle includes a support structure defining an interior volume configured to receive an air flow; a plurality of mixing tubes disposed within the interior volume, wherein each of the plurality of mixing tubes comprises a respective fuel injector; and an outer annular wall configured to direct an air flow from an annulus between a liner and a flow sleeve of the turbine combustor at least partially radially inward into the interior volume through an air inlet and toward the plurality of mixing tubes, wherein the outer annular wall at least partially defines an air flow passage extending from the annulus to the interior volume.