Gas Turbine Fuel Nozzle Mixing Tubes for Hydrogen Flame Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Turbine engines using hydrocarbon fuels produce environmentally unwanted byproducts such as NOx, CO, UHC, and sulfur oxides, and transitioning to hydrogen fuel requires improved combustion techniques to manage higher flame temperatures and stability.
Innovation Solution
A fuel nozzle assembly with mixing tubes featuring turbulators and varying mixing lengths and orientations to control fuel-air mixtures, reducing NOx emissions and enhancing flame stability by providing leaner and richer mixtures in the combustion chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogen fuel is used in the turbine engine, then flame temperature increases and burning velocity increases, but nitrogen oxide emissions increase and flame stability becomes more difficult to control
Solution Approach 1:
The fuel nozzle assembly is divided into multiple mixing tubes with different mixing lengths (first, second, and third mixing lengths). Each mixing tube creates a distinct fuel-air mixture zone, allowing the system to simultaneously produce lean and rich mixtures. This segmentation enables better control over combustion characteristics and reduces peak flame temperatures that lead to NOx formation.
Solution Approach 2:
Different regions of the combustion chamber receive different fuel-air mixture qualities through the varied mixing tube lengths. The shorter mixing tubes provide leaner mixtures while longer mixing tubes provide richer mixtures. This local variation in mixture quality allows optimization of combustion in different zones, reducing overall NOx emissions while maintaining stable flame characteristics.
2Temperature
If hydrogen fuel is used in the turbine engine, then flame temperature increases, but flame stability becomes more difficult to control
Solution Approach 1:
The combustion process is segmented into multiple zones with different mixture strengths through the use of mixing tubes with varying lengths. This creates a distributed combustion pattern where multiple flame zones support each other, enhancing overall flame stability despite the high flame temperature characteristic of hydrogen combustion.
Solution Approach 2:
The mixing tube lengths are specifically designed to create different residence times and mixing characteristics for the fuel-air mixture. By varying the mixing length parameter, the system optimizes the fuel-air mixing ratio in different zones, ensuring stable combustion across the range of operating conditions while managing the high flame temperature of hydrogen.
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 solution effectively reduces NOx emissions and improves flame stability in hydrogen-fueled turbine engines by optimizing fuel-air mixing, leading to cleaner combustion and better engine operability.
Implementation Method 1
a turbulator disposed at least partially upstream of the gaseous fuel orifice
Implementation Method 2
an air flow passage that extends from a first end of the gaseous fuel nozzle assembly toward a second end, the air flow passage terminating in a mixing tube outlet fluidly coupled to the combustion chamber
Implementation Method 3
a combustor can be provided within the turbine engine and is fluidly coupled with a turbine into which the combusted gases flow
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A gas turbine engine (10), comprising a compressor section (12), a combustion section (14), and a turbine section (16) in serial flow arrangement, with the combustion section (14) comprising a combustion liner at least partially defining a combustion chamber (50) and a gaseous fuel nozzle assembly (48) comprising a plurality of mixing tubes (100, 200, 300). The plurality of mixing tubes (100, 200, 300) can have an air flow passage (140) terminating in a mixing tube outlet (142) fluidly coupled to the combustion chamber (50), a gaseous fuel orifice (150) fluidly coupled to the air flow passage (140), and a turbulator (160) disposed at least partially upstream of the gaseous fuel orifice (150).