Fuel Mixer Structure to Prevent Hydrogen Flame Holding
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Solution Overview
Problem
Gas turbine engines using hydrogen fuel face challenges with flame holding due to higher flame speeds, leading to durability issues in combustor components, particularly in high-temperature environments.
Innovation Solution
A fuel nozzle structure is designed to enhance combustion efficiency and prevent flame holding by incorporating a fuel mixer that uses a common flow passage to sandwich fuel between co-flowing air streams, reducing shear forces and maintaining high axial velocity to stabilize the flame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If hydrogen fuel is used in gas turbine engines, then combustion efficiency is improved, but flame holding occurs due to higher flame speeds
Solution Approach 1:
The fuel injection system is segmented into multiple nozzles with different injection patterns (central nozzle for pilot fuel, annular nozzles for main fuel). This segmentation allows different zones to have different fuel-air mixing characteristics, preventing flame holding while maintaining combustion efficiency.
Solution Approach 2:
Different regions of the combustor are given different local qualities: the central region receives pilot fuel for stable ignition, while the annular regions receive main fuel for efficient combustion. The fuel-air mixing ratios and velocities are optimized locally to prevent flame holding in each specific zone.
2Reliability
If fuel is injected at high velocity to prevent flame holding, then flame stability is improved, but shear forces increase causing durability issues
Solution Approach 1:
The fuel injection system uses dynamic velocity profiling where pilot fuel is injected at high velocity for flame stability, while main fuel is injected at controlled velocities. The system dynamically balances velocity requirements for stability versus shear force reduction through multi-stage injection timing and pressure control.
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 reduces the risk of flame holding, allowing the use of higher temperature fuels like hydrogen, thereby improving durability and operational safety of the combustor.
Implementation Method 1
uses a common flow passage to sandwich fuel between co-flowing air streams, reducing shear forces and maintaining high axial velocity to stabilize the flame
Implementation Method 2
designed to enhance combustion efficiency and prevent flame holding by incorporating a fuel mixer that uses a common flow passage to sandwich fuel between co-flowing air streams, reducing shear forces and maintaining high axial velocity to stabilize the flame
Implementation Method 3
A gas turbine engine includes a turbine that is driven by combustion of a combustible fuel within a combustor of the engine
Implementation Method 4
allowing the use of higher temperature fuels like hydrogen, thereby improving durability and operational safety of the combustor
Data Source
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AI summary
A turbine engine (10) can include a compressor section (12), a combustion section (14), and a turbine section (16) in serial flow arrangement. The combustion section (14) can include a combustor (30) with a fuel mixer (90). The fuel mixer (90) can include an outer wall (121, 221, 321, 421) defining a longitudinal axis (124) and having a mixture outlet (110, 210, 310, 410), a first compressed air flow passage (141, 241, 341. 441), and a second compressed air flow passage (142, 242, 342, 442).