Distributed-Mixing Combustor Structure for Hydrogen Flashback Control
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Solution Overview
Problem
The use of hydrogen as a fuel in gas turbine engines poses challenges due to its gaseous state and higher flammability, which can lead to flashback issues if the local flame speed exceeds the fuel-air mixture inlet speed, particularly in combustor structures designed for aviation fuel.
Innovation Solution
A combustor design incorporating a liner with a fuel and air mixing body featuring radial distribution passages and cellular material, where fuel is distributed radially outward through injection ports into mixing passages with varying cross-sectional areas and air inlets, enhancing mixing and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If hydrogen fuel is used in gas turbine engines, then fuel efficiency and environmental performance are improved, but flashback risk increases due to higher flame speed
Solution Approach 1:
The combustor is divided into multiple zones: a premixing zone with cellular material for controlled mixing, and a combustion zone separated by a liner. This segmentation allows hydrogen fuel to be thoroughly mixed with air in controlled cells before reaching the combustion zone, reducing flashback risk while maintaining efficiency
Solution Approach 2:
Cellular material acts as an intermediary between fuel injection and combustion. The cellular structure provides a large surface area for controlled fuel-air mixing and acts as a physical barrier that prevents flame propagation back into the fuel supply system, enabling safe hydrogen combustion
2Device complexity
If conventional combustor structure is used, then structural simplicity is maintained, but mixing efficiency deteriorates for gaseous hydrogen fuel
Solution Approach 1:
Cellular material with porous structure is used in the premixing zone. The porous structure provides numerous flow paths and a large surface area for hydrogen fuel and air to mix thoroughly before combustion, significantly improving mixing stability compared to conventional smooth-walled combustors
Solution Approach 2:
The mixing process transitions from a simple linear flow to a three-dimensional mixing pattern within the cellular structure. Fuel and air are distributed through the cellular matrix, creating extensive contact surfaces and improving mixing efficiency in multiple spatial dimensions
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 improves fuel-air mixing and stability, reducing the risk of flashback and ensuring efficient combustion of hydrogen fuel.
Implementation Method 1
cellular material in the mixing passages at a location at which the fuel is injected into the mixing passages
Data Source
AI summary
A combustor includes a liner defining a combustion chamber and receiving a fuel and air mixing body. The mixing body has a central fuel supply, and radial distribution passages communicating fuel from the central fuel supply radially outwardly relative to a central axis of the central fuel supply and to mixing passages. The radial distribution passages have injection ports in the mixing passages. The mixing passages extend from a rear face of the mixing body to an inner face facing into the combustion chamber. Air inlets in the mixing body communicate air into the mixing passages, and there is cellular material in the mixing passages at a location at which the fuel is injected into the mixing passages. A gas turbine engine is also disclosed.