Integrated Fuel Cell Combustor for Aircraft Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircraft manufacturers face challenges in improving fuel efficiency and reducing harmful emissions from turbofan engines, as current electrically powered actuators are inefficient and low NOx combustors can produce unstable flames leading to flameout, while traditional generators are less than 45% efficient and heavy fuel cells require additional equipment.
Innovation Solution
A fuel cell/combustor system that includes a fuel reformer to convert aviation fuel into reformed fuel, which is then used in a fuel cell to generate electrical power and unspent reformed fuel is burned in a combustion chamber with aviation fuel to provide propulsive power, stabilizing the flame and reducing emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional generators are used to provide electrical power for aircraft actuators, then the power demand can be met, but the generator size must increase and efficiency remains below 45%
Solution Approach 1:
The patent combines a fuel cell system with a combustor system into an integrated power generation unit. The fuel cell generates electrical power with high efficiency while its exhaust products are fed to the combustor to provide additional power, merging two power generation processes into a unified system that overcomes the limitations of traditional generators.
Solution Approach 2:
The integrated system serves multiple functions: the fuel cell provides efficient electrical power generation, the combustor provides additional power output, and the system collectively meets the aircraft's power demands while improving overall efficiency beyond what a single generator could achieve.
2Use of energy by moving object
If fuel cells are used to generate electrical power with higher efficiency, then power generation efficiency improves, but the fuel cell becomes heavy due to peripheral equipment such as compressors
Solution Approach 1:
The fuel cell is integrated with the combustor system, combining two power generation components into a unified structure. This merger allows the system to achieve high electrical power generation efficiency while sharing common infrastructure, thereby reducing the overall weight compared to a standalone fuel cell system with all necessary peripheral equipment.
Solution Approach 2:
The integrated fuel cell-combustor system performs multiple functions within a single weight budget: electrical power generation, thermal energy production, and exhaust product utilization. This multi-functionality reduces the need for separate systems and their associated weights.
3Object-generated harmful factors
If low NOx combustors operate with fuel-lean mixture to reduce emissions, then NOx emissions are reduced, but the flame becomes unstable and may blow out
Solution Approach 1:
The patent introduces a pilot flame as an intermediary element that stabilizes the main fuel-lean flame in the combustor. The pilot flame, burning at a different location, provides a stable reference flame that prevents the main flame from blowing out, allowing the system to maintain fuel-lean operation for low NOx emissions while ensuring flame stability.
Solution Approach 2:
The combustor employs different combustion zones with different fuel-to-air ratios: a fuel-rich pilot flame zone for stability and a fuel-lean main combustion zone for low emissions. This local differentiation allows each zone to optimize for its specific function while working together as a unified system.
4Reliability
If a fuel-rich spray is added to stabilize the flame in low NOx combustors, then flame stability improves, but harmful emissions increase
Solution Approach 1:
The combustor is segmented into distinct functional zones: a pilot flame zone that provides stability and a main combustion zone that operates fuel-lean for low emissions. By separating the stability-providing function from the emissions-critical function, the system achieves flame stability without compromising emission performance.
Solution Approach 2:
Different regions of the combustor have different combustion characteristics: the pilot flame region operates fuel-rich for stability while the main combustion region operates fuel-lean for low emissions. This local quality differentiation resolves the contradiction between stability and emissions.
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 system enhances fuel efficiency, reduces emissions, and provides a stable combustion process, potentially eliminating the need for separate generators and reducing engine size by integrating the fuel cell with the turbofan engine, achieving higher efficiency and lower NOx emissions.
Implementation Method 1
a fuel reformer that is coupleable to an aircraft fuel supply to receive aviation fuel
Implementation Method 2
A fuel cell can be coupled to the reformer to receive reformed fuel (e.g., hydrogen and/or carbon monoxide)
Implementation Method 3
The combustion chamber can further include at least one combustion zone coupled to the first and second inlets and positioned to burn both the output products and the aviation fuel
Data Source
AI summary
Fuel cell/combustor systems and methods for aircraft and other applications are disclosed. A system in accordance with one embodiment includes a fuel cell having an outlet positioned to remove output products from the fuel cell. The system can further include a fuel supply carrying a fuel having a different composition than the output products (e.g., aviation fuel), and a combustion chamber. The combustion chamber can in turn include a first inlet coupled to the outlet of the fuel cell to receive output products from the fuel cell, and a second inlet coupled to the fuel supply to receive the fuel. At least one combustion zone can be positioned in fluid communication with the first and second inlets to burn both the output products and the fuel.