Dual-Fuel Aircraft Fuel System Segmentation
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Solution Overview
Problem
The aviation industry faces challenges in adopting hydrogen as a fuel due to its low energy density, high cost, and the lack of infrastructure, which results in heavier and larger tanks, increased weight, and limited operational range, as well as environmental concerns such as contrail formation. Additionally, the production of hydrogen contributes to greenhouse gas emissions unless 'blue' or 'green' methods are used, which are currently more expensive and less widespread.
Innovation Solution
A dual-fuel aircraft design that incorporates both cryogenic and non-cryogenic fuel tanks, where cryogenic fuel is sized for typical mission ranges and non-cryogenic fuel is reserved for longer ranges and contingency scenarios, allowing for flexible fuel usage and reduced infrastructure dependency. This design includes a fuel control system to manage fuel mixing based on mission requirements, environmental conditions, and economic factors, enabling the use of hydrogen and traditional fuels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrogen tanks are sized to provide fuel for both typical mission and reserve fuel requirements, then the aircraft can meet contingency fuel reserves, but the tank volume and weight double
Solution Approach 1:
The fuel system is segmented into two separate tank systems: cryogenic hydrogen tanks sized for typical mission fuel requirements, and non-cryogenic fuel tanks sized for reserve fuel requirements. This segmentation allows each tank type to be optimized for its specific function, avoiding the need to oversized hydrogen tanks to accommodate both mission and reserve fuel needs simultaneously.
Solution Approach 2:
The invention changes the physical state parameter of the reserve fuel from cryogenic (liquid hydrogen) to non-cryogenic (conventional liquid fuel). This parameter change allows reserve fuel to be stored in lighter, simpler tanks without the weight and volume penalties of cryogenic storage, while still meeting fuel reserve requirements.
2Object-generated harmful factors
If the aircraft uses only hydrogen fuel, then it achieves zero carbon emissions, but it is limited to routes with hydrogen refueling infrastructure
Solution Approach 1:
The aircraft is equipped with dual fuel capability, allowing it to operate on hydrogen fuel for zero-emission flights when infrastructure is available, and on conventional non-cryogenic fuel when hydrogen infrastructure is unavailable. This multi-functionality enables the aircraft to serve both environmental goals and operational flexibility requirements.
3Use of energy by moving object
If cryogenic hydrogen tanks are used to achieve high energy density, then the energy to volume ratio improves, but the tank weight and complexity increase
Solution Approach 1:
The fuel storage system is divided into cryogenic hydrogen tanks for mission fuel and non-cryogenic tanks for reserve fuel. This segmentation allows the cryogenic system to be optimized for energy density where it is most needed (during typical mission operations), while avoiding the complexity of cryogenic storage for the entire fuel supply including reserves.
4Object-generated harmful factors
If green hydrogen is produced through electrolysis using renewable energy, then carbon emissions are eliminated, but production cost increases significantly
Solution Approach 1:
The aircraft uses hydrogen fuel for the typical mission portion of operations where infrastructure is available, while using conventional fuel for reserve and contingency situations. This partial application of green hydrogen allows the operator to achieve emissions reductions on the majority of flights without incurring the full cost of green hydrogen for 100% of fuel consumption.
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 dual-fuel aircraft design results in a lighter, more economical, and environmentally friendly aircraft with reduced emissions, increased operational flexibility, and the ability to operate in a broader network, even in areas with limited hydrogen infrastructure, while minimizing contrail formation and providing safety benefits.
Implementation Method 1
it has a very low energy density (energy to volume ratio), so it must be stored compressed or cryogenically liquified
Implementation Method 2
A dual-fuel aircraft design that incorporates both cryogenic and non-cryogenic fuel tanks, where cryogenic fuel is sized for typical mission ranges and non-cryogenic fuel is reserved for longer ranges
Implementation Method 3
Additionally, its combustion does not produce carbon-based gases, which addresses the referenced environmental challenge
Implementation Method 4
Hydrogen can also be produced by electrolysis of water, which produces O2 and H2 but no CO2 byproduct
Data Source
AI summary
An aircraft stores cryogenic fuel in one or more right sized fuel tanks inside the aircraft fuselage or at other appropriate positions on the aircraft, and stores non-cryogenic fuel in plural standard jet fuel tanks e.g., inside the aircraft wings. The tanks are sized to using an automated aircraft sizing computational tool based on the defined missions ranges requirements, tanks sizing logic, Top-Level Aircraft Requirements, and aircraft geometry and engine thrust levels, to iteratively develop at least cryogenic fuel tank size for a particular aircraft. A controller controls selective routing of non-cryogenic fuel or cryogenic (e.g., hydrogen) fuel to dual fuel engines. In one operating mode, the dual fuel engines normally use the cryogenic hydrogen fuel as the main fuel, and reserve the non-cryogenic fuel for application to the dual fuel engines only on an exception basis, thereby providing cleaner and more environmentally friendly operation.