Dual Fuel Aircraft Engine System for Emissions Reduction
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Solution Overview
Problem
The use of alternative fuels like hydrogen or natural gas in gas turbine engines poses challenges due to their lower volumetric energy density and the need for adaptation of existing aircraft fuel systems designed for liquid fuels, including auxiliary systems that require liquid fuel flow for operation.
Innovation Solution
A dual fuel system is implemented, where a jet fuel subsystem and an alternative fuel subsystem operate simultaneously, with a controlled flow rate of jet fuel circulated across auxiliary systems and optionally recirculated, while the alternative fuel is used to satisfy the majority of the power requirement, especially in shorter flights, thereby maximizing the use of alternative fuels and reducing carbon emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If gaseous alternative fuels (hydrogen or natural gas) are used in flight, then carbon emissions are reduced, but the volumetric energy density decreases significantly requiring four times the storage volume
Solution Approach 1:
The fuel system is segmented into two separate subsystems: a jet fuel subsystem for energy-dense storage and an alternative fuel subsystem for emissions reduction. This allows the aircraft to carry smaller volumes of alternative fuel while maintaining sufficient total energy capacity through the combined system architecture.
Solution Approach 2:
The fuel system is designed with multi-functionality to operate with different fuel types. The jet fuel subsystem can serve both as primary fuel and as a supplemental energy source, while the alternative fuel subsystem provides emissions reduction capability. This universal design allows flexible operation modes depending on flight requirements.
2Adaptability or versatility
If existing aircraft fuel systems are retrofitted for gaseous alternative fuels, then alternative fuel use is enabled, but auxiliary systems designed for liquid fuel flow require complex adaptation
Solution Approach 1:
The fuel system is divided into separate jet fuel and alternative fuel subsystems with distinct delivery paths. This segmentation allows auxiliary systems to remain connected to the jet fuel subsystem which provides reliable liquid flow, while the alternative fuel subsystem operates independently for combustion only, minimizing adaptation complexity.
Solution Approach 2:
The jet fuel subsystem acts as an intermediary that provides the necessary liquid fuel flow characteristics to auxiliary systems. By maintaining jet fuel delivery to components requiring liquid flow (such as fuel-draulic actuators and heat exchangers), the system enables alternative fuel use without requiring these auxiliary systems to adapt to gaseous fuel properties.
3Reliability
If jet fuel is used exclusively to maintain liquid flow for auxiliary systems, then auxiliary system operation is ensured, but the proportion of alternative fuel use is reduced
Solution Approach 1:
The system incorporates dynamic control capabilities with actuators and controllers that can adjust fuel delivery in real-time. This allows the system to optimize the balance between jet fuel and alternative fuel delivery based on operational conditions, maximizing alternative fuel utilization while ensuring auxiliary systems receive sufficient liquid fuel flow when needed.
Solution Approach 2:
The fuel delivery system can dynamically change parameters such as flow rates and pressure to optimize performance. By adjusting these parameters, the system maximizes alternative fuel combustion while maintaining adequate jet fuel flow to auxiliary systems only when required for their operation.
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
This approach allows for efficient operation of gas turbine engines using alternative fuels, reducing carbon emissions by maximizing alternative fuel use in short flights and ensuring reliable operation of auxiliary systems, while maintaining the energy density needed for longer flights with jet fuel.
Implementation Method 1
conveying a controlled flow rate of jet fuel across at least one auxiliary system, including the at least one auxiliary system using the controlled flow rate of jet fuel for operation
Implementation Method 2
returning at least a portion of the flow rate of jet fuel from downstream of the at least one auxiliary system to upstream of the at least one auxiliary system
Implementation Method 3
conveying a controlled flow rate of an alternative fuel from a reservoir area of the aircraft to the at least one fuel nozzle
Implementation Method 4
an aircraft gas turbine engine having at least one fuel nozzle open to a combustion chamber
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
The fuel system can have a jet fuel subsystem (50) having a jet fuel conduit (52) extending from a first reservoir area (54) to a fuel nozzle (45) across an auxiliary system (56) operable using a flow of the jet fuel (102), at least one fuel delivery system (160) operable to circulate a controlled flow rate of the jet fuel (102) within said conduit (52) and across the auxiliary system (56), a recirculation conduit (64) branching off from the jet fuel conduit (52) downstream of the auxiliary system (56), an actuator valve (72) operable to selectively direct a flow of jet fuel (102) to the at least one fuel nozzle (45) or to the recirculation conduit (64); and an alternative fuel subsystem (58) having an alternative fuel conduit (60) extending from a second reservoir area (62) to a fuel nozzle (45).