Aircraft Fuel Cell Propulsion for Variable Thrust Control
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Solution Overview
Problem
Aircraft propulsion systems face challenges in providing variable thrust levels efficiently, as gas turbines are economically preferred but inefficient for varying power demands during different flight stages, while hydrogen fuel cells struggle with significant power discrepancies and environmental drawbacks.
Innovation Solution
A dual-fuel cell system with hydrogen and oxygen sources, combined with a control unit and heat exchanger arrangements, allows for controllable power output by selectively activating fuel cells and optimizing fuel delivery, enhancing efficiency and reducing environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If gas turbine engines are used for aircraft propulsion, then high specific power and economic efficiency are achieved, but environmental performance deteriorates and inability to efficiently provide variable thrust levels occurs
Solution Approach 1:
The gas turbine engine is segmented into multiple independent combustors (first combustor and second combustor) that can operate separately or together. This allows the engine to provide variable thrust levels by activating only the required number of combustors, improving environmental performance during cruise while maintaining high specific power during takeoff.
Solution Approach 2:
The engine incorporates variable geometry components including movable stator vanes and adjustable nozzle areas that dynamically adjust during operation. This enables continuous thrust variation and optimizes performance across different flight phases, reducing emissions during cruise while maintaining takeoff capability.
2Force
If gas turbine engines operate at high power during takeoff, then sufficient thrust is provided, but power efficiency deteriorates during cruise when full power is not needed
Solution Approach 1:
The engine divides thrust production into multiple combustors that can be independently controlled. During cruise, only the first combustor operates at lower power, while during takeoff both combustors operate at full power, optimizing the ratio of thrust to fuel consumption across different flight phases.
Solution Approach 2:
The engine changes operational parameters including the number of active combustors, stator vane angles, and nozzle area to match thrust requirements. This allows efficient operation at both high thrust (takeoff) and low thrust (cruise) conditions by adjusting the configuration rather than operating at fixed parameters.
3Object-affected harmful factors
If hydrogen fuel cell systems are used to reduce environmental impact, then clean fuel consumption is achieved, but specific power deteriorates to around 1 kW/kg
Solution Approach 1:
The propulsion system uses a composite approach combining hydrogen fuel cells with a hybrid energy storage system including capacitors and rechargeable batteries. This composite system maintains the environmental benefits of hydrogen while achieving higher effective specific power through the complementary characteristics of different energy storage technologies.
Solution Approach 2:
The system pre-charges energy storage devices during cruise when power demand is low, then discharges them during high-power需求的 takeoff and climb phases. This preliminary action allows the fuel cell system to operate continuously at optimal efficiency while meeting peak power demands without increasing fuel cell size.
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 provides flexible power output matching flight phases, reducing environmental impact by using clean fuels, and overcoming the limitations of traditional gas turbines and hydrogen fuel cells.
Implementation Method 1
at least one fuel cell; wherein a first fuel source is a hydrogen supply arranged to provide hydrogen to a first fuel cell
Implementation Method 2
heat exchanger arrangements
Data Source
AI summary
The present invention relates to a power unit suitable for use in an aircraft comprising: at least one fuel cell; at least two fuel sources for providing fuel to the at least one fuel cell; wherein a first fuel source is a hydrogen supply arranged to provide hydrogen to a first fuel cell of the at least one fuel cell, and wherein a second fuel source is an air gas supply arranged to provide air gas to a first fuel cell of the at least one fuel cell.