Aircraft Fuel Conditioning with Exhaust Heat and Cold-Start Bypass
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Solution Overview
Problem
Existing conditioning systems for hydrogen fuel in aircraft Auxiliary Power Units (APUs) are complex, heavy, and inefficient, requiring multiple circuits and failing to maintain optimal fuel conditions during phase transitions, which can lead to system damage and suboptimal performance.
Innovation Solution
A conditioning system with a single fuel conduit, incorporating a first heat exchanger and a heater, where the heater is used to transition liquid hydrogen to gas form and maintain optimal temperature, and a bypass conduit to avoid cold-start conditions, ensuring the system's components operate efficiently and safely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple circuits and heat exchangers are used to condition hydrogen fuel, then fuel conditioning performance is improved, but system complexity and weight increase
Solution Approach 1:
The patent combines multiple functions into a single heat exchanger unit that performs both heat recovery from exhaust gases and phase transition management for hydrogen fuel. This merging of functions reduces the number of separate circuits and components while maintaining effective fuel conditioning performance.
Solution Approach 2:
The heat exchanger is designed to serve multiple purposes: recovering heat from exhaust gases, managing the phase transition of hydrogen from liquid to gas, and controlling fuel temperature. This multi-functionality eliminates the need for separate dedicated systems for each function, thereby reducing overall system complexity.
2Reliability
If multiple circuits and heat exchangers are used to condition hydrogen fuel, then fuel conditioning performance is improved, but aircraft weight increases
Solution Approach 1:
By merging heat recovery and phase transition management into a single heat exchanger, the patent eliminates redundant components and reduces the overall weight of the conditioning system while maintaining effective hydrogen fuel conditioning performance.
Solution Approach 2:
The multi-functional heat exchanger performs multiple conditioning tasks simultaneously, reducing the total mass of components required. This universal component replaces what would traditionally require several separate systems, thereby decreasing the weight of the stationary conditioning system.
3Use of energy by moving object
If liquid hydrogen is used as fuel, then energy density is improved, but phase transition management complexity increases
Solution Approach 1:
The patent explicitly utilizes the phase transition characteristics of hydrogen by designing the heat exchanger to manage the transition from liquid to gas phase. This approach leverages the physical properties of hydrogen rather than treating phase transitions as a complicating factor, simplifying the management process.
Solution Approach 2:
The heat exchanger is designed to automatically manage the phase transition process using the inherent thermal energy available in the exhaust gas stream. The system self-regulates the phase change without requiring external control mechanisms, thereby reducing operational complexity while maintaining high energy density.
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 optimizes weight and complexity while maintaining hydrogen fuel in optimal conditions, preventing damage and ensuring reliable engine performance by controlling temperature and phase transitions, thus enhancing the APU's operational efficiency and safety.
Implementation Method 1
a first heat exchanger connected to the power unit outlet comprises an exhaust gas inlet, an exhaust gas outlet, a fuel inlet and a fuel outlet... the first heat exchanger is configured to transfer heat from the exhaust gases of the power unit outlet to the fuel of the fuel conduit
Implementation Method 2
heater comprising a fuel inlet and a fuel outlet, the heater being located between the first heat exchanger and the engine and wherein the heater are configured to supply heat to the fuel of the fuel conduit and are also configured to turn the fuel of the fuel conduit from liquid form or supercritical fluid form (SCF) into low temperature gas form
Data Source
AI summary
An aircraft conditioning system including: a fuel inlet (2) to a fuel conduit (3), an engine (4), a first heat exchanger (6) connected to a power unit outlet (5) of the engine, a first portion (3.1) of the fuel conduit (3) connecting the fuel inlet (2) to a fuel inlet (6.3) of the first heat exchanger (6) and a second portion (3.2) connecting a fuel outlet (6.4) of the first heat exchanger (6) to an inlet (4.1) of the engine (4), a heater (7) converting liquid fuel in the fuel conduit (3) to a low temperature gas form, a bypass conduit (8) connecting the first and second portions (3.1, 3.2) wherein the first heat exchanger (6) transfers heat from exhaust gases of the power unit outlet (5) to fuel of the fuel conduit (3).