Hydrogen Fuel Tank Pressure Control via Heat-Exchanger Recirculation

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Solution Overview

Problem

The challenge of maintaining pressure in hydrogen fuel tanks of aircraft during flight, while optimizing fuel consumption and minimizing waste, is not adequately addressed by existing technologies, particularly due to the low energy density and specific storage conditions of hydrogen.

Innovation Solution

A method and system that recirculates unfit fuel from the distribution line through a heat exchanger to adjust temperature and pressure, ensuring optimal conditions for reinjection into the fuel tank, thereby maintaining pressure and preventing fuel loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydrogen is stored in fuel tanks at low temperature and pressure, then storage safety and structural integrity are improved, but fuel consumption efficiency deteriorates due to low energy density by volume

Engineering Contradiction:
Improvestorage safetyVSAvoidfuel consumption efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts temperature and pressure parameters of hydrogen fuel during storage and delivery. By maintaining optimal pressure in the fuel tank and controlling heat exchanger operation, the system balances safe storage conditions with efficient fuel consumption, addressing the contradiction between safety and energy density utilization

Inventive Principle:
Principle #35Parameter changes

2Loss of substance

If recirculation system is implemented to maintain pressure, then fuel waste is reduced, but device complexity increases due to additional components

Engineering Contradiction:
Improvefuel wasteVSAvoidsystem complexity
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The heat exchanger serves multiple functions: it conditions fuel for delivery to the engine, recirculates fuel to maintain tank pressure, and manages thermal conditions. This multi-functionality reduces fuel waste through recirculation while avoiding the need for separate dedicated pressure maintenance equipment, thus limiting complexity increase

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If heat exchanger power is increased to maintain pressure, then pressure maintenance effectiveness is improved, but energy consumption increases

Engineering Contradiction:
Improvepressure maintenanceVSAvoidheat exchanger energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The system uses feedback control where pressure sensors monitor fuel tank pressure and temperature sensors monitor fuel conditions. The controller adjusts heat exchanger power based on this feedback, increasing power only when pressure drops below thresholds and reducing power when pressure is maintained, thereby balancing pressure maintenance effectiveness with energy consumption

Inventive Principle:
Principle #23Feedback

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 effectively maintains fuel tank pressure by recycling unfit fuel, reducing waste, and ensuring efficient hydrogen use, thus optimizing weight distribution and safety in aircraft fuel systems.

Implementation Method 1

providing heat to the first recirculated fuel mass flow by means of the heat exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4635854A1Method for maintaining pressure in a fuel tank
Publication Date: 2025.10.22 AIRBUS OPERATIONS SL
  • EP4635854A1 patent drawingFigure 1
  • EP4635854A1 patent drawingFigure 2
  • EP4635854A1 patent drawingFigure 3

AI summary

The present invention belongs to the field of aircraft engines, and particularly, it belongs to a method for maintaining pressure in a fuel tank of a fuel consuming system of an aircraft and a fuel distribution system thereof.