Hydrogen Tank Layout Behind Pressure Bulkhead for Cryogenic Aircraft

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Solution Overview

Problem

Hydrogen aircrafts using liquid hydrogen face challenges in maintaining and insulating hydrogen tanks due to the need for cryogenic storage, which requires excellent thermal insulation to minimize boil-off gas and simplifies maintenance access.

Innovation Solution

The hydrogen tank is positioned in a non-pressurized accommodation section behind a pressure bulkhead within the fuselage, allowing for improved maintainability and thermal insulation by adopting a spherical shape and utilizing a divided tank configuration with dedicated supply lines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the hydrogen tank is disposed inside the pressurized chamber, then the space utilization is improved, but the maintenance accessibility and thermal insulation performance deteriorate

Engineering Contradiction:

Improvetank capacityVSAvoidmaintenance accessibility

Core Design Contradiction:

Volume of moving objectVSEase of repair

Solution Approach 1:

The fuselage is segmented into a pressurized chamber and a non-pressurized accommodation section. The hydrogen tank is placed in the non-pressurized accommodation section, which is separated from the pressurized chamber by a pressure bulkhead. This segmentation allows the tank to be isolated in a dedicated space that provides both maintenance accessibility and thermal insulation, resolving the contradiction between space utilization and maintenance ease.

Inventive Principle:

Principle #1Segmentation

2Volume of moving object

If the hydrogen tank is disposed inside the pressurized chamber, then the space utilization is improved, but the thermal insulation performance deteriorates

Engineering Contradiction:

Improvetank capacityVSAvoidthermal insulation performance

Core Design Contradiction:

Volume of moving objectVSTemperature

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

3Quantity of substance

If the tank capacity is increased, then the energy storage is improved, but the fuselage cross-sectional area increases

Engineering Contradiction:

Improveliquid hydrogen storage capacityVSAvoidfuselage cross-sectional area

Core Design Contradiction:

Quantity of substanceVSArea of stationary object

Solution Approach 1:

The hydrogen tank is positioned in the longitudinal direction of the fuselage, extending from the rear of the pressure bulkhead toward the rear end of the fuselage. This longitudinal arrangement utilizes the length of the fuselage rather than increasing the cross-sectional area, allowing large tank capacity to be achieved without increasing the fuselage's cross-sectional dimensions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 configuration enhances maintainability and thermal insulation properties while securing large tank capacity without increasing the fuselage's cross-sectional area, reducing maintenance time and effort, and ensuring safety by isolating the tank from the pressurized compartment.

Implementation Method 1

a pressure bulkhead that is disposed at a rear part of the pressurized chamber and has strength to withstand pressurization of the pressurized chamber

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 2

since the hydrogen tank stores cryogenic liquid hydrogen, excellent thermal insulation properties are required so as not to generate boil-off gas (BOG) as much as possible

Methodology Applied

Scientific EffectCryogenic storage: Cryogenics

Implementation Method 3

excellent thermal insulation properties are required so as not to generate boil-off gas (BOG) as much as possible

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 4

a supply line that supplies the liquid hydrogen stored in the hydrogen tank to the propulsion system

Methodology Applied

Scientific EffectFluid flow:

Data Source

PatentUS12473097B2Hydrogen aircraft

Publication Date: 2025.11.18 KAWASAKI JUKOGYO KK

AI summary

A hydrogen aircraft includes: an airframe including a fuselage and a wing; at least one propulsion system fixed to the airframe; a pressurized chamber disposed inside the fuselage; a pressure bulkhead that is disposed at a rear part of the pressurized chamber and has strength to withstand pressurization of the pressurized chamber; a hydrogen tank that is disposed in an accommodation section and stores liquid hydrogen, the accommodation section being installed behind the pressure bulkhead, outside the pressurized chamber, and inside the fuselage; and a supply line that supplies the liquid hydrogen stored in the hydrogen tank to the propulsion system.