Gel Rocket Propulsion for Controllable Underwater Thrust

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Solution Overview

Problem

Existing rocket propulsion systems face challenges in storage and handling safety, controllability, and environmental impact, particularly with solid and liquid propellants, while requiring complex ignition systems and being sensitive to leaks.

Innovation Solution

A propulsion device utilizing gel-like rocket propellants, comprising separate tanks for fuel and oxidizer gels, with independent control valves and a combustion chamber design that includes a secondary combustion zone for water injection, allowing thrust control and efficient combustion, especially in underwater transport devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If solid or liquid propellants are used in rocket propulsion systems, then propulsion performance can be achieved, but storage and handling safety deteriorates and the systems become sensitive to leaks

Engineering Contradiction:
Improvepropulsion performanceVSAvoidstorage and handling safety
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent applies gel propellants which are composite materials combining solid and liquid properties. The gel structure provides the safety and handling advantages of solid propellants while maintaining the performance characteristics of liquid propellants, thus resolving the contradiction between propulsion performance and storage/handling safety

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the physical state parameter of the propellant from pure liquid or solid to gel state. This parameter change fundamentally alters the safety characteristics while preserving propulsion performance, addressing the reliability concern without sacrificing power

Inventive Principle:
Principle #35Parameter changes

2Force

If conventional rocket propulsion systems are used, then thrust can be generated, but the ignition systems become complex and the systems become sensitive to leaks

Engineering Contradiction:
ImprovethrustVSAvoidignition system complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The gel propellant system is designed to be self-igniting through its chemical composition, eliminating the need for complex external ignition systems. The propellant serves its own ignition function, thereby reducing device complexity while maintaining thrust generation capability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts and eliminates the complex ignition system from the propulsion system by using hypergolic gel propellants that ignite automatically upon contact, removing the troublesome ignition component while preserving thrust generation

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If conventional propellant systems are used, then propulsion function is achieved, but environmental hazards increase

Engineering Contradiction:
Improvepropulsion functionVSAvoidenvironmental hazards
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent employs environmentally benign gel propellants that create a safer, more inert operational environment. The propellant formulation minimizes harmful emissions and environmental contamination, reducing object-affected harmful factors while maintaining propulsion functionality

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent converts potentially harmful conventional propellants into beneficial environmentally-friendly gel propellants. The reformulated propellants maintain propulsion effectiveness while eliminating or reducing harmful environmental effects, thus converting the harm into benefit

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Volume of moving object

If compact propulsion systems are designed for underwater transport devices, then device dimensions are reduced, but achieving high speeds including cavitation becomes more difficult

Engineering Contradiction:
Improvepropulsion system dimensionsVSAvoidunderwater speed
Core Design Contradiction:
Volume of moving objectVSSpeed

Solution Approach 1:

The patent changes the operational parameters of the gel propellant system to optimize for high-speed underwater operation. The gel propellant's unique rheological properties allow efficient energy transfer and cavitation generation in compact configurations, enabling high speeds without increasing system volume

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The gel propellant's composite nature enables compact system design while maintaining high-speed capability. The gel structure allows for more efficient combustion and energy release in confined spaces, facilitating both compact dimensions and high underwater speeds including cavitation effects

Inventive Principle:
Principle #40Composite materials

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 a compact, reliable, and safe propulsion unit capable of achieving high underwater speeds, including cavitation or supercavitation, with reduced environmental hazards and improved handling characteristics.

Implementation Method 1

a combustion chamber (170) ending in a thrust nozzle (178)

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

at least one water inlet (150) into the secondary combustion zone (174) or the mixing zone (176)

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4405580B1Use of a rocket propellant, drive device with a rocket propellant and underwater transport device
Publication Date: 2025.11.26 DEUTSCHES ZENTRUM FÜR LUFT UND RAUMFAHRT E V
  • EP4405580B1 patent drawingFigure 1
  • EP4405580B1 patent drawingFigure 2
  • EP4405580B1 patent drawingFigure 3

AI summary

The invention relates to a drive device (100) of an underwater transport device (300), comprising at least one tank (130, 140) with a gel-type rocket propellant with at least one fuel gel (132) and an oxidizer gel (142), comprising a fuel chamber (170) that ends in a thrust nozzle (178). The invention also relates to a use of gel-type, diergolic rocket propellant comprising a fuel gel (132) and an oxidizer gel (142) as fuel for driving an underwater transport device (300).