Submarine Propulsion System Flushing Using Carbon Dioxide

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Solution Overview

Problem

Conventional methods for flushing air-independent propulsion systems in submarines require large amounts of inert gases like nitrogen, which are space-intensive and result in a significant submarine signature due to gas discharge into the water, increasing detection risk.

Innovation Solution

Using carbon dioxide as the flushing gas, which dissolves in water and can be discharged without bubbling, reducing storage volume and signature, and utilizing it in its liquid or supercritical state for efficient inerting of propulsion system components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If nitrogen is used as purge gas, then effective inerting is achieved, but storage volume increases significantly

Engineering Contradiction:
Improveinerting effectivenessVSAvoidstorage volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The invention changes the chemical parameter of the purge gas from nitrogen to carbon dioxide. Carbon dioxide has superior water solubility compared to nitrogen, which fundamentally changes how the gas is disposed of and reduces the required storage volume while maintaining inerting effectiveness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention converts the previously harmful effect of carbon dioxide bubbles (increasing acoustic signature) into a beneficial property by utilizing carbon dioxide's high water solubility. The gas dissolves in water instead of forming bubbles, eliminating the acoustic signature problem while enabling compact storage.

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

2Object-generated harmful factors

If nitrogen is vented into surrounding water, then purge gas is disposed of, but acoustic signature increases

Engineering Contradiction:
Improveacoustic signatureVSAvoidpurge gas discharge
Core Design Contradiction:
Object-generated harmful factorsVSLoss of substance

Solution Approach 1:

The invention changes the physical parameter of gas-water interaction from bubble formation to dissolution. Carbon dioxide's high solubility in water allows it to dissolve rather than form bubbles, fundamentally changing the discharge mechanism from harmful bubble generation to beneficial dissolution.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention converts the previously harmful bubble formation into a beneficial dissolution process. What was once a harmful effect (acoustic signature from bubbles) becomes a beneficial property (silent dissolution of carbon dioxide in water).

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

3Ease of operation

If carbon dioxide is stored in gaseous state, then ease of operation is improved, but storage volume increases

Engineering Contradiction:
Improvegas storage simplicityVSAvoidstorage volume
Core Design Contradiction:
Ease of operationVSVolume of stationary object

Solution Approach 1:

The invention utilizes phase transition of carbon dioxide between gaseous and liquid states. By storing carbon dioxide in liquid form and converting to gas only when needed for purging, the system achieves compact storage while maintaining operational simplicity.

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The invention changes the physical state parameter of carbon dioxide from gaseous to liquid for storage. This phase change reduces storage volume by a factor of approximately 500 times while simple pressure and temperature control enables easy conversion back to gaseous state for operation.

Inventive Principle:
Principle #35Parameter changes

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

Carbon dioxide provides effective inerting with reduced storage needs and minimal signature impact, preventing combustible gas accumulation and corrosion, while allowing for efficient use of exhaust gases, thus enhancing submarine stealth and operational efficiency.

Implementation Method 1

Compared to nitrogen, carbon dioxide has considerably better solubility in water. Therefore, the carbon dioxide used for flushing does not have to be blown out of the boat's hull into the surrounding water, but can first be dissolved in water and then released.

Methodology Applied
Scientific EffectSolubility: Absorption (physical)

Implementation Method 2

carbon dioxide converts to a liquid state at room temperature even when stored at a comparatively low pressure. However, in the liquid state, carbon dioxide occupies a significantly smaller volume than in the gaseous state.

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 3

Carbon dioxide, like nitrogen, is an effective inert gas. After flushing, the flushing gas is dissolved in water and then released from the submarine into the environment.

Methodology Applied
Scientific EffectInerting:

Data Source

PatentEP2151377B1Method for flushing at least one part of a vehicle's propulsion system
Publication Date: 2016.08.31 THYSSENKRUPP MARINE SYST GMBH
  • EP2151377B1 patent drawingFigure 1
  • EP2151377B1 patent drawingFigure 2
  • EP2151377B1 patent drawingFigure 3

AI summary

The method according to the invention uses carbon dioxide as a purge gas for purging at least a part (45) of an air-independent propulsion system (35) of a vehicle (5), in particular a submarine (5). The submarine (5) according to the invention, having an air-independent propulsion system (35), has a carbon dioxide purge gas system (57) for carrying out this method; the carbon dioxide purge gas system (57) has at least one carbon dioxide storage device (65).