Cryogenic Tank Insulation Encapsulation
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Solution Overview
Problem
Existing cryogenic fluid tanks for space launchers face insulation challenges, particularly at very low temperatures, where thermal contraction between the tank wall and insulation foam can lead to cracking, degrading insulation performance.
Innovation Solution
The insulation material is encapsulated in a sealed envelope, which can be under vacuum or negative pressure, and is combined with a flexible or semi-rigid upper layer and a rigid lower layer, reducing thermal differential contraction and preventing cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If rigid, airtight foam insulation is placed on the inner surface of the tank, then satisfactory insulation is provided, but cracks are likely to occur within the insulating structure due to thermal contraction between the tank wall and insulation foam at very low temperatures
Solution Approach 1:
The patent applies this principle by using a flexible membrane envelope to encapsulate the rigid foam insulation material. The membrane allows for thermal contraction at low temperatures without cracking, while still providing an airtight seal. This resolves the contradiction by protecting the rigid foam from direct thermal stress while maintaining insulation effectiveness.
Solution Approach 2:
The patent creates a composite structure combining rigid foam insulation (for thermal performance) with a flexible membrane envelope (for crack prevention). This composite approach allows the system to maintain both good thermal insulation and structural integrity at cryogenic temperatures by letting each material perform its optimal function.
2Loss of energy
If honeycomb-structured insulation is placed between two walls and vacuum-insulated, then good insulation is achieved, but the solution is expensive and complex for large tanks
Solution Approach 1:
The patent extracts the vacuum insulation requirement from the complex honeycomb structure and applies it simply to the membrane envelope containing the foam. This eliminates the need for complex honeycomb structures while maintaining vacuum insulation benefits, reducing both complexity and cost.
Solution Approach 2:
The patent changes the physical state parameter by using atmospheric pressure foam insulation instead of requiring vacuum-maintained honeycomb structures. The membrane envelope provides the necessary containment, allowing the use of simpler, less expensive foam materials at atmospheric pressure while achieving comparable insulation performance.
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 thermal insulation efficiency and prevents cracking, maintaining effective insulation performance even at low temperatures, while being simpler and less expensive than previous solutions.
Implementation Method 1
the insulating material is encapsulated in a sealed envelope, i.e. that the insulating material is covered by the sealed envelope over its entire surface
Implementation Method 2
thermal insulation comprising a so-called upper layer intended to be in contact with the fluid stored in the storage volume
Implementation Method 3
due to the relative thermal contraction between the tank wall (generally an aluminum alloy) and the insulation foam (subjected to a temperature such as 20 K, for example)
Data Source
Figure 1~2
Figure 3
AI summary
Cryogenic fluid tank for space launcher comprising at least one wall (3) delimiting a storage volume for cryogenic fluid, said wall (3) being furnished, on at least one part of its interior surface, with a thermal insulation comprising a so-called upper layer (2) intended to be in contact with the fluid stored in the storage volume, characterized in that the upper layer (2) comprises an insulting material covered, on its face intended to be in contact with the cryogenic fluid stored in the tank, with a leaktight envelope forming a leaktight barrier between the cryogenic fluid stored and the insulating material, and in that the insulating material of the upper layer (2) is completely encapsulated in a leaktight envelope, that is to say the insulating material is covered by the leaktight envelope over the whole of its surface.