Hydrogen Pressure Vessel Liner Thickness for Thermal Contraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In pressure vessels, the liner and reinforcing layer can separate at low temperatures and pressures, leading to localized elongation when hydrogen is filled, as they contract differently, causing frictional contact and potential deformation issues.
Innovation Solution
The thickness of the liner's body portion is set to ensure the outer surface presses the inner surface of the reinforcing layer, preventing separation and elongation by maintaining contact and frictional force, even at low temperatures and pressures, using a material like nylon with a specific thickness and structure to manage thermal contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the liner and reinforcing layer are allowed to separate at low temperatures and pressures, then the manufacturing process is simpler, but localized elongation occurs when hydrogen is filled causing deformation issues
Solution Approach 1:
The patent applies preliminary action by pre-setting the thickness of the liner's body portion to a specific value before operation. This predetermined thickness ensures that when the pressure vessel is in service, the outer surface of the body portion automatically presses the inner surface of the reinforcing layer at low temperatures and pressures, preventing separation and subsequent localized elongation during hydrogen filling without requiring additional active control mechanisms
Solution Approach 2:
The patent utilizes parameter changes by leveraging the temperature-dependent dimensional changes of the liner material. As temperature decreases, the liner contracts, and the pre-calculated thickness ensures sufficient radial outward force is generated to maintain contact with the reinforcing layer. This passive thermal-mechanical parameter change resolves the contradiction by using the operating conditions themselves to prevent the harmful effect
2Reliability
If the thickness of the body portion is increased to maintain contact with the reinforcing layer, then localized elongation is prevented, but the weight of the pressure vessel increases
Solution Approach 1:
The patent optimizes the thickness parameter of the body portion to a specific calculated value that balances two competing requirements: generating sufficient radial force to maintain contact with the reinforcing layer at low temperatures, while minimizing the added weight. This precise parameter optimization prevents over-design and achieves the minimum necessary thickness for reliable operation
Solution Approach 2:
The patent applies local quality by focusing the thickness optimization specifically on the body portion of the liner where the contact force with the reinforcing layer is critical. Rather than uniformly increasing the thickness of the entire pressure vessel, the solution locally adjusts only the necessary parameter in the specific region where the thermal-mechanical interaction occurs, minimizing overall weight impact
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 effectively prevents localized elongation at the boundary between the liner's body and shoulder portions, ensuring the pressure vessel operates reliably by maintaining contact and reducing deformation risks.
Implementation Method 1
the liner and the reinforcing layer may be separated from each other due to a difference between the amount of contraction of the liner and the amount of contraction of the reinforcing layer
Implementation Method 2
maintaining contact and frictional force, even at low temperatures and pressures
Data Source
Figure 1
Figure 2
AI summary
A pressure vessel (10) includes a liner (12) and a reinforcing layer (14). The liner (12) includes a body portion (16) having a cylindrical shape. The liner (12) is configured such that a gas is filled in the liner (12). The reinforcing layer (14) is made of a material having a linear expansion coefficient lower than a linear expansion coefficient of a material of the liner (12). The reinforcing layer (14) is formed in contact with an outer surface (12A) of the body portion (16). The reinforcing layer (14) is configured to cover the liner (12) from outside the liner (12). A thickness of the body portion (16) is set to such a value that the outer surface (12A) of the body portion (16) is not separated from the reinforcing layer (14) when the gas that has been filled in the liner (12) is discharged out of the liner (12).