Superconducting Cable Cryostat Structure for Thermal Contraction
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Solution Overview
Problem
Existing superconducting power transmission systems face challenges in thermal contraction and expansion, leading to potential damage and thermal stress, and struggle to achieve a high degree of vacuum for effective thermal insulation, particularly in long-distance cable projects.
Innovation Solution
A thermally insulated double pipe configuration with a bellows pipe connected to the inner pipe to absorb thermal contraction, a camera system for monitoring and adjusting the cryostat, and the introduction of a gas that solidifies at liquid nitrogen temperature for improved vacuum evacuation and insulation, along with free-supported terminal ends for the superconducting cable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid inner pipe is used to support the superconducting cable, then structural stability is improved, but thermal stress and damage during thermal contraction are worsened
Solution Approach 1:
The inner pipe is designed with a bellows structure that enables dynamic expansion and contraction to accommodate thermal changes. This dynamic structure allows the pipe to flex during thermal contraction without generating excessive stress, while still providing adequate support for the superconducting cable during operation.
Solution Approach 2:
The bellows pipe incorporates flexible corrugated sections that can expand and contract radially and axially. These flexible sections absorb thermal stress through elastic deformation, preventing damage to the rigid components while maintaining structural integrity during temperature cycles.
2Reliability
If conventional evacuation methods are used, then vacuum achievement is possible, but evacuation time is excessively long for long-distance cables
Solution Approach 1:
The long double-pipe structure is divided into multiple evacuation sections with intermediate vacuum outlets. Vacuum pumps can be positioned at multiple locations along the cable route, allowing parallel evacuation of different sections. This segmentation dramatically reduces the total evacuation time compared to pumping out a single continuous long section.
Solution Approach 2:
The inner pipe is equipped with heating elements that can pre-heat the pipe wall before evacuation. This preliminary heating reduces condensation of residual gases on the cold pipe surface during evacuation, improving vacuum quality and reducing the time required to achieve the target vacuum level.
3Device complexity
If the inner pipe is directly connected to the outer pipe, then structural simplicity is improved, but thermal insulation performance is worsened
Solution Approach 1:
The bellows pipe serves as an intermediary thermal break between the inner and outer pipes. Its corrugated structure and material properties create thermal resistance, reducing heat conduction from the outer pipe to the inner superconducting cable while still allowing mechanical connection and flexibility.
4Stability of the object's composition
If fixed terminal ends are used for the superconducting cable, then connection stability is improved, but thermal stress concentration is worsened
Solution Approach 1:
The terminal ends incorporate flexible bellows sections that can dynamically adjust their position during thermal contraction. This dynamic capability allows the rigid connection points to remain stable while the flexible sections absorb the thermal movement, preventing stress concentration at the terminal connections.
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 solution effectively mitigates thermal stress and achieves a higher degree of vacuum, enhancing thermal insulation performance and reducing the time required for evacuation, thereby improving the reliability and efficiency of superconducting power transmission systems.
Implementation Method 1
the inner pipe is cooled following the evacuation to vacuum
Implementation Method 2
a bellows pipe housed within the outer pipe. The bellows pipe is connected to an end(s) of the inner pipe
Implementation Method 3
a thermally insulated double pipe composed by an inner pipe within which a superconducting cable is installed and by an outer pipe within which the inner pipe is housed
Implementation Method 4
a preset sort of gas is introduced into a vacuum region between the inner and outer pipes of the thermally insulated double pipe to effect gas replacement to perform evacuation
Implementation Method 5
The pre-set sort of gas is inclusive of a carbon oxide gas. The pre-set sort of gas is such a gas that solidifies at a temperature higher than the liquid nitrogen temperature
Implementation Method 6
a superconducting cable, such configuration that assures a facilitated laying-down operation
Data Source
AI summary
In a thermally insulated double pipe, a structure is provided in which an inner pipe may be prevented from being appreciably offset relative to an outer pipe due to thermal contraction. The structure includes an inner pipe 101, within which a superconducting cable is mounted, an outer pipe 103 within which the inner pipe is housed, with the inner and outer pipes constituting a thermally insulated double pipe, and an inner pipe support member 104 supporting the inner pipe. The inner pipe support member 104 is secured to the inner and outer pipes.