Closed-Loop Nitrogen Cooling for Superconducting Maglev Vehicles
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Solution Overview
Problem
Current cryogenic systems for high-temperature superconducting magnetic levitation vehicles face inefficiencies in liquid nitrogen replenishment and heat conduction, leading to reduced running efficiency and increased maintenance needs.
Innovation Solution
A superconducting bulk cooling apparatus comprising a refrigerating machine, vacuum box, and Dewar tank with a condensing tank and flexible isolation pipes, forming a closed nitrogen circulation loop for efficient heat exchange and liquid nitrogen replenishment, enhancing heat transfer efficiency and reducing maintenance requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid nitrogen immersion cooling method is used, then cooling effect is improved, but liquid nitrogen needs to be continuously replenished which reduces running efficiency
Solution Approach 1:
The patent recovers nitrogen gas that has evaporated from the liquid nitrogen by condensing it back into liquid form using a condensing tank and refrigerating machine, then returns it to the Dewar tank. This closed-loop recovery system eliminates the need for continuous liquid nitrogen replenishment while maintaining effective cooling of the superconducting bulk.
2Temperature
If refrigerating machine conduction cooling type is used, then cooling is achieved, but refrigerating machine needs long time to reach target temperature and contact area is limited which reduces heat conduction efficiency
Solution Approach 1:
The patent introduces liquid nitrogen as an intermediary cooling medium between the superconducting bulk and the refrigerating machine. The liquid nitrogen directly contacts the superconducting bulk through immersion, providing superior heat transfer compared to limited contact area conduction. The refrigerating machine then cools the liquid nitrogen in the condensing tank, creating an efficient two-stage cooling system.
3Loss of energy
If additional components are added to improve heat efficiency, then heat efficiency is improved, but equipment size becomes excessively large which affects installation
Solution Approach 1:
The patent employs a nested configuration where the condensing tank is placed inside the vacuum box, which itself is inside the Dewar tank. The refrigerating machine is positioned within the vacuum box environment. This nested arrangement allows multiple cooling and insulation functions to be integrated in a compact space, improving heat efficiency without excessively increasing equipment volume for vehicle installation.
4Loss of energy
If vacuum insulation is used, then thermal insulation is improved, but system complexity increases
Solution Approach 1:
The patent uses a vacuum environment (inert atmosphere) within the vacuum box to provide thermal insulation for the condensing tank. This vacuum insulation prevents heat transfer from the external environment to the liquid nitrogen, reducing energy loss and maintaining cooling efficiency. The vacuum box serves as both an insulation chamber and a containment structure, integrating multiple functions.
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 apparatus improves running efficiency by maintaining a stable cooling environment, reducing manual maintenance frequency, and minimizing equipment size, thus enhancing the operational performance of high-temperature superconducting magnetic levitation vehicles.
Implementation Method 1
A heat exchanger for performing heat exchange and condensation on gaseous nitrogen is arranged in the condensing tank
Implementation Method 2
the condensing tank is thermally insulated from an external environment through a vacuum low-temperature environment in the vacuum box
Implementation Method 3
liquid nitrogen condensed on cooling fins of the heat exchanger is returned to the Dewar tank via the liquid nitrogen return pipe on the bottom of the condensing tank under the action of the gravity
Data Source
AI summary
The present invention discloses a superconducting bulk cooling apparatus and cooling method for a high-temperature superconducting magnetic levitation vehicle. The superconducting bulk cooling apparatus for the high-temperature superconducting magnetic levitation vehicle includes a refrigerating machine, a vacuum box and a Dewar tank. A condensing tank is arranged in the vacuum box, and the condensing tank is communicated with the Dewar tank through a nitrogen siphon pipe and a liquid nitrogen return pipe; a heat exchanger connected with the refrigerating machine is arranged in the condensing tank; and a flexible isolation pipe for thermally insulating and isolating the nitrogen siphon pipe and the liquid nitrogen return pipe is connected between the vacuum box and the Dewar tank. The present invention pumps the phase-change nitrogen out of the Dewar tank through a siphoning effect, so that the immersion cooling of high-temperature superconducting bulks is separated from the re-condensation of the nitrogen.