Quantum Magnetic Levitation technology and its applications in exploration projects
Abstract
An energy efficient cryogenic transfer line with magnetic suspension has been prototyped and cryogenically tested. The prototype transfer line exhibits cryogen saving potential of 30–35% in its suspension state as compared to its solid support state. Key technologies developed include novel magnetic levitation using multiple-pole high temperature superconductor (HTS) and rare earth permanent-magnet (PM) elements and a smart cryogenic actuator as the warm support structure. These technologies have vast applications in extremely low thermal leak cryogenic storage/delivery containers, superconducting magnetic bearings, smart thermal switches, etc. This paper reviews the development work and discusses future applications of established technologies.
Introduction
More and more applications [1], [2], [3] of magnetic levitation (MagLev) technology have been exploited in extensive cryogenic engineering domains. As one instance of such endeavors, AMAC International Inc.’s team of scientists and researchers has successfully applied magnetic levitation using HTS and high strength PM in an energy efficient prototype of a cryogen transfer line [4], [5], [6], [7], [8]. The key design issues, such as optimization of levitation unit and “smart” support structure development, are reviewed in this paper. Cryogenic test results are reported as well. The advantages of non-contact insulation through magnetic levitation support enable the associated technologies to promise low thermal loss solutions for space flight vehicles and/or planetary surface operation stations.
As an example, the magnetic levitation technology as developed by AMAC can be extended to the design of zero-boil-off (ZBO) cryotanks [3], [9], [10], [11] that impose much lower cooling power demands on equipped cryocoolers. Also, the fact that cryocoolers are becoming more and more reliable makes it feasible to build flywheels consisting of passive superconducting magnetic bearings (SMBs) [1], [2], i.e. bearings composed of tubular HTS and PM, that can be used in space energy storage systems. A comparison of popular magnetic bearing techniques is given in this paper to demonstrate the benefits that a passive magnetic bearing may produce.
Implementation of a transfer line with magnetic levitation units triggered the question of smart support design, which provides mechanical support when it is so warm that HTS–PM units are deactivated. As a consequence of such studies, a cryogenic actuator made of smart material has been prototyped and tested. Its motion is passively adjusted by temperature change in the system. No powered control units are required. No manual operations are needed either. The design principles of such a smart cryogenic actuator can be adapted for design of automatic thermal conduction switches used in cryogen storage containers, cryogenic valves, seals, and some medical applications.
Section snippets
Design of cryogenic transfer line with magnetic suspension
This Section summarizes the primary considerations on three aspects, i.e. magnetic levitation configuration, thermal, and mechanical design. While the magnetic levitation configuration optimization requires most of the time in the design process, thermal and mechanical design issues had to be analyzed and subsequently, all factors are synthesized for the purpose of improving system energy efficiency.
Smart cryogenic actuator development
A warm support structure is required in such a MagLev transfer line to keep the inner line supported at warm condition when the HTS–PM levitation units are deactivated. This is preferably to be done in a passive way that does not require power supply, control electronics, etc. AMAC has prototyped a smart cryogenic actuator (Fig. 6) to function as a warm support structure in the MagLev cryogenic transfer line. The actuator is attached to the cold inner line so that it is passively controlled by
MagLev transfer line prototype and cryogenic tests
The full-scale prototype MagLev transfer line (Fig. 7a) was constructed with three manually operated warm supports installed. These warm supports are basically stainless steel rods, when switched on, they will introduce thermal conduction as a conventional transfer line does. The smart cryogenic actuator is planned to equip the MagLev transfer line during commercialization stage. Comprehensive cryogenic test results of the MagLev transfer line are presented in other publications [6], [8]. Below
Low thermal leak space cryostats
NASA is planning a number of future missions that will use cryogenics. These include missions with cooled scientific instruments and missions using cryogenic propellants. Minimizing the thermal load on the…
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