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http://dx.doi.org/10.9714/psac.2016.18.1.059

Thermal and structural analysis of a cryogenic conduction cooling system for a HTS NMR magnet

In, Sehwan (Korea Institute of Machinery and Materials)
Hong, Yong-Ju (Korea Institute of Machinery and Materials)
Yeom, Hankil (Korea Institute of Machinery and Materials)
Ko, Junseok (Korea Institute of Machinery and Materials)
Kim, Hyobong (Korea Institute of Machinery and Materials)
Park, Seong-Je (Korea Institute of Machinery and Materials)

Publication Information

Progress in Superconductivity and Cryogenics / v.18, no.1, 2016 , pp. 59-63 More about this Journal

Abstract

The superconducting NMR magnets have used cryogen such as liquid helium for their cooling. The conduction cooling method using cryocoolers, however, makes the cryogenic cooling system for NMR magnets more compact and user-friendly than the cryogen cooling method. This paper describes the thermal and structural analysis of a cryogenic conduction cooling system for a 400 MHz HTS NMR magnet, focusing on the magnet assembly. The highly thermo-conductive cooling plates between HTS double pancake coils are used to transfer the heat generated in coils, namely Joule heating at lap splice joints, to thermal link blocks and finally the cryocooler. The conduction cooling structure of the HTS magnet assembly preliminarily designed is verified by thermal and structural analysis. The orthotropic thermal properties of the HTS coil, thermal contact resistance and radiation heat load are considered in the thermal analysis. The thermal analysis confirms the uniform temperature distribution for the present thermal design of the NMR magnet within 0.2 K. The mechanical stress and the displacement by the electromagnetic force and the thermal contraction are checked to verify structural stability. The structural analysis indicates that the mechanical stress on each component of the magnet is less than its material yield strength and the displacement is acceptable in comparison with the magnet dimension.

Keywords

Conduction cooling; HTS; NMR magnet; Structural analysis; Thermal analysis;

Citations & Related Records

Reference

1	H. Nagai et al., "Development and testing of superfluid-cooled 900 MHz NMR magnet," Cryogenics, vol. 41, pp. 623-630, 2001. DOI
2	Y. Iwasa, J. Bascunan, S. Hahn and D. K. Park, "Solid-cryogen cooling technique for superconducting magnets of NMR and MRI," Phys. Procedia, vol. 36, pp. 1348-1353, 2012. DOI
3	M. Mallett, D. Pooke and T. Husheer, "Cryogen-free, high resolution NMR magnets using high temperature superconductors," 2014 Appl. Supercond. Conf., p. 95, 2014.
4	J. Bascunan, W. Kim, S. Hahn, E. S. Bobrov, H. Lee and Y. Iwasa, "An LTS/HTS NMR magnet operated in the range 600-700 MHz," IEEE Trans. Appl. Supercond., vol. 17, no. 2, pp. 1446-1449, Jun. 2007. DOI
5	S. Hahn, D. K. Park, J. Voccio, J. Bascunan and Y. Iwasa, "No-insulation (NI) HTS inserts for > 1 GHz LTS/HTS magnets," IEEE Trans. Appl. Supercond., vol. 22, no. 3, Art. ID. 4302405, Jun. 2012.
6	M. Song, Y. Tang, J. Li, Y. Zhou, L. Chen and L. Ren, "Thermal analysis of HTS air-core transformer used in voltage compensation type active SFCL," Physica C, vol. 470, pp. 1657-1661, 2010. DOI
7	Y. Nagasaki, T. Nakamura, I. Funaki, Y. Ashida and H. Yamakawa, "Coupled-analysis of current transport performance and thermal behavior of conduction-cooled Bi-2223/Ag double-pancake coil for magnetic sail spacecraft," Physica C, vol. 492, pp. 96-102, 2013. DOI
8	J. Pelegrin et al., "Experimental and numerical analysis of quench propagation on $MgB_2$ tapes and pancake coils," Supercond. Sci. Technol., vol. 26, Art. ID. 045002, 2013.
9	M. D. Sumption et al., "Thermal diffusion and quench propagation in YBCO pancake coils wound with ZnO and Mylar Insulations," Supercond. Sci. Technol., vol. 23, Art. ID. 075004, 2010.
10	E. Gmelin, M. Asen-Palmer, M. Reuther and R. Villar, "Thermal boundary resistance of mechanical contacts between solids at sub-ambient temperatures," J. Phys. D: Appl. Phys., vol. 32, pp. R19-R43, 1999. DOI
11	J. Yu, A. L. Yee and R. E. Schwall, "Thermal conductance of Cu/Cu and Cu/Si interfaces from 85 K to 300 K," Cryogenics, vol. 32, no. 7, pp. 610-615, 1992. DOI
12	M. S. Kim and Y. S. Choi, "Measurement of thermal contact resistance at Cu-Cu interface," Prog. Supercond.and Cryo., vol. 14, no. 4, pp. 1-5, 2012.
13	A. K. Kaw, Mechanics of Composite Materials, CRC Press, New York, 1997.