• Title/Summary/Keyword: cryo-cooler

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Study on Improvement of the Piezoelectric Properties of Acoustic Emission Sensor to be Used for Superconducting Application Systems (초전도 응용기기 안정성 진단을 위한 AE센서용 압전소자의 성능개선 연구)

  • Kim, K.J.;Kim, J.H.;Song, J.B.;Paik, J.H.;Jang, J.Y.;Ko, T.K.;Lee, H.G.
    • Progress in Superconductivity and Cryogenics
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    • v.12 no.3
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    • pp.44-48
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    • 2010
  • Acoustic emission (AE) signal from an HTS tape has a low signal to noise ratio, due to the large amount of noise caused by the boiling of the liquid cryogen or mechanical vibration from the cryo-cooler. In an attempt to improve the sensitivity of the AE sensor, $Pb(Zr_{0.54}Ti_{0.46})O_3$ + 0.2 wt% $Cr_2O_3$ + 1.0 wt.% $Nb_2O_5$ ceramics sintered at $1200^{\circ}C$ was synthesized. In addition, the resonance ($f_r$) and anti-resonance frequencies ($f_a$) were measured using the specimens with various thicknesses (1.0, 1.5, 2.0, 2.5 and 3.0 mm). According to the test results, large AE signals with high frequencies were obtained from the AE sensor fabricated using a piezoelectric disc with a thinner thickness.

Structure Design and Thermal Analysis of Cryogenic Cooling System for a 1500 A, 400 mH Class HTS DC Reactor (1500 A, 400 mH급 초전도 직류 리액터용 극저온 냉각 시스템 구조 설계 및 열 해석)

  • Quan, Dao-Van;Le, Tat-Thang;Sung, Hae-Jin;Park, Min-Won;Yu, In-Keun
    • Journal of Korea Society of Industrial Information Systems
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    • v.23 no.1
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    • pp.31-41
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    • 2018
  • This paper discusses a structure design and thermal analysis of cryogenic conduction cooling system for a high current HTS DC reactor. Dimensions of the conduction cooling system parts including HTS magnets, bobbin structures, current leads, support bars, and thermal exchangers were calculated and drawn using a 3D CAD program. A finite element method model was built for determining the optimal design parameters and analyzing the thermo-mechanical characteristics. The operating current and inductance of the reactor magnet were 1,500 A, 400 mH, respectively. The thermal load of the HTS DC reactor was analyzed for determining the cooling capacity of the cryo-cooler. Hence, we carried out the operating test of conduction cooling system of the 1st stage area with high current flow. The cooper bars was cooled down to 40 K and HTS leads operated stably. As a experiment result, the total heat load of the 1st stage area is 190 W. The study results can be effectively utilized for the design and fabrication of a commercial HTS DC reactor.

A compactly integrated cooling system of a combination dual 1.5-MW HTS motors for electric propulsion

  • Le, T.D.;Kim, J.H.;Hyeon, C.J.;Kim, D.K.;Yoon, Y.S.;Lee, J.;Park, Y.G.;Jeon, H.;Quach, H.L.;Kim, H.M.
    • Progress in Superconductivity and Cryogenics
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    • v.18 no.4
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    • pp.25-29
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    • 2016
  • The high temperature superconducting (HTS) contra-rotating propulsion (CRP) systems comprise two coaxial propellers sited on behind the other and rotate in opposite directions. They have the hydrodynamic advantage of recovering the slipstream rotational energy which would otherwise be lost to a conventional single-screw system. However, the cooling systems used for HTS CRP system need a high cooling power enough to maintain a low temperature of 2G HTS material operating at liquid neon (LNe) temperature (24.5 - 27 K). In this paper, a single thermo-syphon cooling approach using a Gifford-McMahon (G-M) cryo-cooler is presented. First, an optimal thermal design of a 1.5 MW HTS motor was conducted varying to different types of commercial 2G HTS tapes. Then, a mono-cryogenic cooling system for an integration of two 1.5 MW HTS motors will be designed and analyzed. Finally, the 3D finite element analysis (FEA) simulation of thermal characteristics was also performed.