1993 Fiscal Year Final Research Report Summary
Thermal-Engineering Stucy on Early Detection of Quench and Hyper Stabilization Method of Superconducting Coil
| Project/Area Number |
03452126
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thermal engineering
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| Research Institution | Tohoku University |
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Principal Investigator |
AIHARA Toshio Tohoku University, Institute of Fluid Science, Professor, 流体科学研究所, 教授 (90006172)
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| Co-Investigator(Kenkyū-buntansha) |
OHARA Taku Tohoku University, Institute of Fluid Science, Ressearch Associate, 流体科学研究所, 助手 (40211833)
TANI Junji Tohoku University, Institute of Fluid Science, Professor, 流体科学研究所, 教授 (30006192)
TAKAHASHI Hideaki Tohoku University, Faculty of Engineering, Professor, 工学部・付属破壊力学応用研究施設, 教授 (10005267)
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| Project Period (FY) |
1991 – 1993
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| Keywords | Superconductor / Thermal Stability / Immersion Cooling / Forced Cooling / Heat Transfer |
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| Research Abstract |
The aim of this research project is to clarify thermal mechanism of quench in forced-and immersion-cooled superconducting coils, and to establish theory of thermal stability of superconducting coil, and to propose methods for early detection of the quench. The outline of the results obtained in this 3-year research project is given below.
1. Numerical analyzes of quench mechanism and thermal stability of forced-and immersion-cooled superconducting coils were carried out. Various influences of governing factors on them were clarified quantitatively and the basic concept of early prediction of quench was established.
2. Since the quench phenomenon is extremely rapid transient and indeterminate, and it occurs in a very strong magnetic field, it is almost impossible to predict the time and place of its occurrence. hence we propose two novel detecting methods : one is a film thermal sensor, and another is a visualization technique.
Practical applicability of the film thermal sensor was examine
… More
d in an experiment on rapid transient boiling heat transfer of a pulse-heated strip in liquid helium. The data obtained in the experiment are also necessary for the precise analysis of the thermal stability. The test piece was a 20-mum-thick stainless steel strip, both surface of which were coated with PVF film and a carbon-paste film. This strip structure was to simulate an insulated superconductor in practical use and the carbon-paste film performed the part of an electric resistance thermometer. The heat-transfer data were reduced from the experimental raw values by numerical calculation considering the heat capacity and transient temperature distribution of the coating layrs : the obtained results had satisfactory accuracy to apply the film sensor to the early detection of quench initiation.
As for a visualization technique of quench and its rapid propagation was investigated using a pancake-type superconducting coil immesed in liquid helium. It was found that the visualization technique will be a promising tool of the early detectin of quench ; however, we need further research to make applicatin of this charming technique to practical superconducting coils. Less
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