Influence of operating temperature and contact thermal resistance on normal zone propagation in a metal-sheathed high-Tc superconductor tape
✍ Scribed by M.K. Chyu; C.E. Oberly
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 732 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0011-2275
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✦ Synopsis
The primary objective of this study is to examine the influence of operating temperature, ranging from 20 K to 80 K, and contact thermal resistance on the normal zone propagation in a silver-sheathed, YBCO superconductor tape. The distributions of temperature and heat generation are obtained numerically by solving a transient, two-dimensional energy equation with temperature-dependent properties and a current-sharing model. The present results suggest that, as a combined effect Gf greater cooling margin and higher thermal diffusivity, a 20 K operation is considerably more stable than its 80 K counterpart. In addition, during a pulse-induced quench zone propagation, most of the ohmic heating is generated in the YBCO superconductor for a 20 K operation. Conversely, the silver sheath generates most of the heat for an 80 K operation. Imposing transverse cooling significantly promotes stability and reduces normal zone propagation velocity. However, it has little influence on the instantaneous rise in local temperature during a disturbance. Such a temperature spike, largely caused by the low thermal diffusivity of YBCO, may exceed YBCO melting temperature. This detrimental phenomenon is more pronounced as the thermal resistance between the superconductor and metal sheath increases. However, this effect is significant only when the contribution of the interfacial resistance to the transverse resistance results in the latter being comparable to its longitudinal counterpart.