Numerical modeling of normal zone propagation and heat transfer in a superconducting composite tape

A numerical model has been developed to analyze the dynamic evolution of the normal zone in a composite tape made of YBCO superconductor with silver cladding as stabilizer. The model solves the conjugate two-dimensional, transient heat equation coupled with current sharing between a clearly segregated superconductor and stabilizer. Heat removal in the transverse direction is characterized by a heat conductance imposed on the stabilizer's outer surface. The computational results indicate that the present tape configuration is much more stable against a pulse disturbance than its counterparts predicted from the conventional one-dimensional theory with volumetrically averaged properties. Conventional one-dimensional analyses for magnet stability have been demonstrated to be too conservative in many aspects. The detailed distribution of heat generation in the composite depends strongly on both the transverse heat transfer and the magnitude of operating current. Ohmic heating in the stabilizer can be very significant, especially for the cases with low heat conductance and/or a large operating current