Transient Heat Transfer from a Silver Sheathed High-Tc Superconducting Tape in Liquid Nitrogen

摘要

The transient heat transfer from a silver sheathed BiPbSrCaCuO tape in liquid nitrogen was measured for the exponential heat inputs, Qoe~t/T, with the period, T, ranging from 10 ms to 10s. Average temperature of the sheathed tape was estimated by using the result of newly developed estimation method. The critical heat flux (CHF) increases slightly with the decrease of T from 10 s to l s, decreases significantly at T around 900 ms, slightly increases for T down to 100 ms, and increases almost proportional to tau-~1/2 for further decrease of tau down to 10 ms. Direct transition from non-boiling to film boiling was observed for tau<-900 ms. The CHF at the periods of 900 ms and 10 ms are about 15 percent and 40 percent respectively, of the steady-state CHF.