场冷条件下超导块材的吸引力与排斥力

Repulsive force and attractive force of HTS under different field cooling process

基于K im临界态模型,通过考虑超导块材内部屏蔽电流的穿透历史过程,其计算了不同场冷条件下高温超导悬浮系统的悬浮力。其计算结果与实验结果吻合很好。结果显示:超导块材的最大吸引力随场冷高度的升高呈指数关系减小;达到最大吸引力的悬浮高度随场冷高度的增加近似呈线性关系增长。最大排斥力随场冷高度的变化曲线存在临界值:当场冷高度小于临界值时,最大排斥力呈线性关系增加;反之,最大排斥力呈指数关系增长。悬浮力与场冷高度的这些变化规律可以用超导块材内部屏蔽电流的穿透情况进行很好地解释,为超导块材的实际工业应用提供了重要的理论依据。

After the penetration depth of superconducting currents and the internal magnetic field interior of HTS were calculated, the interaction forces between a high -Tc superconductor （HTS） and a permanent magnet （PM） were investigated under different field cooling process based on Kim critical state model. The simulation results were good agreement with the experimen- tal data. It was found that the maximum attractive force decreased as an exponential function with the increasing of field cooling height. The gap between HTS and PM at the maximum attractive force was linear with field cooling height. A transitional value of field cooling height was also found. When the field cooling height was less than the transitional one the maximum repulsive force increase as a linear function, otherwise it showed an increasing exponential relation between the maximum repulsive force and the field cooling height. All these relations can be explained with the penetration history of superconducting currents under field cooling process.