Effect of temperature-dependent critical current density on the fracture behavior for a rectangular superconducting slab with a center crack

Superconducting cables made of high-temperature superconductors have great potential applications in space solar power station. Since the critical current density of high temperature superconductor is dependent of temperature and determines the distribution of the magnetic flux density, temperature change can affect the pinning force. In this paper, model-I crack problem of a long rectangular superconducting slab under thermal effect is investigated. The stress intensity factors of the slab during the field decent of pulsed field magnetization (PFM) and field cooling (FC) are calculated. Compared with that without considering thermal effect, the result shows that once the temperature of the slab rises, the variation of the stress intensity factor will have a peak during the applied magnetic field decent for the PFM. While for the FC, temperature rise causes the stress intensity factor to decrease

Effect of buckling on the cooling performance of free-standing planar thermoelectric coolers

This article investigates the effect of buckling on the cooling performance of planar thermoelectric (TE) coolers (TECs). The TEC is made up of n-type and p-type TE elements with large length-to-thickness ratio. Each TE element is modeled as a fixed–fixed thin plate. Theoretical model for the solutions of temperature and electric potential fields of the TE element after buckling is established. The corresponding coefficient of performance (COP) that indicates the cooling performance of TEC is also given. Influence of Seebeck coefficient, thermal conductivity, temperature difference, and the ratio of length-to-thickness on the cooling performance are discussed. It is found that buckling of TEC will reduce its cooling performance. A bigger Seebeck coefficient and smaller thermal conductivity can both improve the value of COP. It is also found that there is no maximum COP when the temperature difference across the TEC is zero. However, the effect of buckling on the cooling performance of TEC can be ignored if the TEC achieves the maximum COP. The peak value of COP is independent of the ratio of length-to-thickness of the TEC. An optimized value of the electric current corresponding to the maximum COP of the TEC is obtained