A transient temperature field model in a thrust magnetic bearing is built in which the heat resources come mainly from the eddy-current loss of solid cores and the copper loss of coils. The transient temperature field...A transient temperature field model in a thrust magnetic bearing is built in which the heat resources come mainly from the eddy-current loss of solid cores and the copper loss of coils. The transient temperature field, system temperature rise and the thermo-equilibrium state during the rotor starting-up are calculated considering only the copper loss and the eddy-current loss. The numerical results indicate that the temperatures in coils and in magnets rise rapidly, their thermo-equilibrium states are formed within a short time. The temperatures in a thrust-disk and in a rotor rise slowly, their thermo-equilibrium states are formed aller a long period time. The temperatures of the thrust-disk and the rotor are far higher than the temperatures of coils and/or magnets aller the thermo-equilibrium state has come into being.展开更多
The EAST superconducting tokamak, an advanced steady-state plasma physics experimental device, has been built at the Institute of Plasma Physics, Chinese Academy of Sciences. All the toroidal field magnets and poloida...The EAST superconducting tokamak, an advanced steady-state plasma physics experimental device, has been built at the Institute of Plasma Physics, Chinese Academy of Sciences. All the toroidal field magnets and poloidal field magnets, made of NbTi/Cu cable-in-conduit conductor, are cooled with forced flow supercritical helium at 3.8 K. The cryogenic system of EAST consists of a 2 kW/4 K helium refrigerator and a helium distribution system for the cooling of coils, structures, thermal shields, bus-lines, etc. The high-speed turbo-expander is an important refrigerating component of the EAST cryogenic system. In the turbo-expander, the axial supporting technology is critical for the smooth operation of the rotor bearing system. In this paper, hydrostatic thrust bearings are designed based on the axial load of the turbo-expander. Thereafter, a computational fluid dynamics-based numerical model of the aerostatic thrust bearing is set up to evaluate the bearing performance. Tilting effect on the pressure distribution and bearing load is analyzed for the thrust beating. Bearing load and stiffness are compared with different static supply pressures. The net force from the thrust bearings can be calculated for different combinations of bearing clearance and supply pressure.展开更多
基金This project is supported by National Natural Science Foundation of China (No.50505030)Key Technology R&D Program of Shanghai Municipal (No.031111001).
文摘A transient temperature field model in a thrust magnetic bearing is built in which the heat resources come mainly from the eddy-current loss of solid cores and the copper loss of coils. The transient temperature field, system temperature rise and the thermo-equilibrium state during the rotor starting-up are calculated considering only the copper loss and the eddy-current loss. The numerical results indicate that the temperatures in coils and in magnets rise rapidly, their thermo-equilibrium states are formed within a short time. The temperatures in a thrust-disk and in a rotor rise slowly, their thermo-equilibrium states are formed aller a long period time. The temperatures of the thrust-disk and the rotor are far higher than the temperatures of coils and/or magnets aller the thermo-equilibrium state has come into being.
基金supported by National Natural Science Foundation of China(Nos.51406157,51506209)partially supported by the China Postdoctoral Science Foundation(No.2014M552438)
文摘The EAST superconducting tokamak, an advanced steady-state plasma physics experimental device, has been built at the Institute of Plasma Physics, Chinese Academy of Sciences. All the toroidal field magnets and poloidal field magnets, made of NbTi/Cu cable-in-conduit conductor, are cooled with forced flow supercritical helium at 3.8 K. The cryogenic system of EAST consists of a 2 kW/4 K helium refrigerator and a helium distribution system for the cooling of coils, structures, thermal shields, bus-lines, etc. The high-speed turbo-expander is an important refrigerating component of the EAST cryogenic system. In the turbo-expander, the axial supporting technology is critical for the smooth operation of the rotor bearing system. In this paper, hydrostatic thrust bearings are designed based on the axial load of the turbo-expander. Thereafter, a computational fluid dynamics-based numerical model of the aerostatic thrust bearing is set up to evaluate the bearing performance. Tilting effect on the pressure distribution and bearing load is analyzed for the thrust beating. Bearing load and stiffness are compared with different static supply pressures. The net force from the thrust bearings can be calculated for different combinations of bearing clearance and supply pressure.
