结晶器电磁搅拌器的内腔磁场和端部漏磁的数值模拟

Numerical Simulation About the Lumen Magnetic Field and Brow Leakage of M-EMS

借助有限元分析与试验测量相结合的方法,分别研究了相同铁芯高度和安匝数下凸极式和环形式铁芯结晶器电磁搅拌器的内腔磁场和端部漏磁。研究表明,模拟结果与试验结果一致。在搅拌器内腔正中心沿拉速方向(轴向z)上,凸极式和环形式铁芯电磁搅拌器的磁感应强度变化趋势一致,都沿z轴正向变化平缓。而向铁芯表面逐渐靠近时,凸极式电磁搅拌器的磁感应强度沿z轴先逐渐增大,在距搅拌器水平中心面约150mm的铁芯端部达到最大峰值,然后由端部向外急剧降低,呈"山峰"状的分布趋势。在越贴近搅拌器铁芯表面处,这种磁场分布趋势越明显,即端部漏磁越明显。而与凸极式铁芯电磁搅拌器相比较,环形式铁芯电磁搅拌器的端部漏磁明显小很多。磁感应强度沿z轴的变化相对比较平缓,仅在线圈端部约225mm处出现一个较小的峰值,而后陡降,其分布呈"悬崖"状。

A numerical simulation and experimental measurement were adopted to research the lumen magnetic field and brow leakage of salient pole type and toroidal iron core mould electromagnetic stirring system （M-EMS） with the same core height and ampere-turns. The comparison shows that the simulated results conform basically with the experimental data. At the inner center of M-EMS along the casting direction （along the z-axis）, the variation trend of magnetic flux density was accordant between the salient pole type M-EMS and toroidal M-EMS. Both of them changed gently along the z-axis. While closing the iron core of M-EMS, the distribution of magnetic flux density along the z-axis in the salient pole type M-EMS was increased firstly, reached the peak value at the end of the iron core with a distance of 150mm to the central plan of EMS, and then decreased sharply. The distribution trends was like the ＂peaks＂. The closer to the core surface of EMS, the more obvious magnetic field distribution trend of brow leakage can be seen. Compared to the salient pole type M-EMS, the brow leakage of the toroidal M-EMS was significantly smaller. The distribution of magnetic flux density changed gently along the z-axis, only displayed a smaller peak at the end of the coil with the distance about 225 mm, then suddenly reduced and its distribution was like the ＂cliff＂.