Development of the bouble difusion augmentator of interface instability type by using an unsteady Lorentz force

对利用非定常洛伦兹力研制界面不稳定型熔融增强器进行了分析和实验，得出了以下结论：(1)在均匀水平交流磁场产生非定常洛伦兹力的情况下：1)在液态金属表面产生的不稳定波与交流磁场以相同的频率振荡；磁雷诺数Rm、斯图尔特数Np、韦伯数We和雷诺数Re是最不稳定的。iii)波矢与磁场平行的波是最不稳定的。iv)在韦伯数We和雷诺数Re都固定的情况下，随着磁雷诺数的减小，不稳定边界在欧玛-Np平面上向上移动，系统变得稳定；但交流磁场的频率与不稳定…的波数之间的关系当磁雷诺数Rm和雷诺数Re都固定时，不稳定边界在欧米伽-NP平面上向右移动，不稳定波的波数随着韦伯数的减小而减小。然而，交流磁场的频率和不稳定波的波数之间的关系几乎没有改变。即)交流磁场的频率变得更高，感应电流集中在自由表面附近，温度升高。(Ii)实际机器产生不稳定波需要较强的高频磁场。(2)在水平直流磁场和交流磁场同时作用下产生非定常洛伦兹力的情况：i)与交流磁场频率相同的波出现在液态金属表面。ii)产生最大幅度波的直流磁场的最佳强度存在，并随交流磁场的强度而变化不是关于磁场的分布，而是关于容器的形状。较少

Analyzes and experiments were conducted for the development of the bouble difusion augmentator of interface instability type by using an unsteady Lorentz force, and following conclusions were derived :(1) In the case that the unsteady Lorentz force is generated by uniform horizontal AC magnetic field :i) Unstable waves generated on the liquid metal surface oscillate in the same frequency as the AC magnetic field.ii) Unstable conditions are dependent on 4 parameters ; the magnetic Reynolds number Rm, the Stuart number Np, the weber number we , and the Reynolds number Re.iii) The waves which wave vector are parallel with the magnetic field are most unstable.iv) In the case that both the Weber number We and the Reynolds number Re are fixed at some values, unstable boundary moves upward in tha omega-Np plane with a decrease of the magnetic Reynolds number, and the system becomes stable ; however, the relation between the frequency of the AC magnetic field and the wave number of the unstabl … More e wave hardly changes.v) In the case that both the magnetic Reynolds number Rm and the Reynolds number are fixed at some values, unstable boundary moves to the right-hand side in the omega-Np plane and the wave number of the unstable wave decreases with a decrease of the Weber number.vi) In the case that both the magnetic Reynolds number Rm and the Weber number are fixed at some values, unstable boundary moves upward in the omega-Np plane ; however, the relation between the frequency of the AC magnetic field and the wave number of the unstable wave hardly changes.vii) The frequency of the AC magnetic field becomes higher, the induced electric current concentrate around the free surface and the temperature rises severely.viii) Relatively strong magnetic field with a high frequency are needed for the genaration of unstable waves in the actual machine.(2) In the case that the unsteady Lorentz force is generated by simulteneous imposition of horizontal DC and AC magnetic fields :i) The waves with the same frequency as the AC magnetic field appear on the liquid metal surface.ii) The optimum strength of the DC magnetic field that gives the waves of the largest amplitude exists and changes in value according to the strength of AC magnetic field.iii) The oscilation mode depends not on the distribution of the magnetic field but on the shape of the container. Less