简化铝电解槽运动界面的磁场断层成像

Magnetic Field Tomographic Imaging of Moving Interface of Simplified Aluminum Reduction Cell

铝电解槽的界面运动影响了槽内的电流密度分布,对电解铝的电流效率造成了不利影响.但是,到目前为止,在高温条件下,还没有有效方法用以测量铝液界面运动情况.本文采用磁场断层成像技术,通过设计环形传感器阵列测量系统,对电解槽周围的磁场扰动进行了测量.同时,采用CCD相机对界面的位移进行了观测,并根据毕奥-萨伐尔定律对磁场分布进行了计算.结果表明,在频率为9.4Hz的周期性竖直振动下,液态铝界面产生法拉第不稳定性,以4.7Hz的频率起伏振动.在此情况下,由16个二维磁通门传感器组成的环形传感器阵列能够精确测量界面位移对磁场的扰动,考虑到计算仅采用了一个主要的界面模式,与计算结果相比,标准偏差在16%左右,计算结果与测量值定量符合.

The interface movements in aluminum reduction cells influence the distribution of the electrical current density,resulting in adverse effect on the electrical current efficiency.However,up to now,there has been no effective approach to measuring the interface movements.In this paper,a circular magnetic sensor array is designed based on the magnetic field tomography to measure the magnetic field disturbance around a simplified aluminum reduction cell.Besides,a CCD camera is used to measure the interface displacement and the field distribution is calculated by the Biot-Savart Law.It is found that Faraday instability at 4.7 Hz is generated when a vertical vibration with a frequency of 9.4 Hz is imposed.In this case,the circular sensor-array consisting of 16 Fluxgate sensors can effectively measure the magnetic field disturbance.With one main interface mode 21 adopted in the calculation,the standard deviation is about 16% compared with the result obtained by calculation,so the computation result agrees with the experimental results.