Evolution of melt convection in a liquid metal driven by a pulsed electric current  

作　　者：Yanyi Xu Yunhu Zhang Tianqing Zheng Yongyong Gong Changjiang Song Hongxing Zheng Qijie Zhai 徐燕祎;张云虎;郑天晴;龚永勇;宋长江;郑红星;翟启杰(Center for Advanced Solidification Technology,Shanghai University,Shanghai 200072,China;College of Science,Shanghai University,Shanghai 200444,China)

机构地区：[1]Center for Advanced Solidification Technology,Shanghai University,Shanghai 200072,China [2]College of Science,Shanghai University,Shanghai 200444,China

出　　处：《Chinese Physics B》2021年第8期424-432,共9页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.U1760204,51974183,52071194,and 52074180).

摘　　要：Gain refinement in metal alloy can be achieved by applying an electric current pulse(ECP)in solidification process.Forced flow inside the melt has been proved to be a key role in grain refinement.In this paper,the fluid flow inside Ga 20 wt%-In 12 wt%-Sn alloy induced by a damping sinusoidal ECP flowing through two parallel electrodes into the cylindrical melt was investigated by both experimental measurements and numerical simulations.Experimental results showed that a strong descending jet was induced beneath the bottom of electrodes under the application of ECP.Besides,it was found that flow intensity increases with the increase of amplitude,frequency,and pulse width,respectively.In order to unlock the formation mechanism of flow pattern and the relevance of flow intensity varied with electrical parameters,a three-dimensional numerical model under the application of ECP was established.Meanwhile,a comparative study was conducted by numerical simulations to reveal the distributions of electromagnetic fields and forced flow.Numerical results showed that the downward Lorentz force induced by ECP was concentrated beneath the bottom of electrodes.This downward Lorentz force induces a descending jet and provokes a global forced flow.According to numerical simulations,the evolution of flow intensity with electrical parameters under the application of ECP can be understood by the time averaged impulse of Lorentz force.

关 键 词：pulsed electric current flow measurement numerical simulation MAGNETOHYDRODYNAMICS 

分 类 号：O361.3[理学—流体力学]