锌电解槽内气液两相流动的数值模拟

应用FLUENT软件,分别对单组阴阳极、多组阴阳极锌电解槽中的电解液流动进行了数值模拟研究.针对单组阴阳极间的电解液,基于气泡产生及运动的机理计算出单个气泡在静止电解液中的上浮速度为0.017 m/s.气液两相流数值模拟结果表明:在气泡的作用下,电解液沿阳极板向上运动,沿阴极板向下运动,形成一个大的循环;而气泡群上浮的平均速度约为0.021 m/s,与文献实验数据相吻合.针对实际生产中多组阴阳极锌电解槽,气液两相流数值模拟结果表明:在气泡上浮曳力和电解液进出口压差驱动的共同作用下,电解液的运动态势与单组阴阳极仅考虑气泡曳力作用时的状况相同,极间电解液平均流速是无气泡作用时的1.5倍左右,这将有利于加快极板附近电解液的更新,延缓锌离子的贫化.

Numerical Simulation of Gas-Liquid Two-Phase Flow in Zinc Electrowinning

The gas-liquid two-phase flows in zinc electrolytic cells with single plate and multiple plates were respectively numerically simulated with the commercial software of FLUENT. Based on the mechanism of the generation and movement of oxygen bubbles， the rising velocity of a single bubble was calculated. The results indicate that the rising velocity is 0.017m/s. With the effect of bubbles from the anode， the electrolyte near the anode flows upward and oppositely flows downward near the cathodes， forming a large recirculation zone in the cell. The average velocity of bubble cluster is 0.021m/s， which is consistent with the experimental data from the literature. In practical operation， with the joint action of the differential pressure and the bubble drag force， the recirculation of electrolyte flow can be enhanced remarkably. The average velocity of interelectrode fluid is 1.5 times higher than that under the bubble-free condition. This phenomenon indicates that the bubble movement can promote the refreshing of zinc electrolyte and restrain the dilution of zinc ions.