垂直平板电极电化学除垢的气-液流动研究

为研究电化学除垢方法中垂直平板电极反应器的气-液流动特性及其对除垢的影响规律,利用粒子图像测速技术分别研究了电解电压和溶液硬度的变化对垂直平板电极间流场的影响。实验结果表明:垂直平板电极间的流动主要分为气泡上浮推动溶液流动形成的气泡驱动对流和电极周围的高空隙率引起溶液向电极流动的自然对流。在0~30 V的电压下产生的气泡驱动对流的速度不超过0.01 m/s,自然对流的最大速度不超过0.001 5 m/s。流场内溶液对流主要受气泡运动的影响,适当增大电极板产生的气泡量可以强化气泡驱动对流,但过量的气泡聚集在极板周围会减弱气泡驱动对流强度,增大溶液电阻,不利于污垢从溶液中分离。这对于探索反应器中的气-液两相流行为以及优化电化学除垢方法有重要意义。

Gas-Liquid Flow of Electrochemical Descaling with Vertical Plate Electrode

In order to study the gas-liquid flow characteristics of the vertical plate electrode reactor in the electrochemical descaling method and its influence on descaling, the particle image velocimetry technique was used to study the influence of the electrolytic voltage and solution hardness on the flow field between vertical plate electrodes. The experimental results show that the flow between the vertical plate electrodes is mainly divided into the bubble-driven convection and the natural convection. The former convection is formed by the floating of air bubbles. The latter convection is caused by the high porosity around the electrode, which leads to the solution flowing to the electrode. The velocity of bubble-driven convection generated at low voltage of 0 -30 V does not exceed 0.01 m/s, and the maximum speed of natural convection does not exceed 0.001 5 m/s. The convection of the solution in the flow field is mainly affected by the movement of bubbles. Increasing the amount of bubbles generated by the electrode plate appropriately can strengthen the bubble-driven convection, but the accumulation of excessive bubbles around the electrode plate will weaken the strength of the bubble-driven convection. Additionally, increasing the resistance of the solution will make the dirt difficult to be separated from the solution. The above findings are of great significance for exploring the gas-liquid two-phase flow behavior of the reactor and helpful for optimizing the electrochemical descaling method.