Abstract:

To investigate the gas-liquid flow dynamics in net foam generators, this study employed an Eulerian two-fluid model coupled with the standard k-ε turbulence model to simulate the flow characteristics and mixing behavior. The gas-liquid mixing was quantitatively evaluated through two key parameters of foaming volume and foaming multiple. The impacts of critical factors such as gas flow rate, liquid flow rate, and net size on liquid phase distribution, foaming volume, and foaming multiple were investigated. The results indicated that both the average foam velocity u and the cross-sectional area S of the foam region at the outlet increased with the increase of gas flow rate, leading to enhanced foaming volume and multiple. While higher liquid flow rates increased foaming volume, it simultaneously reduced the foaming multiple, thereby affecting foam quality. The size of the net influenced the process in two ways: larger sizes hindered effective gas-liquid mixing, resulting in insufficient foaming, whereas smaller sizes increased fluid flow resistance, which was adverse to foaming efficiency. These findings suggested that optimal net selection should carefully balance foaming capacity with flow resistance to maximize overall system efficiency.

Key words: foam, mixing, gas-liquid flow, computational fluid dynamics, numerical simulation

摘要：

针对网式泡沫发生器内的气液两相流动问题，采用Eulerian双流体模型和标准k-ε湍流模型对网式发泡器中的气液两相流动及混合过程进行了模拟研究，采用发泡量和发泡倍数度量气液两相混合效果。数值模拟研究了气体流量、液体流量、发泡网孔径等影响因素对发泡器内的液相分布、发泡量和发泡倍数的影响。结果表明，气体流量的增加使出口处泡沫的平均速度u和泡沫区域的截面积S增大，从而使发泡量和发泡倍数增大；提高液体流量虽有利于提高发泡量，但是会使发泡倍数降低，从而影响泡沫质量。发泡网孔径的影响主要体现在两个方面：一方面，孔径较大时，气液在发泡网处难以混合产生泡沫，发泡量过低；另一方面，而孔径太小则会导致流体流动阻力增加，不利于发泡产生。因此，发泡网孔径的选择应综合考虑发泡量和流体流动阻力，加以合理优化。

关键词: 泡沫, 混合, 气液两相流, 计算流体力学, 数值模拟