气泡在液体中生成的试验及模拟

Experimentation and numerical simulation of bubble generation in liquid

为系统地研究鼓泡塔反应器内气泡生成的过程,利用高速摄影技术对不同气速下气泡的生成过程进行试验研究。在验证模拟可行性的基础上,运用Fluent 15.0软件模拟计算了气泡剥离时的大小、单个气泡形成所用的时间以及气泡上升过程中的轨迹变化,同时考察了气速、黏度等因素对气泡生成的影响,分析了气泡由形成到上升的全过程。研究结果表明,进气速率越大,气泡生成的频率越快。液相黏度与气泡接近标准球形的程度正相关,气液表面张力与所产生的气泡体积、脱离后维持形状的能力正相关,张力越小气泡越容易破碎。

To study systematically the process of bubble generation in the bubbling tower,the experimentation was conducted by using high-speed photography technology with the different gas velocities.Then,Fluent 15.0 was used to simulate the process and calculate the size of the bubbles separated from the inlet,the time of generating a single bubble,and the trajectory of bubbles during rising process.Simultaneously,considering the influences of gas velocity and viscosity,the whole process from generation to rise was analyzed.Results show that the faster the rate of air intake is,the faster the frequency of bubble formation is;the degree that the bubbles are similar to the standard sphere increases with the liquid viscosity.Moreover,the smaller gas-liquid surface tension indicates the smaller bubble volume,the weaker ability to keep the shape after separating and the more possible bubbles to break.