Abstract:

A novel approach, laser induced fluorescence(LIF)technique, is proposed to visualize gas-liquid mass transfer and reaction in this work.The principle is to quantitatively capture the change of fluorescence signal intensity in liquid phase emitted by a fluorescence dye(e.g., Rhodamine B), where the concentration of the dye varies with time and space due to a coupled reaction by ozone in gas phase.The reaction process inside the liquid phase(droplet in this work)can be recorded, integrating the process of gas-liquid mass transfer and liquid-phase reaction.The experiment illustrated various micromixing behavior characterized by the concentration field inside the droplet under different environmental conditions, such as uniform gas flow with little disturbance and non-uniform gas flow with certain disturbance on the droplet, and the growing process of droplet.The straightforward visualization measurements improved the understanding on the mechanisms of gas-liquid mass transfer and micromixing inside a droplet.

摘要：

提出了一种先进的可视化测量气液传质和反应的激光诱导荧光技术，其基本原理为利用气相中的臭氧氧化液相中的荧光物质，使用相机定量地捕捉液相中荧光物质（如罗丹明B）发出的荧光信号强度的动态变化，从而记录了气液的传质和反应过程。实验结果通过液相浓度场信息展示了液滴内部丰富的微观混合行为，尤其传递和反应行为敏感于液滴周围环境条件，如微小扰动的均匀流场、扰动强化的非均匀流场和液滴尺寸动态生长过程。直观的可视化测量方法提高了对气液传质和液滴内微观混合行为机理的理解。