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.