The investigation of transient reactive bubbly flow simulation data offers a variety of data mining challenges due to the interaction of mass transfer, hydrodynamic and local concentration. Modern visualization techniques for Euler–Euler based multiphase simulations are used to study the hydrodynamic influence on the reactive mass transfer in a cylindrical bubble column at transient conditions, as it is given during start up of the column. We apply a recently new bubble sampling approach to study the bubble dynamics. The approach is able to conserve the number of bubbles, volume of bubbles and shape of bubbles, while an overlapping of bubbles is avoided. The performed streamline investigations of the continuous phase allow for an investigation of the transient movement of the continuous phase at column start up condition. Especially at different volumetric flow rates, the lambda2 criterion is an appropriate tool to identify mixing effects. With the use of ensemble visualization, different transient cases can be compared. For the investigated bubble sizes, it could be shown that the main difference in contact of bubbles with liquid elements is close to the inlet.