(625g) Transient CFD Simulation of Two-Phase Liquid-Liquid Flow in an Oscillatory Baffled Reactor

Authors: 
Zhang, M., Tianjin University
Liu, C., Tianjin University
Fu, C., Tianjin University


Oscillatory baffled reactor is a new type of chemical process intensification equipment. Periodic vortex is generated in the reactor due to its constricted baffle geometry and periodic oscillatory condition, which provide both axial and radial mixing in the reactor, increase the interface area of immiscible two-phase, improve the residence time distribution of dispersed phased, and control particle size and its distribution.

    In the present work, a combination of computational fluid dynamics(CFD) and population balance model(PBM) was applied to study the effect of oscillatory condition (the oscillation amplitude and the frequency), baffle orifice ratio and baffle spacing on the flow field and mass transfer characteristics in an oscillatory baffled reactor.

    The results showed that, the average velocity increased linearly with the increase of oscillatory Reynolds number in one oscillatory cycle, the oscillatory condition had little effect on the volume distribution of dispersed phase. Both the drop size and size distribution greatly decreased with the increase of oscillatory Reynolds number. A correlation between sauter mean diameter, , and the energy dissipation was established  as . The results also indicated that the oscillation amplititude had more influence on the flow filed and droplet size distribution than the oscillatory frequency.

    The effect of baffle orifice of 0.21, 0.25, 0.31 and baffle spacing of 1.0D (D, the reactor diameter), 1.5D, 2.0D on the flow field and drop size distribution was investigated respectively. The optimal baffle orifice was 0.25 and the optimal baffle spacing was 1.5D. Not only the information of the effect of oscillatory condition and geometry on the two-phase flow filed and mass transfer characteristics were obtained by the simulation, but also the results provide a theoretical basis for reactor design and geometry structure improvement.