Cyclohexane/water dispersion behaviour in a stirred batch vessel experimentally and with CFD simulation

Cyclohexane/water dispersion behaviour is studied in a stirred batch vessel with rushton turbine impeller (RTI), experimentally and with computational fluid dynamic (CFD) simulation. The axial and radial holdup profiles and distribution of cyclohexane in the whole vessel are measured by using the sampling withdrawal method from different positions in the vessel at different stirrer velocities. The minimum stirrer velocity to get a complete dispersion and a uniform distribution of cyclohexane in water is also determined. The dispersion behaviour of cyclohexane in water is visualized by using a video camera and a red color tracer. Steady 3-dimensional simulations with Eulerian-Eulerian multi-fluid model are used to calculate the dispersion behaviour and the volumetric fractions of cyclohexane in the vessel by using ICEM CFD and Ansys CFX-11. The two equations k−ε turbulent model is included to calculate the velocity flow field. The interphase momentum transfer and the drag forces between the continuous and dispersed phases are calculated by using algebraic slip mixture (ASM) and Ishii-Zuber models. Sliding mesh model is used to model the interaction between the rotating impeller and the vessel walls. The effect of grid size on the calculations is studied. A good agreement between the predicted CFD and the experimental data is obtained.