3. Results and discussion

ANSYS Fluent 3D pressure-based solver is employed in CFD-PBM modelling. The time step is set to be 0.001 s for all simulations, which is considered to be sufficient for illustrating the timeaveraged characteristics of the flow fields by carrying out the data-sampling statistics for typically 120 s after the quasi-steady state has been achieved. The improved breakup model is integrated into the simulations by using the user define function (UDF). At the inlet boundary, the volume fraction of gas phase is set to be 1. The treatment of the inlet velocity is different from using a constant superficial gas velocity, but a normally distributed velocity profile is applied by using the model proposed by Shi et al. [25], which can accurately reflect the experimental conditions employed in the study by Camarasa et al. [24]. Further information

Figure 5. Comparison of the simulated gas holdup profile to the data reported in Camarasa et al. [24] with three different

Figure 4. Horizontal cross section and front view of the mesh setup for the main body of the bubble column.

76 Heat and Mass Transfer - Advances in Modelling and Experimental Study for Industrial Applications

grid configurations.
