  Bubbly flows, as present in bubble column reactors, can be simulated using a
variety of simulation techniques. In order to gain high resolution CFD methods
are used to simulate a pseudo 2D bubble column using EL and EE techniques. The
forces on bubble dynamics are solved within open access software OpenFOAM with
bubble interactions computed via Monte Carlo methods. The estimated bubble size
distribution and the predicted hold-up are compared to experimental data and
other simulative work using EE approach and show reasonable consensus for both.
Benchmarks with state of the art EE simulations shows that the EL approach is
advantageous if the bubble number stays at a certain level, as the EL approach
scales linearly with the number of bubbles simulated. Therefore, different
computational meshes have been used to also account for influence of the
resolution quality. The EL approach indicated faster solution for all realistic
cases, only deliberate decrease of coalescence rates could push CPU time to the
limits. Critical bubble number - when EE becomes advantageous over the EL
approach - was estimated to be 40.000 in this particular case.
