Baseline model for monodispersed bubbly flows: A code comparison

CFD simulations of dispersed bubbly flow on the scale of technical equipment are feasible within the Eulerian two-fluid framework of interpenetrating continua. However, accurate numerical predictions depend on suitable closure models. A large body of work using different closure relations of varying degree of sophistication exists, but no complete, reliable, and robust formulation has been achieved so far.
An attempt has been made to collect the best available description for the aspects known to be relevant for adiabatic monodisperse bubbly flows, where closure is required for (i) the exchange of momentum between liquid and gas phases, (ii) the effects of the dispersed bubbles on the turbulence of the liquid carrier phase. Apart from interest in its own right, results obtained for this restricted problem also provide a good starting point for the investigation of more complex situations including bubble coalescence and breakup, heat and mass transport, and possibly phase change or chemical reactions.
The resulting model was previously validated by comparing simulations using ANSYS-CFX with experimental data for a number of test cases comprising vertical upward pipe flows and bubble columns. Here, the exact same model (within the limits of what is known about ANSYS-CFX) has been implemented in OpenFOAM v2.2 based on the twoPhaseEulerFoam solver. In this way a comparison becomes possible also between two different numerical approaches.
Both codes are able to reproduce the experimental data with similar quality but differences between the results of both simulation are not negligible. A discussion of possible reasons is given.