Euler-Euler simulation of a bubble column flow up to high gas fraction

•Gas-liquid flow in a bubble column up to high gas fraction is simulated in OpenFOAM.•Established baseline model performs well without swarm corrector up to∼20% gas holdup.•Available expressions for the swarm corrector are not suited for the present application.•Due to the direction of lift force the flow becomes inhomogeneous for larger bubbles.•Suppression of bubble wakes promotes instability but does not affect gas holdup.•Beyond 67% gas holdup, homogeneous flow is impossible because of flooding. This study investigates homogeneous flow in a bubble column up to 50% gas holdup. For low to medium gas holdup below ∼20%, the good performance of an established baseline model is confirmed. In this range, the mixture pressure gradient is decisive in determining the relative velocity, resulting in good predictions without considering swarm effects. However, beyond a gas holdup of ∼20%, a swarm corrector to the drag force becomes necessary, for which several proposals from the literature are evaluated. In addition, the lift force influences the shape of the gas fraction profile depending on the bubble size, which has a significant impact on the liquid flow inside the column. For wall-peaked profiles, the liquid flow remains moderate, while center-peaked profiles strongly boost the liquid velocity. Finally, several mechanisms proposed in the literature for inducing unstable flow based on the lift force, bubble-induced turbulence or flooding are investigated. Of these only the first gave qualitative agreement with the observed gas holdup.