Aerated Stirred Tank
The stirred tank is the workhorse of the chemical industry. Thus the ability to simulate the flow and furthermore to simulate reactions is of importance. In order to deepen our understanding of two-phase Eulerian flow simulation with OpenFOAM we engaged in a validation study of the flow within a stirred tank.
The geometry we used is widely used in research, so there is plenty of literature and published results available for validation. The flow within the stirred tank was investigated with respect to single phase flow (nonaerated tank) and two-phase flow (aerated tank).
Below we see the mesh of the stirred tank. The stator has four baffles and the Rushton turbine has six blades.
Seen below there is a regime map based on [LeeDudukovic]. The regime transition can be estimated with the Flow number (Fl) and the Froude number (Fr). The three general flow regimes of an aerated stirred tank are flooding, loading and recirculating regime. The red arrows in the sketch of the regimes are the bubble trajectories. Our simulations match quite well with the predicted regimes.
[LeeDudukovic] B. W. Lee and M. P. Dudukovic. Determination of flow regime and gas holdup in gas-liquid stirred tanks. Chemical Engineering Science, 109:264–275, 2014.
(Gerhard Holzinger, Supervision: Stefan Pirker)