[sr786]

Hello,

I am currently looking at modelling an unbaffled two phase (air-water) stirred tank reactor using a homogeneous eulerian-eulerian VOF method in FLUENT based on a case study from the literature (DOI:10.1021/ie051021a). I am solving using an implicit method and steady state solution (as opposed to transient and explicit) as the paper managed to model the reactor using steady state.

Other models/solver settings I am also using are: PISO solver for pressure-velocity coupling, standard k-epsilon, first order discretisation schemes for convective terms, PRESTO! for pressure; Modified HRIC for VOF.

When I ran the simulation for different flow speeds ranging (from a-e): 0 RPM, 100 RO, 140 RPM, 195 RPM, 240 RPM, I noticed that the depression of the vortex is too small (as can be seen from contours in ZX plane). Also from the isosurface contours, the air-water interface (for vortex) is wavy when typically in papers it is flat and I do not know why this is.

I have attached some images from my simulation results and the literature paper as a comparison and also my residuals plot (which to me appeared converged). I would appreciate any guidance as I am new to modelling stirred tank reactors.