Momentum source to model mixer
 

Hello All,
I am modeling mixing of oil and water in a tank with a mixer mounted on the tank wall. I want to see using CFD if the mixer is doing its job to keep the oil in suspension form and not letting it to form a separate layer at the top. I am solving transient simulation using VOF multiphase model. To model the free surface of oil/water mixture, I used symmetry BC. To avaoid the complications in meshing, I am modeling mixer as cylindrical fluid zone with MRF to model its rotation and specifying momentum source to model the thrust produced. I want to know if this is the correct approach to model the mixer. I want to avoid sliding mesh and complicated mixer blade geometry. Please let me know your input. Thanks.