(259a) Laminar Flow Pattern and Heat Transfer in a Vessel With Eccentrically Positioned Multiple Inclined Blade Impellers

The laminar flow pattern and the heat transfer from vessel wall to liquid in a vessel provided with three inclined blade impellers mounted on a single vertical shaft have been studied computationally. The axis with the three impellers is at an eccentric position and the flow is certainly laminar due to the high viscosity of the liquid.
The Computational Fluid Dynamics (CFD) simulations have been carried out with the help of the commercial flow solver ANSYS 14.5.  Over 420,000 grid cells were used, almost 170,000 of which were in the impeller zone. To accommodate the revolving impeller, two options have been explored: the Multiple Reference Frame (MRF) option as well as the Sliding Mesh (SM) option, the former resulting in a steady-state solver while the latter is transient.
The flow patterns found with these two options are very different: only the SM option predicts a single circulation over the full vessel height in the part of the vessel opposite to the impeller position. Of course, the heat transfer from vessel wall to highly viscous liquid strongly depends on the flow pattern.