Computational Fluid Dynamic Study of Mixing In Large Scale Diesel Storage Vessels

Appropriate mixing in diesel storage vessels guarantees homogeneity in the final product, preventing the production of off-specification fuels caused by inadequate homogenization in the storage equipments.   Nowadays, Computational Fluid Dynamics has been widely used in the industry to model mixing processes to investigate mixing properties and to perform an eventual process optimization, especially in large scale mixing tanks where experimental work is difficult and expensive. Additionally, good agreement between experimental and CFD-predicted results has been found in literature.

In this work, the CFD technique is used to simulate the hydrodynamic behavior of a current diesel storage tank  located in a Brazilian refinery.  The commercial package ANSYS 12.1 is used to perform the simulations. The Multiple Frames of Reference (MFR) approach is used to model the mixer movement. The turbulence effects are incorporated by means of the Shear Stress Transport (SST) turbulence model. The velocity distribution inside the vessel for two several mixer  layouts was investigated by varying the offset angle from the tank center line. The simulation results obtained for the evaluated scenarios were compared and are in good agreement with the information found in literature for this kind of equipments.