This paper was produced for the 2019 NAFEMS World Congress in Quebec Canada
In the chemical, food, process and pharmaceutical industries, large tanks are filled, mixed, emptied, and refilled with various products many times per day. Prior to refilling the tank with new product, manufacturers must ensure the previous batch residue is completely removed from the tank’s internal surface, as not to affect subsequent product quality. A clean-in-place (or, CIP) system is the typical procedure used to clean a tank after use and before product changeover. The process involves installing a dynamic nozzle system, in which water or cleaning solution jets from the nozzle and forces the nozzle to spin along two axes. This nozzle motion and the jetting water/solution form a lattice of track marks within the tank, which eventually overlap to clean the tank’s interior. However, to obtain a fully cleaned surface optimally, operating parameters must be controlled. Computational Fluid Dynamics can help in optimizing these operating conditions.
Due to the large variation in length scales (nozzle vs. tank) and time scales (jet flow vs. tank surface coverage) two modeling approaches will be presented. The first approach, tank level, will highlight how the complex nozzle motion (combination of spinning and orbiting motion) can be controlled to affect the coverage. A Lagrangian particle tracking approach (Discrete Phase Model or DPM) will be used to model this process. The second modeling approach, jet level, will focus on the details of the individual jets to accurately predict the impinging force on the mixing tank surface. A detailed Eulerian (Volume of Fluid or VOF) approach will be used to model the details of the jet.