CFD Simulation of Oil Dispersions in Vertical Upflows Used in Deepwater Oil Spills

Deepwater oil spill due to leakage or accident in oil transportation pipelines is one of the important issues from environmental aspect. Recently as a result of increase number of such accidents the study of oil dispersion in vertical up-flows received high attention in academic research centers. Immiscible liquid dispersions are also widely used in chemical process; petroleum industries, polymerization, heterogeneous chemical synthesis etc. are usual examples. In most of these chemical processes, the rate of interphase heat & mass transfer is known to strongly affect the overall performance and depends on the interfacial contact area between the phases. This study at 3D dynamic CFD simulations of immiscible liquid dispersion has been performed on a vertical pipe. With specific reference to dispersed liquid-liquid flows, it is seen that the two-fluid approach (Eulerian-Eulerian approach) is extensively used for multiphase modeling, especially when detailed predictions are desirable over a range of holdups in exchange for a reasonable amount of computation power. The results of CFD predictions have been compared with the experiments of Farrar and Bruun (1996) and Al-Deen and Bruun (1997). These simulations have also been done to understand the effect of various significant forces in turbulent liquid dispersions (drag, lift, turbulent dispersion and added mass). Several expressions for these forces were tested in order to choose the best combination. Further, the problem has been simulated using different turbulence model (kappa-epsilon, RSM and...). It has been found that lift force is more important than turbulent dispersion and added mass. Interphase closure guidelines for liquid-liquid bubbly flows were developed based on simulation results that yielded the best agreement with experimental data. Extend of this study to the open and unconfined space could be applied to the CFD simulation of plume formation and it is dynamic in oil rising in deepwater oil leakage of transportation pipeline.