Dynamics of particles in a vortex separator (VS) modeled by dissipative hydrodynamics (DHD) and computational fluid dynamics (CFD) simulations

Albert S. Kim, Hyun Ah Son, Sungsu Lee, and Hyeon Ju Kim
Civil and Environmental Engineering, University of Hawaii at Manoa, United States

Keywords: Vortex separator, cyclone-separator, coaxial-flow, dissipative hydrodynamics, computational fluid dynamics

Microscopic behavior of multi-particles in a complex flow field is simulated using the dissipative hydrodynamics. A standard coaxial cylinder is used as a model vortex separator. The velocity field inside the coaxial cylinder is independently calculated using commercial CFD software, FLUENT, and perturbation theories. In seawater, particles have spherical shapes of various sizes on the order of 10 microns to 10 mm, and undergo linear and angular motion in the ambient flow. Each particle has 11 degrees of freedom: 6 for translation and rotation, and 5 for symmetric traceless stresslet. Due to the large particle sizes, Brownian motion is readily discarded in DHD simulations so that the Langevin equation is used as a governing equation and integrated with respect to time to calculate translational/rotational positions and velocities of all the particles. This research suggests a fundamental methodology for dynamic simulations of many particles in macroscopically complex flow fields by seamlessly linking DHD and CFD; and, more importantly, provides in-depth understanding of the dynamic behavior of particles at the microscopic level. A series of DHD/CFD simulation results can be statistically analyzed to suggest optimal geometric designs and operational conditions.

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