Simulation of the Effect of Atmospheric Pressure on the Performance of Laboratory Two-Stage Dense Medium Separator

The effects of atmospheric pressure of the site of installation of a centrifugal two-stage heavy medium separator is of crucial importance because the pressure difference between the medium input and the sink output streams is adjusted by the back pressure rings. However, contrary to the dense medium cyclone, the raw feed ore into this separator is sluiced without pumping.  In this research, the effect of atmospheric pressure on the flow pattern inside the Tri-Flo separator is investigated using the computaional fluid dynamic (CFD) simulation. Therefore, the volume of fluid (VOF) model and discrete phase model (DPM) were used for the calculation of the diameter of the air core and the behavior of solid particles, respectively. Reynols stress model (RSM) was used for turbulence modeling. Simulations were performed in three different atmospheric pressure including 1, 0.86 and 0.64 atm, representing the site of installation at sea level and heights of 1250 meters and 3500 meters above the sea level, respectively. The CFD simulation results showed that the change in atmospheric pressure has some effects on the flow fields, macroscopic parameters and the performance of the Tri-Flo separator. The results of simulation were validated against the experimental data achived using the transparent laboratort Tri-Flo separator. The fluid velocity in output streams and the size and the pattern of air core were used for validation. The decrease in Ecart propale error (Ep) of the separator and increase in the medium recovery were observed, when the atmospheric pressure was decreased. However, the effects were in the margin of 2%. According to the results of this research, the Tri-Flo separator can be used in different elevations from the sea level, without serious problem in the operation regime.