Numerical Simulation Of The Gas-injected Liquid-liquid Hydrocyclone

Gas-injected liquid-liquid hydrocyclone, a new kind of high efficient centrifugal separation equipment. It has many advantage, such as compact structure, large capacity and high floatation speed. So it has been widely used in many industries.By selecting the RSM model and mixture model combining with discrete phase model of FLUENT applications, the CFD analysis on Gas-injected liquid-liquid hydrocyclone were performed. The influent of main operating parameters such as split ratio, aeration rate and the oil droplet size to the distribution of velocity, pressure and oil concentration in flow field, and to the separation efficiency have been analysis in detail. By comparing the experimental values with the numerical ones, there's a little errors between the simulated and experimental values, but not more than 5%, so selected model is correct and feasible.Through calculating the trajectories of the oil droplets while the gas injected into the liquid-liquid hydrocyclone, it shows that the time of oil droplets escapeing out of the hydrocyclone was shorten, due to the effect of the tiny bubble, separating the oil droplets from the water will be quick. Under the same working conditions, Gas-injected liquid-liquid hydrocyclone has higher efficiency of oil-water separator, the separation efficiency can reach 95%, that increased 5% to 8% when compared with no gas injection.In this paper, the discrete phase model was used to simulate the oil droplets motion, which takes account of and particle collisions and breakage in liquid-liquid hydrocyclones. The calculate results was compared with those obtained form model no particle collisions and breakage, the results coming from collision and broken are more consistent with the practical, so the calculation results were acceptable.Therefore, these results will provide great help for research of Gas-injected liquid-liquid hydrocyclone.