Study On Numerical Simulation Of Separation Process And Droplets Breakage In Hydrocyclones For Oil-water Separation

The hydrocyclone for oil-water separation is a kind of separators widely used inpetrochemical industry. Droplet breakage in the hydrocyclone，which will reduce theseparation efficiency, has attracted broad attention of academia. It is one of the bottlenecksthat should be solved in the development and popularization of oil-water hydrocyclones, soit is of great theoretical and practical importance.Firstly， theory of the separation force within the single-droplet was analyzed. Themechanism and mathematical model of droplet breakage in turbulent flow were alsosummarized.The thesis focused on the use of the Reynolds stress model RSM and Mixture modelto simulate the internal oil phase concentration distribution volume in the hydrocyclone foroil-water separation when the particle size of oil droplets were5μm,10μm,20μm,30μm,40μm,50μm and60μm. The influence of droplet size on the separation efficiency and otherparameters were studied, and the paper’s existing experimental data were compared toverify the consistency of the simulated results. The law of the experimental results andsimulation results are consistent, namely the separation efficiency increases with theincrease of import oil droplets size. The velocity distribution, pressure distribution andturbulent kinetic energy distribution were also analyzed in the hydrocyclone for oil-waterseparation.On the basis of the numerical simulation for the two-phase turbulent flow field, the k-εturbulence model and the volume of fluid model (VOF) were adopt to simulate the crushingprocess of the dispersed droplets. A90°arc channel was chosen to approximate the innerflow field, and the factors affecting droplet breakage were studied. The initial velocity anddiameter of droplet as a geometric factor were selected to analyze the impact of thefragmentation process, as well as two dimensionless parameters. It was found that theWeber number of droplets play a catalytic role, the greater the Weber number was, the easier the droplets are likely broke; while the Reynolds number play a disincentive role fordroplet breakage, the greater the Reynolds was, the droplets are less likely to break. Finally,breakage Angle expressions were gotten by dimensional analysis of the parameter ondroplets broken.