The Numerical Simulation And Analysis On Separation Performance Of Vertical Oil-Water Separator In Ship

In the constraints of ship cabin space, the actual use of oil-water separation devices on the ship mostly is a combination method of vertical gravity and coalescence. The small handing capacity, low efficiency and other factors limit the use of oil-water separator on ship. So it is necessary to make research on improving the handing capacity and separation efficiency of the equipment.This thesis selects the CYF-B marine vertical oil-water separator as the original object of the study, and simplifies the structure of some components to establish suitable geometric model for the solver to calculate. First, substituting the oil-water mixed phase by single-phase of water to simulate the internal flow field distribution of separation installed inlet components, steady-flow component and both of them; Secondly, using the method of control variables and the Mixture Phase Model to simulate the influencing factors of oil-water separator’s efficiency; Finally, the inlet components, the steady-flow component and the outlet position has been optimized, what’s more, this thesis simulates the particles’trajectory in the separator under Lagrangian coordinate system by adjusting the geometric model and meshing scheme of the oil-water separator and using the Species Transport Model and the Discrete Phase Model.The results of numerical simulation show that:(1) The inlet component can reduce the kinetic energy of the separation’s internal flow field, the steady-flow component can make uniform distribution of the velocity of the entire flow field. They can both reduce the kinetic energy and make uniform distribution of the velocity of the flow field when they act on the separator at the same time;(2) Factors affecting the efficiency of oil-water separator contains:separator’s handling capacity, operating temperature, the discrepancy of density between oil and water, the particles’diameter and the viscosity of the oil, the impact of these factors on the separator’s efficiency isn’t linear, there is a optimal value to make the coordination between the influencing factors and the separation efficiency to be all right;(3) The flow of the fluid becomes more stable and the vortex in the flow field is inhibited when the oil-outlet is put into the left side of the upper part of the separator. And the inlet component of the separator should be placed horizontally if there’s no special requirements. The distance between the two plates should be keep about24mm when double steady-flow component is installed;(4) The particles’ trajectory in the separator is chaotic, and the most important influencing factors is the situation of the flow field inside separator which plays a decisive role in affecting the particles’trajectory and residence time in separator.The compare between numerical simulation results and real experimental data proved the correctness of the oil-water separator’s geometry and computational model established in the thesis, so the simulation results in the thesis make some guiding sense in improving the efficiency and the optimization of the separator.