| As a separation equipment liquid-liquid hydrocyclone is widely used in petroleum industry, marine industry, water treatment industry. The hydrocyclone is rotating around the axis of itself,as it is used in some certain condition, such as when the hydrocyclone is used with screw pump in downhole water-oil separation process, the hydrocyclone rotates with the rotor of screw pump. The axial rotating hydrocyclone is studied based on this problem in this paper.The structure of hydrocyclone is simple, but the flow and separation process are relatively complex. Main separation zone is the diametervariable circular tube where the flow is not only the typical multiphase flow but also strong spin flow with backflow. If it ratates around its axis, the internal flow field will become more complex. Which have with both flow characteristics of traditional hydrocyclone and rotating pipe, the distribution of velocity, pressure and turbulent kinetic energy in hydrocyclone can be all vary, and the oil droplets migration and separating efficiency are effected, owing to the coupling effect of the spiral flow of conservation of angular momentum and the wall rotation during operation. Numerical simulation technology is an effective method to investigate the eddy flow properties of internal flow field, turbulence properties and the oil droplets trajectories of migration. It has been widely used in flow field study of hydrocyclone and achieved good effect.Based on two-phase flow and turbulence theory, the numerical calculation model of liquid-liquid two-phase flow in aixial rotating hydrocyclone is founded in whirl cylindrical coordinate system. Reasonable advection dispersion of discrete format, pressure-velocity coupled method and liquid-liquid two-phase towing function are determined. The internal three-dimensional flow field of 28mmThew hydrocyclone is studied by numerical simulation based on boundary layer theory and unequilibrium wall function method. In-depth study is done to the eddy flow characteristics and two-phase separation characteristics of internal flow field. The influence of variation of operating parameters such as speed, flux and split ratio on velocity distribution, pressure drop and separation characteristics, and compare the results of static and rotation wall. Study on the influence of operation parameters, such as rotating speed, flux and split radio, on both internal velocity, pressure and separation efficiency, and receive the evolution. Use of mathematical methods, the tangential velocity, axial velocity and pressure and flow relationships obtained by numerical simulation is fit to the curves under different rotating speed.Although numerical simulation has many advantages, experimental study is reliable method to examine the numerical simulation results. The aixial rotating hydrocyclone experiment system is founded and the oil-water separation experiment is done and pressure drop and separating efficiency are obtained. Through analysis of the experimental data by the statistical analysis method, the primary and secondary factors influencing separation efficiency are obtained. The systematic evaluation on structure separation performance and energy losses is achieved.The experiment the pressure drop and separation efficiency data obtained by numerical simulation were compared to test data, and the reliability of numerical simulation results is verified.To sum up, through numerical simulation and experimental research method, the high swirling turbulent flow, two-phase separation characteristics and structure of energy loss are studied, the results of static wall were compared to the results of rotating wall, and then the internal flow characteristics are forecasted and evaluated. The study results can provide the reference for application of liquid-liquid hydrocyclone under rotation conditions, expand application range of hydrocyclone separation technology basic theory, simultaneously it can be used as basic research for flow rules in the similar fluid machinery. |
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