Separation Mechanism And Characteristic Study On The Gas-liquid Cylindrical Cyclone

Focus on de-gassing of oilfield produced fluid,the structure of a gas-liquid cylindrical cyclone(GLCC)is designed by the analysis and research on gas-liquid separation process.Based on CFD(Computational Fluid Dynamic)numerical simulation analysis,mechanism analysis,and laboratory experimental study,study on the flow field characteristics and separation performance of the GLCC is carried out.Velocity field of the GLCC is analyzed.The flowing characteristics of turbulent flow,such as overflow short-circuit-flow,underflow short-circuit-flow,circulation flow,and their effects on the separation performance of a GLCC are analyzed in detail.The flowing structure of gas-liquid two-phase flow and the existing condition and characteristics of main flow patterns are introduced.According to separation principle and process of the GLCC,and the flow field analysis results,the inner flow field of a GLCC is theoretically divided into several zones.The distribution characteristics and changing rules of velocity,pressure,gas volume fraction in each zone are described.Combining with the flow field features of each zone and the separation principle of the gas-liquid cylindrical cyclone,main measures and ideas for improving GLCC are proposed accordingly,e.g.,by raising the tangential rotating velocity of the inner flow filed of a GLCC,enlarging the intrusion length of overflow tube,reducing or erasing the occupied space of the centered gas core,improving the movement status of the separated gas that have been driven to the center of GLCC,compensating the revolving momentum of the mixed medium around the bottom of GLCC so as to enhance its separation effect,etc.All of these measures are believed to provide useful technological support for structural optimization design of GLCC.Some main factors influencing the separation performance of GLCC are analyzed and summarized.CFD simulation analysis is carried out.The structures and parameters,such as inlet flow path,inlet size,inlet position,underflow structure,length of vortex cavity,diameter of vortex cavity,diameter of overflow tube,intrusion length of overflow tube,are optimization designed.The distribution rule of the inner flow field of GLCC,pressure characteristics and separation performance and the influencing law are summarized.A GLCC structure with a lower underflow gas fraction,better de-gassing efficiency,and lower pressure loss is designed.The numerical simulation analysis on parameters such as inlet velocity,inlet gas-liquid ratio,and split ratio is carried out.The effect of operating parameters on flow field distribution,separation performance and pressure characteristics of GLCC is analyzed.The main separation performance and pressure characteristics of GLCC are mastered.Laboratory experimental study on GLCC is carried out.By combining numerical simulation with experimental methods,the optimum flowrate and optimum split ratio of the new structure GLCC.Comparison experiments on the length of vortex cavity,diameter of vortex cavity,intrusion length of overflow tube.The optimum structure is.defined.The influencing and changing trend of experimental results is in accordance with that of the numerical simulation results.It indicates that the model selection and analysis method of the numerical simulation analysis are feasible.The study would provide useful technological support for experimental study and actual applications.This study would provide a better basis for further development of theoretical analysis,flow field analysis,and oilfield experimental research of GLCC.