| With the rapid development of subsea oil and gas exploitation,the demand for the related underwater process equipment is increasing fast.In order to reduce the energy consuming,people expect to separate the gas and oil phase directly on the seabed.Accordingly,an advanced Gas-Liquid Cylindrical Cylone(GLCC)separator is developed.To help the stable operation of GLCC,investigations on the factors that influced the performance of GLCC are necesary.In this paper,the hydrodynamic properties such as the velocity,pressure drop,turbulent behavior,vortices stability and the liquid volume fraction distribution of a GLCC is numerically investigated.The main results of this study are summarized as following:(1)Various turbulent models including RNG k-ε,standard k-ε,RSM model were applied to run the simulation.When compared to the experimental data,RNG k-εmodel is proved to be more accurate to describe the experimental pressure drop in GLCC.For gas-liquid two phase model,Eulerian-Eulerian model based on multi-phase VOF model is found suitable to show the gas-liquid interaction observed in experiment.(2)The tangiential velocity in the main body of GLCC presents an M-shaped distribution,and its global value decreases when the location increase along the axial direction.The nozzle structure has a great effect on the tangential velocity.Compared to the crescent nozzle,the rectangular nozzle produces less loss of velocity.When the cross section of rectangular nozzle decreases,the tangential velocity increases and causes a shear action to GLCC wall.(3)For gas-liquid multiphase system,the pressure drop rise linearly with the increase of the liquid volume fraction as well as the gas flow rate.However,the static pressure does not change a lot across the whole GLCC body only an impacted zone is observed at the left side of the inlet.It shows that the size of the impacted zone is significantly affected by the nozzle type and nozzle crosssectional width.The crescent nozzle makes the zone area bigger than the rectangular nozzle.For the rectangular nozzle,a smaller crossectional area produces bigger impact zone.(4)In terms of the swirling attenuation of GLCC,the gas-liquid two phase flow is observed swirl and decay along the axial direction.At z<1700 mm,the attenuation rate decrease faster with the decrease of inlet gas velocity.For z>1700 mm,the effect of inlet gas velocity becomes smaller and the attenuation rate changes slowly.The vortex stability(S_V)swings greatly in GLCC.Compared with the rectangular nozzle,the crescent nozzle has a greater S_V along the GLCC axial direction.With the decrease of the crossectional area of a rectangular nozzle,the vortex core seems to be more stable.(5)A part of the liquids that enters the GLCC is found held at the connection point of nozzle and GLCC cylinder,which is defined as retension region.This region is affected by the nozzle type and nozzle crosssectional area.In addition,a gas vortex is found in the GLCC body below the inlet.The structure of the gas vortex is largly affected by the operation conditions and the structure of the nozzle. |
