Study On Numerical Simulation Of The Flow Field And Control Method In A Water-sparged Aerocyclone

Water-sparged aerocyclone(WSA)is a new highly efficient gas-liquid mass transfer device.The reynolds stress model and VOF model,which have been made the experimental verification,can better simulate the two-phase flow of gas pressure drop characteristics and liquid reflux ratio of the WSA.By simulating the process of jet atomization?the flow field distribution?pressure field distribution,and study the mechanism of jet atomization and control methods,concluded as follow:1.Both simulation and experiment results illustrated that the gas phase pressure drop of the WSA will go through a low pressure drop zone,a pressure drop jump zone,a pressure drop transitional zone and a high pressure drop zone with the increase of gas inlet velocity.The water jet presents steady jet,deformation and bag-like breakup,bag-like breakup and shear atomization,shear atomization and liquid drop centrifugation,respectively,in the above-mentioned pressure drop areas.2.In the simulation of velocity field,tangential velocity is the highest,followed by axial velocity,the minimum is radial velocity.Axial velocity is gradually increased with increasing gas velocity in the axial direction,axial velocity also increases,but the asymmetry of axial velocity distribution increases.The overall trend in the axial direction of the axial velocity of the annulus portion is vertically downward,while in the exhaust pipe is upright.Radial velocity is the largest of change in the value and the maximum value appears the bottom vicinity of the exhaust pipe.The maximum tangential velocity emerges near the entrance of gas,but in which area there are local reflux,with the gas velocity increases,the recirculation zones gradually disappear.Thus increasing inlet gas velocity is an effective way to improve the efficiency of the WSA.3.As it can be seen from the turbulent kinetic energy distribution,under the same conditions gas velocity,turbulent kinetic energy of coupling space in the vertical downward decreases.With the increase of gas velocity,turbulent kinetic energy on the average value changes larger in the vertical direction.4.By numerical simulation of WSA pressure field,when the gas velocity is 16 m·s-1,its maximum pressure region is most symmetrical distribution,which illustrates related properties of gas-liquid mass transfer stabilized state.Probably gas-liquid mass transfer results from steady to unsteady slowly transition to maximize the effect of mass transfer.Generally speaking,with the increase of gas velocity,turbulent kinetic energy distributionof the symmetry in each cross section gradually weakened.With the gas velocity changes gradually,In the area of the separation space maximum turbulent kinetic energy distribution gradually take polymerization near the bottom of the exhaust pipe.Overall,on the different cross section of the couple spatial the increase or decrease in the mean dynamic pressure significantly higher than the static pressure and total pressure,static pressure and the total pressure value is insignificant.Different cross-sections of the dynamic pressure in the WSA coupling space,drop kick zone exhibits abruptly phenomenon.5.By using the stabilizing the data by linear regression for each drop zone,the turning points between adjacent regions are obtained.Jet atomization occurs in the pressure drop transitional zone and the high pressure drop zone.With inlet gas velocity increasing to a certain value,The effect of jet atomization could reach the best.When inlet gas velocity is in the vicinity of the turning point between the pressure drop transitional zone and the high pressure drop zone,Jet atomization achieve the best effect and maximum interphase mass transfer area.