Experiment And Simulation Study On Hydrodynamic Property In Pulsed Extraction Column

Pulsed extraction column is an important chemical equipment,and it has been widely used in spent fuel reprocessing plant.Extensive work has been carried out to study the hydrodynamic and mass transfer characteristic in the pulsed extraction column.Nevertheless,the design and scaling-up of the extraction column is still a problem.The study of the flow filed of single phase flow and local hydrodynamic properties(such as holdup of the dispersed phase,drop size and distribution,droplet velocity)of two-phase flow,is of considerable importance for the proper design and scaling-up of pulsed extraction column.Thus,in this paper,the flow filed of single phase flow and hydrodynamic properties of two-phase flow have been studied by means of tri-sensor optical probe technology and computational fluid dynamics(CFD)software,three contents have been included as following.The first part: the flow filed characteristic of single phase flow in the pulsed disc and doughnut extraction column has been studied by software Fluent14.5,and two-dimensional(2D)and three-dimensional(3D)model have been built by software Gambit 2.4.6,the influence of pulsed operating parameters(pulse amplitude and frequency),geometric institutions(plate spacing,inner diameter of the column)on the velocity and turbulent kinetic energy field of single phase flow has been analysed,and the simulation results of 2D and 3D have been compared with experimental data of published literature.The second part: the dispersed holdup and drop size of two-phase flow in the pulsed disc and doughnut extraction column have been studied by software Fluent14.5,33.5% tributyl phosphate(TBP)in hydrogen tetrapylene(HTP)is used as the continuous phase and nitric acid aqueous solution(1.9mol/L)is the dispersed phase,the influence of pulsed operating parameters(pulse amplitude and frequency),geometric institutions(plate spacing inner diameter of the column)on the dispersed holdup,drop size and distribution of two phase flow has been analysed,and the simulation results of 2D and 3D have been compared with experimental data of published literature.The third part: the dispersed droplet velocity of two-phase flow in the pulsed sieve plate extraction column has been studied by means of tri-sensor optical probe technology and computational fluid dynamics(CFD)software Fluent14.5.Two liquids consisting of the dispersed phase(kerosene)and continuous phase(water)were introduced in countercurrent operation.The influence of pulsed operating parameters(pulse amplitude and frequency)and two-phase superficial velocities on the dispersed droplet velocity of two-phase flow has been analysed,2D mode of the all column has been built by software Gambit2.4.6,experiment results have been verified by the simulation results from Fluent14.5.As it is for the pulsed disc and doughnut extraction column,the results indicate that pulsed operating parameters and plate spacing affect the flow filed characteristic of single phase flow significantly,however the inner diameter of the column has little influence on it.Dispersed phase holdup increases slightly with an increase in pulse amplitude,but increases significantly with an increase in pulse frequency,in addition,it increases with an decrease in plate spacing,and little effect on the dispersed phase holdup has been found with the increase of inner diameter of the column.Dispersed phase droplet size decreases with an increase in pulsed operating parameters,and in low pulsation intensity,droplet size decreases more dramatically,furthermore,droplet size increases with an increase in plate spacing and inner diameter of the column.As it is for the pulsed sieve plate extraction column,the tri-sensor optical probe experiment results indicated that a decrease in droplet velocity with the increase in pulsation intensity,the continuous superficial velocity has little influence on the droplet velocity,droplet velocity decreases with an increase in the dispersed superficial velocity,the above experiment results have been verified by the simulation results,the average deviation between caculated and measured value is about 24.2%.In addition,it can be found that droplet velocity increases with the increase of the height of column.