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A Study On Hydrodynamic Characteristics In A Pulsed Extraction Column By Four-Sensor Optical Fiber Probe And CFD Simulation

Posted on:2018-04-16Degree:MasterType:Thesis
Country:ChinaCandidate:C C FanFull Text:PDF
GTID:2322330542487490Subject:Engineering
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Pulsed sieve plate extraction column is a solvent extraction equipment with high production capacity,high separation efficiency and not sensitive to interfacial dirt,it has become one of the most important equipment in the Purex Process(Plutonium Uranium Recovery by Extraction).The knowledge of various dispersed phase properties such as droplet velocity,drop size,holdup of the dispersed phase,is of considerable importance for the proper design and scaling-up of extraction columns.The study methods of two-phase flow character in sieve plate extraction column include experimental measurement and CFD(Computational Fluid Dynamics).In this paper,the characteristics of the flow field in the pulsed sieve plate column were studied by using four sensor optical fiber probe technique and CFD(Computational Fluid Dynamics)software ANSYS Fluent 16.0.In this paper,30%TBP/kerosene was used as the dispersed phase and 1mol/L nitric acid was used as the continuous phase in the pulsed sieve plate extraction column with a diameter of 38 mm.The four fiber probe is made by myself.Based on the assumption that the dispersed phase droplet is a rigid sphere,the mathematical principle of measuring the local hydrodynamic properties of the dispersed phase droplets with four sensor optical fiber probe is deduced in detail.The experimental results show that with the increase of the pulse intensity,the droplet velocity and droplet Sauter diameter decreases,the holdup increasesed;with the increase of dispersed phase apparent velocity,the droplet velocity and holdup increased;with the increase of continuous phase apparent velocity,the droplet velocity decreases and the holdup increased.Apparent velocity of two-phase fluid has little effect on droplet sauter diameter.The average retention fraction was measured by volume displacement method.The relative error between the local holdup and the mean holdup was less than 19%.In this paper,ANSYS-Fluent 16.0 was used to simulate the flow field characteristics of the dispersed phase in the extraction column.The calculation of the mathematical model was based on Eulerian multiphase model,k-? turbulence model,schiller-naumunn-pb drag force model,population balance model and virtual mass force.The hydrodynamic properties of the dispersed phase were studied in the presence of 1 mol/L nitric acid and30% TBP/kerosene as the dispersed phase and continuous phase respectively.The simulation results show that with the increase of the column height,the dispersed dropletsauter diameter and velocity were increased,and the higher of column height,the increase rate was greater.The holdup of the dispersed phase decreases slightly with the increase of the column height.The experimental results and simulation results were compared.The comparison results show that the relative error of the experimental with the simulation of droplet sauter diameter is less than 12.6%.The relative error of the experimental with the simulation of mean droplet velocity is less than 19.9%.The results show that CFD(Computational Fluid Dynamics)can well simulate the hydrodynamic properties of the dispersed phase in the pulsed sieve plate extraction column.In the case of reverse phase,that is,30% TBP/kerosene is continuous phase,1mol/L nitric acid is dispersed phase,with the increases of dispersed phase,the droplet diameter and average velocity are decrease significantly.
Keywords/Search Tags:pulsed extraction column, four-sensor optical fiber probe technology, hydrodynamic characteristics, CFD
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