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

Spent nuclear fuel reprocessing technology is an important part of the nuclear fuel cycle,and pulsed extraction column is one of the most crucial extraction equipment in the PUREX process.The studies on the hydrodynamic performance in a pulsed extraction column can help understand the operation rules in the column,and has important significance to the amplification and design of a pulsed extraction column.In this paper,dispersed phase hydrodynamic characteristics were determined with the four-sensor optical fiber probe technology in a pulsed sieve plate extraction column at various operating conditions.Furthermore,the influences of the pulsed intensity,the continuous and the dispersed phase superficial velocities on the hydrodynamic characteristics were investigated.A complete set of four-sensor optical fiber probe technology which can be used in liquidliquid system has been developed based on the gas-liquid two-phase flow model of Lucas in this paper.This four-sensor optical fiber probe technology can also be used to obtain the information of the droplet diameter and the local holdup in the pulsed extraction column.The hydrodynamic behaviors have been studied in a ?38mm pulsed sieve-plate extraction column by the four-sensor optical fiber probe technology.The experiments include two parts.In the first part,water was taken as the continuous phase and kerosene was used as the dispersed phase.The experimental results indicate that the droplets move up not simply in vertical,and most of the droplets deviate from the axial with an angle in the range of 20°to 40°.Pulsation intensity is the main factor affecting the droplet velocity.The mean velocity decreases with the increases of the pulse intensity,and decreases with the increase of the continuous phase superficial velocity.The dispersed phase superficial velocity has no obvious effect on the mean velocity.The Sauter mean diameter decreases with an increase of the pulsation intensity,while increases with an increase of the dispersed phase superficial velocity.The dependence of the Sauter mean diameter on the continuous phase superficial velocity is relatively weak.Both the local holdup and the mean holdup increase with the increase of the pulse intensity and the twophase superficial velocities.In the second part,water was taken as the continuous phase and 40% octanol(kerosene)was used as the dispersed phase.The experimental results indicate that the angle between velocity direction and the vertical direction distributes in the range of 0° to 70°,mainly distribute in the range of 30° to 60°.The hydrodynamic behavior variation tendency in this part is basically consistent with that of the first part.The holdup increases while the mean velocity and the Sauter mean diameter decrease with an increase of the pulsation intensity.With an increase of the dispersed phase superficial velocity,the holdup and the droplet size increase,and the mean velocity little fluctuates.The mean velocity decreases and the holdup increases with an increase of the continuous phase superficial velocity,while the effect of the continuous phase superficial velocity on the Sauter mean diameter is not obvious.