水下切粒PCW系统流场调控及优化

针对高聚物颗粒在水下,切粒工艺PCW系统的水力输送环节中出现的碰撞及滞留现象,避免其造成颗粒堵塞、成品颗粒粘连、料粉含量高的问题,以改善颗粒在水力输送环节竖直输送管段中的碰撞及滞留现象为目的,对高聚物颗粒的最佳水力输送速度进行研究。采用CFD-DEM耦合数值模拟与竖直提升试验台实验相结合的研究方法,分析了输送水流速对高聚物颗粒在竖直管段中碰撞及滞留现象的影响。结果表明,当低相输送时(颗粒体积分数低于1%),高聚物颗粒的碰撞及滞留现象均随输送流速增大而有明显改善,且存在最佳优化值。对于直径为5~15 mm、密度为1. 2~2 g/cm3的高聚物颗粒,其竖直输送段流速最佳优化值为1. 9 m/s。

Flow Field Control and Optimization of Underwater Granular PCW System

Aiming at the collision and detention of polymer particles in the hydraulic conveying link of PCW system in underwater granulation process,avoiding the problems of particle blockage,product particle adhesion and high powder content,the optimal hydraulic conveying speed of polymer particles was studied in order to improve the collision and detention of particles in the vertical conveying section of the hydraulic conveying link.The effects of conveying water velocity on collision and retention of polymer particles in vertical pipe were studied by CFD-DEM coupled numerical simulation and experimental study on vertical lifting test rig.The results showed that the collision and retention phenomena of polymer particles were improved with the increase of conveying velocity when the volume fraction of particles is less than 1%,and there was an optimum value.For polymer particles with diameter of 5~15 mm and density of 1.2~2 g/cm3,the optimum flow velocity in vertical conveying section was 1.9 m/s.