Study on the distribution characteristics of aerosol produced by powder dumping in glove box

Objective To investigate the effects of particle size, wind speed and dumping velocity on aerosol concentration distribution during powder dumping in a reprocessing plant. Methods CeO 2 powder was selected as the substitute material of PuO 2. FLUENT software was used to calculate the pouring process of CeO 2 powder under different operation conditions. Then the aerosol concentration distribution under different dumping speeds was measured by particle size spectrometer to verify the accuracy of simulation results. Results The particles with small particle size are more likely to be separated from the mainstream area by the drag force of the surrounding gas, and the radius of the diffusion range also increases with the decrease of the particle size. 2) When the ventilation speed is less than 1 m/s, the dust lifting can be reduced and the concentration of dust particles in the chamber can be reduced to a certain extent. 3) In the process of powder dumping, the spoon is rotated anticlockwise at a speed of 100° in 2~3 s, and less dust aerosol is produced on the right side of the tray. Conclusion When operating the powder particles with smaller particle size, more attention should be paid to the monitoring of aerosol at different positions; the change of air inlet velocity makes the flow field in glove box more complex, and the volume fraction of dust particles is related to the size and location of vortex formed by airflow. The greater the wind speed, the greater the impact on the powder dumping process. The experimental results are basically consistent with the simulation results, and the results show that the lower the dumping speed, the smaller the aerosol concentration near the tray. 摘要： 目的 考察粒径、风速和倾倒速度对后处理厂粉末倾倒过程产生的气溶胶浓度分布的影响。 方法 选择 CeO 2 粉末作为 PuO 2 替代材料, 用 FLUENT 软件对不同操作条件下 CeO 2 粉末倾倒过程进行数值计算, 再利用粒径谱 仪对不同倾倒速度下的气溶胶浓度分布进行测量, 验证模拟结果准确性。 结果 小粒径的颗粒更可能受周围气体的 曳力影响而从主流区域脱离出来形成散射粉尘, 其扩散范围的半径也随着粒径的减小而扩大。通风速度在 1 m/s 以下可以减少操作过程粉尘的扬起, 在一定程度上降低箱室内粉尘颗粒的浓度。粉末倾倒过程, 以 2~3 s 将勺子逆时 针旋转 100° 的速度倾倒粉末在托盘右侧产生的粉尘气溶胶较少。 结论 在对粒径较小的粉末颗粒进行操作时, 不同 位置气溶胶的监测应该引起更多的关注;进风速度的变化使得手套箱内的流场变得复杂, 粉尘颗粒的体积分数与气流 形成涡流的大小和涡流位置有关, 风速越大, 对粉末倾倒过程的影响越大;实验结果与模拟结果基本相符, 较慢的倾倒 速度在托盘附近处产生的气溶胶颗粒较少。