放射性气溶胶测量腔室内颗粒输运沉积模拟研究

Simulation and analysis of particles transportion and deposition in radioactive aerosols measuring chamber

核设施运行过程中,需要对放射性气溶胶进行连续监测,以保护工作人员的辐射安全。本文利用流体力学仿真软件Fluent,以放射性气溶胶监测仪的测量腔室作为研究对象,采用离散相模型(Discrete Phase Model, DPM)对其内的气溶胶粒子进行输运沉积模拟与分析。结果表明:气溶胶颗粒输运沉积受到粒子尺寸、流速及流动空间等影响。一定范围内,颗粒的流速越大、尺寸越小,则在测量腔室内透过率越高,即到达腔室出口测量滤膜上被探测到的气溶胶粒子数目越多。当气溶胶粒径在1~2μm,入口流速为1.85~3.18 m·s-1时,颗粒穿透率在80%~60%。模拟结果可为后续相关放射性气溶胶颗粒输运沉积、处理、探测效率等提供参考。

[Background] Radioactive aerosols monitoring is required to protect workers for radiation safety, during the operation of the nuclear facility. [Purpose] This paper aims to study the measuring chamber of the radioactive aerosols continuous monitor. [Methods] The computational fluid dynamics （CFD） codes Fluent was applied for particle transport deposition of radioactive aerosol in the measuring chamber. The transportation and deposition of aerosol particles were simulated and analyzed by the discrete phase model （DPM）. Transportation and deposition affected by the size, velocity and flow space of the particles were investigated. [Results] Under certain conditions, the larger the particle flow rate and the smaller the particle size, the higher penetration rate of the chamber to the filter papers for measurement can be obtained. Meanwhile, when the kinetic diameter of aerosol particles between 1-2 μm, the inlet flow rate between 1.85-3.18 m.s^-1, the penetration rate of particles were about 80%-60%. [Conclusion] The simulation results provide the reference and foundation for radioactive aerosol transportation and deposition, treatment and detection which related to the subsequent project.