安全壳过滤排放系统文丘里洗涤器除碘性能分析

Analysis of iodine-removing performance of venturi scrubber in containment filtration and discharge system

本文通过CFD(Computational Fluid Dynamics)数值模拟方法,对文丘里洗涤器运行工况进行模拟计算。分析入口气相流速、系统压力的改变对引射量的影响,并与实验方法结合,探讨文丘里洗涤器引射能力对除碘效率的影响,并对某核电厂安全壳过滤排放系统排放工况提出指导性建议。结果表明:提高入口气相流速可提升引射量,且引射量呈现近似线性增长关系,同时吸液管内外侧压差呈现近似抛物线规律,系统除碘效率在初始阶段与引射量的增长趋势保持一致,随后在引射量达到一定水平后趋于稳定。为保证较高除碘效率,系统排放风量应保持在3300 m^(3)/h以上;在0.1~0.5 MPa系统压力范围内,除碘效率均可保持在较高水平,压力增大有助于引射量提升,并且在高流量区提高更加明显。

In this paper,the operation conditions of Venturi scrubbers in nuclear power plants is simulated with a CFD numerical simulation method.The influence of the change of air flow velocity and system pressure on the ejection volume was analyzed.Combined with the experiment method,the influence of the ejection capacity of the Venturi scrubber on iodine removal efficiency was discussed,and some guiding suggestions for the discharge conditions of the containment filtration and discharge system of a nuclear power plant were put forward.The results show that increasing air flow velocity can increase the injection amount,and the injection amount presents an approximate linear growth relationship.Meanwhile,the pressure difference between the inside and outside of the suction tube presents an approximate parabola law.The iodine removal efficiency of the system is consistent with the increasing trend of the injection amount in the initial stage,and then tends to be stable after the injection amount reaches a certain level.In order to ensure a high iodine removal efficiency,the exhaust air flow of the system should be kept above 3300 m3/h.In the range of 0.1 to 0.5 MPa system pressure,the iodine removal efficiency can be maintained at a high level.The increase of pressure is helpful to the increase of ejection capacity,and the increase is more obvious in the high flow area.