利用物理与数值模型对旋流式水砂分离器性能的评估

Performance evaluation of swirling hydrodynamic separators using physical and numerical models

在市政环境工程领域,旋流式水砂分离器(以下简称分离器)主要用于控制雨水排放过程中的总悬浮固体(TSS)浓度,以减轻排放对自然水体潜在的负面影响.为此研究一种特殊设计的分离器,其主要特征为入口与出口切向连接产生旋流,可增强颗粒的沉降和分离.利用实验模型和数值模拟对该分离器效能进行综合分析,探究其在不同流量条件下对不同粒径颗粒物的去除率,以及分离器尺寸大小对颗粒物去除率的影响.结果表明:在流量为5 L·s^(-1)以上时,对粒径小于200μm的颗粒物,去除率下降显著;对粒径大于200μm的颗粒物,由于其受水流作用较弱,沉降速度较快,去除率相对较高.此外,流量的增加导致流速增大,水停留时间缩短,进而降低了颗粒物的去除率.研究发现,当分离器直径增大至原设计的1.5倍时,颗粒物的去除率最大可提升28%.同时,引入Péclet数评估方法,作为衡量颗粒物去除率的关键指标.该研究结果可为分离器的设计和优化提供参考,有助于提高分离器在实际应用中的性能.

In the field of municipal environmental engineering,hydrodynamic separators are primarily used to control the concentration of Total Suspended Solids(TSS) in stormwater discharge to mitigate its potential negative impact on natural water bodies.This paper studies a specially designed hydrodynamic separator,whose core feature is the tangential connection of the inlet and outlet to generate a vortex,which can enhance the sedimentation and separation of particles in stormwater.Both experimental models and numerical simulations are used to analyze the separator's performance comprehensively,by exploring its removal efficiency for particles of different sizes under various flow conditions,as well as the impact of the separator's size on the particle removal rate.The results show that,when the flow rate is above 5 L·s^(-1),the removal efficiency decreases significantly for particles smaller than 200 μm;while for particles larger than 200 μm,it would have a faster sedimentation rate and relatively higher removal rate due to weaker water flow effects.Additionally,an increase in flow rate shall lead to an increase in flow velocity thus a reduction in water retention time,and consequently a decrease in particle removal rate.The study also found that,when the diameter of the hydrodynamic separator is increased to 1.5 times that of the original design,the particle removal rate shall be increased by up to 28%.During study,the Péclet number assessment method is introduced as a key indicator for measuring the removal efficiency of particles.The research results can provide a reference for the design and optimization of hydrodynamic separators,thus help improve their performance in practical applications.