基于CFD的雨水调蓄池颗粒物沉淀特性研究

雨水调蓄池在峰值流量和合流制溢流污染控制中发挥着重要作用,但对于雨水径流中颗粒物在调蓄池的沉淀特性尚缺乏系统研究。运用计算流体力学(computational fluid dynamics, CFD)模拟技术,系统研究了雨水调蓄池不同构造和不同工况条件下颗粒物的沉淀特性。模拟结果表明:进水流速由0.276 m/s增加到0.553 m/s时,普通(Ⅰ型)、增加挡板(Ⅱ型)、增加消能孔(Ⅲ型)构造调蓄池颗粒物去除率分别降低14.90%、13.89%和15.32%。当进水中颗粒物粒径由0.075 mm增加到0.15 mm时,Ⅰ型、Ⅱ型、Ⅲ型构造调蓄池颗粒物去除率分别增加9.10%、62.48%和36.65%;进水浓度由1000 mg/L增加到2000 mg/L时,Ⅰ型、Ⅱ型、Ⅲ型构造调蓄池颗粒物去除率分别增加3.60%、2.84%和13.30%。各影响因素对Ⅰ型调蓄池水质控制效果影响的重要程度顺序为进水流速>颗粒物粒径>进水浓度,其对Ⅱ型、Ⅲ型调蓄池水质控制效果影响的重要程度顺序为颗粒物粒径>进水流速>进水浓度。

SEDIMENTATION CHARACTERISTICS OF PARTICULATE MATTERS IN RUNOFF DETENTION TANK VIA CFD METHOD

The runoff detention tank plays an important role in peak flow control and combined sewer overflow pollution control, but the sedimentation characteristics of particles in the stormwater runoff detention tank are still lack of systematic study. Using computational fluid dynamics(CFD) simulation technology, the sedimentation characteristics of particles in the runoff detention tank under different structures and different working conditions were systematically studied. The simulation results showed that when the influent velocity increased from 0.276 m/s to 0.553 m/s, the particle removal rate of the detention tank with smooth bottom(typeⅠ), additional baffles(typeⅡ) and energy dissipating holes(type Ⅲ) decreased by 14.90%, 13.89% and 15.32%, respectively. When the particle size of influent increased from 0.075 mm to 0.15 mm, the particle removal rate increased by 9.10%, 62.48% and 36.65% in the detention tank of typeⅠ, typeⅡand type Ⅲ structure, respectively; when the influent particle concentration increased from 1000 mg/L to 2000 mg/L, the particle removal rate increased by 3.60%, 2.84% and 13.30% in the detention tank of typeⅠ, typeⅡ and type Ⅲ structure, respectively. The importance of different influencing factors on the water quality control in the typeⅠdetention tank was in sequence of influent velocity>particle size>influent particle concentration, and that on the water quality control in both the type Ⅱ and type Ⅲ detention tank were in sequence of particle size>influent velocity>influent particle concentration.