Environmental Engineering Sciences, University of Florida, 110 Black Hall, Gainesville, Florida 32611-6450, United States.
Environ Sci Technol. 2011 Jul 1;45(13):5605-13. doi: 10.1021/es103584c. Epub 2011 Jun 6.
Computational fluid dynamics (CFD) is emerging as a model for resolving the fate of particulate matter (PM) by unit operations subject to rainfall-runoff loadings. However, compared to steady flow CFD models, there are greater computational requirements for unsteady hydrodynamics and PM loading models. Therefore this study examines if integrating a stepwise steady flow CFD model can reproduce PM separation by common unit operations loaded by unsteady flow and PM loadings, thereby reducing computational effort. Utilizing monitored unit operation data from unsteady events as a metric, this study compares the two CFD modeling approaches for a hydrodynamic separator (HS), a primary clarifier (PC) tank, and a volumetric clarifying filtration system (VCF). Results indicate that while unsteady CFD models reproduce PM separation of each unit operation, stepwise steady CFD models result in significant deviation for HS and PC models as compared to monitored data; overestimating the physical size requirements of each unit required to reproduce monitored PM separation results. In contrast, the stepwise steady flow approach reproduces PM separation by the VCF, a combined gravitational sedimentation and media filtration unit operation that provides attenuation of turbulent energy and flow velocity.
计算流体动力学 (CFD) 作为一种模型，正在崭露头角，可以解决受降雨-径流负荷影响的颗粒物 (PM) 的命运问题。然而，与稳定流 CFD 模型相比，非稳定水动力和 PM 负荷模型需要更大的计算要求。因此，本研究探讨了整合逐步稳定流 CFD 模型是否可以再现受非稳定流和 PM 负荷影响的常见单元操作对 PM 的分离，从而减少计算工作量。本研究利用非稳定事件中监测到的单元操作数据作为指标，比较了两种 CFD 建模方法在水力分离器 (HS)、初次沉淀池 (PC) 罐和容积澄清过滤系统 (VCF) 中的应用。结果表明，虽然非稳定 CFD 模型可以再现每个单元操作的 PM 分离，但与监测数据相比，逐步稳定 CFD 模型会导致 HS 和 PC 模型的显著偏差；高估了为再现监测 PM 分离结果所需的每个单元的物理尺寸要求。相比之下，逐步稳定流方法再现了 VCF 的 PM 分离，VCF 是一种组合的重力沉淀和介质过滤单元操作，可衰减湍流动能和流速。
