Development of a flocculation sub-model for a 3-D CFD model based on rectangular settling tanks.
Development of a flocculation sub-model for a 3-D CFD model based on rectangular settling tanks.
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开发基于矩形沉降池的 3-D CFD 模型的絮凝子模型。
DOI：
10.2166/wst.2011.035
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
J. McCorquodale
中科院分区：
文献类型：
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作者：
M. Gong;S. Xanthos;K. Ramalingam;K. Ramalingam;J. Fillos;K. Beckmann;A. Deur;J. McCorquodale
为了评估性能和评价提高矩形Gould II型最终沉淀池（FST）效率的替代方案，纽约市环境保护部和纽约城市学院开发了一个三维计算机模型，描述了该池的实际结构配置以及当前和建议的水力和固体负荷率。Fluent 6.3.26™是计算流体动力学（CFD）模型的基础平台，其中包含SS沉降特性、湍流、絮凝和流变的子模型。这是补充现场和实验室规模的实验，以量化的系数积分的子模型。开发的3D模型可以用来考虑不同的挡板安排，污泥提取机制和加载替代FST。矩形槽前半部尤其是进口挡板前后区域的絮凝是影响悬浮物捕集效率的重要参数之一。通过在槽内设置一个附加的挡板来捕获中、小粒径的颗粒，可以进一步提高絮凝效果。这是优化油箱性能时采用的方法之一，其中CCNY 3D CFD模型用于确定油箱内挡板的位置。本文介绍了絮凝子模型的发展和已知的帕克方程中的絮凝系数与初始混合液悬浮固体（MLSS）浓度X0的关系。提出了一个新的修正方程，去除破碎系数的依赖性的初始值的X0的基础上使用正常和低浓度的混合液悬浮固体值在絮凝实验进行的初步数据。
To assess performance and evaluate alternatives to improve the efficiency of rectangular Gould II type final settling tanks (FSTs), New York City Department of Environmental Protection and City College of NY developed a 3D computer model depicting the actual structural configuration of the tanks and the current and proposed hydraulic and solids loading rates. Fluent 6.3.26™ was the base platform for the computational fluid dynamics (CFD) model, for which sub-models of the SS settling characteristics, turbulence, flocculation and rheology were incorporated. This was supplemented by field and bench scale experiments to quantify the coefficients integral to the sub-models. The 3D model developed can be used to consider different baffle arrangements, sludge withdrawal mechanisms and loading alternatives to the FSTs. Flocculation in the front half of the rectangular tank especially in the region before and after the inlet baffle is one of the vital parameters that influences the capture efficiency of SS. Flocculation could be further improved by capturing medium and small size particles by creating an additional zone with an in-tank baffle. This was one of the methods that was adopted in optimizing the performance of the tank where the CCNY 3D CFD model was used to locate the in-tank baffle position. This paper describes the development of the flocculation sub-model and the relationship of the flocculation coefficients in the known Parker equation to the initial mixed liquor suspended solids (MLSS) concentration X0. A new modified equation is proposed removing the dependency of the breakup coefficient to the initial value of X0 based on preliminary data using normal and low concentration mixed liquor suspended solids values in flocculation experiments performed.