辐流式二沉池的流场仿真及评价指标的构建

Flow Field Simulation for Radial Flow Secondary Clarifier and the Development of its Corresponding Evaluation Indicators

为了定量分析周进周出辐流式二沉池的内部流场结构、优化污泥絮体沉淀的水力条件,采用计算流体力学(Computational Fluid Dynamics,CFD)的方法对其进行数学建模及流场分析,创新提出了相应评价指标,包括:配水均匀性、流程池径比及沉淀时间比率。研究结果表明:利用流体体积(VOF)模型及k-ωSST湍流模型搭建的CFD模型适用于评估周进周出辐流式二沉池进水廊道配水均匀性;利用单相流模型及k-ωSST湍流模型搭建的CFD模型适用于评估池内流程池径比及沉淀时间比率;综合使用CFD模拟分析与经验公式设计优化配置导流装置调控流场,其配水均匀性、流程池径比及沉淀时间比率分别提升了20.0%,35.4%和39.0%。

To quantitative analysis the internal flow pattern structure,optimize the hydraulics for sludge flocculation in peripheral feed peripheral outflow secondary clarifier,Computational Fluid Dynamics(CFD)was used as a method to build numerical model and flow pattern analysis.Some key evaluation indicators innovatively were proposed,including the equivalence of flow distribution,the ratio of flow path and diameter,utilization of nominal precipitation time.The result are as follows.Using VOF model and k-ωSST turbulence model can well build a CFD model for evaluating the feed channel’s ability to equally distribute inflow;using single phase flow model and k-ωSST turbulence model can build a CFD model to investigate and evaluate the ratio of flow path and diameter and utilization of nominal precipitation time.Using method of both CFD analysis and empirical formulas,an optimized flow control device is developed for a case study,which improves the above indicators by 20.0%,35.4%and 39.0%,respectively.