As an vital sewage treatment structure, the operation performance of secondary settling tank determines the effluent quality of the treated sewage. The dynamic behaviour of the two-phase flow in the secondary settling tank had an great influence on the sludge settling process, and its numerical modelling and simulation techniques were of great importance to the optimization of the operating conditions and structural design of the secondary settling tank. In this paper, firstly, three different models, including mixture model, component transport model and VOF-component transport coupling model, commonly adopted in the secondary settling tank simulation were discussed, in terms of model principle, model accuracy, advantages and disadvantages. Secondly, the sludge settlement velocity, the rheological properties of mixed liquid, the external wind field and the secondary settling tank structure and other factors affecting the accurate simulation of the two-phase flow dynamics in the secondary settling tank, were discussed and analysed, and the current research progress and shortcomings were also pointed out. Finally, the research orientation of numerical modelling and simulation for the secondary sedimentation tank in the future were pointed out. This paper can provide references for the researches on secondary settling tanks by means of numerical simulation.%二沉池作为重要的污水处理构筑物,其运行性能决定着出水水质.二沉池两相流动的动力学行为对污泥沉降过程产生重要影响,其数值模型化及模拟对二沉池运行条件及结构设计优化具有重要意义.首先对应用于二沉池模拟的混合模型、组分输运模型、VOF-组分输运耦合模型的原理、模型精度、优缺点进行了探讨;其次,对影响二沉池内两相流动精确模拟的污泥沉降速度、混合液流变性质、外界风场、二沉池结构等因素进行阐述与分析,并梳理了目前的研究进展及不足;最后指出了今后二沉池数值模型及模拟的研究方向,以期为采用数值模拟手段对二沉池的研究提供借鉴和参考.
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