Modeling the Mixing Phenomenon in Water Distribution Networks: A State-of-the-Art Review

This paper presents a state-of-the-art review of modeling the mixing phenomenon of junctions in water distribution systems (WDSs). Firstly, the basic concepts and governing equations of the mixing phenomenon are presented. The complete mixing simplifying assumption used in the existing tools of WDSs modeling and management (EPANET, WaterCAD) is described. The paper goes on to show that the complete mixing simplifying assumption can lead to erroneous results. Then, the most frequent incomplete mixing models are described, including AZRED, EPANET-BAM, EPANET-BAM-WRAP, and two analytical models. Also, a summary of all the existing mixing models is provided, trying to determine which mixing model is better to use for a specific urban water distribution network. Because this question can only be partially answered, the paper ends by proposing potential future developments in modeling the mixing in junctions: taking into account the effect of the chemical reaction on the mixing phenomenon in junctions, and considering real-world pipe sizes and pressure to study the mixing phenomenon. (C) 2021 American Society of Civil Engineers.