基于大涡模拟供水管网N型节点水质混合研究

Large Eddy Simulation Solute Mixing at N Junctions in Water Distribution Systems

建立供水水质模型对供水管网水质进行模拟是管网运行和管理的重要手段。目前水质模型中均假设溶质在节点处混合是完全和瞬时的,而近年来许多研究表明节点该假设存在误差。研究节点水质混合模型,对于供水管网水质模拟是否准确至关重要。节点水质混合研究主要通过物理实验与数值模拟。本文结合现有的研究成果,利用大涡模拟(LES)和组分输运模型溶质标量对供水管网N型节点进行研究,模拟结果表明在节点内部存在复杂的涡流结构,入流雷诺数比和支管间距(L/D)对节点混合程度有较大影响。

Establishing a water quality model to simulate water quality of water distribution systems(WDSs)is an important means of pipe network operation and management.Current models assume that solute mixing at the junction is complete and instantaneous.However,many studies in recent years show that such an assumption can lead to an erroneous prediction of water quality.Therefore,it is very important to study the junction mixing model and establish an accurate water quality model of WDSs.The junction mixing is studied by physical experiment and numerical simulation.This paper combines the existing research results,the large eddy simulation(LES)and component transport model solute scalar are used to study the N-type junction of WDSs.The results show that there are complex vortexes inside the junctions.The ratio of Reynolds number of inlets and mixing pipe length(L/D)have a great influence on the mixing degree of the junctions.