The analysis of the water distribution network is complicated and requires several assumptions to simplify its problem definition. Demand Driven Analysis (DDA) is typically used to analyse the network assuming that all network nodes can deliver the required demand regardless of the available pressure. In the case of analysing an existing network under deficit condition such as pipe breakage or extra demand required for firefighting, assumptions used to simulate the network with DDA is not valid. Node Head Flow Relationship (NHFR) should be considered through Pressure Driven Analysis (PDA) to analyse the network. Most PDA methods assume that the networks are airtight which means that if the pressure at any demand node is negative, delivered demand will be equal to zero and the flow is permitted in the connected pipes (Siphonic flow). This assumption is hydraulically incorrect since the air is allowed to get into the connected pipes and prevent their flow leading to node isolation. In this paper, a new Pressure Driven Analysis to Prevent Siphonic Flow (PDA-SF) approach is proposed to analyze the network under deficit conditions and consider isolating the nodes that show available head less than node elevation. The PDA-SF was tested and compared to previous methods in four case studies under steady state analysis or extended period simulation. The case studies cover also different network conditions whether node isolation is needed or not. The PDA-SF was able to solve different networks where other methods failed to achieve the required demand or service pressure. The new PDA-SF method shall enable peers and modelers to better simulate and analysis water distribution networks.

配水网络的分析很复杂，需要几个假设来简化其问题定义。需求驱动分析 (DDA) 通常用于分析网络，假设所有网络节点都可以提供所需的需求，而不管可用压力如何。在分析现有网络在管道破损或消防所需的额外需求等不足条件下的情况下，用于模拟 DDA 网络的假设是无效的。应通过压力驱动分析（PDA）考虑节点水头流量关系（NHFR）来分析网络。大多数 PDA 方法假设网络是密闭的，这意味着如果任何需求节点处的压力为负，则交付的需求将等于零，并且允许在连接的管道中流动（虹吸流动）。这种假设在水力上是不正确的，因为允许空气进入连接的管道并阻止它们的流动导致节点隔离。在本文中，提出了一种新的压力驱动分析以防止虹吸流（PDA-SF）方法来分析不足条件下的网络，并考虑隔离显示可用水头小于节点高度的节点。在稳态分析或延长周期模拟的四个案例研究中，对 PDA-SF 进行了测试并与之前的方法进行了比较。案例研究还涵盖了不同的网络条件，无论是否需要节点隔离。PDA-SF 能够解决其他方法无法达到所需需求或服务压力的不同网络。新的 PDA-SF 方法将使同行和建模者能够更好地模拟和分析配水网络。