New pressure driven approach for modelling of water distribution networks

Abstract

A number of pressure driven analysis (PDA) based hydraulic solvers have been proposed in the literature to address issues of negative pressures estimated by demand driven analysis (DDA) solvers such as EPANET. However, the PDA methods reported so far attempt to achieve this by either developing a new PDA methodology, which requires modifying the source code of hydraulic solvers, or using iterative type approaches where artificial elements (like suitably chosen reservoirs) are added to network nodes until convergence is achieved. None of this is ideal, as the former is difficult to implement and the latter results in computationally inefficient PDA solvers that are difficult, and sometimes even impossible, to use in larger networks, especially under the Extended Period Simulation (EPS) conditions. The PDA modelling approach proposed here does not require either of the above as it is based on a single iteration type algorithm which involves connecting a set of artificial elements to each network node with demand and deficient pressure. This set consists of a check valve (CV), a flow control valve (FCV) and a flow emitter. The new PDA method developed was validated on a number of benchmark and real-life networks under different flow conditions, clearly demonstrating its advantages when compared to existing methods. The key advantages include the simplicity of its implementation and the ability to predict network pressures and flows in a consistently accurate, numerically stable and computationally efficient manner under pressure deficient and normal flow conditions in both steady-state and extended period simulations.