Modelo hidráulico baseado no método das características: análise de convergência e comparações com o EPANET

Abstract

This paper presents an evaluation of a MOC based model to perform water network analysis in steady- state and quasi-steady-state flow. The model was developed in DELPHI programming language, introducing new features to the CALHIDREDMT model, first presented by Righetto (1994). Simulations were performed in networks equipped with reservoirs, tanks, pumping stations and boosters, considering both steady-state situations, as well as extended-periods (24 hours). The results were compared with simulations performed in the EPANET model. For pressures and flows, considering elements such as reservoirs, pumping stations and boosters, relative errors inferior to 1% were observed. When modeling tanks, flow values presented relative errors similar to the other elements, although pressure values presented a greater deviation, with a maximum relative error of 6.6%. This fact is associated with limitations in the methodology of both models to deal with tank problems, which are best handled with inertial models. Convergence issues of the MOC were analyzed, considering networks with strongly variable pipe lengths, different values of the celerity wave (a numerical parameter of the model) and the fact that gradual demand inputs are used until the complete nodal values area reached, during a pre-determined number of time-steps at the beginning of the simulation.