A minimum pressure approach for water distribution network modelling

Abstract

Abstract A new criterion for water distribution network (WDN) modelling is proposed, according to the assumption of pipe permeability to the air and a zero minimum pressure in all the WDN nodes. The two sets of pipes and internal nodes are divided in four sub-sets, corresponding to nodes with zero pressure (ID), nodes with pressure greater than zero (IN), pipes with channel flow (LD) and pipes with fully pressurized flow (LN). An iterative procedure, based on Newton-Rampson (NR) and Linear Theory (LT) methods, is available for the solution of both the diffusive and the convective problems, holding respectively for the IN + LN elements and the ID + LD elements, when the sub-set decomposition is known. A practical procedure is also provided for the solution of the general problem when the decomposition is not known. Applications to two different networks show the difference between the solutions obtained assuming a head driven demand with and without the application of the minimum pressure criterion.