Nodal analysis models of water supply networks

摘要

There are three methods for analyzing flow and pressure distribution in looped water supply networks (the loop method, the node method, the element method) taking into consideration hydraulic parameters chosen as unknown. For all these methods, the nonlinear system of equations can be solved by iterative procedures (Hardy-Cross, Newton-Raphson, linear theory). In the case of extending or rehability distribution networks the unknown parameters being the piezometric heads at nodes, the node method for network analysis is prefered. In this paper is formulated a generalized classic model for the nodal analysis of complex looped systems with nonstandard network components and the solvability of new problems, alongside the determination of pressure state in the system. Also, this paper shows a different approach to this problem by using the method of variational formulations for the development of an improved model based on the unconditional optimization procedures. This model has the advantage that it uses a specialized optimization algorithm which minimizes directly an objective multivariable function without constraints, implemented in a computer program. The paper compares proposed models to the classic Hardy-Cross method, and shows the good performance of these models.