Optimal Diameter Selection for Pipe Networks

A new approach to the least cost design of water distribution networks has been developed. The method is based on traditional techniques of pipe network analysis by computer; initially assumed pipe diameters are successively adjusted using an optimization technique which is based on a cost function incorporating the various capital and operating costs. Final design total costs for a given network have been found to be approximately the same regardless of the initially assumed values of pipe diameter although the final arrangements of pipe diameter are not necessarily identical. Since the method considers all physical components of the network, both from the point of view of the flow and pressure distribution and the costs, the design represents the global optimum as opposed to a typical element optimum which has been considered by other workers. The method contains no constraints such as assumed fixed pressure heads or pipe flows and may be applied to either closed loop or open loop networks of any size. Provided a computer program for analyzing pipe networks is available, the optimization technique developed represents a simple addition to the basic program.