Optimum Design of Multiple Source Pipeline Networks

The numerous and diversified demands for water in urban, as well as rural areas, dictate the use of large and complex transmission and distribution systems to supply these demands. The cost of water supply systems is very high. The annual investment for water distribution in the United States is reported to be of the order of $1.5 billion. The initial cost of the network depends on the. Size of pumps and the diameters and lengths of the pipes used. In addition to the cost of installation, or fixed costs, there are operating costs caused by the losses in the system. These operating costs will be called friction costs. The frictional costs are directly proportional to the rate of fl9w through pipes. For example, for the same rate of flow, a pipe with bigger diameter offers less resistance and less friction cost than a smaller one. Unfortunately, bigger pipes are more costly to install. than the smaller ones. Generally, the requirements at the demand points are specified in terms of flow rates at minimum pressures. The demand flow rate is fixed, but the minimum pressure may be exceeded. These flow and pressure requirements for a given network can be met by several Kenneth E. Case and John A. White. Formulation of a Water Supply Problem. Hence, an optimal combination of lengths of various diameters could be obtained which satisfies the given set of conditions. A network is defined as a specific combination of pipe lengths of various diameters which is used for the distribution of a fluid. There are two types of networks that can be used: open loop and closed loop . A combination of these is often used. An open loop or branched network-is defined as a pipeline network in which the water source is connected by a single path to each individual demand point. A node is defined as a point where the flow splits or combines, such as a pipe tee or cross. A line is defined as that part of the loop which connects either two adjacent nodes, a node and an adjacent demand point, or the supply point and either an adjacent node or demand point. A line may consist of one or more pipes of different diameters