Ant-colony-based simulation–optimization modeling for the design of a forced water pipeline system considering the effects of dynamic pressures

Valve and pump shut-off in water pipeline systems lead to transient flow. This flow is a complex phenomenon and is potentially a very serious problem causing extra dynamic pressure in the system. Within the last few decades, the evolutionary and meta-heuristic algorithms, such as genetic algorithms, simulated annealing. More recently, however, ant-colony optimization algorithms have received considerable attention. In this paper the procedure and application of the ant-colony optimization algorithm to the design of a water supply pipeline system, considering dynamic pressures arising from valve closure, is presented. A simulation–optimization interaction loop (SOIL) is defined that cycles between the steady-state and transient flow modules to describe the hydraulics of the pipeline and ant colony optimization algorithm. A hydraulic simulation module is coupled with the ant colony optimization algorithm to form an efficient and powerful software program which locates the pumping stations at any possible or predefined locations while optimizing their specifications, along with pipe diameters, at each decision point. The model may equally regard or disregard the dynamic pressures. Two examples are provided to illustrate the proposed methodology which is limited to the solution of any gravity and/or forced water supply pipeline which is typical for water supply systems.