Transient protection optimization of pipelines using air-chamber and air-inlet valves

摘要

Air-chambers are mechanical devices capable of decreasing positive and increasing negative water-hammer pressures in pumping pipelines; however, large size air-chambers might increase the costs substantially. Also, air-inlet valves are powerful devices which can efficiently control negative pressures. Obtaining the best protection scheme where transient pressures are maintained in a safe bound while minimizing the protection cost is an optimization problem. In this research, a single objective optimization model is introduced in which the types and locations of air-inlet valves and the size of air-chamber are determined such that the total cost is minimized while all pressures along the pipeline are in the allowable range. Maximum and minimum transient pressures are considered as constraints in the optimization analysis using penalty functions. A self-adaptive real genetic algorithm is used to solve the problem. The model is applied to a real transmission pipeline with 4 m(3)/s flow capacity. The results indicate that the proposed model is capable to determine proper number of air-inlet valves, their locations and types so that the air-chamber size and the total cost are substantially reduced.