Transient analysis of water supply mains

Abstract

Typical upset sources (like sudden valve closure, pump failure etc.) in a liquid service pipeline network may result in problems due to water hammer. Steep pressure increase (upsurge) and decrease (downsurge) are often generated by such events and the pressure upset quickly propagates over the system along the associated pipeline. The pressure wave propagation may cause over pressurization or vacuum; sometimes it may also induce secondary pressure upset due to vapour cavity formation and collapse (vaporization and condensation) at highly elevated portions, dead ends, etc. Steep pressure changes may induce impulsive fluid dynamic loads on the pipeline which may cause serious piping vibration and damage to pipe supports, valve and equipment casings. An attempt has been made to model and simulate the flow in water mains to identify the magnitude and location of upsurge and downsurge pressures in the pipeline. A program has been developed to serve this purpose using the object oriented programming approach. The method of characteristics is used to compute the flow parameters. A GUI is created to model the system and obtain real time system data as graphical outputs and spreadsheets which can be easily interpreted by the user. Thus the simulation helps decide the kind of safety device required in the water mains. The results have been verified on an existing experimental set up.