Pressure surge analysis in pump systems

Abstract

Power failure of pumps, sudden valve actions, and the operation of automatic control systems may cause water hammer problems in a liquid service pipelines. Steep pressure increase and decrease are often generated by such events. This pressure upset quickly propagates over the system along the associated piping. The increasing pressure propagation may cause overpressure problem, while the decreasing pressure propagation may cause vacuum problem and sometimes induce secondary pressure upset due to vapour cavity formation and collapse (vaporization and condensation) at highly elevated portions, dead ends etc. A mathematical model consists of a set of partial differential equations of hyperbolic type, which have been transformed by the method of characteristics into ordinary differential equations which are solved by the predictor-corrector method. The method of characteristics is used to find the pressure increase and decrease and hence help to decide the kind of safety device required in the water mains. Interactive software is developed that provides user to draw network structure of pipelines with components like valves, pumps etc. and also obtain the result in graphs. Thus, allowing user to not only detect faults but also provides information about which anti-surge device is to be used in order to increase the life of water mains.