Water Hammer Analysis for Pumps in Parallel Operation

Abstract

In pumping stations several pumps having different characteristics often are installed in parallel and operated partially or totally depending on the demand for water, in order to maintain better efficiency of the plant. This paper presents a method of analysis of water hammer in parallel operation of different pumps. As one example for this analysis the parallel operation of two pumps is chosen, and the transient phenomena of each pump following power failure are calculated. By these calculations a result as follows has been confirmed : When power failure occurs in parallel operation of two different pumps and there is a certain difference in the speed drop of each pump, the discharge of one pump, of which the speed reduces more slowly than the speed of the other pump, does not decrease but increases for a short time after power failure.