Design for Protection Against Water Hammer in Pump-Discharge Lines

Abstract

<p>A computer program has been developed to compute water hammer transients in pump-discharge lines (forcemains), resulting from power failure at the pumps. The program incorporates various boundary conditions as subroutines. Hence the pump(s) can be placed anywhere in the pipeline, with or without discharge valves (or check valves), and the program can accept a large number of surge-control devices, similarly placed anywhere in the pipeline. Such devices include valves, check valves, surge tanks, one-way surge tanks, and pressure vessels. An explicit finite-differences scheme employing the method of characteristics is used throughout. It proved to be accurate and stable. The program is written in a dimensionless and general form. Several checks were made to prove the validity of the computer model. Comparisons with field observations, graphical analysis, and/or water hammer design charts were made, depending on the data available in the literature for each boundary condition. An exhaustive search through the literature was made. Computer plots are developed which proved valuable in presenting the results. The computer model was applied to the water hammer problem in the Ancaster forcemain, and a "best" protective device is suggested.</p>