Author(s): A. C. Demetracopoulos; C. Hadjitheodorou; P. C. Yannopoulos

Linked Author(s): Alex C. Demetracopoulos

Keywords: Water hammer; Branching pipelines; Air chambers

Abstract: Transient flow conditions in pipelines conveying fluids are caused by sudden operational changes in hydraulic components, such as valves or pumps. An algorithm was developed which analyzes water hammer conditions in a branching network of pipes conveying water to a reservoir from a number of deep wells, due to the unexpected power failure to one or more of the submersible pumps supplying the system. The solution algorithm employs the method of characteristics. In addition to inertia and compressibility, the solution takes into consideration the effects of pipe junctions, and the inertia of the water filled pump impeller. The relatively low values of impeller moment of inertia of modern submersible pumps result in very small closing times for the pump discharge check valve, i.e. the time after power failure in which the pump discharge becomes zero is very small, causing intense pressure fluctuations due to water hammer. Strategically placed air chambers, in conjunction with the appropriate pipe wall thickness, effectively control the positive pressures, but are unable to eliminate extensive negative pressures in the well pipe. Effective control of such pressures may be attained by either decreasing the pump discharge, or by increasing the diameter for a portion of the well pipe.

DOI:

Year: 2003