HYDRAULIC TRANSIENTS IN PIPE NETWORKS

Abstract

The term water hammer, which is synonymously used with the term hydraulic transients in pipe networks, describes the effects of unsteady flow of liquids in pipelines. It occurs due to the momentum of flowing liquid being disturbed by closing of valve or by similar activity and is accompanied by the rise and fall of pressure from the steady state condition. The governing equations for water hammer are equation of continuity and equation of motion. Generally fluid transients are analyzed using "Method of Characteristics" the present steady is an extension of conventional method of characteristics that allows transient conditions to be efficiently calculated. In particular treating, both boundary conditions and network topology in a general and comprehensive fashion simplifies the solution of many combinations of hydraulic devices. An explicit algorithm is implemented for a general hydraulic element called an external energy dissipater. This boundary condition eventually represents surge tanks, relief valves, storage reservoirs, valves discharging to the atmosphere, and many other common devices. Significantly the solution remains explicit even if friction losses and inertia effects are presented in both the storage element and a connecting pipe. This comprehensive approach to transient analysis simplifies control logic, encourages accurate reporting of field data and improves execution times. In the present study an attempt has been made to analyze water hammer in two pipe networks. The first network is analyzed using the conventional method of characteristics and the second network using the comprehensive approach.