Hydraulic transients for a pipe line network of treated effluent rising main using SAP 2R

Abstract

Hydraulic transients occur as a direct result of rapid variations of flow field in pressurized systems. The change in velocity from valve closures or pump operations causes pressure surges that are propagated away from the source throughout the pipeline. The associated pressure changes during a transient period are quite large and occur quickly (within a few seconds). It should also be noted that when the maximum pressures exceed the bar ratings (mechanical strength) of the piping material, failure can occur. Similarly, if the minimum pressure drops below the vapour pressure of the fluid, cavitation can occur. The purpose of the present study is to model and simulate the hydraulic transients in a pipeline network system of the treated effluent rising main of Mpophomeni sanitation scheme using SAP 2R. A total of five scenarios were simulated using different combinations. The simulation results show that the transient pressures in the pipeline exceeded the bar rating of the pipe where the bursts or cavitation may occur for the simulated scenario, but transient pressures were reduced to a safe limit after providing water hammer protection devices. HIGHLIGHTS Water hammer analysis is done on a pipe line network system using SAP2R.; Water hammer pressure is observed and discussed on various sections of the pipeline.; The method of characteristics is used for solving the hydraulic transient equations.; Water hammer protection devices are suggested to keep transient pressure to a safe limit.;

Keywords

• cavitations
• hydraulic transient
• pipe network
• sap2r
• water hammer