Analysis of the Effects of Valve Propagated Pressure Surge on Pipe Flow

Abstract

This paper analyses the effects of pressure surge on pipe flow. The surge pressure investigated is that propagated by the emergency relief coupling valve (ERV) connected to a loading system carrying crude oil from four flow stations. The results of the analysis show remarkable changes in the fluid parameters arising from the shut down of the loading system by the ERV in the event of storm. For instance, in pipe 1 the pressure dropped from an initial value of 25 × 105 N/m2 to 19 × 105 N/m2, while the velocity of flow increased from 1.76 m/s to 2.97 m/s. The system showed high Reynolds number indicating turbulent flow and the Mach number in pipe IV as high as 3.6 indicating supersonic flow. The consequence of the pressure drop is column separation or cavitations. If the bubbles collapse, re-surge pressures occur leading to possible leakages and rupture of the pipes. All these can be minimized by selecting appropriate surge suppression devices for the system.