Investigation of the Effects of Hydraulic Transients Due to Instantaneous Valve Closure in a Petroleum Pipeline

Abstract

Pressure surge analysis of petroleum pipeline transporting automotive gas oil (AGO) also known as Diesel oil was carried out in this research work. Pressure transient analysis is often more significant than the steady state analysis that engineers usually use in pipeline design. Pressure transient analysis helps to understand the additional pressures the pipeline can be subjected to as a result of instantaneous rapid valve closures or pump failure. The fluid pressure and flow rate in the pipeline system may change significantly at some intervals of time due to the valve closure and such types of unsteady situations are encountered more often in pipelines where the valves are suddenly closed. In this paper, pressure surge due to instantaneous valve closure in a petroleum pipeline conveying AGO was studied in a virtual environment. WANDA Transient 4.5.1210 commercial software was used for the analysis of the pressure surge in the pipeline due to instantaneous valve closure time of 4.75s. It was observed in the study that pressure at some nodes rise significantly up to about 1400 kPa against the initial inlet pressure of 120 kPa due to the instantaneous valve closure and it drastically drops at some nodes to negative pressure of about -100 kPa and hence the formation of cavitations. The analysis showed that the magnitude of the pressure surge decreases as the valve closure is decreased.