Risks of hydraulic shocks in pressure pipelines during aboveground laying in permafrost conditions

Emperor Alexander I St. Petersburg State Transport University (PGUPS), Moskovsky pr., 9, 190031 Saint Petersburg, Russia

^* Corresponding author: olk1975@mail.ru

Abstract

Under permafrost conditions, there are a large number of factors that complicate the construction and operation of pressure hydraulic transport systems. While designing new pressure systems and reconstructing existing ones, it is necessary to take into account possible unsteady processes in pressure pipelines. Elimination of the consequences of emergency situations accompanied by water leakage is difficult in harsh climatic conditions, while thermal effects on soils are not always possible to avoid. The purpose of the study was to identify the factors that most affect the risk of hydraulic shocks in pressure pipelines during aboveground laying of pipelines characteristic of permafrost areas. The method of characteristics used to solve differential equations of unsteady fluid motion is the basis of a computational model for determining flow parameters in the event of hydraulic shocks. On the basis of the calculations carried out, the diagrams of pressure changes in a pressure pipeline made of steel pipes are analyzed in the article. The influence of the propagation velocity of the hydraulic shock wave and the velocity of the steady-state fluid flow on the nature of the flow of the unsteady process and the amount of pressure during hydraulic shock in the pressure pipeline during overhead laying is estimated. Applying of activities aimed at preventing the occurrence of hydraulic shocks, including combined ones in order to increase the reliability of their action, is much cheaper than replacing damaged pipes and equipment, eliminating washouts with leaking water, loss of drinking water.