Numerical Modelling of Transient Flow In Long Oil Pipe Line System


The problem of unsteady flow are frequently encountered in long oilpipelines without the provision of surge tank due to sudden closing oropening of valve and pump trip. The oil-hammer are analyzed andpredicted by using the Eulerian approach (MOC) and the Lagrangianapproach (WCM). The investigation was carried out for sufficiently longtime to demonstrate changing of pressure head with time. Transientconditions arising in long oil pipeline with pumping station, valve andbranches are studied in details for KRK pipeline by these two pproaches.A Computer programs for all these components were developed.The effect of valve closure, line branch junction and pump shut-down are studied taking into account the effect of line friction on pressure wave. Anumerical model "UNSTEADY_ FRIC_WH" using MOC and Barr's explicit friction factor has been presented for solution of the transient flowsituation of water hammer. Assessment of friction factor at any section in this unsteady transient flow conditions clearly indicates the effectiveness of using variable friction factor in contrast to the steady state friction as in the available numerical models.