"> Maher Saadeh . Prof., Al Baath University, Homs – Syria
Shaker Aljanabi, Ass. Prof., University of technology, Baghdad, Iraq
The problem of unsteady flow are frequently encountered in long oil pipelines without the provision of surge tank due to sudden closing or opening of valve and pump trip. Transient analysis of the pipe flow is often more important than the analysis of the steady-state operating conditions ,that engineers normally use to with stand these additional loads resulting from rapid flow change situations. The oil-hammer are analyzed and predicted by using the Eulerian approach (MOC )and the Lagrangian approach (WCM). The investigation was carried out for sufficiently long time to demonstrate changing of pressure head with time. Transient conditions arising in long oil pipeline with pumping station, valve and branches are studied in details for KRK pipeline by these two approaches. 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. A numerical model " UNSTEADY_ FRIC_WH " using MOC and Barr's explicit friction factor has been presented for solution of the transient flow situation of water hammer. Assessment of friction factor at any section in this unsteady transient low conditions clearly indicates the effectiveness of using variable friction factor in contrast to the steady state friction as in the available numerical models.