The disturbance in velocity distribution generates hydraulic instability of pumping units, which leads to failure, damage and other operation and maintenance difficulties. The objective of this research is to predict and enhance the hydraulic problems in the sump intake of FARASKOUR drainage pumping station on faraskour drain Damietta governorate. The first and fifth units of the operating, water were not analyzed, study of the hydraulic problems of the suction basin of the new pump station due to the sharp rotation in the suction guide from the sharp rotation to the quay station and the continuous discontinuation of the first and fifth units due to the lack of regular water entering the unit, and recommend the suitable modifications to eliminate the operations and maintenance costs.
A numerical simulation was done to investigate the hydraulic stability of the station. There are four cases were done. The first case, when all units “five units” operates at the same time, the second case when three units operate “1, 2 and 3”, the third case when other three units “3, 4 and 5” operates, and the last case when three units operate “1, 3 and 5”. The ANSYS R18.1 flow simulation software, Computational Fluid Dynamics (CFD) is used to simulate the flow conditions at different working pumping units and different water levels to predict the hydraulic problem at the suction side.
The results indicated that the problem of flow is due to the sharp bending of the suction channel at the entrance of the units to the station, leading to two negative phenomena, the first one not to distribute well to the incoming lines of the units, and the second is appearance of places of relatively low speeds. The internal bending of the stream just before the entry of units directly to this area negatively affects the work of units (4, 5) and the problem becomes more specific with the formation of depositions.
In general, the results indicated that with five pumping units’ scenarios in operation appear dead zones in the inner curvature of the intake. From simulation results, the geometry of the intake is proper for running four parallel flow pumps with the designed flow rate and reduces the distance from both sides of the canal (make Protection basin).