Application of Modern Technique to Predict and Enhance Flow Problems on Pump Suction Intake for Irrigation Improvement Projects

Abstract

The Irrigation Improvement Project (IIP) is being implemented at a national scale in Egypt with a target of improving the old irrigation system in the Nile Delta for increasing water use efficiency and agricultural production. The objective of this research is to study the influence of existing circular sump shape on the flow conditions of mesqa pump station. The adverse flow conditions at a pump intake lead to occurrence of swirl and vortices, which in turn reduce the pump efficiency, induce vibrations and excessive bearing loads resulting in operational and maintenance cost and leading to other operating difficulties. The field measurements are conducted on the Efrank (1) mesqa pumping station at Kafr El-Dawar command area, El-Beheara Governorate. The 3D CFD model solves the Reynolds averaged Navier–Stokes (RANS) equations with the k–ε turbulence model with wall function for predicting the occurrence of vortices and swirl in pump intakes. Various modification of existing circular sump shapes are studied, in both circular and rectangular shaped sumps. The modifications are tested under the wide range of sump water level. These modifications are responsible to reduce or eliminate the flow pre-swirling and vortex. In this study, three different modifications are done, installing submerged cone under the suction pipes, installing vertical splitter wall between two suction pipes and using rectangular sump shape. The research shows that, existing circular sump shape generates swirl flow and vortex at the sump and suction pipes of pumping units. The submerged cone under suction pipes doesn’t reduce the swirl flow and vortex. Furthermore, when using rectangular sump shape, the stream line plots show occurrence of two strong vortices on the water surface. The installation of vertical splitter wall between the two vertical suction pipes reduces the pre-swirling surface flow and improves the pump performance.