an investigation of the effect of submergence and the distance between suction pipe and bottom of the sump on flow pattern in the sump

water conveyance through pumping takes a lot of energy and cost and therefore, its application should be accompanied by exact design of pumping station as well as correct positions of pumps and their subsidiary apparatus. sumps are designed for many pumping stations and often face the problems of vortex and irregular flows. therefore an investigation of the general flow pattern in sumps in different hydraulic and geometric conditions and a study of the negative pressure at the bottom of the sump could help the appropriate operation of pumping project as well as reduction in the costs. these parameters could be related to energy consumption for pumping a definite discharge or volume of water, as the results reveal increase in the energy consumption due to improper design parameters and due to growing vortex formation. in this study, based upon the 3d velocity measurements in pump sump and recording of the observations, the differences of flow patterns by change of two parameters, namely: the submergence of the suction pipe and the distance between suction pipe and sump bottom at different discharge levels were investigated. the results reveal the obvious effects of these parameters on vortex formation and the negative pressure exerted at sump bottom. they also necessitate more research on the suggested relationships to augment and adjust them to varying situations.