The article analyzes the possibility of creating an low-flow (13–35 m3/day) electric centrifugal pump (ECP) unit for marginal wells-producers which is not inferior in terms of efficiency to ECP units of average productivity with taking into account complicated pump operating conditions. A new approach to increasing the hydraulic efficiency of low-flow ECP unit is considered. The reason that restricts the use of ECP for the operation of wells with low productivity is the low efficiency. This is due to hydraulic losses in the narrow flow channels of the impeller and the design features of pumps with a wide size. The results showed that the slotted flow channel is characterized by the largest specific surface area and the smallest hydraulic radius, respectively, losses due to hydraulic friction will be the greatest compared to losses in other forms of the channel. Studies of the influence of the width and shape of the flowing channels of the impellers are carried out. It was established that an increase in the width of the flowing channels of the impeller for low-flow pumps entails a decrease in its radial size and leads to a decrease in the flow and pressure.
When designing a low-flow pump for the basic version adopted ECP-80 pump with a two-fold reduction in diameter, expansion flow channel to a square cross-section shape and increased frequency rotation of the impeller from 3000 to 6000 min-1. Calculated speed coefficient of the designed pump 122.5 is located in the zone of the highest efficiency of the pump and characterizes the designed pump as highly efficient in terms of hydraulic efficiency. The efficiency of operation of a low-flow ECPU is considered depending on the layout length of the section.
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