Justification of the need to study the processes occurring at the inlet to the impeller of a centrifugal pump

One of the ways to improve the designs of pumping units is to reduce internal losses: mechanical, volumetric and hydraulic. Existing methods make it possible to determine with sufficient accuracy the numerical values of mechanical losses and losses due to volumetric leaks. The greatest difficulty here is represented by hydraulic losses, which are influenced not only by many factors, but it is also not possible to determine the magnitude of their total effect. An analysis of domestic and foreign literature sources confirms that hydraulic losses are the most significant for improving pump designs. Considering the hydraulic losses, it should be noted that during internal overflows through the slot seals of the impellers, part of the liquid released from the wheel reenters it. This leads to a deterioration in the performance of the pumps. The designers of pump designs associated changes in their basic performance indicators, as a rule, only with volumetric outflows through the slot seals of the impellers, without taking into account the influence of highpressure jet flows on the main flow of the pumped liquid. In the article, the result of the study of the processes occurring at the inlet to the working wheel of a dynamic pump is the introduction of changes to its design: the structural diagram of a fragment of a centrifugal pump presented in the article, in which changes in the angles of meeting of flows from a highpressure area to a lowpressure area through the front slot seal and the discharge opening of the impeller with the main flow are proposed. the pumped liquid. The introduction of the proposed design changes made it possible to minimize the inhibitory effect of the flow of volumetric leaks through the rear slot seal to the main pumped stream, as well as to obtain a positive effect on the advancement of the ejected main stream of the pumping medium.