No abstract

No abstract

In this article, data are reported on creation of a two-tier impeller for a centrifugal pump in the reservoir pressure management (RPM) system. The design was based on numerical experiment performed with the aid of ANSYS CFX 11 software. The new design of the impeller with addition of a second row of blades made it possible to heighten the (pressure) head to the required level while retaining the efficiency of the basic design. A comparison of full-scale test data for a batch of pumps with a fixed set of modernization and forecast characteristics showed fairly good agreement. The two-tier impeller test data help consider such a method of elevating impeller head promising. The work on the determination of the influence of geometry of the second tier (row) of blades on variation of head and efficiency should be continued.During operation of pumps of reservoir maintenance systems, problems arise from time to time because of the need for raising the pump head. In this connection, it is necessary to keep the overall dimensions of the new flow section (impeller and guide device) unchanged because it has to be installed in the base members (locating body parts). If the outer diameter of the guide device and its width were to be kept unchanged, the problem cannot be solved merely by relative enlargement of the outer diameter of the impeller because that will lead to the fact that the ratio of the outer diameters of the guide device and the impeller will exceed the recommended values from the standpoint of attaining high efficiency. This article gives a description of a new flow section of the pump TsNS 180-1900 for raising the head to 2200-2300 m for a delivery of 200 m 3 /h. In [1] is shown the prospect of use of two-tier (two-row) blade cascades (Fig. 1) in impellers of centrifugal pumps for head elevation. In the noted case, a solution was found through addition of a second tier (row) of shortened blades (which ensured head elevation by ≈7 % of the total increment) and enlargement of the outer diameter of the impeller within the permissible limits as well as through some adjustment of the geometry of the entering elements of the guide device. Also, from [2] it is evident that head elevation depends on the radius of the entry point of the additional blades as well as on the position of the leading (entering) edge in the interblade channel. The maximum head elevation occurs in the case where the start of the short blades lies on the radius on which the relative speed curve changes sharply on the operating side of the blade (the circumfluence was calculated by the Rauchman method [3]). These conclusions are validated as well by studies of liquid flow in the impeller channel of high-speed pump [4]. Evidently, the degree of influence of the position of the leading (entering edges of the additional row of blades on the head and the quantum of loss, which determines the change in efficiency, may be different for a specific blade system.In this work, the problem of determination of the best position of the leading edge of the...

The article presents the results of research devoted to the design and numerical calculation of a low-flow high-head centrifugal pump with Barske-type impeller using computer simulation methods. The main features of fluid flow hydrodynamics, as well as the influence of a number of design geometry on the energy and cavitation characteristics of the pump, are found. The focus is on the analysis of the influence of the end gap between the impeller blades and the casing, as well as the cavitation qualities of the pump. The issue of cavitation qualities of a pump with different geometry of the pump inlet area investigated. In addition, a comparison of different outlet types and the selection of the best option provided. Analysis of the importance of installing the ribs in the suction line, taking into account the vortex structure of the flow in the impeller, was carried out. In addition, the results of changes in energy characteristics when pumping a working fluid with high kinematic viscosity are given.