The reliability of pumping units at nuclear power plants (NPPs) is critical in terms of their energy efficiency and safety. Remarkably, WWER-1000 reactors at Ukrainian NPPs are equipped with outdated pumping units that have already served their full-service life. This fact leads to an urgent need to develop a new, more efficient pump. In the article, a promising pump, ACNA 600-35, was developed. It was designed to increase the energy efficiency of pumps TX 800/70/8-K-2E, applied at the holding pool and the industrial circuit of the nuclear reactor. Since these pumps should be imported from the monopoly suppliers, this affects both the energy efficiency of pumping equipment and the energy independence of Eastern Europe. The proposed pump ACNA 600-35 is characterized by an increased efficiency of up to 0.12–0.13 compared with the TX 800/70/8-K-2E pump. In general, the life cycle cost of the proposed pump is 15–20% lower than for the analog TX 800/70/8-K-2E. The design of the developed pump ACNA 600-35 and the related pumping unit based on its production at industrial facilities allows for further development of the industrial and fuel-energy complex, increasing the state’s energy independence and employment. According to expert estimates, the average economic effect from supplying the developed pump can reach 10 mln USD/year.

Developing ways to increase centrifugal pumps’ pressure and power characteristics is a critical problem in up-to-date engineering. There are many ways to resolve it, but each has advantages and flaws. The presented article aimed to ensure higher energy efficiency indicators by using a counter-rotating pumping stage with trimming. During the research, the comprehensive approach was based on CFD modeling and the Moore–Penrose pseudoinverse approach for overestimated systems. According to the obtained data, pumps with a counter-rotating stage allowed the pressure head to be significantly increased compared with the standard design of the flow part. Notably, for pumping units CPS 180/1900 with a basic stage, the pressure head of 127 m was reached. However, when using a counter-rotating stage, the pressure head could be increased up to 270 m, which was 2.1 times higher. Therefore, to ensure unchanged characteristics when using centrifugal pumps with the counter-rotating stage, the weight and size indicators can be significantly reduced compared to the traditional design scheme. The proposed numerical and analytical approaches allow estimating the highest pressure and energy characteristics values.

Author(s): Mandryka A.1*, Majid A. P.2, Ratushnyi O.1, Kulikov O.1, Sukhostavets D.1 Affiliation(s): 1 Department of Applied Hydroaeromechanics, Sumy State

The paper raises the question of the possibility of reducing the energy loss of the stage of the centrifugal pump on the disk friction, the relative value of which for the stages of low and ultralow speed can be a significant proportion (up to 40%) of all losses. This is seen as one of the effective ways to increase the efficiency of such stages of centrifugal pumps.

The presented research examines the impact of the high viscosity factor of the pumped liquid on the performance characteristics of oil well centrifugal pumps. It aims to develop a refined semi-empirical technique for predicting the performance curves of small-sized oil submersible pumps, specifically at the working stages of a series of electrical submersible centrifugal pumps (ESPs), taking into account the influence of high rotation speeds. To solve this problem, experimental research methods were employed, and a computational-analytical approach was developed based on the fundamental laws of hydrodynamics. The article also presents scientific substantiation of the influence of the high rotation speed factor on the degree of proportionality of changes in the energy efficiency of pumping highly viscous liquids by small pump stages, using similarity laws. As a result, a calculation technique was proposed, which contains empirical coefficients determined experimentally. As a result, a comprehensive technique was developed to predict the performance characteristics of high-speed ESPs when pumping highly viscous liquids. Practical recommendations for industrial applications were also provided. Overall, the essential problem of coordinating the operational characteristics of submersible oil pumps and wells was solved by adjusting the rotation speed, thereby reducing the impact of the pumped viscous medium on the pumping parameters. Based on the research results, the operating characteristic ranges for the corresponding standard-size series submersible centrifugal oil pumps were determined, for which the developed refined technique provided reliable calculation results.

The article is devoted to studying the contra-rotating stages with different impellers and blade discs. Determining the reduction of volumetric losses by modeling the contra-rotating stages in the software package ANSYS CFX. The work aimed to create and study the flow and characteristics: semi-open, closed impellers, and blade discs. As a result of the work, the following contra-rotating stages were determined and compared: the semi-opened impeller with the semi-opened blade disc; the closed impeller with the closed blade disc; the semi-opened impeller with the closed blade disc; the closed impeller with the semi-opened blade disc. As a result of research, fluid flows in contra-rotating stages and their characteristics in the form of pressure and efficiency were obtained. According to the obtained data, the expediency of using contra-rotating stages as a working body of the pump is written.