Power Technology and Engineering

Rastorguyev, I. A.; Mukhina, L. N.

doi: 10.1007/s10749-023-01666-xpmid: N/A

The article substantiates the design solutions by creating a three-dimensional groundwater flow model to obtain predictive water inflows into the designed vertical and horizontal drainage systems for the periods of construction and operation of hydroelectric power plants.

Tsimbelman, N. Ya.; Bekker, A. T.

doi: 10.1007/s10749-023-01667-wpmid: N/A

The paper presents the results of studies aimed at developing a computational modeling methodology for calculating the stress-strain state of hydraulic structures containing thin shells filled with soil.

Musayev, V. K.

doi: 10.1007/s10749-023-01668-9pmid: N/A

The article considers mathematical modeling of unsteady plane, diffraction, surface, and flexural waves in various complex-shaped objects. To solve this problem, the research uses the wave equation of solid mechanics. Based on the finite element method, a technique, an algorithm, and a software system for solving linear unsteady dynamic problems of the theory of elasticity have been developed. The Fortran-90 programming language was used to design the software system. The area under study is divided by the space and time coordinates into linear finite elements. An explicit two-layer scheme is obtained. The article proposes a quasiregular approach to solving a system of linear second-order ordinary differential equations in displacements with initial conditions and to the approximation of the area under study. The technique is based on the following schemes: point, line, and plane. The study makes comparison with the results of both analytical and experimental methods, as well as considers the problem of the plane longitudinal elastic wave action on a free circular hole. The article also deals with the problem of the plane longitudinal elastic wave action on a reinforced circular hole and the problem of the seismic unsteady wave action on concrete dams with a foundation (the Kurpsay and Koyna dams) under the influence of a plane longitudinal elastic wave. Flexural waves predominate in the considered seismic dam safety problems. The performed investigation of the unsteady wave stress state shows that the numerical simulation results correspond to the post-earthquake damage patterns observed in the Koyna Dam. The research solves the problem of mathematical modeling of unsteady elastic stress waves in a half-plane with an air-filled cavity (the width/height ratio is one to ten) under seismic action as well as for a localized explosive loading in the triangular pulse form (Dirac delta function).

Tolstikov, V. V.; Tareq, S. S.

doi: 10.1007/s10749-023-01669-8pmid: N/A

The results of studying the load-bearing capacity of a dam made of cemented sand and gravel (CSG) are presented. The dam was considered to have a homogeneous symmetrical profile with horizontal equivalent m = 0.5. CRACK software was used. The results of the study lay the foundation for further analysis of the safety of CSG dams.

Volgina, L. V.

doi: 10.1007/s10749-023-01670-1pmid: N/A

Two options for the transportation of a mixture of lignin and water are considered. One option is to rehabilitate an existing pipeline using the modern sliplining method. In this case, the capacity of the pipeline decreases, which leads to an increase in friction losses. The second option is to lay a new pipeline. The average velocity ensuring two-phase flow without sedimentation is calculated. The proposed options are analyzed.

Golubev, A. V.

doi: 10.1007/s10749-023-01671-0pmid: N/A

The results of studying pumping stations of service water systems (SWS) used to cool the condensers of high-power steam turbines are described. The features of transient processes during start-ups of pumping units at stations with different configurations and equipment are considered. Such systems are classified according to the transient conditions. The main characteristics of the software in terms of the factors taken into account and the mathematical apparatus used, the features of the processes in the condenser of a steam turbine, the energy characteristics of angular-flow pumps are given. The start-up processes in various SWS systems (with spillways, with cooling towers, with or without control valves) and the limitations of the parameters of starting processes that ensure their successful and safe operation are described. The transient processes are studied using the method of mathematical simulation and taking into account the elasticity of water.

Gutkin, Yu. M.

doi: 10.1007/s10749-023-01672-zpmid: N/A

Ajustification of the invariance of the general active soil pressure under the local force impact on the wedge of failure is presented. Amethod for redistributing the lateral soil pressure with height is proposed, when the upper console of the face wall of the bulwark heaps against the ground. The bulwark calculation results, obtained by considering such redistribution, are provided. A good agreement with the experimental data is shown.

Vasilchenko, K. I.; Georgievskaya, E. V.; Bashmakov, A. O.

doi: 10.1007/s10749-023-01673-ypmid: N/A

The article presents the key findings of an inspection of the technical condition and calculations for the strength and durability of the supporting structures of a hydroelectric generator and discusses the recommendations for the repair and reinforcement of structural elements. There are contradictions between the unsatisfactory actual technical condition of the structure and their “very good” technical condition index.

Okhapkin, G. V.

doi: 10.1007/s10749-023-01674-xpmid: N/A

The article discusses approaches to a digital transformation of the choice of technical solutions for restoring concrete bulk structures of hydraulic engineering structures (HES). The current state of the HES concrete structure is one of the most pressing issues of recent times. Particularly, choosing established technical solutions for restoring concrete is crucial. The imperfection of the regulatory and technical foundation is one of the most significant problems with the current state of the HES that can be resolved using digital transformation. The research led to the development of an algorithm for selecting technical solutions for restoring the bulk structure of HES concrete.

Smetanin, V. I.; Zhogin, I. M.

doi: 10.1007/s10749-023-01675-wpmid: N/A

The paper presents the methodology of dredging and the use of a sorting and distributing device that sorts, distributes, and stacks larger particles of the solid phase of the slurry in the side prisms and smaller particles and screening in the middle part of the backfill dams or dumps. These are the final link in the technological chain of dredging operations.