Global Energy

RAR RUS 7-23 KINDRA Vladimir MAKSIMOV Igor ZUIKIN Roman ROGALEV Nikolay ROGALEV Andrey DEVELOPMENT AND RESEARCH OF TRINARY CYCLE POWER PLANTS WITH STEAM COOLING OF GAS TURBINES The task of increasing the efficiency of the domestic electric power industry is important for ensuring the sustainable development of the country. Today, the most efficient technology for producing electricity in large volumes is based on the use of a binary steam-gas cycle. At the same time, the potential for increasing the efficiency of combined-cycle power units remains quite high. In particular, a possible way to increase energy efficiency may be to reduce the consumption for cooling the hot path of a gas turbine by switching from air to steam coolant. The use of air as a coolant has found wide application due to the possibility of its intake from the compressor stages, but the thermophysical properties of the air environment predetermine a relatively high consumption for the cooling system and, as a consequence, a reduced level of energy efficiency of a gas turbine unit. An alternative solution may be to use water vapor taken from a steam turbine or waste heat boiler as a coolant. Such a transition will lead to a reduction in cooling costs due to ensuring the required level of heat transfer at lower cooling flow rates. The objective of the work is to develop and study combined-cycle power plants with steam cooling of gas turbines and an additional cycle on a low-boiling coolant for utilization of low-potential heat of exhaust gases. In this work, a method for recalculating an air coolant to a steam one is described and estimates of the effect of such a replacement on the total consumption of the cooling medium for the GTPP-160 gas turbine unit are given. In addition, based on mathematical modeling, it was found that in a trinary cycle, replacing the air cooling system with a steam one will lead to an increase in net efficiency by an average of 1.23% when extracting steam from the steam turbine compartment and by 0.53% when generating steam in a separate low-pressure steam generator. 10.18721/JEST.30401 621.311.22 combined cycle gas turbine gas turbine steam cooling trinary cycle energy efficiency https://engtech.spbstu.ru/article/2024.130.1/ Rogalev%2C-Rogalev%2C-Kindra.pdf

RAR RUS 24-36 Mikhailov Vladimir SuKhorukov Yuriy teploobmen@ckti.ru. Lanin Aleksandr Homenok Leinid Esin Sergey Kolenov Evgeniy V. Shevoldin A. Gorynin Vladimir z1dehy97@mail.wplus.net JSC "Atomproekt" Rogozhkin Vladimir JOINT SOLUTION OF FRESHWATER AND CLIMATE ISSUES OF WATERLESS AND DESERT REGIONS The article proposes an aerocondensate technology for joint regulation of freshwater resources and climate for the purpose of large-scale water supply for the population, humidification of deserts and arid lands in Saudi Arabia, Africa and other climatically problematic regions. The technical and economic characteristics of the COOLERs megasystem with a capacity of waste-free industrial collection of freshwater condensate of up to 30 thousand tons/day and with the generation of high-altitude umbrella clouds of the cirrus type with a thickness of 0.5–2.0 km and a mass from 10 tons to several thousand tons are formulated to reduce solar radiation by 40% over an area of up to 100 thousand square kilometers to ensure access of humid marine atmospheric masses to the territory of deserts and the continent. Freshwater condensate is produced due to the presence of virtually unlimited and environmentally friendly atmospheric moisture of the seas and oceans by using a turbocompressor system for cooling the air during its adiabatic expansion. The basis for the implementation of the aerocondensate technology for regulating water resources and climate is the electrical energy of nuclear power plants and thermal power plants in problematic regions. 10.18721/JEST.30402 621.319.4 aerocondensate technology joint regulation fresh water climate natural basis technical and economic characteristics COOLERs megasystem atmospheric moisture of the seas industrial collection of freshwater condensate https://engtech.spbstu.ru/article/2024.130.2/ Gorinin%2C-Rogozhkin%2C-Mihaylov.pdf

RAR RUS 37-52 Popovich Anatoliy popovicha@mail.ru Repnin Arseniy Borisov Evgenii INVESTIGATION OF MULTI-MATERIAL SAMPLES WITH THREE-DIMENSIONAL COMPOSITION CHANGE OBTAINED BY SELECTIVE LASER MELTING METHOD The aim of this work was to develop a technology for the manufacturing multi-material VZh159/CuCr1Zr samples using selective laser melting with a change in chemical composition in three directions. The microstructure was investigated using an optical microscope, a scanning electron microscope was used to analyze the chemical composition, and the phase composition was estimated using X-ray diffractometer. Mechanical tests were carried out on universal testing machines. It was found that the microstructure of the CuCr1Zr alloy zone was columnar grains with epitaxial growth along the direction of sample fabrication. There is a interfacial zone between the two alloys, in which the alloys are mixed. It has an average chemical composition, no new phases are formed in it, and peaks corresponding to the phases for both alloys are observed. The interfacial zone continues to exist until the sixth layer of CuCr1Zr alloy is deposited and melted onto VZh159 alloy (approximately 300 µm). The multi-material samples showed mechanical properties more than 2 times higher values in tensile tests (430 MPa vs 203 MPa), but did not exceed the values for VZh159 (1202 MPa). The relative elongation in tension and compression of the multi-material sample was less than that of VZh159, CuCr1Zr and Inconel 718. The analysis of multi-material samples with a change in chemical composition in three directions showed that the presence of an alloy mixing zone in one printing layer of 350–400 µm will be sufficient to eliminate defects. The materials of the article were presented at the International Scientific and Practical Conference “Advanced Engineering Technologies (AET 2024)” held in St. Petersburg on May 13–17, 2024. 10.18721/JEST.30403 621.762 selective laser melting multi-materials mechanical properties VZh159/CuCr1Zr https://engtech.spbstu.ru/article/2024.130.3/ Repnin%2C-Borisov%2C-Popovich.pdf

RAR RUS 53-64 ZAKHAROV Pavel MIHAILOVSKIY Georgiy Nguyen Van V. FORMATION OF WEAR-RESISTANT LAYERS BY ARC WELDING USING FLUX-CORED WIRES The problem of increasing the wear resistance of parts operating under conditions of abrasive wear is very important today. There are many technologies and alloying systems used to create wear-resistant layers. A promising technology in terms of productivity and obtaining thick surfacing layers is arc welding using flux-cored wires. The article discusses the formation of layers using flux-cored wires, followed by the study of microstructure, microhardness, and X-ray diffraction analysis. The results show that the use of arc welding in shielding gases and flux-cored wires allows one to obtain high-quality coatings without surface defects such as cracks and pores. Also, microstructure data show that when arc welding performs with ПП-НП80Х20Р3Т wire, a dendritic structure with chromium carbides is formed along the grain boundaries, and layers made with ПП-НП80Х20Р3Т wire are characterized by the highest hardness value compared to other wires considered in this work. 10.18721/JEST.30404 621.791.011 arc welding chromium carbide microhardness wear-resistant coatings martensite https://engtech.spbstu.ru/article/2024.130.4/ Mihaylovskiy%2C-Nguen%2C-Zaharov.pdf

RAR RUS 65-73 Popovich Anatoliy popovicha@mail.ru Voevodenko Daniil Starikov Kirill RESEARCH OF MICROSTRUCTURE AND CHANGES IN CHEMICAL COMPOSITION OF DOMESTIC ANALOGUE OF HEAT-RESISTANT NICKEL ALLOY GTD111 AFTER SELECTIVE LASER MELTING The paper presents the results of the study of microstructure and chemical composition of the domestic analogue of heat-resistant nickel alloy GTD111 obtained by selective laser melting (SLM). A detailed study of the morphology of the powder used in the process, as well as an analysis of the structure and phase composition of the obtained samples were carried out. Special attention is paid to the influence of alloying elements, such as tantalum, on the formation of topologically close-packed phases and their distribution in the alloy. The results of the work demonstrate the compliance of the chemical composition of the final material with the initial specifications, and also emphasize the importance of adjusting the chemical composition to optimize the properties of the alloy. The obtained data allow us to draw conclusions about the prospects of application of rhenium-free nickel alloys in high-temperature conditions, as well as the potential of using SLM technology to create topologically complex and thermostable structural materials. 10.18721/JEST.30405 621.762 selective laser melting chemical composition directional structure nickel-based superalloy GTD111 γ′-phase https://engtech.spbstu.ru/article/2024.130.5/ Voevodenko%2C-Starikov%2C-Popovich.pdf

RAR RUS 74-86 Ermakov Boris NECHAEV Daniil KARPOV Ivan Shvecov Oleg shvec_off@mail.ru LEBEDEV Mikhail USE OF POLYMER COMPOSITE MATERIALS IN CONSTRUCTION AND DEVELOPMENT OF DEPOSITS ON PERMAFROST SOILS Current trends in the development of the oil and gas sector of the Russian Federation predetermine the development of new oil and gas fields in the most remote and hard-to-reach regions of the country. These are mainly the northern and northeastern territories, characterized by almost complete absence of transport routes, small population and complex geological features – permafrost soils, and high level of waterlogging of the surface – active – layer. The paper presents the results of a comprehensive study of the influence of these factors on the performance of bored piles for the foundations of field development made of fiberglass pipes. The possibility of monitoring the actual state of pile material by non-destructive method, by installing and studying the degradation of properties of witness samples, is shown. The use of laboratory studies to assess the actual state can hardly be considered optimal, since it requires long-exposures of material samples in specialized containers, which is quite difficult to implement in the conditions of production laboratories. 10.18721/JEST.30406 678 permafrost soils fiberglass pipes pile foundations degradation of PCM properties under low-temperature operation conditions water absorption witness samples https://engtech.spbstu.ru/article/2024.130.6/ Shvetsov%2C-Lebedev%2C-Ermakov.pdf

RAR RUS 87-95 BLINOV Sviatoslav LEVITSKY Alexey. Zotov Oleg zog-58@mail.ru GOLUBKOV Nikita FEATURES OF PHASE TRANSFORMATIONS IN EQUILIBRIUM AND NONEQUILIBRIUM STATE IN 40С2 STEEL PRODUCTS In this paper, the processes of microstructure formation in 40С2 steel depending on various cooling rates were studied. The study began with constructing a polythermal section of the equilibrium phase diagram for the given chemical composition of steel using Thermo-Calc software. This made it possible to determine the temperatures at the start and end of phase transformations. Next, the microstructure of steel was examined at various cooling rates: 1, 10, 20, 50 and 100 °C/s. Each of these cooling rates led to the formation of different structural elements in steel, such as ferrite, pearlite and martensite. These structural changes directly affect the mechanical properties of the material, such as strength and hardness. As a result, a thermokinetic diagram of austenite decomposition for 40С2 steel was constructed. This diagram reflects the relationship between temperature and time required to transform austenite into more stable phases at various cooling rates. The results of the study are of significant importance for understanding and optimizing heat treatment technologies in accordance with the requirements for the specified mechanical properties of the final product. 10.18721/JEST.30407 669.017.3 thermokinetic diagram microstructure cooling rate clip https://engtech.spbstu.ru/article/2024.130.7/ 1Zotov%2C-Golubkov%2C-Blinov%2C-Levitskiy.pdf

RAR RUS 96-105 LEVITSKY Alexey. BLINOV Sviatoslav Zotov Oleg zog-58@mail.ru GOLUBKOV Nikita INVESTIGATION OF THE EFFECT OF HEAT TREATMENT MODES ON THE STRUCTURE AND MECHANICAL PROPERTIES OF 40С2 STEEL BAR CLIPS BY PHYSICAL MODELING Using physical modeling methods on a Gleeble 3800-GTC machine, heat treatment of 40С2 steel bar clips was simulated. Modeling was performed on 6 mm diameter samples, which is acceptable for modeling the heat treatment of an 18 mm diameter bar due to the high hardenability of 40C2 steel. The study showed the effect of heat treatment modes on the structure formation. It was found that the best mechanical properties are achieved after preliminary heating with high-frequency currents (HFC) – 940±10℃, quenching – 860±10℃ and tempering – 350±10℃. The negative effect of low heating temperature with HFC in combination with low quenching temperature was also shown. 10.18721/JEST.30408 669-15 clips heat treatment microstructure mechanical properties https://engtech.spbstu.ru/article/2024.130.8/ Zotov%2C-Golubkov%2C-Levitskiy%2C-Blinov.pdf

RAR RUS 106-118 Repnin Arseniy Popovich Anatoliy popovicha@mail.ru GRACHEVA Anna POLOZOV Igor DEVELOPMENT AND INVESTIGATION OF COMPOSITIONS FOR GRADIENT COMPOSITE MATERIALS OBTAINED BY SLM Functionally graded materials (FGMs) are promising materials characterized by gradual transitions either in composition, or in microstructure, or in density. Additive manufacturing can be used to enhance the potential of these materials. An analysis of existing studies of FGMs obtained by selective laser melting (SLM) shows that the research on the effect of changing the number of particles on the structure and properties is poorly represented. Studies of composite FGMs with a large number of reinforcing particles, especially using high-heating equipment, are limited. The aim of this work is to study composite samples of VZh159 + WC, the compositions of which can be used to manufacture FGMs by SLM. To achieve this goal, defects, microstructure, chemical and phase compositions, as well as hardness in composite samples have been investigated. An important aspect of this work is to investigate the possibility of obtaining FGMs from metals with a high content of reinforcing particles using high-temperature heating by SLM method. It was found that after the manufacture of composite samples by SLM method, undissolved WC particles and pores in the granules of this material are visible in them, there are no other defects. When the WC content in the composite materials increases, there is a change in the microstructure – an increase in the number of WC dendrites in the composite matrix. In the samples of VZh159 + 20% WC in the matrix, a certain amount of W is observed, which could get there from the disintegrated WC granules. It was found that with the increase in the amount of WC in composite samples, the microhardness of the matrix increases and reaches 1122.9 HV at 80% WC. 10.18721/JEST.30409 621.762 laser melting composite materials functionally graded materials high-temperature heating WC VZh159 https://engtech.spbstu.ru/article/2024.130.9/ Gracheva%2C-Polozov%2C-Repnin%2C-Popovich.pdf

RAR RUS 119-129 Ermakov Boris Shvecov Oleg shvec_off@mail.ru YALYGIN Sergey SHAPOSHNIKOV Nikita THE EFFECT OF OPERATING TEMPERATURE ON THE NATURE OF FRACTURE AND FATIGUE PROPERTIES OF WELDED JOINTS MADE OF STEEL 10 PIPE BLANKS The effect of microstructure on fatigue properties and fracture mechanisms of welded joints of steel 10 used in pile foundations has been experimentally investigated. It has been established that the cause of the occurrence and development of repeated cracks in building structures where repair welding work was performed in the cold season is the high cooling rate of the welded joint, leading to the appearance of an overheating of the Widmanstätten structure in the section of the heat-affected zone. Accordingly, such structures are unsuitable for the perception of alternating loads. However, in order to ensure the operability of repair welded joints made in the cold season, it is necessary to perform additional technological operations that reduce the cooling rate. 10.18721/JEST.30410 553.981.2:658.58 piles steel 10 HAZ Widmanstätten microstructure fatigue endurance limit fatigue failure https://engtech.spbstu.ru/article/2024.130.10/ Yaligin%2C-Shaposhnikov%2C-Ermakov%2C-Shvetsov.pdf