Global Energy

RAR RUS 7-22 Rassokhin Victor GONG Bowen IZBIAKOV Nikita Barskov Victor viktorbarskov@ntcmtt.ru HUA Lun MODERNIZATION OF THE EXPERIMENTAL STAND FOR VALIDATION OF NUMERICAL MODELING OF SUPERCRITICAL CARBON DIOXIDE TO AIR AS A WORKING FLUID FOR TURBOMACHINES By the middle of the century, electricity generation will more than double, leading to increased greenhouse gas emissions, which increase the likelihood of global warming. One of the most promising ways to generate electric energy is the Brayton cycle with supercritical carbon dioxide as a working fluid. This fluid has a high energy density and stable thermal and chemical properties. To further investigate the gas dynamics and structural characteristics of the turbine flow paths operating on supercritical carbon dioxide, it is necessary to create a full-scale experimental stand. However, the properties of the working fluid are not yet fully understood, that is why the creation of such a stand requires high costs and increased safety measures, since its operation is characterized by high temperature and pressure. In this work, supercritical carbon dioxide to air is simulated using the similarity technique. To validate numerical experiments conducted in Ansys Workbench software package, an experimental stand at Peter the Great St. Petersburg Polytechnic University was selected. A comprehensive evaluation of technical condition of the stand was conducted, and some units were replaced and modernized. As part of the stand preparation, thermal and resource calculations of the bearings were performed, and new oil injection nozzles for the bearings were designed and manufactured. Tests of the oil system were conducted, which showed that the volumetric flow rate meets the optimum values from the bearing technical data sheet. The volumetric flow rate of water in the system was also measured. A modern measuring system was developed, ensuring high experimental accuracy and allowing to obtain the main characteristics of the turbine in real time for further experimental studies. 10.18721/JEST.30301 621.4 supercritical carbon dioxide Brayton cycle turbomachinery experimental stand theory of similarity validation https://engtech.spbstu.ru/article/2024.129.1/ Gun%2C-Izbyakov%2C-Barskov.pdf

RAR RUS 23-42 Klimenko Vladimir Klimenko Aleksandr V. Tereshin Alekseii MIKUSHINA Olga V. PROSPECTS FOR ACHIEVING CARBON NEUTRALITY BY DEVELOPING COUNTRIES The article examines the prospects for achieving carbon neutrality by the largest developing countries (China, India, Indonesia, Brazil, Iran, and Saudi Arabia). An analysis of the structure of energy and land use in these countries is carried out. Scenario estimates of the dynamics of carbon indicators for the economies of the countries under study are developed. It is shown that the current pace of decarbonization and development of the carbon capture and storage (CCS) industry in the countries under study do not allow them to fulfill their commitments to achieve climate neutrality in 2050–2070. This goal cannot be achieved before the end of the century. The central challenge in achieving climate neutrality is the rapid and large-scale implementation of CCS technologies in all their possible manifestations. Of the countries under study, however, only China and Brazil have their own carbon storage capabilities for more than a hundred years. Despite the fact that climate change occupies almost a leading place on the global agenda, the actual results of efforts in this area are far from declared, and it is no longer possible to keep warming within 1.5°C. The key task is to minimize the time that the global climate system remains in the dangerous extreme zone (above 1.5°C), which will require the creation of a global economy with negative greenhouse gas emissions. 10.18721/JEST.30302 620.9 developing countries energy greenhouse gas emissions and absorption climate neutrality scenarios https://engtech.spbstu.ru/article/2024.129.2/ Klimenko%2C-Klimenko%2C-Tereshin%2C-Mikushina.pdf

RAR RUS 43-51 ZAITCEVA Maria Y. Erutin Danil Popovich Anatoliy popovicha@mail.ru Sufiiarov Vadim EFFECT OF PRE-HEATING DURING SELECTIVE LASER MELTING OF CHROMIUM STEEL ON STRUCTURE AND PROPERTIES The paper presents the results of investigation of the influence of platform pre-heating temperature during selective laser melting (SLM) and subsequent heat treatment on the microstructure, phase composition and mechanical properties of chromium steel. The dependence of the porosity of the compact material on energy density of SLM was revealed. The microstructure of the samples is characterized by narrow grains elongated along the building orientation. During printing with platform pre-heating, the average length of grains increases from 156 to 563 μm, while the average width stays the same, about 30 µm. After heat treatment, carbides of the MC and M23C6 types are located at the grain boundaries. X-ray diffraction patterns of the samples contain peaks corresponding to the body-centered cubic lattice. Platform pre-heating during SLM process allowed to increase the ductility of the material by 6% (from 12 to 18%), while maintaining the strength properties. The results showed that the application of platform pre-heating and subsequent heat treatment enables to control the microstructure and mechanical properties. 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.30303 621.762 selective laser melting additive manufacturing chromium steel platform pre-heating heat treatment https://engtech.spbstu.ru/article/2024.129.3/ Zaytseva%2C-Erutin%2C-Popovich%2C-Sufiyarov.pdf

RAR RUS 52-63 MIKULENKO Anastasia D. PANCHENKO Evgenii V. Ozhegov Mikhail Naumov Anton RESEARCH AND MODELING OF THE TEMPERATURE FIELD DURING FRICTION STIR SPOT WELDING OF SHEET ALUMINUM ALLOYS This work is devoted to the study of the distribution of temperature fields during friction stir spot welding (FSSW) of 2 mm thick aluminum sheets made of Al5Mg and V95AT using computer modeling. The model was created in the DEFORM-2D/3D software package for modeling metal forming processes. As a result of the work, a FSSW process model was created for aluminum alloys Al5Mg and V95AT, which was verified using experimental temperature measurement data using thermocouples. Using a verified model, the influence of process parameters on the temperature fields of aluminum alloys was studied. The results of the study showed that the main influence on the temperature increase during FSSW is the rotation speed of the tool, as well as the thermal conductivity of the material itself. The complication of the shoulder geometry, in particular the application of threads, additionally increases heat generation and the abrupt behavior of the temperature. 10.18721/JEST.30304 621.791.1 computer modeling friction stir spot welding aluminum alloys Al5Mg V95AT1 thermal cycles temperature field DEFORM-3D https://engtech.spbstu.ru/article/2024.129.4/ Mikulenko%2C-Panchenko%2C-Ozhegov%2C-Naumov.pdf

RAR RUS 64-72 Abdrakhmanova Anna Sotov Anton Zaytsev Alexander Popovich Anatoliy popovicha@mail.ru ADDITIVE MANUFACTURING OF POLYMER FUNCTIONAL CELLULAR STRUCTURES WITH SHAPE MEMORY EFFECT USING FDM TECHNOLOGY The paper investigates the effect of printing modes using FDM technology and annealing heat treatment on the ratio of recovery to the original shape and temporary shape fixation on samples made of elastic polymers with shape memory effect. The experiments showed that for all the studied polymers, the optimal recovery ratio is achieved by selecting the printing mode with an upper limit in the extrusion temperature range recommended by the manufacturer and annealing to remove residual stresses. The results of the conducted investigation showed the optimal values of the recovery and shape fixation ratios equal to 98.6% and 94.5%, respectively. 10.18721/JEST.30305 621.763 additive manufacturing FDM printing thermoplastic polyurethane shape memory effect cellular structure shape recovery shape fixation https://engtech.spbstu.ru/article/2024.129.5/ Abdrahmanova%2C-Sotov%2C-Zaytsev%2C-Popovich.pdf

RAR RUS 72-82 TEPLUKHIN Gelii N. TEPLUKHIN Vasilii G. KUZNETSOV Ruslan V. Radkevich Mihail THE EFFECT OF CARBON CONTENT ON THE MARTENSITE START TEMPERATURE IN NICKEL-ALLOYED STEELS Retained austenite is a very important structural component, especially in high-alloy and high-carbon steels. With certain alloying and heat treatment, its amount can be up to 95–98%. Therefore, it is essential to determine the start temperature of the martensitic transformation (martensite point) depending on the chemical composition. At present, there is no definite expression for this dependence. Researchers use numerous calculation models and experimental data. In this paper, the dependence of the martensite point on the carbon content in steels alloyed with a non-carbide-forming element – nickel – is considered. The work uses a structural method for determining the martensite point using a high-temperature metallographic unit. Actually, nickel has the greatest effect on the martensite point in low-carbon steels. With an increase in the carbon content, the effect of nickel weakens, and for steel 143N4, the martensite point is even higher than in carbon steel with a similar carbon content. It was found that at high carbon content, even while rapid cooling, graphitization occurs. It should be considered the reason for the increase in the martensite point. 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 13–16, 2024. 10.18721/JEST.30306 621.785-97 retained austenite martensite point carbon content alloy steel high-temperature metallography graphitization https://engtech.spbstu.ru/article/2024.129.6/ Tepluhin%2C-Tepluhin%2C-Kuznetsov%2C-Radkevich.pdf

RAR RUS 83-91 Voevodenko Daniil Starikov Kirill Popovich Anatoliy popovicha@mail.ru RESEARCH OF THE INFLUENCE OF SELECTIVE LASER MELTING PARAMETERS ON THE FORMATION OF DEFECTS AND MICROSTRUCTURE IN NICKEL-BASED SUPERALLOYS The paper investigates the effect of various parameters on the selective laser melting (SLM) process on the formation of defects and microstructure in nickel-based superalloys. Experimental specimens were fabricated using a High-Temperature Layer-by-Layer Laser Synthesis Plant “Mercury” equipped with an inductive high-temperature heating system. By varying the energy parameters of the SLM, data on the dependence of the linear energy density on the number and types of emerging defects, such as macro-cracks and micro-defects, were obtained. The results showed that an increase in linear energy density contributes to a significant reduction of defects in the structure of the samples. Based on the analysis, the features of microstructure formation and the causes of defects at different SLM modes were revealed. The obtained results can be used to optimize the process parameters and improve the quality of products made of nickel-based superalloys manufactured by the additive manufacturing method. 10.18721/JEST.30307 621.762 selective laser melting defects directional structure nickel-based superalloy γ′-phase https://engtech.spbstu.ru/article/2024.129.7/ Voevodenko%2C-Starikov%2C-Popovich.pdf