Global Energy

RAR RUS 7-17 AbaYdullin Bulat RAYKOVSKY Nikolai ZHUKOV Aleksandr INVESTIGATION OF THE CHARACTERISTICS OF AN OIL-FREE ROTARY-VANE COMPRESSOR WITH A NEW DESIGN SCHEME In this paper, comparative theoretical studies of the influence of design and operating parameters on the characteristics of an oil-free rotary-vane compressor with traditional and new design scheme are performed. The main system of calculation equations for conducting research is presented. As a result of the theoretical study, it was found that at a rotor speed of an oil-free rotary-vane compressor stage from 1000 rpm to 2000 rpm for the considered variants of design schemes, high values of the coefficient are not provided. The traditional design of an oil-free rotary-vane compressor does not allow for high values of effective energy conversion efficiency (more than 70%). At the same time, the use of a new design scheme in an oil-free rotary-vane compressor makes allows for effective efficiency values at a rotor speed of less than 3000 rpm. Based on the given conditions, namely: λ ≥ 0,8 and ηeff ≥ 0,75, the following design recommendations can be made: ensure the rotor speed n = 3000 rpm, cylinder radius Rc ≥ 0,075 m. 10.18721/JEST.31201 621.514 rotary-vane compressor new design scheme method theoretical studies energy characteristics https://engtech.spbstu.ru/article/2025.132.1/ Kalashnikov%2C-Raykovskiy%2C-Zhukov.pdf

RAR RUS 18-28 KOCHETKOVA Elena LEBEDEVA Alla MINEVICH Tatiana Modulina Aleksandra tee.deep@eef.spbstu.ru CALCULATION OF THE LEAKAGE INDUCTANCE OF THE WINDING END PART OF AN ASYNCHRONIZED SYNCHRONOUS GENERATOR (ASG) BASED ON THE SCALAR POTENTIAL METHOD The construction of a three-dimensional calculation model of a magnetic field based on replacing the eddy field of currents with a potential field of magnetic charges is considered. The method allows introducing a generalized scalar potential in the calculation domain, including areas occupied by current. The proposed method allows taking into account the diversity and complexity of the design of an electrical device, which is shown by a practical example of constructing a quasi-potential model containing various types of fictitious magnetic charges replacing real currents. The model is formed to calculate the magnetic field generated by a section of the frontal part of the winding of an asynchronized synchronous generator. Numerical implementation of the problem of calculating the magnetic field is proposed to be performed by a variational method using the finite element method. Minimization of the functional is carried out on a set of values of the scalar magnetic potential at nodes that are vertices of volumetric elements. The results of the magnetic field calculation are supposed to be used for further calculation of the leakage inductance of the end parts of the rotor windings. 10.18721/JEST.31202 621.3 magnetic field generalized scalar potential end part asynchronous synchronous generator leakage inductance https://engtech.spbstu.ru/article/2025.132.2/ Kochetkova%2C-Lebedeva%2C-Minevich%2C-Modulina.pdf

RAR RUS 29-41 Busarov Sergei S. Yusha Vladimir L. ANALYSIS OF TEMPERATURE CONDITIONS OF COMBINED MULTI-STAGE COMPRESSOR UNITS BASED ON SCREW OIL-FILLED AND PISTON LOW-SPEED LONG-STROKE COMPRESSORS The article considers the temperature conditions of combined multi-stage compressor units based on screw oil-filled and piston low-speed long-stroke compressors as part of air and nitrogen mobile compressor stations. Based on the results of the calculation and theoretical studies, the relationship between the design of low-flow medium- and high-pressure booster piston compressors based on long-stroke low-speed stages with their temperature conditions and the thermal load on heat exchangers has been established. It has been shown that at a fixed operating mode of a low-pressure screw oil-filled compressor, the use of booster piston compressors based on a low-speed long-stroke stage allows reducing the thermal load on heat exchangers and ensuring a safe temperature regime during operation in a wide range of atmospheric temperatures. The results obtained allow us to predict improvements in the specific overall dimensions and weight characteristics of mobile compressor stations. 10.18721/JEST.31203 621.51+621.56 combined multi-stage compressor units screw compressor piston compressor low-speed long-stroke stage working processes gas temperature overall dimensions weight https://engtech.spbstu.ru/article/2025.132.3/ Busarov%2C-Yusha.pdf

RAR RUS 42-56 MOZZHEGOROVA Yulia ILINYKH Galina KOROTAEV Vladimir CARBON FOOTPRINT OF A SOLID OXIDE FUEL CELL POWER PLANT Currently, interest in solid oxide fuel cell (SOFC) power plants as small-scale generation facilities has increased. To assess the carbon footprint of fuel use in a SOFC power plant, it is necessary to take into account the stages of the fuel and power plant life cycles. The article presents an integrated approach to assessing the life cycle of SOFC power plants and analyzing their environmental impact. The main parameters, characteristics, and resources used to assess the life cycle stages of SOFC power plants are presented, and the contribution of materials to the carbon footprint of power plant production is assessed. A 2.5 kW SOFC pilot power plant developed in Russia was used for the research. Based on the carbon footprint assessment of the SOFC power plant under consideration, it was determined that the main contribution is made by the operation stage (about 70%), while the total carbon footprint was 516.9 g CO2-eq./kWh. It was determined that the carbon footprint of the considered power plant based on SOFC with a capacity of 2.5 kW is comparable to the carbon footprint of other power plants, which indicates its efficiency in terms of greenhouse gas emissions. 10.18721/JEST.31204 504.75/620.9 solid oxide fuel cell small generation power plants carbon footprint life cycle assessment https://engtech.spbstu.ru/article/2025.132.4/ Mozzhegorova%2C-Ilinih%2C-Korotaev.pdf

RAR RUS 57-69 Kadi-Ogly Evgeny B-7916-2013 6601971248 0000-0002-1173-8727 Peter the Great St. Petersburg Polytechnic University, Russia Korovkin Nikolay nikolay.korovkin@gmail.com

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

CALCULATION METHOD FOR MAGNETIC FIELD, CURRENTS, LOSSES, AND LEAKAGE REACTANCE IN THE BAR-TYPE ARMATURE WINDING OF INDIRECTLY COOLED AC ELECTRICAL MACHINE BASED ON STRAIGHTEN MODEL The paper describes a calculation method for the distribution of the magnetic field, currents, losses, and leakage reactances in the slot parts of bar-type armature winding of indirectly cooled AC electrical machines performed on the base of finite element method of AC magnetic field modeling in a 2D formulation considering electric circuit. The implemented method accounts for the transposition of the strands of the bars along the length of the slot part, the location of the bars in the stator slot, the features of the machine slot geometry and the diagram of armature winding connections, giving the opportunity to simulate different conditions of the winding operation. The method is based on straighten model of generalized electrical machine, which allows to simplify the problem without considerable loss of the solution accuracy. A comparative analysis of the calculation results demonstrates the acceptability of the proposed method. This method could be recommended for calculating various modes, losses and inductive reactances of transposed AC windings in the design and analysis of electrical machines with indirect cooling. 10.18721/JEST.31205 621.313.322 electrical machine armature winding with indirect cooling strand transposition AC magnetic field strands field-circuit formulation losses leakage reactances straighten model of an electrical machine https://engtech.spbstu.ru/article/2025.132.5/ (1)-Kadi-Ogli%2C-Korovkin.pdf

RAR RUS 70-84 KRAFT Vadim JAYASINGHE Nilan Borisova Margarita VAGANOV Gleb CHARGE ACCUMULATION AND RELAXATION IN FILM AND FIBROUS POLYIMIDES The processes of accumulation and relaxation of the space charge largely determine the main characteristics of insulating materials: conductivity, polarization, dielectric losses and long-term electrical strength, therefore, the service life of the insulation. The accumulation of the space charge is an undesirable phenomenon, because it distorts the electric field, worsens the electrical strength and reduces the life of the insulation. On the other hand, the value of the space charge and its stability over time determines the ability of sensors and microphones to operate. This paper presents the results of studying the electrophysical properties of thermoplastic polyimides (TP PI) R-BAPB, R-BAPS, obtained on the basis of 1,3-bis-(3,3’,4,4’- dicarboxyphenoxy)benzene (R dianhydride), 4,4’-bis-(4”-aminophenoxy)biphenyl (diamine BAPB) and bis-(4-aminophenoxy)diphenylsulfone (diamine BAPS) and thermosetting polyimide PMDA-ODA (based on pyromellite dianhydride (PMDA) and 4,4’-oxidiphenylenediamine (ODA)). Particular attention was paid to the analysis of the effect of the material structure on its ability to retain charge for a long time (electret effect). The properties of PMDA-ODA materials made in the form of a film obtained by casting and a nonwoven material obtained by electroforming were studied. The stability of the electret potential difference over a long period of time and in a wide temperature range was measured. The characteristics of relaxation processes were determined by thermal activation spectroscopy methods. The mechanisms of charge accumulation and relaxation, the effect of temperature and electric field in the sample on the stability of the space charge were considered. The results of experimental studies were analyzed based on theoretical models and modern concepts of charge relaxation processes. 10.18721/JEST.31206 691.175.5/.8 charge accumulation charge relaxation thermoplastic polyimides R-BAPB R-BAPS PMDA-ODA nonwoven fabric relaxation processes TSD https://engtech.spbstu.ru/article/2025.132.6/ Kraft%2C-Dzhayasinghe%2C-Borisova%2C-Vaganov.pdf

RAR RUS 85-96 Kadi-Ogly Evgeny B-7916-2013 6601971248 0000-0002-1173-8727 Peter the Great St. Petersburg Polytechnic University, Russia Korovkin Nikolay nikolay.korovkin@gmail.com

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

RESULTS OF VARIANT CALCULATIONS OF MAGNETIC FIELD, CURRENTS, LOSSES, AND LEAKAGE REACTANCE IN THE BAR-TYPE ARMATURE WINDING OF INDIRECTLY COOLED AC ELECTRICAL MACHINE BASED ON FIELD-CIRCUIT FORMULATION The article presents the results of variant calculations of magnetic field, currents, losses, and leakage reactances in the slot parts of bar-type armature winding of indirectly cooled AC electrical machines performed on the base of finite element analysis of AC magnetic field problem in a 2D formulation considering electric circuit. The implemented method accounts for the design and transposition of the strands of the bars along the length of the armature slot part, the location of the bars in the armature slots, the features of the indirectly cooled machine slot geometry and the diagram of armature winding connections. The method is based on straighten model of generalized electrical machine, which allows to simplify the problem without considerable loss of the solution accuracy. For the parameters of the windings of a generalized electrical machine, the article presents the dependences of losses in the winding bars, coefficients of stray losses (Field factors) and slot leakage reactances on the dimensions of the strands and geometric dimensions of the slots. An analysis of the impact of parametric variations on the efficiency and dynamic characteristics of the machine is carried out. A comparison of the obtained results provides prerequisites for searching for the optimal dimensions of slot geometry. 10.18721/JEST.31207 621.313.322 electrical machine armature winding with indirect cooling strand transposition AC magnetic field simulation simulation of processes in strands of the armature winding field-circuit formulation losses leakage reactances straighten model of an https://engtech.spbstu.ru/article/2025.132.7/ Kadi-Ogli%2C-Korovkin.pdf

RAR RUS 97-113 Repnin Arseniy Borisov Evgenii Popovich Anatoliy popovicha@mail.ru FORMATION OF INTERLAYER IN MULTI-MATERIAL INCONEL 718 AND TI6AL4V ALLOY PRODUCTS OBTAINED BY SELECTIVE LASER MELTING This study examines the Inconel 718/Ti6Al4V multi-material with Cu and Cu+Nb interlayer produced by selective laser melting (SLM). To achieve this, it is important to investigate the microstructure, the chemical and phase composition, and the hardness of the interfacial zone in the multi-material samples, as well as to determine the effect of the use of interlayer on the mechanical properties of multi-material samples. It was observed that no significant defects were present in the alloy regions (Ti6Al4V and Inconel 718) of multi-materials. However, defects were identified in the Cu and Nb regions, as well as in the Cu/Nb interfacial zone. The interfacial zones of the Ti6Al4V/Nb and Inconel 718/Cu exhibited a sharp transition in the chemical composition. A comparable pattern was observed in Ti6Al4V/Cu interfacial zone, while the Nb/Cu interfacial zone exhibited a gradual transition from one element to another. The formation of island macro-segregation was observed in all interfacial zones: Ti6Al4V/Cu, Ti6Al4V/Nb, Nb/Cu and Inconel 718/Cu. No new phases were identified in the production of the multi-material samples. The multi-material samples with the Cu+Nb interlayer exhibited enhanced mechanical properties compared with samples with Cu interlayer. The tensile strength of the multi-material sample with Cu interlayer reached 790 MPa, while with the Cu+Nb interlayer reached 910 MPa. These values are relatively high, but nevertheless lie below Inconel 718 or Ti6Al4V alloy properties. 10.18721/JEST.31208 621.762 selective laser melting multi-materials interlayer Inconel 718 Ti6Al4V https://engtech.spbstu.ru/article/2025.132.8/ Repnin%2C-Borisov%2C-Popovich.pdf

RAR RUS 114-124 KRAVTSOV Dmitry Arsentyeva Xenia xenia.ars@gmail.com Mamutov Viacheslav vmamutov@mail.ru STEPANOV Andrei COMBINED TESTS FOR DETERMINATION OF MECHANICAL PROPERTIES OF KOVAR-COPPER BIMETAL The article describes the production experience in developing a technological process for manufacturing the “Header” part made of 0.18 mm thick Kovar-Copper bimetal. Examples of defects arising during the manufacture of the part according to the technological process, which was analytically calculated using the derived analytical methods, are given. The need for computer modeling of the main manufacturing operations for production of “Header” part, as well as the need for determination of mechanical properties of the blank material is shown. A method of tensile testing of non-standard samples and variants of tooling that can be used for determination of different mechanical properties are given, as well as test faults that can occur due to small thickness of samples. A computer model for determination of mechanical properties of the bimetal that cannot be obtained by experiment is developed and adjusted; the prospects for using the model for determination of properties of multilayer materials consisting of two or more layers are described. The mechanical properties of the Kovar-Copper bimetal obtained from experimental and computer studies are given. 10.18721/JEST.31209 620.172.2 sheet metal forming bimetal mechanical properties computer modeling https://engtech.spbstu.ru/article/2025.132.9/ Kravtsov%2C-Arsenteva%2C-Mamutov%2C-Stepanov.pdf

RAR RUS 125-135 KRASIKOV Aleksey MERKULOVA Maria STARITSYN Mikhail PROPERTIES OF NI-P-W COATINGS AND TECHNOLOGICAL FEATURES OF THEIR ELECTRODEPOSITION A study of the electrodeposition of Ni-P-W coatings from pyrophosphate and citrate electrolytes was conducted. It was shown that for active inclusion of tungsten in the coating, it is advisable to use a citrate electrolyte with a temperature of 70°C, which allows obtaining coatings containing 11.5% P and 5% W without microcracks. Heat treatment of the coating of this chemical composition at 350°C leads to an increase in microhardness to a value of 10.1 GPa, which corresponds to hard chromium plating. In this case, a nanocrystalline structure is formed, consisting of the Ni3P and Ni5P2 phases, and a nickel-based solid solution. Due to the mutual diffusion of the base metal and the coating during annealing, the adhesion of the coating increases on both carbon and stainless steels. Exposure of steel samples with a Ni-P-W coating to 3.5% NaCl showed that the coating has high corrosion resistance. In general, the level of properties of the Ni-P-W coating corresponds to hard galvanic chromium, but does not have microcracks. 10.18721/JEST.31210 620-419.8:621 galvanic coatings Ni-P-W coating heat treatment of coatings citrate electrolyte performance properties https://engtech.spbstu.ru/article/2025.132.10/ Krasikov%2C-Merkulova%2C-Staritsin.pdf

MIS RUS 136-143 Moguchev Karachurina Gabidullina Developing Market-Relevant Competencies: USPTU Case Study . . https://engtech.spbstu.ru/article/2025.132.11/ Moguchev%2C-Karachurin%2C-Gabidullina.pdf

MIS RUS 144-145 Bogdanov . . https://engtech.spbstu.ru/article/2025.132.12/ Bogdanov.pdf