Global Energy

RAR RUS 7-20 Sokolova Ekaterina Sadeghi Khashayar Abolghasem Mehran Ghazaie Seyed Hadi AAU-2845-2020 56042381200 0000-0002-6289-325X Peter the Great St. Petersburg Polytechnic University, Russia Sergeev Vitaly vitaly.sergeev@spbstu.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

Savitskaya Anna CYCLING OF A THERMAL ACTUATOR MADE OF NITI ALLOY MANUFACTURED BY SELECTIVE LASER MELTING This article presents the results of a study on the shape recovery characteristics of a thermal actuator with complex geometry during cyclic actuation. The actuator was fabricated from a nickel-titanium shape memory alloy (Nitinol) using selective laser melting. Cyclic testing was conducted over 20 cycles at a strain of 25.53%. The phenomenon of shape memory effect stabilization during cycling was observed. The shape recovery ratio of the thermal actuator was determined throughout the cycling process. It was found that the shape recovery ratio stabilized at 99% or higher between cycles 9 and 20, with a maximum value of 99.59% achieved at cycle 17. The accumulated irreversible strain after cycling was determined to be 10.46%. The minimum irreversible strain per cycle was 0.10% at cycle 17. The study confirms the functionality and effectiveness of the selected thermal actuator geometry, demonstrating the promise for further research and development in this area. 10.18721/JEST.32207 621.762 thermal actuator titanium nickelide selective laser melting cycling https://engtech.spbstu.ru/article/2026.136.1/ sokolova_sadegi_abolgasem_i_dr_.pdf

RAR RUS 21-28 Busarov Sergei S. Bakulin Konstantin OPERATION OF A FLEXIBLE PISTON STAGE Modern piston compressors have relatively high performance characteristics, with a delivery ratio of at least 0.85 in many cases. The main potential for further performance improvement lies in reducing the impact of clearance volume, which accounts for 10–15%. There are known designs in which the clearance volume is practically eliminated through the use of elastomeric elements. This article examines the operation of a piston compressor stage with a flexible piston, which, through deformation of the end surface made of an elastomer, allows the working chamber volume to be increased at the bottom dead center position. Thus, under the operating conditions considered, the performance increase ranges from 6 to 40%. The operating process itself is also of interest. Indicator and temperature charts show faster pressure rise and temperature increase when using the proposed design. Further studies will present the results of modeling the elastic deformation state of the elastomeric element, determining the actual capabilities of existing materials for increasing the chamber volume. 10.18721/JEST.32202 621.513 mathematical model piston stage performance clearance volume flexible piston https://engtech.spbstu.ru/article/2026.136.2/ busarov_bakulin.pdf

RAR RUS 29-43 Shengxi Feng FEDOTOV Nikita Mannanov E. Feklistov Efrem Shikova Tatiana Belko Viktor NUMERICAL STUDY OF A GRADED CORONA PROTECTION DESIGN FOR THE END-WINDING PART OF A HIGH-POWER TURBOGENERATOR STATOR BAR A numerical study was conducted to optimize the design of a graded corona protection system for the end-winding part of a high-power turbogenerator stator bar. Using parametric electro-thermal modeling in COMSOL Multiphysics, the influence of material nonlinearity, multi-stage architecture, coating thickness, and applied voltage level on electric field distribution and thermal loss density were analyzed. It was established that materials with nonlinear conductivity are necessary to achieve safe electric field strength levels. For high-power, high-voltage generators (≥ 26 kV), a three-stage design with a specific resistance gradient is optimal and meets technical requirements. It was found that the primary heat generation zone is located in the corona protection stage closest to the slot, and the increase in losses exhibits a significantly nonlinear dependence on voltage. An optimal coating thickness range (0.2–0.4 mm) was determined to ensure reliable operation under test overvoltages. The results provide a methodological basis for designing corona protection systems, thereby reducing the scope of full-scale tests. 621.3 10.18721/JEST.32203 turbogenerator stator winding stator bar insulation system partial discharge corona protection system nonlinear materials numerical simulation electro-thermal modeling https://engtech.spbstu.ru/article/2026.136.3/ fen_fedotov_mannanov_i_dr_.pdf

RAR RUS 44-58 Emelyanov Oleg oaemel2@gmail.com Greshnyakov Georgii Chesnokov Evgenii PULSED THERMAL MODE OF POWER CABLE: A COMBINED NUMERICAL ANALYTICAL APPROACH FOR CALCULATION The article presents the results of modeling the temperature regime of the electric cable under conditions of a pulse load with high current pulse duty cycle. In these conditions, the IEC and CIGRE standards are not applicable. Therefore, a numerical model for calculating the electrical thermal regime in the COMSOL Multiphysics environment has been proposed. The current pulses are characterized by the pulse front of 10 ms and exponential decrease over several tens of seconds, with a maximum value of 1.5 kA, followed by a 1200-second period, which corresponds to operating modes of the ITER thermonuclear reactor. After approximately 18000 seconds, the core temperature reaches a steady-state periodicity. At the same time, the estimated time required for the task is about 40 hours and depends on the cooling conditions and the pulse period. Based on the calculation of the initial transient temperature function for a single pulse, we propose a numerical and analytical approach to calculate the steady-state electrothermal mode. This significantly reduces the calculation time to 2 hours. 10.18721/JEST.32204 621.315.2.016.2 pulse cable temperature transient state numerical-analytical calculation steady-state mode https://engtech.spbstu.ru/article/2026.136.4/ emelyanov_greshnyakov_chesnokov.pdf

RAR RUS 59-72 Sokolova Ekaterina Ghazaie Seyed Hadi Dehghani Fatima Sadeghi Khashayar AAU-2845-2020 56042381200 0000-0002-6289-325X Peter the Great St. Petersburg Polytechnic University, Russia Sergeev Vitaly vitaly.sergeev@spbstu.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

Sizova Elizaveta INTEGRATION OF HIGH-TEMPERATURE ELECTROLYSIS WITH A MODULAR SUPERCRITICAL CO2 FAST REACTOR: A TECHNO-ECONOMIC ASSESSMENT This paper presents the results of a techno-economic analysis of integrating a small modular supercritical CO2-cooled fast reactor (SMSC-GFR) with a high-temperature steam electrolysis unit for combined electricity and hydrogen production. Three power cycle confi-gurations are considered: subcritical Rankine, supercritical Rankine, and closed Brayton cycle using supercritical CO2. Thermodynamic modeling is performed in Aspen HYSYS, while the economic assessment employs a custom methodology that accounts for equipment modularity and learning effects. The Brayton cycle achieves the highest efficiency in both standalone (48.8%) and cogeneration (53.1% at 0.6 kg/s H2) modes. This cycle also exhibits the lowest power loss factor (0.36), providing a distinct advantage in system scalability. As the number of reactor modules increases from 1 to 10, the levelized cost of hydrogen decreases from $3.81 to $3.28 per kilogram. The findings confirm the viability of modular nuclear-hydrogen systems based on the SMSC-GFR and Brayton cycle, combining high thermodynamic performance, scalability, and economic competitiveness. 10.18721/JEST.32205 621.039.5:661.961.1 small modular reactor supercritical carbon dioxide high-temperature steam electrolysis Brayton cycle cogeneration levelized cost of hydrogen https://engtech.spbstu.ru/article/2026.136.5/ sokolova_gazai_dehgani_i_dr_.pdf

RAR RUS 73-84 Peter the Great St. Petersburg polytechnic university Kalimov Alexander VAZHNOV Sergey ZAIB Shah APPLICATION OF A MODIFIED PERTURBATION AND OBSERVATION METHOD FOR TRACKING THE MAXIMUM POWER POINT IN PHOTOVOLTAIC SYSTEMS The Perturb and Observe (P&O) method is a widely used algorithm for the Maximum Power Point Tracking (MPPT) in photovoltaic systems. This study presents a modified version of the P&O algorithm aimed at improving the efficiency of this process. The study highlights the limitations of the classical P&O method under conditions of rapidly changing irradiance and temperature, which lead to delays and incorrect decisions in achieving the MPP. To overcome these problems, it is proposed to modify the P&O algorithm by introducing adaptive perturbation of the output voltage and additional analysis of power variations. This modification makes it possible to increase the accuracy of MPPT, reduce power fluctuations, and improve the overall efficiency of the algorithm under discussion. The study implements both the classical P&O algorithm and its modified version using MATLAB Simulink software. The results demonstrate that the proposed MPPT algorithm is superior to traditional schemes, providing improved tracking characteristics, higher accuracy, and increased efficiency of photovoltaic systems. 10.18721/JEST.32206 621.311.243 solar panel photovoltaic system perturb and observe method maximum power point step-up DC-DC converter https://engtech.spbstu.ru/article/2026.136.6/ kalimov_vazhnov_zaib.pdf

RAR RUS 85-94 Yasmeen F. Tarek M. Basith M.A. Metal oxide-based hybrid supercapacitors with aqueous electrolytes . . https://engtech.spbstu.ru/article/2026.136.7/ (na_russ_)_yasmin_tarek_basit.pdf

RAR RUS 108-118 NOVICHKOV Maksim GURIN Sergey AGAFONOV Dmitry PECHERSKAYA Ekaterina CHEMICAL DEPOSITION OF PLATINUM ON ION-EXCHANGE MEMBRANES WITH PREFORMED GROWTH CENTERS The article discusses a combined method for the formation of a catalytic coating on the surface of polymer electrolytic membranes. The proposed approach combines preliminary magnetron sputtering of platinum to create adsorption centers and subsequent chemical precipitation of the metal from solution. A comparative analysis of various compositions of solutions for chemical precipitation was carried out and the optimal composition based on hexachloroplatinic acid, hydrazine and ammonium hydroxide was determined, ensuring the formation of a uniform and durable coating at a temperature of 20–22 °C. It has been experimentally shown that the combined technology makes it possible to create a porous nanostructured surface with high adhesion of the catalytic layer, resistant to mechanical stress. The study of the operating characteristics of the membrane-electrode unit demonstrated a significant increase in hydrogen production compared to samples obtained only by magnetron sputtering or only by chemical deposition. 10.18721/JEST.32208 541.138 catalyst electrochemical activity ion-exchange membrane hydrogen fuel cell https://engtech.spbstu.ru/article/2026.136.8/ novichkov_gurin_agafonov_pecherskaya.pdf

RAR RUS 119-130 Voevodenko Daniil POLOZOV Igor Popovich Anatoliy popovicha@mail.ru INVESTIGATION OF THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF SAMPLES WITH A TPMS STRUCTURE MADE OF TI-10TA-2NB-2ZR ALLOY OBTAINED BY SELECTIVE LASER MELTING The microstructure, phase composition, and mechanical properties of dense and porous specimens made of biocompatible β-titanium alloy Ti-10Ta-2Nb-2Zr produced by selective laser melting (SLM) were investigated. An optimal processing window (volumetric energy density of 61.7–94.1 J/mm3) was established, yielding a relative density of up to 99.92%. The as-built condition exhibited a fine acicular α′-martensitic structure, which provided high strength (ultimate tensile strength of 642 MPa, yield strength of 552 MPa) together with a reduced elastic modulus of 88 GPa. Annealing at 900 °C resulted in recrystallization and formation of an equilibrium lamellar α+β structure, further decreasing the elastic modulus to 85 GPa while maintaining sufficient ductility (elongation ~20%). To mimic trabecular bone, triply periodic minimal surface (TPMS) structures (Schwartz, Gyroid, Split) with 50% porosity were fabricated. Their effective elastic modulus (9.1–9.6 GPa) is comparable to that of bone tissue, thus addressing the stress shielding issue. The obtained results demonstrate the high potential of the Ti-10Ta-2Nb-2Zr alloy and SLM technology for manufacturing personalized orthopedic implants with improved biomechanical compatibility. 10.18721/JEST.32209 621.762 selective laser melting β-titanium alloy triple periodic minimum surfaces TPMS modulus of elasticity biocompatible implants mechanical properties https://engtech.spbstu.ru/article/2026.136.9/ voevodenko_polozov_popovich.pdf