Global Energy

RAR RUS 5-22 Babichenko I. Mikhailov A. Sokolov K. 8840090300 Peter the Great St. Petersburg Polytechnic University, Russia Borovkov Alexey

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

Galerkin Yuriy galerkin@pef.spbstu.ru Maksimenko Maksimenko I. A. Rekstin Semenovskiy Vasilii B. swb@neva.ru EXPERIENCE IN GAS DYNAMIC DESIGN OF TURBOEXPANDER CENTRIFUGAL COMPRESSORS. INLET TRACT CFD ANALYSIS Compressors of various purposes and types play an important role in the gas and oil industry. In the gas industry, the installed capacity of centrifugal compressors is about 55 million kW. The role of turboexpander aggregates is quantitatively secondary in comparison with pipeline compressors(about 1 million kW of installed capacity), but without turboexpander aggregates, it is impossible to transport and process natural and petroleum gas. It is important that turboexpander aggregate compressors operate with high efficiency and provide all the variety of possible operating flow rates. The main domestic manufacturer of turboexpander aggregates, JSC Turboholod, has been subcontracting the St. Petersburg Polytechnic University for compressor design since mid-2000. Prof. Y. Galerkin’s Universal Modeling Method has been well proven and widely applied in design practice. SPbPU and JSC Turboholod constantly cooperate since then. By 2021, 22 types of centrifugal compressors have been designed for more than 120 turboexpander aggregates operating in the industry. The unit capacity of the compressor is up to 6500 kW, the outlet pressure is up to 12 MPa, the total capacity of the turboexpanders is more than 400 MW. Although computational fluid dynamic methods still cannot correctly calculate the gas dynamic characteristics of a centrifugal compressor, the calculation of the flow in the stationary elements of the flow path provides correct information. The analysis of the inlet tract, consisting of a supply pipe, a connecting pipe and the compressor inlet nozzle, gave information about the flow structure, showed the problem areas of the inlet tract, made it possible to estimate the loss of efficiency in the tract, and outline the directions for improving this element of the flow path in perspective designs. 10.18721/JEST.27201 621.515 turboexpander aggregate centrifugal compressor computational fluid dynamic inlet tract inlet nozzle the loss coefficient the loss of efficiency https://engtech.spbstu.ru/article/2021.116.1/ Babichenko%2C-Mihaylov.pdf

RAR RUS 23-37 Gorynin Vladimir z1dehy97@mail.wplus.net JSC "Atomproekt" Rogozhkin Vladimir A-9655-2014 7007045735 0000-0001-7385-147X Peter the Great St. Petersburg Polytechnic University, Russia Kondrat'ev Sergey petroprom2013@yandex.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

Mischin Evgeniy B. Kolenov Evgeniy V. Shevoldin A. CLIMATE CONTROL COOLER: THE SOLUTION TO THE DESERT PROBLEM The paper proposes a geoengineering technology and technical system “Land Coolers” for generating high-altitude cloud umbrella-shade zones for the purpose of controlled cooling of the Earth’s surface and surface atmosphere of the desert, a hot place with extreme survival conditions on our planet. This is achieved by obtaining cirrus-type clouds (Cirrus spissatus and Cirrostratus) using the resources of sea moisture, the discharge energy of nuclear or thermal stations (installations) and the dominant flow of high-altitude (geostrophic) winds. System “Land Coolers” (Cooler) can be used to reduce solar radiation not only in deserts and semi-deserts, but also in other dehydrated areas on Earth. The umbrella-cloud technogenic formation of an optically dense shade over the desert contributes to the arrival of marine clouds and rain first to the coastal zone, and then to its deeper areas to soften the desert climate and induce its subsequent greening. Universal system “Land Coolers” can also be used to solve the current problem of water scarcity by waste-free and environmentally friendly production of large volumes of natural fresh water of rain and drinking quality from atmospheric condensate in the sea area. 10.18721/JEST.27202 551.576 water cooler climate regulation desert problems geoengineering technology and the “Land Coolers” system cooling of the Earth’s surface and the surface atmosphere of the desert high-altitude man-made cirrus cloud cover rain precipitation https://engtech.spbstu.ru/article/2021.116.2/ Gorinin%2C-Rogozhkin.pdf

RAR RUS 38-49 Mannanov E. Filin A. ELECTRICAL INSULATION THERMAL STATE OF TURBINE GENERATORS STATOR WINDINGS WITH AIR-COOLING Within the research, mathematical models were developed to evaluate the thermal state of the insulation system in the rods of the stator winding and for a comparative analysis of thermophysical effects on the state of structural elements of the insulation system at the slot part, frontal part of the stator winding and at the zone of winding exit from the slot. The authors analyze the obtained experimental data and the mathematical modeling results of thermophysical processes for the insulation structure implemented using Global VPI and Resin Rich technologies as applied to the air-cooled turbine generator with output of 225 MW. In light of the fact, the standard thermal control system does not provide information about the average and maximum temperature drops across the insulation thickness, the maximum copper temperature of the stator winding rods, the average temperature on the insulation surface, the calculated identification of loaded critical zones in the elements of the insulation structure is a vital task in the design of turbine generators. Adopting sound design decisions minimizes local overheating and increases the insulation system reliability. 10.18721/JEST.27203 62-1/-9 turbine generator main insulation stator winding finite element method thermal state https://engtech.spbstu.ru/article/2021.116.3/ Mannanov%2C-Filin.pdf

RAR RUS 50-61 Kozik Elena S. Bogodukhov Stanislav I. Stanislav I. Garipov V. Shvidenko Ekaterina V. INFLUENCE OF HIGH-TEMPERATURE ION NITRIDING REGIMES ON THE PROPERTIES OF THE VK8 HARD ALLOY The most applicable methods for increasing the resistance of hard alloys are mechanical treatment, application of wear-resistant films and coatings. Along with this, heat treatment is another promising direction of improving the operational properties of cutting tools. The general disadvantages of these methods are a slight increase in durability and insufficient stability of the results obtained. In this regard, we carried out a series of experimental tests aimed at studying the effect of heat treatment of hard alloy products on their performance characteristics (hardness and wear resistance). The use of hardening technologies for processing cutting tools to reduce the instability of its cutting properties remains an urgent problem. There are various methods of hardening carbide cutting tools, which are conventionally divided into three groups: machining, coating and heat treatment, while heat treatment is easy to implement and allows obtaining acceptable results. The modes of heat treatment of powdered hard alloys differ significantly from the modes of processing compact steels. The presence of porosity intensifies many chemical processes during heat treatment due to the significant surface activity of products made of powder materials and increases the sensitivity to oxidation and decarburization during heating for quenching. The purpose of this work was to determine the influence of the effect of heat treatment (change in heating temperatures before quenching and tempering) on the hardness, strength, bending and wear resistance of hard alloy samples. 10.18721/JEST.27204 621.671 hard alloys of the VK8 brand high-temperature ion nitriding hardness strength structure https://engtech.spbstu.ru/article/2021.116.4/ Kozik%2C-Bogoduhov.pdf

RAR RUS 62-72 Vassilyeva Yu. Pak A. SYNTHESIS OF MOLYBDENUM CARBIDE IN SELF-SHIELDING ELECTRIC ARC PLASMA The paper presents the results of vacuum-free electric arc synthesis of catalysts based on molybdenum carbides, which can be used for hydrogen production by electrochemical water splitting. The synthesis of carbide phases is possible due to self-shielding effect of the reaction volume during DC arcing in open-air environment. According to X-ray diffractometry data, there are two phases of molybdenum carbides in the synthesized product: Mo2C and Mo1.2C0.8, the phase of initial molybdenum, and the phase of graphite were identified. In a series of experiments, the authors were able to control the phase composition of the synthesis product by changing the distance between the initial reagents and the zone of initiation and combustion of the arc discharge. The estimated catalytic activity of the synthesized samples is close to the activity of catalysts based on molybdenum carbides obtained by other methods. 10.18721/JEST.27205 66.091.3 molybdenum carbide electric arc plasma vacuum-free method electrocatalyst hydrogen production https://engtech.spbstu.ru/article/2021.116.5/ Vasileva%2C-Pak.pdf

RAR RUS 73-83 Kozik Elena S. Bogodukhov Stanislav I. Stanislav I. Shvidenko Ekaterina V. Rudnev R. HEAT TREATMENT OF VK4 ALLOY In this work, we studied the effect of multiple, stepwise hardening with intermediate tempering on the physical, mechanical and operational characteristics of hard alloys. Alloy VK4 was used as the initial material (non-resurfacing 4-sided plates and sticks with a size of 5×5×35 mm). The physical and mechanical properties of the initial hard alloys WC-Co (VK4) were determined. Then, prospecting work was carried out on 11 modes of heat treatment in salt baths. In each mode,10–15 plates were examined. After conducting prospecting studies, the stages and structural changes in the process of double heat treatment of sintered hard alloys were established. The physical properties of the VK4 hard alloy after heat treatment practically did not change (the coercive force increased by 2 times), however, an increase of 10–30% in ultimate strength in compression and hardness was noted. As a result of the tests carried out, it was found that the plates treated by the proposed methods of heat treatment increased their durability by 1.5–2 times. 10.18721/JEST.27206 621.672 hard alloy VK4 cutting wear physical and mechanical properties,salt baths durability https://engtech.spbstu.ru/article/2021.116.6/ Kozik-Rudnev.pdf