Global Energy

RAR RUS 7-20 Galerkin Yuriy galerkin@pef.spbstu.ru Rekstin Drozdov Alexandr A_drozdi@mail.ru Marenina Lyubov' N. EFFECT OF GAS FLOW IN IMPELLER-HOUSING GAPS OF CENTRIFUGAL COMPRESSOR STAGE ON EFFICIENCY AND AXI-AL FORCE When operating powerful centrifugal compressors, in particular, pipeline compressors, some modes of operation pose problems with the thrust bearing capacity. Back in 1970, the senior of the authors carried out a numerical study of the effect of flow rotation in the housing–impeller gaps. It was shown that in the impeller–shroud gap the flow rotates faster than in the gap near the main disk. The reason is that the leakage flow of the labyrinth seal of the shroud enters this gap. The flow introduces the rotation created by the impeller blades. The authors made a compu-tational CFD study of the effect of friction stress in the housing–shroud gap on the thrust force and efficiency of the centrifugal stage. Calculations of a stage with an impeller diameter of 409 mm are made with a hydraulically smooth housing wall in the gap near the shroud at rough-ness of 0.25, 05, 0.75, 1.0, 1.5 mm. With a roughness of 0.25 mm, the axial force decreased by 21% at the cost of reducing the efficiency by 0.5% for a stage with a flow coefficient Φ = 0.0492. With a roughness of 1.5 mm, the efficiency decreased by 0.9%, and the axial force de-creased by 32.6%. In exceptional cases and as a temporary measure to decrease the thrust force, it is possible to use deceleration of the flow in the gap at the shroud disk. A special calculation showed the role of leakage in the labyrinth seal. With a hermetic labyrinth seal, the efficiency would be higher by 0.9%, the loading factor would be higher by 0.8%, and the axial force would be less by 22.8%. The calculation also showed that during corrosion of the housing walls within both gaps, friction losses on the surfaces slow down the flow rotation in both gaps, reduce the efficiency, but have practically no impact on the thrust force. 10.18721/JEST.28401 621.515 centrifugal compressor stage impeller cavity parasitic losses disc friction coefficient leakage coefficient https://engtech.spbstu.ru/article/2022.122.1/ Galerkin%2C-Rekstin%2C-Drozdov%2C-Marenina.pdf

RAR RUS 21-30 Sinitsin Anton Akhmetova Irina Soloveva Olga NON-DESTRUCTIVE THERMAL CONTROL OF A STRUCTURALLY INSULATED ENCLOSURE The requirements for modern structures to ensure the energy efficiency of buildings must be implemented through an accurate diagnosis of the situation before the actual modernization of the building. This paper describes the benefits of non-destructive thermal testing for evaluating building performance and designing accurate energy retrofit projects for the residential sector. Infrared diagnostics allows you to quickly and accurately assess the performance of building en-velopes, identify areas where high heat losses are observed for their subsequent elimination. This article presents the technical features of thermal imaging of the building envelope of a block-modular multi-apartment residential building. To prioritize building modernization measures, thermal imaging identifies areas of high heat loss and low insulation efficiency. Based on the rel-evance and practical significance of building thermography when considering issues of energy saving and energy efficiency, the authors presented some features and results of external and in-ternal thermography using the example of a dwelling in an apartment building. 10.18721/JEST.28402 621.386 energy saving building modernization thermal infrared radiation non-destructive testing heat loss https://engtech.spbstu.ru/article/2022.122.2/ Sinitsin%2C-Ahmetova%2C-Soloveva.pdf

RAR RUS 31-45 Griffiths Steven Uratani Joao ZERO AND LOW-CARBON AMMONIA SHIPPING FUEL . . https://engtech.spbstu.ru/article/2022.122.3/ Stiven-Griffits%2C-Dzhoao-Uratani.pdf

RAR RUS 59-78 Bozieva Ayshat Zadneprovskaya Elena Allakhverdiev Suleyman BIOHYDROGEN PRODUCTION: RECENT ACHIEVEMENTS AND STATE OF THE ART The growing population of the planet, the increase in demand for energy, the depletion of fossil fuels and the detrimental effect of their combustion products on the ecological state of the biosphere, as well as on global climate change, are not only urgent problems of our time, but also a powerful incentive to search for alternative energy sources. Molecular hydrogen is an energy carrier with a high specific heat of combustion and a zero carbon emission, since water is formed as a result of the oxidation of hydrogen. H2 produced by microorganisms is called “biohydrogen”. This review considers the modern achievements of science in the field of studying hydrogen bioenergy. 10.18721/JEST.28404 579.69 biohydrogen biophotolysis cyanobacteria microalgae photosynthesis https://engtech.spbstu.ru/article/2022.122.4/ Bozieva%2C-Zadneprovskaya%2C-Allahverdiev.pdf

RAR RUS 79-89 Fedyukhin Akhmetova Irina Solovev Sergei EFFICIENCY ANALYSIS OF MODERN HEAT-INSULATING MATERIALS FOR HIGH-TEMPERATURE PIPELINES The strategy for improving the efficiency and environmental friendliness of heat supply systems should be based on reducing the consumption of thermal energy by the end consumer, as well as reducing losses in the production and transmission of thermal energy. One of the topical areas of research is the development of heat-insulating materials with high heat-insulating properties. This work is devoted to the study and comparison of the properties of heat-insulating materials, as well as the problems that arise during their installation and operation. Mineral wool and aerogel are considered as an example. The prospect of replacing high-temperature thermal insulation, which is widely used in industry, with a modern material developed on the basis of aerogel was studied. The temperature gradient across the thickness of the thermal insulation was calculated using a numerical tool developed in ANSYS. The results show that aerogel outperforms mineral wool in all key thermophysical characteristics. At the same time, the only obstacle to the widespread industrial production and use of aerogel in the high-temperature thermal insulation segment is its market value, which is still several times higher than that of mineral wool with equivalent thermal insulation characteristics. 10.18721/JEST.28405 621.396.93:614.8 high-temperature thermal insulation aerogel thermal conductivity numerical simulation experiment https://engtech.spbstu.ru/article/2022.122.5/ Fedyuhin%2C-Ahmetova%2C-Solovev.pdf

RAR RUS 90-109 Sokolov Yuriy s5577@inbox.ru SIMULATION OF THE PRODUCTION SYSTEM OF ELECTRON BEAM WELDING The article explores the internal laws of the production system (PS) of electron beam welding (EBW) using the theory of hierarchical systems, which offers various ways of decomposition of a complex system in the form of hierarchies of strata, organization and complexity of decision making. The article considers a stratified representation of PSs for electron beam welding. The given hierarchical abstraction, consisting of technological, instrumental, measuring, informational, algorithmic and system strata, is a tool for in-depth description of the PS, its elements and relationships. The stratified representation of the PS allows revealing the interaction of inherently heterogeneous levels and inter-level connections that have different interfaces. The hierarchical abstraction given in the article, consisting of technological, instrumental, measuring, informational, algorithmic, system strata , reveals the content of the EBW PS, which is characterized by a consistent vertical arrangement of subsystems, the priority of the actions of the upper-level subsystems, the dependence of the actions of the upper-level subsystems on the actual execution by the lower levels of their functions. 10.18721/JEST.28406 621.791.722: 621.762.04 production system; structure; strata; equipment; design; process; electron beam; control; measurement; algorithms https://engtech.spbstu.ru/article/2022.122.6/ Sokolov.pdf

RAR RUS 110-122 Nguyen Van T. Balanovskiy Andrey Nguyen Van V. FEATURES OF THE FORMATION OF SURFACE LAYERS DURING PLASMA HEATING OF TIN BRONZE PRE-COATING We experimented with obtaining surface layers by plasma heating of a pre-coating of tin bronze (PRV-BrO10 alloy) of various thicknesses (0.25; 0.5; 1.00 mm) when exposed to various currents (100; 140; 160 A). The resulting layers have different depths of the hardened layer and different structures. With a pre-coating layer thickness of 0.25 and 0.5 mm, high current easily causes defects. With a thicker pre-coating layer (1 mm), the dissolution of tin bronze into steel is limited. Low current of the plasma arc (100 A) limits the diffusion and transformation of the molten pool sufficient to saturate the thick pre-coating layer (0.5 and 1 mm) with alloying elements. Saturated zones rich in iron are represented by high dispersion and microhardness, which is mainly in the range of 400–600 HV. 10.18721/JEST.28407 691.735: 669.017.15: 620.183 surface layer formation plasma heating tin bronze structure microhardness current strength pre-coating https://engtech.spbstu.ru/article/2022.122.7/ Nguen-(OSOBENNOSTI)%2C-Balanovskiy%2C-Nguen.pdf

RAR RUS 123-135 Nguyen Van T. Balanovskiy Andrey Nguyen Van V. ESTIMATION OF ABRASIVE WEAR RESISTANCE OF PLASMA ALLOYED LAYERS BASED ON TIN BRONZE AND CHROMIUM CARBIDE This paper presents a study of the characteristics and resistance to abrasive wear of surface alloyed layers during plasma heating of a mixture containing tin bronze and chromium carbide. It was established that depending on the composition of the mixture, the thickness of the coating, the processing mode, the resulting layers differ in structure, chemical and phase composition. The addition of chromium carbide with a mass fraction of 20% makes it possible to increase the microhardness of the alloyed layer based on tin bronze up to 700 HV with the formation of a martensitic structure. Tests for abrasive wear were carried out at a load of 5, 20, 50 N and with codirectional rotation of the holder to the abrasive wheel. The obtained results showed that the wear resistance of the Fe-Cu-Sn and Fe-Cr-C-Cu-Sn alloyed layers is higher compared to the Cu-Sn layer. In particular, the Fe-Cr-C-Cu-Sn layer is the best option. 10.18721/JEST.28408 620.178.162: 539.53 abrasive wear alloyed layer chromium carbide tin bronze microhardness wear resistance surface hardening https://engtech.spbstu.ru/article/2022.122.8/ Nguen-(OTsENKA)%2C-Balanovskiy%2C-Nguen.pdf

RAR RUS 136-146 Ryzhenkov Artem Volkov Alexander V. Trushin Evgeniy Cherepanov Sergey CHANGE OF WETTABILITY OF STAINLESS STEEL SURFACE BASED ON LASER TEXTURING OF RELIEF The use of hydrophobic metal surfaces in heat and power equipment makes it possible to reduce hydraulic resistance and the rate of formation of deposits during transportation of liquid media, to intensify heat exchange processes. To achieve the hydrophobic state on the surface it is necessary to create a micro-roughness in the form of a multimodal relief and to reduce the surface energy. One of the most promising ways to create structured relief is laser modification of the surface (laser ablation). The paper presents the results of studies to determine the influence of laser energy density on the geometric characteristics of the formed relief and wettability properties of the surface of stainless steel grade AISI 304. It was found that by forming a structured relief with a subsequent decrease in surface energy using a surface-active substance, it is possible to achieve an angle of wetting of 149.6° at the energy density of laser radiation of 200 J/cm2. https://doi.org/10.18721/JEST.28409 62-45 energy efficiency hydrophobicity wetting angle laser radiation relief https://engtech.spbstu.ru/article/2022.122.9/ Rizhenkov%2C-Volkov%2C-Trushin%2C-CHerepanov.pdf