NTU "KhPI" Bulletin: Power and heat engineering processes and equipment最新文献

{"title":"Mathematical Modeling of the Correction of the Shape of the Rotor of the Hydraulic Unit in a Three-Dimensional Setting","authors":"Pavlo Makarov","doi":"10.20998/2078-774x.2023.01.04","DOIUrl":"https://doi.org/10.20998/2078-774x.2023.01.04","url":null,"abstract":"The presented work is devoted to the wedging of the rotor rim of the hydraulic unit to restore its geometry. To assess the technical condition of the rotor, measurements of its shape are performed beforehand. The shape of the rotor is decomposed into a Fourier series, and the location of its geometric axis and ellipticity are determined. Based on this, a decision is made about the need for work on the centering of the hydraulic unit. Then, the vibrations of the critical components of the hydraulic unit are measured at idle without excitation and with excitation, under load in generator and pump modes to assess the possibility of its further operation. At this stage, the reasons for the unsatisfactory vibration condition of the hydraulic unit are determined. At the last stage, the boundary conditions are determined and the problem statement is performed for performing a mechanical calculation in a three-dimensional setting to take into account expansions that compensate for mechanical deformations. The calculation itself is carried out and a decision is made to wedge the rotor rim of the hydraulic unit.","PeriodicalId":416126,"journal":{"name":"NTU \"KhPI\" Bulletin: Power and heat engineering processes and equipment","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133803008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Increasing the Metal Heating Efficiency in High-Temperature Units","authors":"Bogdan Petrik, I. Nazarenko, O.A. Petryk","doi":"10.20998/2078-774x.2023.01.10","DOIUrl":"https://doi.org/10.20998/2078-774x.2023.01.10","url":null,"abstract":"This research paper delves into the improvement of the thermal modes of metal heating in the heating wells and it evaluates the metal heating modes in high-temperature units that affect the quality of products. Consideration was given to the main factors that affect the production cost, namely, slag consumption and conventional fuel consumption at different heating temperatures and metal holding times. The described calculations can be used in industry to improve the production process and reduce the cost of production. The research topic relating to metal heating modes in heating wells is relevant in the context of increasing the efficiency of the production of metal products and reducing production costs. The main problem is the instability of thermal processes in heating wells under variable technological regimes. The purpose of this study was to improve the thermal modes of metal heating in heating wells in order to increase production efficiency and reduce costs. The effect of the technological process delays on thermal processes in heating wells has been studied. To analyze thermal processes in heating wells, a calculation method was used that enabled the assessment of the effect of the changed technological regimes on metal heating indices. The calculation of the thickness of the burning-out crust can be used to preemptively control the metal heating process and prevent the dissection and oxidation of sub-crustal gas bubbles. It will help avoid the formation of such defects as the torn edge and reduce the amount of melted metal, as well as reduce the consumption of slagged metal. The obtained results can be used in the production of metal articles for further research to improve the technological regimes of metal heating in heating wells, in particular, to take into account the influence of other factors on thermal processes and to study the possibilities of using the latest technologies to increase the efficiency and competitiveness of production.","PeriodicalId":416126,"journal":{"name":"NTU \"KhPI\" Bulletin: Power and heat engineering processes and equipment","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130977815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Construction Materials of Active Zones of New Generation Nuclear Reactors","authors":"O. Yefimov, M. Pylypenko, L. Tiutiunyk, T. Harkusha, Tetyana Yesipenko, A. Motovilnik","doi":"10.20998/2078-774x.2023.01.07","DOIUrl":"https://doi.org/10.20998/2078-774x.2023.01.07","url":null,"abstract":"The materials of the article consider the analysis of construction materials of active zones of new generation nuclear reactors. The analysis reflects general ideas about the development of reactor technologies: in the 1950s and 1960s, the first generation of reactors was created; in the early 1970s, the operation of industrial reactors began - reactors of the second generation: pressurized water reactors (WWER, PWR), boiling water reactors (RBMK, BWR), heavy water reactors (CANDU), as well as gas-cooled reactors (AGR). Further development of some types of reactors made it possible to create reactors of the third generation in the 1980s. Priority when choosing directions of development in the category of revolutionary projects should have proposals capable of bringing a new quality to solving the problems of the nuclear energy industry of the future. Promising reactors have advantages in economy, safety, reliability and non-proliferation of nuclear materials. The effectiveness and reliability of structural materials are determined by the totality of changes in the characteristics of the materials as a result of the entire complex of phenomena occurring in them in the field of irradiation, in connection with the changing parameters and operating conditions. The use of high-purity metals as initial components of new structural materials and the development or optimization of their smelting technologies should ensure the required level of characteristics and properties of products made from them. The implementation of these concepts should be ensured by the development of new structural materials: ferritic-martensitic and austenitic steels, nickel and other new alloys.","PeriodicalId":416126,"journal":{"name":"NTU \"KhPI\" Bulletin: Power and heat engineering processes and equipment","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117120192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Development and Investigation of the Diffusion-Stabilizing Burner with the Niche","authors":"O. Chernousenko, L. Butovsky, O. Moroz, A. Kunyk, Dmutro Khilimonchuk","doi":"10.20998/2078-774x.2022.01.08","DOIUrl":"https://doi.org/10.20998/2078-774x.2022.01.08","url":null,"abstract":"The article presents the results of researches of the development and field tests in bench conditions of the microdiffusion stabilizer burner device of a rectangular slot type with a niche deepening along the entire perimeter of the burner. The air passes through a rectangular slot, gaseous fuel for combustion is supplied to the recirculation zone through a system of holes in the end wall of the stabilizer. On the side of the output end of the stabilizer, there is a niche deepening. As studies have shown, the niche deepening is an additional source of stabilization and intensification of torch burning. The experimental data and calculated dependences on the stabilization of the torch in the modes of “poor” disruption are obtained. It is shown that the stable operation of the burner on the lean limit expands – the coefficient of excess air increases with an increase in the width of the stabilizer, the diameter of the gas distribution holes, the coefficient of shading of the burner and air temperature, as well as with a decrease in the speed of the air flow. The research results showed that “rich” flame failure – flame failure with a gradual increase in gas flow occurs at air excess ratios less than unity. This ensures the reliable operation of the burner at the calculated operating modes with respect to the coefficient of excess air a = 1.15 – 6.0 and the air flow speed Wp = 12.0 m/s. A dependence was obtained that determines the influence of regime and design factors on the characteristics of a rich flare failure. The sustainability of the burner operation on the rich limit increases – the coefficient of excess air decreases, with an increase in the width of the stabilizer, the shading coefficient of the burner, air temperature and a decrease in air velocity. The experimental data and calculated dependences on the length of the combustion zone in the burner device are obtained. It was established that at the calculated coefficient of excess air a = 2.0 and higher coefficients, complete combustion of fuel occurs on the length of the combustion space X = 1000 mm. The relative length of the flame decreases when the shading coefficient of the burner and the air temperature increases. Measurements of harmful nitrogen oxides showed that the maximum content of oxides is observed at the coefficient of excess air a = 1.0 and is 125 mg/m3, which is less than the limit values which allowed by regulatory documents.","PeriodicalId":416126,"journal":{"name":"NTU \"KhPI\" Bulletin: Power and heat engineering processes and equipment","volume":"557 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127079816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of the Model for Calculating the Mass of the Coolant of the First Circuit of the Nuclear Power Plant with VVER-1000 Units","authors":"Kostyantyn Koba, S. Lys, T. Kravets, O. Yurasova, I. Galyanchuk","doi":"10.20998/2078-774x.2023.01.12","DOIUrl":"https://doi.org/10.20998/2078-774x.2023.01.12","url":null,"abstract":"During the design of the nuclear power plant with VVER-1000 units, which today form the basis of the nuclear power industry of Ukraine, the development of information and computing systems (IСS) was insufficient to solve many tasks due to the small capacities of computing systems. Currently, newer ones, the computing capabilities of which are thousands of times greater than their predecessors, have replaced many IСS. IСS download currently does not exceed 1 %...2 %, this is due to the use of simplified models. A model is proposed that adequately describes the considered processes and can work in real time, which significantly increases the range of use. It has a small computational effort, so it can be implemented on the existing IСS. A method has been proposed which, as a result of testing, has shown its effectiveness and, in some cases, higher accuracy and resolution.","PeriodicalId":416126,"journal":{"name":"NTU \"KhPI\" Bulletin: Power and heat engineering processes and equipment","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130265734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Methodology for calculating hydrogenerators in strength problemsMethodology for Calculating Hydrogenerators in Strength Problems","authors":"I. Kobzar","doi":"10.20998/2078-774x.2023.01.03","DOIUrl":"https://doi.org/10.20998/2078-774x.2023.01.03","url":null,"abstract":"In the presented scientific work, the basic design versions of the thrust bearings of Hydrogenerators are considered. The main causes of emergencies in the thrust bearing unit of a high-power Hydrogenerator are considered. The main requirements for the operation of thrust bearings are submitted. Cause-and-effect relationships of emerging and development of defects are established. Existing methods for calculating the stressed state of a thrust bearing in the classical formulation for a stationary mode of operation are considered. The main features of the operation of the thrust bearing unit are investigated in relation to the features of the sliding bearings. The calculation of the elastic chambers of the hydraulic thrust bearing in a three-dimensional formulation is carried out, taking into account the physical properties of the oil, the material of the chambers and distribution of the acting loads. It is shown that the applied designs of Join Stock Company “Ukrainian Energy Machines” can be used in high-power Hydrogenerators.","PeriodicalId":416126,"journal":{"name":"NTU \"KhPI\" Bulletin: Power and heat engineering processes and equipment","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121847738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Methodology for Determining the Tension of Banding Rings of Medium-Power Turbogenerators","authors":"O. Tretiak, S. Kravchenko, Oleg Bogozhavets, V. Nazarenko, A. Zhukov","doi":"10.20998/2078-774x.2023.01.06","DOIUrl":"https://doi.org/10.20998/2078-774x.2023.01.06","url":null,"abstract":"The presented work is devoted to the methodology of determining the tension of the banding rings by the method of calculating the stresses in the details of the banding assembly of the rotor. Taking into account the load from the action of centrifugal forces on the part of the copper coils, thermal loads and landing of the banding ring, the data for the calculation were determined. After that, the static calculation of the centering ring at rest, the static calculation of the centering ring at the nominal rotation frequency and the static calculation of the centering ring at the stolen rotation frequency were carried out. These calculations were performed for the first time in a three-dimensional setting using the method of mathematical modeling. The maximum stresses arising in the centering ring at rest and having a local character were determined. It was also determined that for all modes the stress did not exceed the permissible value.","PeriodicalId":416126,"journal":{"name":"NTU \"KhPI\" Bulletin: Power and heat engineering processes and equipment","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123146216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving the Efficiency of the Furnace Process of Low-Temperature Low-Capacity Furnaces","authors":"Mykhailo Abdulin, Yu.O. Bietin","doi":"10.20998/2078-774x.2023.01.09","DOIUrl":"https://doi.org/10.20998/2078-774x.2023.01.09","url":null,"abstract":"A review of studies of furnace processes in industrial furnaces has shown that there is a sufficient number of studies for high-temperature and medium-temperature furnaces. However, there is an insufficient understanding of furnace processes in low-temperature low-power furnaces. One of the most important factors in the working process of low-temperature ovens, in contrast to high-temperature and medium-temperature ovens, is a significantly lower level of temperature inhomogeneity. For example, in heating ovens in the machine-building industry, the temperature inhomogeneity is 30 °С…50 °C, while in baking ovens, temperature fluctuations of 5 °C…10 °C are permissible.The aim of this article is to analyze the efficiency of the organization of combustion processes in industrial baking ovens operating on natural gas, which are organized by two different combustion technologies: in a cupcake baking oven, the combustion process is organized using a vortex-type burner device operating in a pulse mode; in a wafer sheet baking oven, microflame gas combustion technology is implemented. Some disadvantages of using the above-mentioned technologies for the studied furnaces have been identified and ways to eliminate them by organizing furnace processes in these furnaces using jet-niche gas combustion technology have been proposed. Namely, the modernization of these furnaces with the replacement of standard burners with burners that implement the principles of jet-niche technology.","PeriodicalId":416126,"journal":{"name":"NTU \"KhPI\" Bulletin: Power and heat engineering processes and equipment","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122628730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reducing the Harmful Impact of Boiler Plants on the Environment","authors":"O. Voinov, Yurii Elkin","doi":"10.20998/2078-774x.2023.01.11","DOIUrl":"https://doi.org/10.20998/2078-774x.2023.01.11","url":null,"abstract":"World production makes an ever-increasing harmful impact on the natural environment. As a matter of fact, mankind is facing the problem of saving the natural environment. As for the production branches the energy industry has the strongest harmful effect, and as for the production facilities the boiler plants that emit heat and harmful substances into the environment are the most environmentally aggressive. The global fleet of boiler plants is huge and complicated. As the boiler plant wears out, the levels of its environmental, economic and general technical efficiency are increasingly decreased, and the intensity of the harmful impact on the environment is increased worsening progressively its condition. The self-healing process of the natural environment lags behind the process of harmful effects on it. As a matter of fact, the problem of reducing the harmful effects of boiler plants on the environment has arisen. The purpose of this study was to analyze the phenomenon of interaction between the energy sector, primarily boiler plants and the natural environment and search for the ways to resolve the existing contradictions of this interaction. The task of improving the environmental friendliness of worn-out power equipment and, above all, boiler plants is an urgent issue. The purpose of this research paper was to analyze the possibilities of solving the problem of ecological interaction of boiler plants with the natural environment through their partial, full or redundant renovations. This research is relevant, because the boiler plants of the domestic fleet are extremely worn out. Full or redundant renovation is highly resource intensive and appropriate resources are currently unavailable. A realistic way to solve the problem of reducing the harmful effects of boiler plants on the environment is to increase the environmental friendliness of worn-out boiler equipment by partially upgrading it using relatively simple and affordable methods, such as normalizing the boiler air mode, reducing heat losses with exhaust gases, rationalizing and implementing daily and weekly schedules of the boiler operation in order to extend the full load carrying mode. Successful implementation of the forthcoming program of partial renovation of worn-out boiler plants will ensure a significant reduction of their harmful impact on the environment.","PeriodicalId":416126,"journal":{"name":"NTU \"KhPI\" Bulletin: Power and heat engineering processes and equipment","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120935246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Peculiarities of the Calculations of the Gas Turbine Cooling Systems","authors":"A. Tarasov, Oksana Lytvynenko, Irina Myhaylova, V. Ismailov, S. Naumenko","doi":"10.20998/2078-774x.2023.01.05","DOIUrl":"https://doi.org/10.20998/2078-774x.2023.01.05","url":null,"abstract":"Gas turbine cooling systems have the branched networks of various channels whose hydraulic and heat exchange capabilities define the air flow required for the cooling of turbine parts and, thus, directly influence the efficiency of gas turbines. Cooling system elements are, in particular, the throttles, diaphragms, seals, openings that act as regulating parts or elements to maintain pressure in the system. As a rule, the channels of this type have a significant pressure drop, and therefore during the calculations it is necessary to very carefully consider a change in air density along the channel. Therefore, we present in this paper the method developed by the authors for determining the hydraulic resistance in the openings, and the data obtained by it perfectly agree with the experimental data. It is shown how to take into account the effect of the air compressibility on the coefficient of hydraulic resistance in the cooling channels that allows for the use of the numerous experimental dependencies for the coefficients of hydraulic resistance of incompressible liquids. A method of calculating hydraulic resistances of the openings by defragmenting their total hydraulic resistance into separate components has been proposed. A generalized dependence was established for the hydraulic resistance of the discharge openings in the discs and in the mounting gaps between the shanks of the blades and the discs, taking into account the transverse air flows.","PeriodicalId":416126,"journal":{"name":"NTU \"KhPI\" Bulletin: Power and heat engineering processes and equipment","volume":"417 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131525804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}