Thermal Engineering最新文献

{"title":"Simulation of R-21 Saturated Vapor Condensation in a Fragment of a Tube Bundle Using the 3D VOF Method","authors":"K. B. Minko,&nbsp;M. V. Minko,&nbsp;A. A. Klement’ev","doi":"10.1134/S0040601524700824","DOIUrl":"10.1134/S0040601524700824","url":null,"abstract":"<p>The Volume of Fluid (VOF) method supplemented with heat and mass transfer models at the interphase boundary is actively employed in the investigation of film condensation and film boiling, in the calculation of evaporators, for predicting the dynamics of vapor bubble collapse in a pool of subcooled liquid, or for other purposes. The original VOF algorithm proposed by Hirt is intended for the simulation of a single-phase incompressible liquid with a free boundary at which a constant pressure is specified. The extension of the VOF-algorithm to a two-phase fluid, especially with mass transfer, is not a common problem from the standpoint of the rigor of mathematical formulation. In our previous studies, approaches have been developed to the 2D and 3D simulation of heat and mass transfer processes during vapor condensation on the surface of horizontal smooth tubes, and condensation on a smooth tube bundle was simulated in 2D formulation. This paper presents the results of 3D simulation of R-21 refrigerant condensation in a small-sized tube bundle. Characteristics of the tube bundle are the same as those of the tube bundle tested at the Institute of Thermophysics of the Siberian Branch of the Russian Academy of Sciences (SB RAS) (tube diameter is 16 mm, transverse pitch is 26 mm, longitudinal pitch is 15 mm). The condensation was examined in saturated vapor flow at a temperature of <span>({{T}_{{sat}}})</span> = 333.15 K incoming onto the tube bundle at a velocity of up to 0.9 m/s. The 3D predictions agree qualitatively and quantitatively with the 2D predictions and the experimental data. The distribution of condensate in the tube bundle is presented. The spectrums of fluctuations in the average heat transfer for tubes are analyzed. It is pointed out that the thermal boundary layer development region induced by the condensate falling from the upper to lower tubes should be considered.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"72 3","pages":"252 - 263"},"PeriodicalIF":0.9,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809184","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":"Processing of Ash and Slag Waste from Coal-Fired Thermal Power Plants and Extraction of Commercial Products from the Waste (Review)","authors":"L. M. Delitsyn,&nbsp;R. V. Kulumbegov,&nbsp;O. S. Popel’,&nbsp;Yu. A. Borisov,&nbsp;Sh. A. Gadzhiev","doi":"10.1134/S0040601524700836","DOIUrl":"10.1134/S0040601524700836","url":null,"abstract":"<p>Ash dumps of 170 large Russian coal-fired thermal power plants (TPPs) store more than 2 billion t of ash and slag waste (ASW) at present. They occupy approximately 50 000 ha and represent main sources of environmental pollution. The amount of ASW increases by approximately 20 million t every year. Besides the recorded amount of ASW, there is also waste that is not recorded in official documents. At the same time, the latter waste is man-made sources of commercial products. Direct large-scale application of ash is limited by the instability of its properties and its noncompliance with the applicable technical requirements for the products of its processing employed in various applications in power, metallurgical, chemical, construction, and other industries. Processing of ash and slag waste and gradual removal of ash dumps are a crucial state problem whose solution requires the development of appropriate industrial processes. The review examines modern methods of large-scale processing of ash and slag waste from coal-fired TPPs with extraction of commercial materials suitable for application in various industries. The emergence of a wide range of physical, chemical, and biological processes for ash processing enables the problem of reclamation of most ash dumps to be successfully solved. The attention was focused on such technologies as flotation enrichment, magnetic separation, and thermochemical methods. The mechanism of adsorption of functional groups of various collectors on the surface of carbon ash particles is examined. A large section of the review is devoted to acid, alkaline, and thermochemical methods of extracting alumina from ash and belite sludge. Attention is also focused on works dealing with the extraction of precious and rare earth metals from ash. Some new developing areas of microbiological extraction of metals from ash are also presented.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"72 3","pages":"203 - 220"},"PeriodicalIF":0.9,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809188","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 Use of Carbon Dioxide as Working Fluid for a Single-Stage Mixed-Flow Turbine","authors":"Gong Bowen,&nbsp;Hua Lun,&nbsp;Xu Guisheng,&nbsp;Afzal Umar,&nbsp;M. A. Laptev,&nbsp;V. V. Barskov,&nbsp;V. A. Rassokhin,&nbsp;A. G. Pulin","doi":"10.1134/S0040601524700800","DOIUrl":"10.1134/S0040601524700800","url":null,"abstract":"<p>The article considers the use of supercritical carbon dioxide (sCO₂) as working fluid in the turbine stage consisting of a vane row and a mixed-flow blade row. The operation of the existing turbine on natural gas combustion products and on supercritical carbon dioxide is analyzed by way of comparison. The numerical simulation results show that the use of supercritical carbon dioxide makes it possible to increase the turbine power output to 14.3 MW. This is more than a factor of 30 higher than the power output of the same turbine operating on natural gas combustion products. Such a significant increase of power output is achieved without changing the turbine stage design, which points to the possibility of modernizing the existing units without the need to make essential changes of the design. The turbine stage efficiency during its operation on supercritical carbon dioxide was estimated at 0.87, and that during operation on natural gas combustion products was 0.88. Despite an insignificant drop of the efficiency, the total increase of the power output results in that the use of sCO₂ is economically feasible. Based on the data obtained, a conclusion has been drawn that it is advisable to use the existing turbine stages for operation on supercritical carbon dioxide. This opens the prospects in achieving more efficient operation of power systems without the need to develop new types of turbines, decreasing capital outlays, and more rapidly introducing new technologies. The transition for using supercritical carbon dioxide as working fluid can result in obtaining a significantly higher output of turbine units while retaining high efficiency indicators and making minor changes in the equipment design.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"72 3","pages":"173 - 180"},"PeriodicalIF":0.9,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0040601524700800.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative 4E-Analysis of A KCS11 with and without Solar Energy for Fluegas Waste Heat Recovery in a Coal-Fired Power Plant","authors":"Goutam Khankari,&nbsp;Sumit Srivastava,&nbsp;Rajib Khan,&nbsp;D. V. Rajan,&nbsp;Dinesh Kr. Singh","doi":"10.1134/S0040601524700848","DOIUrl":"10.1134/S0040601524700848","url":null,"abstract":"<p>A comparative performance analysis of a Kalina Cycle System 11 (KCS11) without and with solar energy is done based on 4E-analysis (energy, exergy, environment, and economic) for generating additional electricity from fluegas waste energy of a 660 MWe Supercritical (SupC) coal-fired power plant. The result shows that the integration of solar assisted KCS11 with main steam power plant increases the net plant energy and exergy efficiencies by about 0.04 and 0.03% points, respectively due to additional electricity generation of 647.43 kW at 40 K of superheat. Condenser and evaporator are the maximum contributor of energy and exergy losses, respectively in the proposed systems. Energetic performance of solar assisted Kalina cycle is higher than the standalone KCS11 due to decrease in turbine exhaust pressure and additional poor exergetic performance of solar heater causes less exergy efficient of solar assisted KCS11 compared to standalone KCS11. Use of solar integrated KCS11 reduces the annual <span>({text{C}}{{{text{O}}}_{{text{2}}}})</span> emission by about 1089.58 t at full load which is nearly 1.25 times higher than the standalone KCS11. The Levelized Cost of Electricity (LCoE) for producing additional electricity by solar energy at 40 K of super-heat is about 0.13 $/kW h which is 8.5% lower value compared to the solar thermal power plant.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"72 3","pages":"229 - 239"},"PeriodicalIF":0.9,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809180","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":"A Model for Determining the Rate of Interfacial Heat and Mass Transfer Using the VOF Method for Numerically Solving Evaporation and Condensation Problems","authors":"K. B. Minko,&nbsp;G. G. Yan’kov,&nbsp;T. A. Gataulin,&nbsp;V. I. Artemov,&nbsp;A. P. Zheleznov","doi":"10.1134/S0040601524700769","DOIUrl":"10.1134/S0040601524700769","url":null,"abstract":"<p>The volume-of-fluid (VOF) method, supplemented by models of interfacial heat and mass transfer, is a universal and very effective tool for simulation and detailed analysis of intricate processes occurring in systems with phase transitions. The key feature of this method is that it can quite accurately and in detail describe the physical pattern of running processes in the presence of a sharp phase boundary and provide quantitative data on the distribution of local heat-transfer characteristics and the dynamics of the interphase boundary and associated phenomena, thereby making the VOF method advantageous in researches and engineering practice. Development and improvement of heat and mass transfer models and efficient numerical VOF algorithms, as well as preparation of recommendations for the application of these approaches, are an urgent problem. This paper proposes an approach to the prediction of interfacial heat and mass transfer rate, which is based on the analysis of phase transitions in single-component systems using the linear theory of nonequilibrium processes. The results are presented of verification calculations performed for several standard problems. The classical problems of one-dimensional boiling and condensation (the Stefan problem) are examined as are such problems as vapor condensation in tubes of different orientations, condensation from stagnant or moving vapor on the surface of smooth horizontal tubes, and film boiling on the surface of horizontal cylinders. The predictions are verified against classical solutions and available experimental data. Calculations were carried out for fluids with different thermophysical properties, including water, pentane, propane, R-113, R-21, and R-142b. The maximum ratio of the densities of liquid and vapor phases was as high as 1600 (water at atmospheric pressure). The simulation results demonstrate the versatility of the proposed approach, which allows us to recommend it for solving a variety of engineering problems.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"72 3","pages":"240 - 251"},"PeriodicalIF":0.9,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143809183","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 Influence of Air Inleakages on the Dynamic Characteristics of the Steam Turbine Unit Condenser‒Ejector System","authors":"K. E. Aronson,&nbsp;A. Yu. Ryabchikov,&nbsp;D. V. Brezgin,&nbsp;D. Yu. Balakin,&nbsp;N. V. Zhelonkin,&nbsp;A. L. Demidov","doi":"10.1134/S0040601524700654","DOIUrl":"10.1134/S0040601524700654","url":null,"abstract":"<p>The results obtained from experimental investigations of the dynamic characteristics of a condenser and new ejector are presented. The investigations were carried out at a thermal power plant under the turbine commercial operation conditions using an extended arrangement for measuring the ejector operation parameters and an automated data-acquisition system. The dependences of the ejector’s first stage suction pressure on the dry (atmospheric) air flowrate and the pressure in the condenser and in the ejector’s first stage receiving chamber on the steam–air mixture flowrate during their joint operation are obtained. It is proposed to determine the maximal volumetric throughput of the ejector operating on dry air with using the minimal slope factor as a function of the air flowrate. With an increase of air inleakages into the steam turbine unit vacuum chamber, the pressure difference at the initial and total air inleakages at the ejector suction varies according to a linear law and that in the condenser according to an exponential law. By using the measurement system, the condenser’s and ejector’s dynamic characteristics were determined. It has been found that the pressure growth rate at the ejector suction increases with increasing the amount of air admitted into the condenser. The time taken for the pressure to become stable remains approximately the same. However, the pressure growth rate in the condenser does not depend on the amount of air admitted, and the time taken for the pressure to become stable increases exponentially with increasing the amount of air admitted. For diagnosing the vacuum system malfunctions in controlling the steam turbine unit’s operation mode, it is recommended to provide indication of the ejector suction pressure on the turbine control board. As regards the pressure sensor, it is proposed to install it on the common pipeline supplying steam–air mixture to the ejectors. The investigation of the condenser–ejector system dynamic characteristics will make it possible to improve the turbine vacuum protection, which is one of the turbine protection system components.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"72 2","pages":"91 - 97"},"PeriodicalIF":0.9,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143583626","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":"Processing Carbon Dioxide Into Ethanol Based on Thermal Energy Supported by Solar Energy","authors":"U. Das,&nbsp;T. H. Dar,&nbsp;C. Nandi","doi":"10.1134/S0040601524700770","DOIUrl":"10.1134/S0040601524700770","url":null,"abstract":"<p>The thermal power plant recognized as the most pollutants emitted power plant in the world. The use of the solar systems is essential for reducing carbon emissions from thermal power plants. Such hybrid systems need a skillful energy management technology as well as incorporation of carbon conversion technology that will help to run the system expertly to maintain the power generation-demand balance and make the thermal plant more cleaner than before respectively. This work describes a fuzzy logic-based energy management system for a thermal-solar hybrid system and a carbon conversion technology to convert the captured carbon into the chemical products after calculating the environmental impact of a stand-alone thermal power plant through life cycle assessment (LCA) tool. The results of a case study demonstrate that the suggested schemes are feasible, effective and environmentally acceptable. Thermal-solar-based hybrid power plant can work environmentally harmlessly if the carbon produced from the plant is converted into the chemical product.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"72 2","pages":"144 - 156"},"PeriodicalIF":0.9,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143583623","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":"CFD-Simulation of Bulk Condensation Considering the Finite Rate of Interphase Heat Transfer","authors":"A. A. Sidorov,&nbsp;A. K. Yastrebov","doi":"10.1134/S0040601524700757","DOIUrl":"10.1134/S0040601524700757","url":null,"abstract":"<p>The work is devoted to simulation of the bulk condensation in a supersonic flow of a vapor-gas mixture through the Laval nozzle considering the finite rate of the interphase heat transfer. Numerical methods are examined for predicting the temperature of droplets using the improved VOF (Volume of Fluid) and Eulerian multiphase models. It has been demonstrated that, compared to the Eulerian model, the VOF model more accurately predicts the known experimental data and provides the numerical solution whose stability is less susceptible to the effect of high intensity source terms. Comparison of the predictions with the experimental data of other authors has revealed that the two-temperature model more accurately describes the flow with bulk condensation than the single-temperature model does. The application of a single-temperature approximation is justified when the impurity content in the mixture does not exceed 2% (by weight) since the zone of the active condensation onset is relocated considerably compared to its relocation in the case of the two-temperature approximation. However, the single-temperature approximation is recommended only for calculating the overall heat release level that could be beneficial, for example, for quick assessment of the effect of bulk condensation on turbine stage performance. The previously obtained estimates confirmed the applicability of the single-temperature formulation at an impurity content as high as 5 wt %, but solving this problem in 3D formulation improved the accuracy of these estimates. It has been revealed that the assumption about the flow homogeneity along the channel height (as one of the assumptions employed in one-dimensional calculations) during bulk condensation in a slot-type Laval nozzle is not valid on changing-over to a three-dimensional two-temperature formulation: supersaturation persists at the phase boundary, as a result of which the droplet growth process continues at the circumference of the flow.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"72 2","pages":"117 - 130"},"PeriodicalIF":0.9,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143583621","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":"Renovation of Grid-Tied Solar Photovoltaic Plants: Problems and Prospects","authors":"A. B. Tarasenko,&nbsp;S. V. Kiseleva","doi":"10.1134/S0040601524700733","DOIUrl":"10.1134/S0040601524700733","url":null,"abstract":"<p>Rapid development of energy technologies results, in particular, in that photovoltaic modules often become obsolete even before the end of their assigned service life. It is sufficient to say that, for the period from 2014 to nowadays, the average efficiency of photovoltaic modules has increased from 14–15 to 21%. The prices for photovoltaic products also continue to decrease. In this connection, the possibility of substituting the equipment of existing solar power plants with more advanced components is of interest. Photovoltaic module replacement versions, as well as technical and economic aspects of this process, are discussed taking Russia’s first grid-tied photovoltaic plant Kosh-Agach-1 as an example. The modern types of photovoltaic modules and the options of using them for solar plant renovation purposes are analyzed. The prime cost of the electricity generated is estimated with taking into account the replacements of modules and inverters. Special attention is paid to the compatibility of new modules with the old support structures and inverter equipment. The decrease of electricity prime cost after installing the new modules serves as the main renovation feasibility criterion. It is shown that the refurbishment of plants equipped with thin-film silicon modules by replacing them with domestically produced or Chinese modules consisting of silicon photovoltaic plates 166 × 166 mm in size looks to be the most promising option. The minimal prime cost of generated electricity is achieved in the case of using heterojunction modules and modules on the basis of photovoltaic converters with a rear contact.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"72 2","pages":"131 - 143"},"PeriodicalIF":0.9,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143583627","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":"Development of Adsorbent out of Waste from a Thermal Power Plant’s Water-Treatment Plant for Removal of Carbon Dioxide","authors":"A. A. Filimonova,&nbsp;A. Yu. Vlasova,&nbsp;N. D. Chichirova,&nbsp;R. F. Kamalieva","doi":"10.1134/S004060152470071X","DOIUrl":"10.1134/S004060152470071X","url":null,"abstract":"<p>It is possible at present to reduce the emission of harmful substances into the environment during the operation of industrial enterprises by cleaning emissions and modernizing existing technological equipment. A survey of purification plants showed that sorption technologies are more accessible and simpler. Adsorption is an effective physical and chemical process for capturing carbon dioxide. The modern market offers a wide range of adsorbents that can be used to capture harmful substances, but, as a rule, for reasons of economic efficiency, it is more profitable to use secondary resources: production waste. At energy sector enterprises, various wastes are generated during the generation of thermal and electrical energy. Thus, when preparing a heat carrier at water-treatment plants, wastewater after clarifiers and ion exchange filters can be utilized to create a sorption material capable of capturing carbon dioxide, one of the main greenhouse gases. Obtaining adsorbents from waste from water-treatment plants will reduce the volume of sludge-storage facilities or eliminate their use altogether. Industrial waste is a secondary raw material and, as a rule, is inferior in its original form to traditional industrial adsorbents in terms of the activity indicator, which characterizes the ability to capture carbon dioxide. Therefore, to obtain high absorption capacity, waste is combined and activated. An adsorbent obtained from waste from water-treatment plants of thermal power plants is presented. The waste used was sludge water discharges and spent regeneration solutions after the softening filter. The component composition of the adsorbent and the method of its preparation by activation and preparation of waste are described. The efficiency of the developed adsorbent was tested on a laboratory setup. Comparative results of laboratory studies with the most frequently used adsorbents are presented. The results of determining the strength, porosity, permeability coefficient, and specific surface area of the studied adsorbents are presented.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"72 2","pages":"166 - 171"},"PeriodicalIF":0.9,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143583630","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}