Thermal Engineering最新文献

{"title":"Simulation of Natural Convection Heat Transfer Using Computational Modeling of Perforated Annular Fins Coupled with Vertical Cylinder","authors":"Muthuraman Subbiah,&nbsp;Sivaraj Murugan,&nbsp;Kumar Ayyappan","doi":"10.1134/S0040601524601074","DOIUrl":"10.1134/S0040601524601074","url":null,"abstract":"<p>This study examines the impact of annular fins extending from a heated vertical cylinder on heat transfer efficiency resulting from free convection. This study on conjugate heat transfer is conducted for three Rayleigh numbers in a laminar flow regime, with differing quantities of fins along the height of the cylinder. The fluid dynamics and energy equations were resolved utilizing Fluent Software to comprehend the relationship between heat transfer and flow characteristics. The grid dependence test and data validation against published work have been executed successfully. The Nusselt number increases with the Rayleigh number, regardless of the quantity and type of fins employed. The heat transfer improvements attributed to perforated fins exceed those of solid fins. A comparative analysis between solid and perforated annular fins reveals that perforated fins provide superior heat transfer performance due to improved fluid mixing, reduced thermal resistance, and enhanced boundary-layer disruption. The maximum enhancement in the Nusselt number is observed to be approximately 49% for the configuration with the highest number of perforated fins compared to the corresponding solid fin arrangement. Flow field visualizations, temperature contours, and velocity distributions further confirm the strong correlation between flow behavior and heat transfer characteristics. The findings highlight the effectiveness of perforated annular fins as a passive technique for natural convection heat transfer augmentation in vertical cylindrical systems.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"73 5","pages":"362 - 370"},"PeriodicalIF":1.3,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148342890","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 a Performance Database of a Three-Blade Row Axial Compressor for Machine Learning Models Validation","authors":"S. A. Galaev,&nbsp;V. V. Ris,&nbsp;A. G. Abramov,&nbsp;V. A. Baranov,&nbsp;E. E. Kitanina","doi":"10.1134/S0040601526700072","DOIUrl":"10.1134/S0040601526700072","url":null,"abstract":"<p>Machine learning models should be selected and tested proceeding from reliable databases containing the characteristics of compressor unit individual stages representing their geometrical and operating parameters in a sufficiently wide variation ranges. The article outlines a procedure and results of producing a database for the characteristics of the one-and-a half stage (three-row) section of an axial compressor with varying the 3D rotor blade contours. The loss coefficient and pressure difference sensitivities to the variation of geometrical parameters were analyzed, and four parameters were chosen based on the analysis results: the blade leading edge design angle and the profile stagger angle, both in the blade hub and shroud sections. The database for the head and loss in the section consisting of 2360 examples was compiled by independently varying each of the four parameters. The data for the flow passage design versions were obtained using a numerical method. Transonic turbulent flow of compressible gas in the section was modeled using the RANS/URANS methods depending on the averaged flow pattern. The large amount of computations carried out at Peter the Great St. Petersburg Polytechnic University Supercomputer Center for a relatively short period of time involved the need to set up a fully automated procedure for constructing the blade contours, generating computation meshes (with a size of about 500 thousand nodes), specifying input data, and processing the results. The key aspects of these procedures are described. Owing to the obtained systematic data, it has become possible to reveal, at a fairly good quantitative level, the ways in which the varied parameters influence the compressor section characteristics, and to test the machine learning models for predicting the loss coefficient and pressure difference.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"73 5","pages":"326 - 338"},"PeriodicalIF":1.3,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148342847","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":"Erratum to: Improving the Shell-and-Tube Condenser Design for an ORC Unit Operating on Pentane as Working Fluid","authors":"I. S. Antanenkova,&nbsp;A. A. Antanenkov,&nbsp;V. I. Kuznetsov,&nbsp;D. S. Pisarev","doi":"10.1134/S0040601526170027","DOIUrl":"10.1134/S0040601526170027","url":null,"abstract":"","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"73 5","pages":"388 - 388"},"PeriodicalIF":1.3,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0040601526170027.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148342892","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":"Design Calculation of the Low Pressure Direct Contact Heater’s Bubbling Stage for Main Condensate Deep Degassing and Heating","authors":"Yu. G. Sukhorukov,&nbsp;B. F. Balunov,&nbsp;V. D. Lychakov,&nbsp;E. A. Sukhorukova,&nbsp;Yu. V. Usov,&nbsp;K. A. Grigor’ev,&nbsp;D. S. Evsikov","doi":"10.1134/S0040601526700114","DOIUrl":"10.1134/S0040601526700114","url":null,"abstract":"<p>The article presents recommendations on calculating the intensity of thermal-hydraulic processes in the structural parts of a low-pressure direct-contact heater’s submerged bubbling device. These recommendations are based on the results of experimental studies carried out at NPO TsKTI with the aim to determine the bubbled condensate void fraction that ensures its maximum turbulization (at the minimal cost) and helps achieve the minimal subcooling of condensate and its fastest degassing to equilibrium state (no more than 10 ppb for dissolved oxygen, which is equivalent to around 50 ppb for dissolved air), and also a high coefficient of heat transfer to the external surface of heat absorbing tubes placed in the bubbled condensate volume (the vertical high pressure heater’s hot leg lower part flooded by condensate with the built-in condensate cooler separated from the hot leg). The article proposes relationships for calculating the minimal steam velocity in the holes of the steam distribution header to ensure the continuity (with respect to condensate) of its operation and void fraction in bubbling low-pressure steam in vertical channels larger than 100 mm in diameter. The article also gives recommendations on calculating the average initial size of steam bubbles passed through the layer of slightly subcooled water (condensate), condensation rate of these bubbles and the height of their full condensation section. The presented information can be applied in working out a procedure for carrying out thermal hydraulic design calculation of heat transfer devices that use steam bubbled through a heated water layer, which helps ensure its deep degassing.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"73 5","pages":"371 - 379"},"PeriodicalIF":1.3,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148342891","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":"Experimental Investigation of Surface Material Impact on Nanofluid Subcooled Flow Boiling","authors":"B. Soleimani,&nbsp;M. Ziabasharhagh","doi":"10.1134/S0040601524600949","DOIUrl":"10.1134/S0040601524600949","url":null,"abstract":"<p>Boiling heat transfer (BHT) is impacted by a variety of parameters. Surface characteristics such as roughness and material are some of them which have significant effect on the flow boiling (FB). The surface material’s impacts on subcooled flow boiling heat transfer (SFB-HT) in a channel at various velocities and roughness are experimentally investigated for water-alumina nanofluid (concentration: 0.1 vol %). For these experiments, a Plexiglas channel with a length of 120 cm, and dimensions of 20 × 30 mm² is designed and constructed. At the bottom of the channel, a cylindrical heater with a 12 mm diameter was positioned. The tests were carried out using three different heaters made from aluminum, brass, and copper, each tested at three different velocities and surface roughness levels. The study’s findings indicate that brass surfaces demonstrate superior heat transfer capabilities, whereas copper surfaces show the poorest performance. But, the aluminum performance with respect to the copper was not very promising. Finally, a non-dimensional correlation is provided to evaluate the SFB’s Nusselt number, incorporating variables like velocity, surface material, and roughness type.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"73 5","pages":"351 - 361"},"PeriodicalIF":1.3,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148342849","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":"Biomass Oxygen-Free Steam Gasification in a Spouted Bed","authors":"S. A. Shevyrev,&nbsp;P. A. Strizhak","doi":"10.1134/S0040601526700102","DOIUrl":"10.1134/S0040601526700102","url":null,"abstract":"<p>The article presents the results of studying the biomass gasification process in a spouted bed at a temperature of 750‒950°C under atmospheric pressure, and with varying steam flowrate. The characteristics of producer gas and solid residue are determined. The quasi-stationary gasification process energy efficiency in using the gas obtained is quantified. The total H₂ and CO concentration in the producer gas mixture reached 57 vol %. It is shown that in the course of steam gasification, CH₄ with a maximum concentration of up to 27 vol % is produced. The carbon dioxide concentration in the product gas mixture obtained in the course of biomass steam gasification may reach 30 vol % or higher under different experimental conditions. The carbon dioxide concentration can be reduced by implementing the Boudouard reaction in the technological cycle when adding CO₂ to steam. In analyzing the results of studying the composition of the gas and solid residue generated, the gasification process effectiveness coefficient with respect to cold gas was calculated as a ratio of the synthesized gas to initial biomass heating values. It has been determined that the process energy efficiency depends on the reaction thermobaric conditions and also on the gasifying medium composition, and reaches the maximum value equal to 84% with the average value equal to about 52% in the studied ranges of temperature and steam flowrate. It is shown that the most rational approach seems to be a combined use of biomass and black coal for obtaining producer gas with the maximum values of H₂ and CO concentrations. Recommendations on how to use the study results for development of gasification technologies have been formulated. It is proposed to use combined coal and biomass gasification with the aim to obtain higher concentration of product gas target components, in particular, CO.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"73 5","pages":"339 - 350"},"PeriodicalIF":1.3,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148342848","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 Erosion Wear on the Gas Dynamic Indicators, Strength, and Dynamic Characteristics of the T-35/59-1.3 Steam Turbine Last Stage Rotor Blades","authors":"R. S. Kiselev,&nbsp;A. S. Poruchenko,&nbsp;N. V. Gridchin,&nbsp;N. V. Golovinkin,&nbsp;S. V. Prokuratov","doi":"10.1134/S0040601526700060","DOIUrl":"10.1134/S0040601526700060","url":null,"abstract":"<p>Erosion wear of the blade airfoil causes essentially worsened conditions of its streamlining and, hence, a decrease in the steam turbine unit stage efficiency as a whole, as well as the occurrence of vortex zones, which in turn may cause some loss of the blade row aeroelasticity. The article addresses a study of the effect of progressive erosion wear on the turbine stage economic efficiency and strength reliability, and a method for predicting the change in its characteristics throughout the service life is proposed. A classification of erosion kinds in steam turbines is given. Criteria, basic methods for decreasing the influence of erosion wear, and the droplet erosion mechanism are considered. Generalized results of experiments on studying the erosion wear of the last stage blades in OK-12A turbine drives and PT-25-90/10 steam turbines are given. The article also presents an assessment of how this wear affects the turbine machine stage gas dynamic parameters based on the results of CFD simulation of the flow in the blade after it has been in operation from 10 to 120 thousand h, and also the rotor blade strength and dynamic characteristics. The article gives the results of calculations showing essential decrease in the stage efficiency with respect to its nominal value for the ideal blade profile, static strength calculations, and modal analysis of the blade that had experienced wear for 120 thousand h of operation, which were carried out using the finite element method (FEM) on a 3D model. In solving the elasticity theory FEM problem, the blade stress-and-strain states before and after it had been in operation for 120 thousand h were determined. In the course of a computational study carried out using the ANSYS Mechanical software system, data have been obtained testifying that the blade erosion wear occurred for 120 thousand h of blade operation does not degrade its static strength and standardized detuning from resonance for the operating rotation frequency.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"73 4","pages":"237 - 247"},"PeriodicalIF":1.0,"publicationDate":"2026-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147872292","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":"Calculations of Thermal-Hydraulic Parameters for the Conditions of the DENOPI Project MIDI Facility Simulating Loss of PWR/VVER Reactors Spent Fuel Pool Cooling","authors":"D. N. Moisin,&nbsp;O. E. Stepanov,&nbsp;M. M. Bedretdinov","doi":"10.1134/S0040601526700047","DOIUrl":"10.1134/S0040601526700047","url":null,"abstract":"<p>Currently, a large number of experimental setups (facilities) for studying thermal-hydraulic processes in spent fuel pools (SFPs) are developed around the world; the experimental French MIDI facility constructed within the framework of the DENOPI Project can, in particular, be regarded as one of such facilities. It is intended for simulating the initial stage of an accident in a PWR type reactor SPF. For validating the analysis models, European scientists have carried out three experiments on this facility for three configurations of spent fuel pool charges. In this study, for carrying out subsequent thermal-hydraulic calculations based on the performed experiments, the KORSAR/GP computer code certified for safety analysis was used, which made it possible to simulate heat fluxes and hydrodynamics in different parts of the MIDI experimental facility. The activities on applying this code included the development of analysis diagrams describing the flow pass channels and heat conducting structurers for each component of the facility, which made it possible to take into account the key aspects of heat transfer in the spent fuel pool considered. The calculation results have shown a linear growth of temperature and a water level variation, features confirming an adequate behavior of the analysis model. The data obtained can serve for substantiating the possibility of applying the developed model for analyzing accident conditions associated with loss of cooling in SFPs. The results of calculations carried out using the KORSAR/GP code have for the first time been compared with the experimental data obtained on the MIDI experimental facility. The developers of similar thermal-hydraulic codes in other countries also actively conduct similar investigations.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"73 4","pages":"248 - 257"},"PeriodicalIF":1.0,"publicationDate":"2026-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147872399","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":"Identification of Fouling Profile for a Tube in the Presence of Turbulence Flow to Manage Energy Consumption in Heat Exchangers","authors":"Moein Azizi,&nbsp;Koorosh Goudarzi,&nbsp;Ali Tayebi","doi":"10.1134/S0040601524600585","DOIUrl":"10.1134/S0040601524600585","url":null,"abstract":"<p>In most heating systems, one of the factors that increase energy consumption and reduce the efficiency of heat exchangers are foulings, settling of dissolved or suspended solids in a fluid is called fouling. Foulings are placed in layers on the heat transfer surfaces and they reduce the efficiency of the heat exchanger and increase energy consumption. For this reason, descaling is very important. In order to ensure the exact time of descaling, accurate information about the amount of fouling in the heat exchanger must be available. In this research, the goal is estimation of the fouling profile in a pipe with the presence of turbulent flow using the inverse heat transfer method (IHTM). For this purpose, the conjugate gradient method with adjoint problem (CGMwAP) is used to identify the fouling profile. The model used for a tube heat exchanger, the working fluid is pure water and the precipitating solution is calcium sulfate. This research was done through OpenFoam software. The results of the research showed that the optimal conditions for the analysis of inverse heat transfer using the CGMwAP is using the turbulence model <i>k</i>–ω SST, standard deviation of the temperature 0.0005 and 8 temperature sensors. In this research, the results showed that this method estimates the fouling profile well in the turbulent flow with Reynolds number 5000, 7000 and 9000. Also, the results showed that this algorithm can estimate sinusoidal, zigzag and uniform fouling profiles well.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"73 4","pages":"282 - 296"},"PeriodicalIF":1.0,"publicationDate":"2026-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147872290","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 Effect the Choice of Turbulent Models Has on the Numerical Simulation Results for Condensation in Channels","authors":"K. B. Minko,&nbsp;G. G. Yan’kov,&nbsp;A. P. Zheleznov","doi":"10.1134/S0040601526700035","DOIUrl":"10.1134/S0040601526700035","url":null,"abstract":"<p>The aim of the study was to develop practical recommendations on selecting the turbulence models to ensure correct description of condensation processes in two-phase flows in different flow regimes. The existing approaches to modeling condensation in channels are analyzed using the volume of fluid (VOF) method. It is shown that the numerical simulation results depend essentially on the choice of turbulence model and the way in which turbulent viscosity is damped near the phase interface boundary. It is noted that application of widely known models, such as the Launder–Sharma <i>k</i>–ε model and the Menter basic SST <i>k</i>–ω model may yield results significantly deviating from experimental data as a consequence of incorrectly described turbulent transfer in a liquid film. The effect the choice of turbulence model has on the accuracy with which the heat transfer during R-134a refrigerant condensation in a microchannel with a diameter of 1 mm is numerically simulated is studied. The calculations were carried out using the ANES CFD code, which implements the VOF method, and two models of mass transfer at the phase interface boundary—a modified Lee model and a model similar to the Tanasawa model. The low Reynolds Menter SST <i>k</i>–ω model (with and without damping) and the Launder–Sharma model are considered. The studies were carried out for mass flux values ranging from 100 to 1000 kg/(m² s). A comparison with experimental data has shown that the best agreement is reached in the case of using the low Reynolds SST <i>k</i>–ω model with turbulence damping near the phase interface boundary in combination with the Tanasawa model. The average deviation does not exceed 15% and even 10% at high mass flux levels. It has been determined that with taking damping into account, it becomes possible to describe the condensate film laminar flow in a correct manner without the need to artificially set the turbulent viscosity coefficient equal to zero. It is shown that at low mass flux levels, the best coincidence with experimental data is ensured in stating the problem with a specified heat flux, whereas at high mass flux levels the best correspondence to experimental data is reached when specifying a constant wall temperature. The obtained results can be used during practical simulation of condensation processes in microchannels.</p>","PeriodicalId":799,"journal":{"name":"Thermal Engineering","volume":"73 4","pages":"258 - 272"},"PeriodicalIF":1.0,"publicationDate":"2026-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147872289","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}