135 research outputs found
In Memory of Noskov Alexander Semenovich (1947-2024)
No full textПолучено: 23.12.2024. Прошла рецензирование: 23.12.2024. Принята к публикации: 24.12.2024. Доступно он-лайн: 17.01.2025.Received: 23.12.2024. Revised: 23.12.2024. Accepted: 24.12.2024. Available on-line: 17.01.2025.Прошел год как не стало Александра Семеновича Носкова (ушел из жизни 17 февраля 2024 года), ученого и наставника, профессора кафедры гидравлики Уральского федерального университета, доктора технических наук, Почетного работника высшего профессионального образования Российской Федерации, Почетного строителя России, Ветерана труда. Александр Семенович стоял у истоков создания научного журнала «Российский журнал строительных наук и технологий» (Russian Journal of Construction Science and Technology – RJCST) и являлся его главным редактором с 2015 по 2022 г.A year has passed since the death of Alexander Semenovich Noskov (he passed away on February 17, 2024), a scientist and mentor, professor of the Department of Hydraulics at the Ural Federal University, Doctor of Technical Sciences, Honorary Worker of Higher Professional Education of the Russian Federation, Honorary Builder of Russia, Veteran of labor. Alexander Semenovich was at the origin of the scientific journal "Russian Journal of Construction Science and Technology" (RJCST) and was its editor-in-chief from 2015 to 2022
Analysis of the local entropy generation in a double-circuit vortex tube
No full textThe method of entropy generation analysis has been implemented with the aim to investigate a double-circuit vortex tube thermodynamics. The value of the enthalpy growth rate was utilized as an indicator of the useful work done by the system. Post-processing of the numerical simulation results was carried out in order to determine the irreversible energy transformations within the computational domain. Particular attention was paid to comparative analysis of the standard k-ε and SAS-SST turbulence models from thermodynamic point of view. The near main nozzle area was mentioned as a source of irreversible energy losses because of active production of turbulence dissipation due to high local values of mean rate of strain tensor modulus. Existence of the negative work area, designated as a parasitic zone, was found in the center of the vortex tube in the close proximity to the additional flow inlet. Its formation can be explained by insufficient turbulent interactions between central and peripheral flows. It was shown that this area contributes significantly to the irreversibility and should be eliminated. The integral characteristics were developed on the ground of the three dimensional distribution of both entropy generation and enthalpy growth rate. The given characteristics are suggested to be used as objectives for the optimization studies. The vortex tube diameter, main nozzle geometry and the turbulization of the additional flow were suggested to be optimized
Numerical investigation of a double-circuit Ranque-Hilsch vortex tube
No full textThe present paper reports a numerical investigation of a double-circuit RanqueeHilsch vortex tube.
Different turbulence models, namely keε, keε RNG, SAS-SST, RSM-LRR and LES, have been tested, in
order to understand which is the most suitable for the considered problem. The analysis is conducted on
a full three-dimensional model and the results show that LES turbulence model provides the best accuracy
of temperature separation prediction, standard keε and keε RNG have the worst accuracy,
whereas RSM-LRR and SAS-SST turbulence models take an intermediate position. On the contrary, LES
model is the most expensive in terms of computational time and resources. The results obtained with LES
highlight very high radial velocity values, which result in the enhancement of the turbulent heat and
mass transfer, which implies a more accurate prediction of the temperature separation effect. The present
study concludes that LES model provides the best accuracy for the simulation of a double-circuit
RanqueeHilsch vortex tube, but at the same time RSM-LRR and SAS-SST models are a good compromise
between computational efficiency and accuracy
A comparison of the application of RSM and LES turbulence models in the numerical simulation of thermal and flow patterns in a double-circuit Ranque-Hilsch vortex tube
No full textThe present paper reports an investigation of a double-circuit Ranque-Hilsch vortex tube using a fully
three-dimensional numerical model of the turbulent compressible air flow. The main purpose of the
paper is to perform a detailed analysis of the thermal and flow patterns obtained with RSM-LRR and
LES turbulence models in order to understand which one is able to represent the Ranque-Hilsch energy
separation effect observed in a double-circuit vortex tube in the most effective way.
The LES turbulence model is found to represent the qualitative turbulence of the flow better than the
RSM-LRR model. The detailed analysis of turbulence characteristics estimated by LES model indicates that
turbulence has a significant impact on the energy separation phenomenon.
Both LES and RSM-LRR turbulence models are shown to have a weak accuracy in the prediction of the
integral characteristics of a double-circuit vortex tube.
An attempt was made to improve the results achieved with LES turbulence model by means of a grid
refinement and an increase of Smagorinsky constant value, but they were found to have a limited impact.
This leads to the conclusion that more advanced kinds of LES turbulence model should be investigated in
order to increase the accuracy of the simulation of a double-circuit vortex tube
Breakthrough directions in chemical reaction engineering at the intersection of fundamental research and engineering science approaches
No full textChemical reaction engineering has gradually evolved into a scientific discipline that studies the interaction of chemical reactions with numerous physical factors, such as heat and mass exchange, phase transfer, fluid dynamics etc., in chemical reactors of various scale and type. The methodology of this discipline is based on physical chemistry, catalysis, physics, mathematics, advanced computing and data processing technologies and other advanced areas of science and technology. Chemical reaction engineering is a general methodology for efficient tool for development, scale-up and optimization of chemical reactors and chemical processes. CRE covers a wide range of existing and future technologies for the petroleum and natural gas processing, metallurgy, chemical industry, energy manufacturing and storage, manufacturing of renewable feedstocks, environment protection and utilization of wastes, biotech and pharmaceutical industries. The purpose of this VSI is to publish selected novel contributions across the entire innovative research range - from the fundamental foundations of the reaction engineering to applied developments for emerging applications. These contributions were selected from the proceedings of the XIV International Conference on Chemical Reactors ChemReactor-24, which was organized by Boreskov Institute of Catalysis of the Siberian Branch of the Academy of Sciences, Novosibirsk, Russia together with Politecnico di Milano, Italy. The conference was traditionally held under the auspices of the European Federation of the Chemical Engineering. The conference took place during 12–17 September 2021. Though, all previous conferences were held in a usual format, the pandemia limitations forced us to make it the online event. Despite complicated conditions, the conference brought together 251 researchers and engineers from 38 countries all over the world. The conference was traditionally devoted to the fundamental aspects and practical application of the catalytic processes and chemical reactors, as well as to the development of the novel technologies
David R. Francis, Ambassador to Four Russian Governments
No full textThis article examines the tenure of David R. Francis, U.S. ambassador to Russia from 1916 to 1918, highlighting his challenges in navigating the collapse of the Russian Empire, the rise of the Provisional Government, and the Bolshevik Revolution. Despite his lack of diplomatic experience, Francis grappled with complex issues, including prisoner-of-war management, strained U.S.-Russian relations, and Allied intervention efforts. The author argues that Francis\u27 performance reflects broader shortcomings of Wilsonian diplomacy, characterized by liberal illusions and democratic prejudices ill-suited to revolutionary Russia. Through a critical analysis of Francis’ actions and memoirs, the article questions his legacy while situating his failures within the context of U.S. foreign policy under Woodrow Wilson.
Open-data-driven embeddable quality management services for map-based web applications
No full textVarious map-centered web services facilitate citizens’ lives. Web-map applications exist for many years already. Due to simplification and improvement of technologies supporting WebGIS, map-based services become more popular and important nowadays. Data quality assurance for such services is a significant challenge. Since many of such applications intensively use open data, approaches focused on open solutions are required. This work proposes a data-quality concept, which is based on intrinsic and comparable approaches. OpenStreetMap (OSM) allows intrinsic data evaluation. Moreover, it is used as a reference dataset for quality assessment of public-sector-information Open Data layers. Equidistant point (EDP)-based statistics enables to filter out low-quality Open Data features. A data-type model carries out the inventory of OSM data. The comparison of raster web-map tile file sizes and calculation of a simplified data quality indicator make it possible to specify acceptable data quality levels. Embeddable instances of quality assurance web services incorporate data features with acceptable quality. This work provides all required software and data for the deployment of such services under liberal licenses. Concrete instructions allow users to adopt the proposed solutions for their platforms. Some generic use cases illustrate the advantages of the introduced shared web services
Theoretical basis and devedopment of hydrodynamic methods of influence on processes in steel melting bathes and ladles
No full textThe processes in the steel melting converter bath and ladle were studied. The purpose was the development of theoretical basis for processes taking place in converter at the bottom blown and solution of ferroalloy lumps. Object of location were studied experimentaly. Methods for gas-liquid system investigations were developed. The results of hydrodynamic and heat-mass-transfere effects in combined blown converter were analysed. The appropiatenesses of solution of moving ferroalloy lumps were determined. The results obtained were used in the project of combined blown converters and development of technology of metal treatment out furnaceAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio
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