3,531 research outputs found

    Simulation of electromagnetic parameters in a laboratory installation

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    The paper devoted to the numerical simulation of electromagnetic and heat transfer processes in laboratory installation with two concentric cylindrical electrodes and liquid metal. The electromagnetic and temperature fields of laboratory installation are presented. The results obtained for the laboratory installation can be used in the metallurgical industry for the simulation and optimization of electrometallurgical furnaces. © Published under licence by IOP Publishing Ltd.The authors acknowledge the support of the Russian Science Foundation under the project no. 19-79-00118

    Simulation of the electromagnetic processes in a metallurgical furnace with two bottom electrodes

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    The paper presented electromagnetic processes occurring in an ore reduction furnace with two bottom electrodes. The physical and mathematical formulations of the problem are given, as well as the methodology and algorithm for the numerical simulation of the problem. © Published under licence by IOP Publishing Ltd.The authors acknowledge the support of the Russian Science Foundation under the project no. 19-79-00118

    Modeling and simulation of heat/mass transport, nucleation and growth kinetics in phase transformations

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    The present theme issue is devoted to recent trends and research directions in the phase transformation phenomena occurring in metastable and heterogeneous materials. All papers are concerned with modern theories, experiments, and computer simulations in the wide area of phase transformations. Particular attention is paid to traditional research domains representing the theoretical background for recent simulations and experiments that are as well specifically highlighted herein. Such rapidly developing research directions as phase-field modeling, laser treatment of surfaces, nanostructures, and influence of external fields on the microstructure formation are specially covered in this issue. © 2020, EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature

    Influence of joule heat and heat of electric arc on the vortex flow in DC arc furnace

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    The paper devoted to the numerical simulation of processes in DC electric arc furnaces with the bottom electrode. These furnaces have shown higher efficiency, low heat loss, lower components wear and higher quality of steel production. The biggest disadvantage of such furnaces is a high rate of fettle wear near the bottom electrode that connected with electrovortex flow. Electrovortex flows appearing under electromagnetic forces as a result of non-homogeneous distribution of the current density through the liquid conductor. This effect can be observed in many technological processes: Electro slag remelting process (including DC and AC metallurgical furnaces, electrolysis cells and submerged-resistor induction furnaces), arc welding, processes of semiconductor crystals growing, electro vortex engines etc. © Published under licence by IOP Publishing Ltd.Russian Science Foundation, RSF: 19-79-00118The research was supported by Russian Science Foundation (project No. 19-79-00118)

    On the Theory of Directional Solidification in the Presence of a Mushy Zone

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    Abstract: A model is developed for the directional solidification of a binary melt with a two-phase zone (mushy zone), where the fraction of the liquid phase is described by a space–time scaling relation. Self-similar variables are introduced and the interphase boundary growth is inversely proportional to the square root of time. The mathematical model of the process is reformulated using self-similar variables. Exact self-similar solutions of heat-and-mass transfer equations are determined in the presence of two mobile phase-transition boundaries, namely, solid–mushy zone and mushy zone–liquid ones. The temperature and impurity concentration distributions in the solid phase, the mushy zone, and the melt are found as integral expressions. A decrease in the dimensionless cooled-boundary temperature leads to an increase in the solidification rate and the fraction of the liquid phase. The solidification rate, the parabolic growth constants, and the fraction of the liquid phase at the solid–mushy zone boundary are determined depending on the scaling parameter and the thermophysical constants of the solidifying melt. The positions of the solid–mushy zone and mushy zone–binary melt phase transition boundaries are found. The dependences of the solidification rate (inversely proportional to the square root of time) are analyzed. The scaling parameter significantly is shown to substantially affect the solidification rate and the fraction of the liquid phase in the phase transformation region. The developed model and the method of its solution can be generalized to the case of directional solidification of multicomponent melts in the presence of several phase transformation regions (e.g., main and cotectic two-phase zones during the solidification of three-component melts). © 2021, Pleiades Publishing, Ltd.This work was supported by the Russian Foundation for Basic Research (project no. 18-58-00034 Bel_a) and the Belarussian Foundation for Basic Research (project no. F18R-195)

    Modeling of recirculating hemodynamic flows close to coronary artery stenosis

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    The study addresses the simulation of flow in a straight vessel with two ideal stenoses of 75% and 50%. The blood flow was simulated using the Navier-Stokes hydrodynamic model, and the non-Newtonian properties were determined by the Carreau rheological model. It was founded that a low-velocity recirculation zone forms immediately behind the stenoses, the size of which depends on the velocity of blood flow.В работе рассматривается моделирование течения крови в прямом сосуде с двумя идеальными стенозами 75% и 50%. Моделирование потока крови производилось с помощью гидродинамической модели НавьеСтокса, а неньютоновские свойства определялись реологической моделью Карро. Установлено, что непосредственно за стенозами образуется низкоскоростная зона рециркуляции, размеры которой зависят от скорости тока крови

    THE ROLE OF FLUID VELOCITY ON THE SHAPE OF DENDRITIC TIPS

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    This study is concerned the shape of dendritic tip grown from an undercooled melt in the presence of fluid velocity. The tip shape function is derived and tested against numerical simulations when a forced convection plays a decisive role.L.V.T. acknowledges the financial support from the Russian Science Foundation (project no. 21-79-10012)

    The effectiveness of parallelizing an algorithm of the PFC equation solution using PetIGA library

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    The paper presents an algorithm for solving the equation of Phase Field Crystal (PFC) in a hyperbolic statement that allows to describe the phase transitions of metastable or unstable state at the nuclear density scale, described by a differential equation of the sixth order with respect to the space variable and the second order with respect to the time variable. The algorithm is based on the method of isogeometric analysis (IGA) and is implemented by PetIGA library. The resulting code allows parallel computations, which significantly speeds up the process of solving a problem. The effectiveness of used instruments during the calculations on high-performance computing clusters is evaluated. An analysis of the effectiveness of the current algorithm is carried out for heterogeneous computer systems

    SCIENTIFIC COMPUTATIONAL WEB SERVICE FOR RESEARCH OF THE MICROSTRUCTURE TRANSITIONS DURING SOLIDIFICATION

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    The concept of the computational web service is presented, within the flexible multisolver framework of which the opportunity of cloud computing and processing for studying the mi-crostructural characteristics of a substance during its solidification are implemented.Работа выполнена при поддержке Российского научного фонда, грант 19-71-10044

    Modeling of rheological characteristics of blood in coronary artery with stenosis

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    The aim of the study — to demonstrate the essential influence of rheological processes in the blood on the flow characteristics in arteries with stenosis.Цель исследования — оценить влияние реологических процессов в крови на характеристики ее течения в артерии со стенозом
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