Mihails Ščepanskis

University of Latvia | LU · Department of Physics

Recent developments in additive manufacturing (also called 3D printing of inductors) have opened new possibilities in the induction heating field by making inductors that have a longer service life and are more reproducible. Computer simulations were done to compare inductors made with two different techniques – conventional manufacturing and addit...

Simulation is a useful tool to predict microstructure distribution in a workpiece. The hardening profile does not give the full information about the hardening process. It is important to also know the microstructure distribution. Slice of the whole piece is simulated to make calculations faster. Current in the inductor 8000A, frequency 15 kHz. The...

We investigate directional solidification of the melt with solid inclusions by means of a non-invasive imaging technique-neutron radiography. For the first time results have revealed particle trapping in the solidifying melt at macro scale. It is shown that particle solidification in volume can be achieved when liquid and solid phases form a mushy...

The paper analyzes hardened zone thickness of a splined shaft after scanning induction heating with a two-turn inductor. The analysis is done by means of 3D simulation. While it is demonstrated that quick 2D axial-symmetric approximation could give reasonable estimations for gear hardening, the wider splines benefit from 3D simulation. Hardening pr...

Barber's pole and striation effect is a localized overheating as a result of magnetic field redistribution in vicinity of the regions when temperature locally has passed the Curie point and, consequently, the material locally lost ferromagnetic properties. - Appears when the temperature approaches Curie point - The number of stripes depends on the...

In this presentation we list features and benefits of induction heating; describe main applications; obstacles and solutions of induction heating; advantages and disadvantages of computer simulation vs physical testing; what should be taken into account when choosing the right simulation software. Induction heating is an efficient way to quickly he...

There's an opinion that simulation of real induction cases takes too much time. Our opinion - it depends on optimization. We're sharing our experience on how to optimize simulation time of 3D induction heating tasks.

The paper describes simulation of induction heating process of ferromagnetic steel, when a full non-linear model is used: a temperature dependent B-H curve is taken into account. The full B(H,T) model is essential to obtain accurate results, which are confirmed by experimental validation. The paper also points out sensitivity of the model to slight...

The paper reports the empirical observations of voltage generation in a lubricated tribocontact with different oils altering load, sliding and temperature. The investigation is done in the context of research of the root cause of white etching cracks (WEC) failure in bearings. Tested oils of different additive packages found completely different el...

An open-source library called EOF which provides efficient two-way coupling between the finite element multi-physics simulation software Elmer and computational fluid dynamics software OpenFOAM is presented. Library controls interpolation and communication of fields between two codes. The main focus of this code is industrial magnetohydrodynamics w...

This paper presents qualitative and quantitative characterization of two-phase liquid metal flows agitated by the stirrer on rotating permanent magnets. The stirrer was designed to fulfil various eddy flows, which may have different rate of solid particle entrapment from the liquid surface and their homogenization. The flow was characterized by vis...

In this work, the stirring of liquid gallium in a rectangular crucible induced by four counter-rotating permanent magnets is investigated numerically. The mean velocity and turbulence kinetic energy for different distances of the magnets from the vessel with liquid metal and the magnet rotation rate are investigated. The flow is modeled using two t...

Understanding and optimization of movement of inclusions in intense liquid metal flows is significantly important for different types of melting, stirring and casting equipment, including electroinductive technologies that are able to agitate flow in conductive liquid significantly beyond turbulence level. Such investigation match various industria...

In this work, liquid gallium flow induced by four counter rotating permanent magnets in a rectangular vessel is investigated numerically and compared to the results obtained with the novel neutron radiography method. It is observed experimentally that the expected symmetric four-vortex structure transits to three eddies. We captured this effect num...

The paper contains a theoretical investigation of magnetohydrodynamic force experienced by iron particles (well-conducting and ferromagnetic) in well-conducting liquid. The investigation is performed by extending the Leenov and Kolin's theory to take into account the second-order effect. Therefore, the limits of the parent model are taken over to t...

This experiment allowed to performed first time dynamic investigation of solid inclusions in electromagnetically stirred liquid metal. The well-known Particle Image Velocimetry technique was adopted and successfully applied for analysis of the neutron experiment providing full dynamics of particles in a liquid metal flow.

Despite the ongoing debates on influence of hydrogen uptake and penetration in the steel, pulsed and extraordinary fatigue on white etching cracks (WEC) formation in bearing steel SAE52100, the present work advocates an alternative hypothesis on electrothermal initiation of the WEC. Electrical current in bearings is generally associated with a brea...

Due to the non-transparency of metals it is nearly impossible to observe how inclusions behave within a liquid metal. At the same time numerical models, which generally are powerful tools for design of different types of metallurgical and other equipment associated with liquid metal, usually contain a high number of degrees of freedom due to the co...

This paper presents the analysis of the first dynamic neutron radiography experiment that visualized motion of solid particles in liquid metal, which was stirred by a system of four counter-rotating magnets. The paper also contains the quantitative results derived from neutron images: the distribution of particle concentration, number of admixed pa...

We perform a numerical study of a disks type electromagnetic induction pump based on permanent rotating magnets (PMP). The theoretical analysis of such pumps is complicated and cumbersome since the system is non-symmetrical and highly three-dimensional, so that the magnetic field and, hence, the induced electromagnetic forces are distributed non-un...

Due to the non-transparency of metals it is nearly impossible to observe how solid inclusions behave within a liquid metal. At the same time numerical models, which generally are powerful tools for design of different types of metallurgical equipment, usually contain a high number of degrees of freedom due to the complexity of turbulent flows of li...

The present paper contains a report on the first neutron radiography experiment that visualized the motion of solid particles in liquid gallium in a rectangular vessel, which was stirred by a system of four counter-rotating magnets. The experiment has demonstrated that the neutron radiography is a promising experimental method for the investigation...

Despite the ongoing debates on influence of hydrogen uptake and penetration in the steel, pulsed and extraordinary fatigue on white etching cracks (WEC) formation in bearing steel SAE52100, the present paper proposes an alternative hypothesis on electrothermal initiation of the WEC. The hypothesis points to differences between electrical and therma...

This paper presents the analysis of the possibility to use molten salt as a physical model of liquid metal for experimental study of turbulent electromagnetically driven flows. The conclusion is—the molten salt is not suitable for this goal. The conclusion is done based on the results on numerical simulation.

This paper reports an iterative numerical algorithm for the calculation of an electromagnetic force and velocity field induced by a system of rotating permanent magnets in liquid metal. Particularly, a system of two pairs of counter-rotating permanent magnets placed at the opposite sides of a rectangular vessel with liquid gallium is considered. We...

The paper presents a methodology for identification of homogenization time of alloying inclusions in an induction crucible furnace. The methodology is based on the Large Eddy Simulation (LES) Euler-Lagrange calculation of inclusions and a regression model for size of the inclusions and their density. The presented regression model avoids the repeat...

The first neutron radiography experiment, which visualized motion of solid particles in liquid metal in a rectangular vessel stirred by a system of four counter-rotating magnets, was carried out. The experiment demonstrated that the neutron radiography is a promising experimental method for investigation of dynamics of particles in liquid metal.

It is of considerable basic scientific interest and commercially relevant to the involved industries to better understand the movement of impurities in electromagnetically agitated liquid metals. Both, gaseous and solid inclusions are of concern as they are detrimental to the quality of the final product. While the admixture of gas in certain insta...

The present paper contains a description and first results of a recent neutron radiography experiment that visualized admixing of solid particles in liquid gallium in a rectangular vessel, which was stirred by a system of four counter-rotating magnets.

An electromagnetic (EM) impact to changes in microstructures of bearing steel, which occur during their exploitation, is investigated with a stress on white etching areas (WEA) formation. The early WEA is an urgent problem in bearing industry as far as this phenomenon leads to unpredictable decay of bearings. In this work a new hypothesis of impact...

The paper presents the numerical and the experimental investigation of the particle-laden recirculated turbulent flow of liquid metal that is driven by electromagnetic force. Such flow is typical for induction metallurgical furnaces. The paper describes the behaviour of solid spherical particles that are mixed in the flow from a top surface of a me...

The short video presented the raw results of the first neutron radiography experiment on visualisation of motion of solid inclusions in the flow of liquid metal. The flow in the rectangular vessel was induced by four counter-rotating magnets. The experiment was carried out in Paul Scherrer Institute (Villigen, Switzerland) on July 24-27, 2014.

The present paper reports the first step of research project, which contains a fundamental numerical investigation of the flow of liquid gallium in the system of 4 counter-rotated cylindrical magnets and an innovative neutron radiography experiment. The design of the experimental set-up is reported. Numerical aspects of the modeling of such a syste...

A disks type electromagnetic induction pump based on permanent rotating magnets is studied numerically. The theoretical analysis of such pumps is cumbersome since the magnetic field and, hence, the induced electromagnetic forces are distributed non-uniformly in both radial and transverse directions. In this work, the 3D numerical model of a liquid...

The thesis presents numerical and experimental investigation of the particle laden recirculated turbulent flow of liquid metal, which is driven by electromagnetic force. The calss of such flows is typical for induction metallurgical furnaces. The LES-based Euler-Lagrange model with extended set of forces, which influence the motion of inertial forc...

Experimental and numerical investigation of the particle laden recirculated turbulent flow, which is driven by EM force, is presented. Such flows are typical for induction metallurgical furnaces. The analysis is focused on the behaviour of the particles and their concentration.Experimental investigation is fulfilled utilizing the new technique: fer...

The paper presents a spectral analysis of oscillations, which appear in the middle zone of induction crucible furnaces (ICF) between the mean vortexes of the turbulent EMinduced recirculated flow of liquid metal. It is known that these pulsations ensure the axial homogenization of alloying inclusions in the ICF, which is a very essential engineerin...

The paper refers to the dynamics of solid inclusion in the turbulent flow of liquid metal in induction furnaces. The numerical analysis is carried out adopting LES-based Euler-Lagrange approach in the limit of dilute conditions. The model is verified with the original experimental technique, which deals with ferromagnetic particles in the flow of W...

The paper refers to the dynamics of solid inclusion in the turbulent flow of liquid metal in induction furnaces. The numerical analysis is carried out adopting LES-based Euler-Lagrange approach in the limit of dilute conditions. The admixing of carbon particles in induction crucible furnace from the open surface of a melt is simulated. The behaviou...

The present paper contains an analysis of the statistical distribution of forces affecting non-conducting particles dispersed in an EM induced recirculated flow in induction furnaces. The simulation is conducted adopting the LES-based Euler-Lagrange approach in the limit of dilute conditions (one-way coupling). It is done by means of a development...

The process of homogenization of alloying particles in induction crucible furnace (ICF) was analyzed and physical explanation of observed dependences was given last year (M. Šcepanskis et. al. Proceeding of Modeling of Material Processes, Riga, 2010, pp. 259-264). It was also noticed that after initial period, which is important for this process an...

The large oscillations of the axial component of liquid velocity in the middle zone of induction crucible furnaces (ICF) are observed. These pulsations produce the oscillations of particle transport appearing during the process of homogenization, which is important step of industrial processing of metals. The experimental and numerical results of t...

The present paper contains the result of the numerical modelling for the process of particle homogenization in the flow of induction crucible furnaces that includes two mean toroidal recirculated vortices. The LES method is used to simulate the flow of liquid metal and the Lagrangian equation is used for particle tracking. The algorithm is implemen...

The paper contains the description of the further development of particles libraries in OpenFOAM in fine near-wall cells. We simulate the flow of induction crucible furnace (ICF) with high Reynolds number. In this case the motion of liquid metal is governed by the Lorenz force and the penetration depth of electromagnetic field is relatively small....

The present paper contains the result of the numerical modelling of the industrial process of the particle homogenization in induction crucible furnaces. The LES method is used to simulate the flow of liquid metal and the Lagrangian equation is used for particle tracking. The algorithm is implemented by means of the development of the OpenFOAM soft...

The process of the motion of solid particles in the metal melt is simulated in the present paper. The model consists of the flow and the particles movement calculation at each time step. The simulation of the EM induction governed turbulent flow is carried out using the Large Eddy Simulation (LES) method with the Smagorinsky subgrid viscosity model...

The process of electromagnetic mixing of alloying admixtures in the metal melt is simulated in the present paper. The simulation of the EM induction governed a turbulent flow is carried out using the Large Eddy Simulation (LES) method with the Smagorinsky subgrid viscosity model. The motion of the admixture particles is simulated using the Lagrangi...

Oscillations in concentration and grain size could occur in the process of amino acid sorption on ion-exchanger grains. This phenomenon has been observed in several experimental works. The theoretical explanation of the phenomenon was given earlier by means of an elementary model. In this work the process was studied using a physically more sophist...