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1

Unsteady magnetohydrodynamic free convection and heat transfer flow of Al2O3‒Cu/water nanofluid over a non-linear stretching sheet in a porous medium

Mathews Joel, Hymavathi Talla

Archives of Thermodynamics

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2024

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Vol. 45, no 1

165--173

EN

This article investigates the impact of time-dependent magnetohydrodynamics free convection flow of a nanofluid over a non-linear stretching sheet immersed in a porous medium. The combination of water as a base fluid and two different types of nanoparticles, namely aluminum oxide (Al2O3) and copper (Cu) is taken into account. The impacts of thermal radiation, viscous dissipation and heat source/sink are examined. The governing coupled non-linear partial differential equations are reduced to ordinary differential equations using suitable similarity transformations. The solutions of the principal equations are computed in closed form by applying the MATLAB bvp4c method. The velocity and temperature profiles, as well as the skin friction coefficient and Nusselt number, are discussed through graphs and tables for various flow parameters. The current simulations are suitable for the thermal flow processing of magnetic nanomaterials in the chemical engineering and metallurgy industries. From the results, it is noticed that the results of copper nanofluid have a better impact than those of aluminium nanofluid.

2

Analytical analysis of thermal conductivity by laminar flow under the influence of mhd using Vogel’s model

Nawaz Rashid, Farooq Muhammad, Rehman Siddiq Ur, Ismail Gamal M., Ahmad Hijaz

Acta Mechanica et Automatica

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2024

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Vol. 18, no. 3

548--563

EN

The main aim of this work is to study the influence of thermal conductivity of uniform couple stress fluid of inclined Poiseuille flow in the presence of magneto hydrodynamic (MHD) between two parallel plates. A well-known Vogel’s viscosity model is used. The momentum and energy equations are solved analytically by utilizing Homotopy Perturbation method (HPM) and Optimal Homotopy Asymptotic Method (OHAM). The results include the velocity profile, average velocity, volume flux, Shear Stress, Skin friction and the temperature distribution between the plates. Particular attention is given to the effect of MHD Γ on the velocity field and temperature distribution. As can be seen, that there exists direct relation between MHD parameter Γ and velocity profile and bears inverse relation with temperature distribution. In addition to that, influence of non-dimensional parameters like G, A, a, B and γ on the velocity field and temperature distribution are also discussed graphically. The physical characteristics of the problem have been well discussed in graphs for several parameters of interest. The results reveal that both techniques are reliable and are in great agreement with each other.

3

Substrates with different magnetic properties versus iron-nickel film electrodeposition

Białostocka Anna M., Klekotka Marcin, Klekotka Urszula, Żabiński Piotr R., Kalska-Szostko Beata

Chemistry-Didactics-Ecology-Metrology

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2023

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R. 28, NR 1-2

157--170

EN

The hereby work presents the iron-nickel alloys electroplated on the different metallic substrates (aluminium, silver, brass) using galvanostatic deposition, with and without presence of the external magnetic field (EMF). The films were obtained in the same electrochemical bath composition - mixture of iron and nickel sulphates (without presence of additives) in the molar ratio of 2 : 1 (Ni : Fe), the electric current density (50.0 mA/cm2), and the time (3600 s). The mutual alignment of the electric (E) and magnetic field (B) was changeable - parallel and perpendicular. The source of EMF was a set of two permanent magnets (magnetic field strength ranged from 80 mT to 400 mT). It was analysed the surface microstructure, composition, morphology, thickness and the mechanical properties (roughness, work of adhesion). The surface morphology and the thickness of films were observed by Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM). The elemental composition of all FeNi films was measured using Wavelength Dispersive X-Ray Fluorescence (WDXRF). The crystalographic analysis of the deposits was carried out by X-Ray Diffraction. Depending on the used substrate, modified external magnetic field orientation influenced the tribological and physio-chemical properties of the deposited layers. The diamagnetic substrates and EMF application reduced the FeNi thickness and the average crystallites size, in contrast to the paramagnetic substrate. Parallel EMF increased the value of the tribological parameters for CuZn and Ag but decreased for Al. The content of FeNi structure was rising in the case of diamagnetic substrate and the dependence was opposite on the paramagnetic substrate.

4

About Unusual Diffraction and Thermal Self-Action of Magnetosonic Beam

Perelomova Anna

Archives of Acoustics

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2022

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Vol. 47, No. 3

355--362

EN

The dynamics of slightly diverging two-dimensional beams whose direction forms a constant angle θ with the equilibrium straight magnetic strength is considered. The approximate dispersion relations and corresponding links which specify hydrodynamic perturbations in confined beams are derived. The study is dedicated to the diffraction of a magnetosonic beam and nonlinear thermal self-action of a beam in a thermoconducting gaseous plasma. It is shown that the divergence of a beam and its thermal self-action is unusual in some particular cases of parallel propagation (θ = 0) and has no analogues in the dynamics of the Newtonian beams. The nonlinear attenuation of Newtonian beams leads to their defocusing in gases, whereas the unusual cases correspond to the focusing in a presence of magnetic field. The examples of numerical calculations of thermal self-action of magnetoacoustic beams with shock fronts are considered in the usual and unusual cases of diffraction concerning stationary and non-stationary self-action. It is discovered that the diffraction is more (θ = 0) or less (θ = π/2) manifested as compared to that of the Newtonian beams. The beams which propagate oblique to the magnetic field do not reveal diffraction. The special case, when the sound and Alfvénic speeds are equal, is discussed. This magnetosonic beams incorporate acoustic and Alfvénic properties and do not undergo diffraction in this particular case.

5

Periodic flow of a second grade fluid due to the disks executing non-torsional oscillations in an orthogonal rheometer under the influence of a magnetic field

Ersoy H. Volkan

International Journal of Applied Mechanics and Engineering

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2021

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Vol. 26, no. 3

62--71

EN

The present paper studies the periodic flow of a second grade fluid generated by non-torsional oscillations of the disks rotating in the eccentric form under the application of a magnetic field. Subsequent to the rotational motion of the disks at a common angular velocity about two vertical axes, they perform oscillations horizontally in a symmetrical manner. The exact analytical solutions are derived for both the velocity field and the tangential force per unit area exerted on one of the disks by the fluid. Special attention is paid to the influence of the applied magnetic field and it is investigated how the magnetic field controls the flow when the frequency of oscillation is less than or equal to or greater than the angular velocity of the disks. It is found that the application of the magnetic field leads to thinner boundary layers developed on the disks and the changes in the values of the shear stress components which represent the tangential force exerted on the disks occur at larger amplitude.

6

Effect of Hall currents on unsteady magnetohydrodynamic two-ionized fluid flow and heat transfer in a channel

Raju T. Linga, Rao V. Gowrisankara

International Journal of Applied Mechanics and Engineering

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2021

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Vol. 26, no. 2

84--106

EN

An unsteady magnetohydrodynamic (MHD) heat transfer two-fluid flow of ionized gases through a horizontal channel between parallel non-conducting plates, by taking Hall currents into account is studied. The governing partial differential equations that describe the flow and heat transfer under the adopted conditions are solved for the velocity and temperature distributions by a regular perturbation technique. Profiles for the velocity and temperature distributions as well the rates of heat transfer coefficient are presented graphically, and a parametric study is performed. The results reveal that the combined effects of the Hartmann number, Hall parameter, and the ratios of viscosities, heights, electrical and thermal conductivities have a significant impact on an unsteady MHD heat transfer two-ionized fluid flow characteristics.

7

Capture efficiency of magnetically labeled particles traveling through an intracranial aneurysm

Cardona M., Ramírez J., Benavides-Moran A. G.

International Journal of Applied Mechanics and Engineering

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2021

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Vol. 26, no. 1

65--75

EN

Cell manipulation using external magnetic fields has been proposed to accelerate the neck reendothelization of saccular unruptured stented intracranial aneurysms. This work presents a computational fluid dynamics (CFD) model of a Saccular Brain Aneurysm that incorporates a helicoidal stent. An Eulerian-Lagrangian model implemented in ANSYS-Fluent is used to simulate the hemodynamics in the aneurysm. In silico studies have been conducted to describe the incidence of the magnetic field direction, frequency and amplitude on the blood hemodynamics and particle capture efficiency, when an external magnetic field is used to trap magnetically labeled particles traveling through the aneurysm. It is found that the magnetic field direction affects the particle concentration in the target region. Simulation results show that the highest particle capture efficiency is obtained with a 1T magnetic field amplitude in an open bore MRI scanner, when a permanent magnet is used.

8

Radiative MHD Walter’s liquid-B flow past a semi-infinite vertical plate in the presence of viscous dissipation with a heat source

Damala Chenna Kesavaiah, Bhumarapu Venkateswarlu, Makinde Oluwole Daniel

Engineering Transactions

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2021

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Vol. 69, iss. 4

373--401

EN

The free convective magnetohydrodynamics (MHD) flow of a non-Newtonian fluid due to a semi-infinite vertical plate under the influence of radiation and viscous dissipation is investigated. The system of partial differential equations is derived and solved for the solutions of velocity and temperature profiles along with the Nusselt number and skin friction by using the perturbation technique. The related important dimensionless parameters of Eckert, Grashof, and Prandtl numbers, magnetic field, radiation and heat source are discussed and shown in graphs. Also, the Nusselt number and skin friction at the plate are obtained and presented in the tabular forms. Finally, the corresponding result of Newtonian fluid is obtained by setting viscoelastic parameter k1 = 0. It is worth mentioning that the obtained results coincide with the previously published results.

9

Effect of thermal radiation on biomagnetic fluid flow and heat transfer over an unsteady stretching sheet

Alam Jahangir Md., Murtaza Ghulam Md., Tzirtzilakis Efstratios E., Ferdows Mohammad

Computer Assisted Methods in Engineering and Science

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2021

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Vol. 28, no. 2

81--104

EN

This study examines the influence of thermal radiation on biomagnetic fluid, namelyblood that passes through a two-dimensional stretching sheet in the presence of magneticdipole. This analysis is conducted to observe the behavior of blood flow for an unsteadycase, which will help in developing new solutions to treat diseases and disorders related tohuman body. Our model is namely biomagnetic fluid dynamics (BFD), which is consistentwith two principles: ferrohydrodynamic (FHD) and magnetohydrodynamic (MHD), whereblood is treated as electrically conductive. It is assumed that the implemented magneticfield is sufficiently strong to saturate the ferrofluid, and the variation of magnetization withtemperature may be approximated with the aid of a function of temperature distinction.The governing partial differential equations (PDEs) converted into ordinary differentialequations (ODEs) using similarity transformation and numerical results are thus obtainedby using the bvp4c function technique in MATLAB software with considering applicableboundary conditions. With the help of graphs, we discuss the impact of various param-eters, namely radiation parameter, unsteady parameter, permeability parameter, suctionparameter, magnetic field parameter, ferromagnetic parameter, Prandtl number, velocityand thermal slip parameter on fluid (blood) flow and heat transfer in the boundary layer.The rate of heat transfer and skin friction coefficient is also computationally obtained forthe requirement of this study. The fluid velocity decreases with increasing values of themagnetic parameter, ferromagnetic interaction parameter, radiation parameter whereastemperature profile increases for the unsteady parameter, Prandtl number, and permeability parameter. From the analysis, it is also observed that the skin friction coefficientdecreases and the rate of heat transfer increases respectively with increasing values ofthe ferromagnetic interaction parameter. The most important part of the present analy-sis is that we neither neglect the magnetization nor electrical conductivity of the bloodthroughout this study. To make the results more feasible, they are compared with thedata previously published in the literature and found to be in good accuracy.

10

Optimization of heat transfer properties of nanofluid flow over a shrinking surface through mathematical modeling

Bhandari A., Pavan Kumar Pannala R. K.

International Journal of Applied Mechanics and Engineering

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2020

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Vol. 25, no. 2

40--56

EN

In the current study, a three dimensional incompressible magnetohydrodynamic (MHD) nanofluid flow over a shrinking surface with associated thermal buoyancy, thermal radiation, and heating absorption effects, as well as viscous dissipation have been investigated. The model has been represented in a set of partial differential equations and is transformed using suitable similarity transformations which are then solved by using the finite element method through COMSOL. The results for velocity and temperature profiles are provided for various values of the shrinking parameter, Biot’s number, heat generation/absorption parameter, thermal Grashof number, nanoparticle volume fraction, permeability parameter, magnetic parameter and radiation parameter.

11

Mixed convective flow of unsteady hydromagnetic couple stress fluid through a vertical channel filled with porous medium

Makhalemele C. R., Rundora L., Adesanya S. O.

International Journal of Applied Mechanics and Engineering

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2020

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Vol. 25, no. 4

148--161

EN

In this paper, the mixed convective flow of an electrically conducting, viscous incompressible couple stress fluid through a vertical channel filled with a saturated porous medium has been investigated. The fluid is assumed to be driven by both buoyancy force and oscillatory pressure gradient parallel to the channel plates. A uniform magnetic field of strength 0B is imposed transverse to the channel boundaries. The temperature of the right channel plate is assumed to vary periodically, and the temperature difference between the plates is high enough to induce radiative heat transfer. Under these assumptions, the equations governing the two-dimensional couple stress fluid flow are formulated and exact solutions of the velocity and the temperature fields are obtained. The effects of radiation, Hall current, porous medium permeability and other various flow parameters on the flow and heat transfer are presented graphically and discussed extensively.

12

MHD mixed convection in copper-water nanofluid filled lid-driven square cavity containing multiple adiabatic obstacles with discrete heating

Gorla R. S. R., Siddiqa S., Hasan A. A., Salah T., Rashad A. M.

International Journal of Applied Mechanics and Engineering

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2020

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Vol. 25, no. 2

57--74

EN

The objective of the present work is to investigate the influence of nanoparticles of copper within the base fluid (water) on magneto-hydrodynamic mixed-convection flow in a square cavity with internal generation. A control finite volume method and SIMPLER algorithm are used in the numerical calculations. The geometry is a lid-driven square cavity with four interior square adiabatic obstacles. A uniform heat source is located in a part of the left wall and a part of the right wall of the enclosure is maintained at cooler temperature while the remaining parts of the two walls are thermally insulated. Both the upper and bottom walls of the cavity are considered to be adiabatic. A comparison with previously published works shows a very good agreement. It is observed that the Richardson number, Ri, significantly alters the behavior of streamlines when increased from 0.1 to 100.0. Also, the heat source position parameter, D, significantly changes the pattern of isotherms and its strength shifted when D moves from 0.3 to 0.7.

13

Symulacja prostego silnika magnetohydrodynamicznego

Lipiński Sz., Supińska D.

Maszyny Elektryczne : zeszyty problemowe

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2018

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Nr 3 (119)

65--69

PL

Silnik magnetohydrodynamiczny jest maszyną elektryczną, w której elementem bezpośrednio wprawianym w ruch jest płyn znajdujący się w polu magnetycznym. W opisanym przykładzie taką rolę pełni osolona woda przewodząca prąd znajdująca się w zewnętrznym polu magnetycznym pochodzącym od magnesu ferrytowego. W artykule zawarto model matematyczny zjawisk pozwalający na przewidywanie zachowania się płynu oraz wykorzystany model numeryczny, który wstępnie zweryfikowano na modelu fizycznym w laboratorium. Omawiane urządzenie wprawia w ruch obrotowy wodę znajdującą się w szalce Petriego, której zewnętrzna ścianka wyłożona jest taśmą miedzianą. Na dnie szalki położony jest magnes ferrytowy w kształcie pierścienia. Całość zasilana jest prądem stałym przepływającym poprzez płyn z umieszczonej centralnie elektrody wykonanej z miedzianego drutu do znajdującej się na zewnątrz elektrody utworzonej z taśmy miedzianej, którą wyłożona jest zewnętrzna ścianka.

EN

Magnetohydrodynamic drive is a type of electric drive, where force acts directly on fluid without mechanical moving parts. The fluid in most cases conducts electric current in magnetic field creating force. Article includes mathematical model allowing to predict fluid behavior together with incorporated numerical model, which was preliminary verified on physical model on test rig. In described example salty water conducts direct current from central electrode made of copper wire to external electrode made of thin copper sheet covering external wall of Petri dish. External magnetic field is provided by ferrite magnet located on the bottom of the vessel. In result water spins in directions according to forces created in conductor exposed to magnetic field.

14

Unsteady two-layered fluid flow of conducting fluids in a channel between parallel porous plates under transverse magnetic field in a rotating system

Linga Raju T., Neela Rao B.

International Journal of Applied Mechanics and Engineering

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2016

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Vol. 21, no. 2

423--446

EN

An unsteady MHD two-layered fluid flow of electrically conducting fluids in a horizontal channel bounded by two parallel porous plates under the influence of a transversely applied uniform strong magnetic field in a rotating system is analyzed. The flow is driven by a common constant pressure gradient in a channel bounded by two parallel porous plates, one being stationary and the other oscillatory. The two fluids are assumed to be incompressible, electrically conducting with different viscosities and electrical conductivities. The governing partial differential equations are reduced to the linear ordinary differential equations using two-term series. The resulting equations are solved analytically to obtain exact solutions for the velocity distributions (primary and secondary) in the two regions respectively, by assuming their solutions as a combination of both the steady state and time dependent components of the solutions. Numerical values of the velocity distributions are computed for different sets of values of the governing parameters involved in the study and their corresponding profiles are also plotted. The details of the flow characteristics and their dependence on the governing parameters involved, such as the Hartmann number, Taylor number, porous parameter, ratio of the viscosities, electrical conductivities and heights are discussed. Also an observation is made how the velocity distributions vary with the rotating hydromagnetic interaction in the case of steady and unsteady flow motions. The primary velocity distributions in the two regions are seen to decrease with an increase in the Taylor number, but an increase in the Taylor number causes a rise in secondary velocity distributions. It is found that an increase in the porous parameter decreases both the primary and secondary velocity distributions in the two regions.

15

Investigation of the influence of supply parameters on the velocity of molten metal in a metallurgical reactor used for platinum recovery

Fornalczyk A., Golak S., Przyłucki R.

Archives of Civil and Mechanical Engineering

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2015

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Vol. 15, no. 1

171--178

EN

Exhaust gases which are introduced into the atmosphere contain impurities such as carbon monoxide, unburned hydrocarbons and nitrogen oxide. Auto catalysts enable air pollution from these exhaust gases to be reduced considerably. Typical auto catalytic converters consist of the carrier (ceramic or metallic) and the catalytic system. Platinum group metals (PGM) are responsible for the catalytic function. All spent auto catalysts should be purchased and processed in order to recover the precious metals from them. This article presents the results of coupled analyses of electromagnetic and flow field calculations. The aim of this research was to design a device for extracting precious metals from used auto catalytic converters. Calculations were made to determine the velocity field distribution of a liquid metal, the movement of which was forced by the electromagnetic field. Computational experiments were conducted to obtain the relationships between the metal velocity distribution, the inductor supply and geometrical parameters in order to improve the construction of the presented device. The calculation shows that viscosity and friction has a greater influence on velocity distribution than forces distribution.

16

Metody zwiększania efektywności przepłukiwania katalizatorów samochodowych ciekłym metalem

Fornalczyk A., Golak S., Przyłucki R.

Przegląd Elektrotechniczny

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2014

|

R. 90, nr 2

60--62

PL

Artykuł dotyczy analizy procesu wypłukiwania metali szlachetnych z wkładów katalizatorów umieszczonych w pierścieniowym kanale przy pomocy ciekłego metalu wprawianego w ruch przez wirujące pole elektromagnetyczne. Wykorzystany w pracy model obliczeniowy obejmował sprzężenie pola elektromagnetycznego i hydrodynamicznego z uwzględnieniem przepływu metalu przez kapilarną strukturę katalizatora. W ramach badań przeprowadzono analizę wpływu lokalizacji wzbudnika na efektywność przepłukiwania wsadu katalizatora.

EN

The paper concerns of precious metals washing out from auto catalytic converters placed in the channel. In this device liquid metal is forced to motion by the rotating magnetic field. The model used in research included the coupling of the electromagnetic and hydrodynamic field taking into account the metal flow through anisotropic porous structure of the catalyst. The study analyzes the influence of inductor location on the efficiency of flushing the catalyst.

17

MHD two-layered unsteady fluid flow and heat transfer through a horizontal channel between

Linga Raju T., Nagavalli M.

International Journal of Applied Mechanics and Engineering

|

2014

|

Vol. 19, no. 1

97--121

EN

An unsteady magnetohydrodynamic (MHD) two-layered fluids flow and heat transfer in a horizontal channel between two parallel plates in the presence of an applied magnetic and electric field is investigated, when the whole system is rotated about an axis perpendicular to the flow. The flow is driven by a constant uniform pressure gradient in the channel bounded by two parallel insulating plates, when both fluids are considered as electrically conducting, incompressible with variable properties, viz. different viscosities, thermal and electrical conductivities. The transport properties of the two fluids are taken to be constant and the bounding plates are maintained at constant and equal temperatures. The governing partial differential equations are then reduced to the ordinary linear differential equations using two-term series. Closed form solutions for primary and secondary velocity, also temperature distributions are obtained in both the fluid regions of the channel. Profiles of these solutions are plotted to discuss the effects of the flow and heat transfer characteristics, and their dependence on the governing parameters involved, such as the Hartmann number, rotation parameter, ratios of the viscosities, heights, electrical and thermal conductivities.

18

Determination of a Mass Transfer Area during Metal Melting in a Vacuum Induction Furnace

Golak S., Przylucki R., Barglik J.

Archives of Metallurgy and Materials

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2014

|

Vol. 59, iss. 1

287--292

EN

In the paper, a simulation model that allows for determination of the actual surface area of inductively stirred liquid metal and the value of metal near-surface velocity during its melting is presented. Also, the effects of induction furnace working frequency on both parameters are demonstrated. The simulation was performed for copper and liquid steel that were melted in two different induction furnaces. The calculation results were also used for determination of coefficients of copper mass transfer in liquid steel and of antimony mass transfer in liquid copper during their stirring in the discussed furnace.

PL

W pracy przedstawiono model symulacyjny pozwalający na wyznaczenie wartości rzeczywistej powierzchni ciekłego metalu mieszanego indukcyjnie jak i wartości prędkości przypowierzchniowej metalu w trakcie jego topienia Wykazano jednocześnie wpływ częstotliwości roboczej pieca indukcyjnego na obydwie wielkości. Symulacji dokonano dla miedzi i ciekłej stali topionych w dwóch różnych piecach indukcyjnych. Wyniki obliczeń posłużyły także do wyznaczenia wartości współczynników transportu masy miedzi w ciekłej stali i antymonu w ciekłej miedzi w przypadku ich mieszania w omawianym agregacie.

19

Metody zwiększania efektywności przepłukiwania katalizatorów samochodowych ciekłym metalem

Fornalczyk A., Golak S., Przyłucki R.

Zeszyty Naukowe. Elektryka / Politechnika Łódzka

|

2013

|

z. 125

37--44

PL

Artykuł dotyczy analizy procesu wypłukiwania metali szlachetnych z wkładów katalizatorów umieszczonych w pierścieniowym kanale przy pomocy ciekłego metalu wprawianego w ruch przez wirujące pole elektromagnetyczne. Wykorzystany w pracy model obliczeniowy obejmował sprzężenie pola elektromagnetycznego i hydrodynamicznego z uwzględnieniem przepływu metalu przez kapilarną strukturę katalizatora. W ramach badań przeprowadzono analizę wpływu lokalizacji wzbudnika na efektywność przepłukiwania wsadu katalizatora.

EN

The paper concerns of precious metals washing out from auto catalytic converters placed in the channel. In this device liquid metal is forced to motion by the rotating magnetic field. The model used in research included the coupling of the electromagnetic and hydrodynamic field taking into account the metal flow through anisotropic porom structure of the catalyst. The study analyzes the influence of inductor location on the efficiency of flushing the catalyst.

20

The influence of the supply parameters on the reinforcement distribution in a composite cast in the electromagnetic field

Golak S.

Przegląd Elektrotechniczny

|

2013

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R. 89, nr 2b

335--338

EN

The basic problem in the process of graded composite casting is to obtain electromagnetic buoyancy that should move the particles, but at the same time to avoid stirring of the liquid metal caused by the field non-uniformity that thwarts the effect of reinforcement segregation. The research presented in the paper was focused on adjusting the supply current, its frequency and the dimensions of the inductor so that the liquid metal flow reduced.

PL

Podstawowym problemem utrudniającym proces odlewania kompozytu gradientowego jest uzyskanie działania wyporu elektromagnetycznego przemieszczającego cząstki, przy jednoczesnym uniknięciu, niweczącego efekt segregacji zbrojenia, mieszania ciekłego metalu spowodowanego niejednorodnością pola sił. Prezentowane badania dotyczyły doboru częstotliwości zasilania, natężenia prądu i rozmiarów wzbudnika w celu ograniczenia ruchu ciekłego metal.