Abdellah Kharicha

Abdellah Kharicha
Montanuniversität Leoben · Department Metallurgy

Associate Professor (Priv.-Doz.)

About

242
Publications
61,320
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1,914
Citations
Citations since 2016
159 Research Items
1524 Citations
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2016201720182019202020212022050100150200250300
Introduction
Since 2018, A. Kharicha has been the head of Christian-Doppler laboratory for the metallurgical applications of Magnetohydrodynamics in Leoben, Austria. Kharicha is also a group leader of the Chair for “Simulation and Modelling of Metallurgical Processes”. The laboratory specializes in the simulations of MHD phenomena occurring in industrial processes involving liquid metals, electrolytes, and plasma media. Examples are: blankets for Fusion reactors, instabilities in aluminium reduction cells, Electroslag-remelting process, vacuum arcs, electric arcs, and continuous casting. As part of the Metallurgy Department, A. Kharicha is also working on different projects concerning the numerical modeling of flow-crystal growth interactions.

Publications

Publications (242)
Article
Full-text available
Due to the extreme thermal conditions and short lifetimes, experimental exploration of cathode spots in vacuum arcs is very difficult. The intensive heat in the cathode spot is believed to be generated by ion bombardment and by Joule heating. However, thermal conditions occurring inside the re-melted material in craters created by cathode spots are...
Article
Full-text available
When a strand is subjected to rolling and pressing during mechanical reduction (MR), deformation-induced strand contraction or dilatation can occur. A novel modelling strategy has been designed to account for this mechanism in a two-phase Eulerian–Eulerian volume-average model with a fixed geometry. The strategy is based on the following ideas: 1)...
Article
Full-text available
Forced convection and its effect on the microstructure evolution of an Al-7wt.%Si alloy during unidirectional solidification were studied experimentally. Under natural convection (gravity), columnar structures develop. However, under forced convection by activating a rotating magnetic field (RMF: 10 mT, 50 Hz), many equiaxed grains form in the half...
Article
Full-text available
A two‐phase solidification model coupling mold electromagnetic stirring (M‐EMS) was used to investigate the initial solidification in the mold region of billet continuous casting. One novelty of this numerical study is to quantify how the M‐EMS induces primary and secondary flows, interacting with the jet flows coming from the submerged entry nozzl...
Data
Animation- Diffusive Arc under an Axial magnetic Field in VAR process
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Animation- Rotating Arc under an Axial magnetic Field in VAR process
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Animation- Eccentric Arc under an Axial magnetic Field in VAR process
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Animation- Centric Arc under an Axial magnetic Field in VAR process
Article
Full-text available
A numerical model coupling electromagnetic field and plasma arc impact with multiphase transport phenomena such as flow, heat transfer and solidification for the vacuum arc remelting (VAR) process is proposed. 3D simulations of the VAR process for refining a Titanium-based (Ti-6Al-4V) alloy are made. Different arc distributions (diffusive, constric...
Article
A mixed columnar-equiaxed solidification model was recently extended to capture the capillary-driven fragmentation phenomenon, which was considered the only mechanism for the formation of equiaxed crystals. The purpose of the present study was to validate the model by replicating a laboratory experiment on the solidification of an aqueous ammonium...
Data
These supplementary results show the instability of the flow inside a thin slab casting mold when the submerged entry nozzle is under moderate one-side clogging. No electromagnetic braking is applied. For the details please refer to the original paper: Vakhrushev et al.: Modeling Asymmetric Flow in the Thin‐Slab Casting Mold Under Electromagnetic...
Data
These supplementary results show the effects of the applied electromagnetic braking on the flow inside a thin slab casting mold when the submerged entry nozzle is under moderate one-side clogging. For the details please refer to the original paper: Vakhrushev et al.: Modeling Asymmetric Flow in the Thin‐Slab Casting Mold Under Electromagnetic Brak...
Data
These supplementary results show the effects of the applied electromagnetic braking on the flow inside a thin slab casting mold when the one-side clogging of the submerged entry nozzle is quite low. For the details please refer to the original paper: Vakhrushev et al.: Modeling Asymmetric Flow in the Thin‐Slab Casting Mold Under Electromagnetic Br...
Data
These supplementary results show the effects of the applied electromagnetic braking on the flow inside a thin slab casting mold when the one-side clogging of the submerged entry nozzle is fully blocking. For the details please refer to the original paper: Vakhrushev et al.: Modeling Asymmetric Flow in the Thin‐Slab Casting Mold Under Electromagnet...
Article
Full-text available
Electromagnetic stirring (EMS) has been recognized as a mature technique in steel industry to control the as-cast structure of steel continuous casting (CC), and computational magnetohydrodynamic (MHD) methods have been applied to study the EMS efficiency. Most MHD methods de-coupled the calculations of electromagnetic and flow fields or simplifica...
Article
Full-text available
Continuous casting is nowadays the world‐leading technology for the steel production. The thin slab casting (TSC) is featured by a slab shape close to the final products, which are casted at a high speed with the fast solidification rate. The quality of the thin slabs strongly depends on the uniformity of the turbulent flow, the super‐heat distribu...
Presentation
Full-text available
This course held in English is designed for students, engineers and scientists from industry and research centers who wish to improve their knowledge in the field of applied Magneto-hydrodynamics. Although the theoretical background of MHD is reviewed, the course is mainly oriented towards the numerical methods and application to industrial process...
Article
Full-text available
A funnel-type mold is commonly used to provide necessary clearance for the submerged entry nozzle in the thin slab casting (TSC). The partially solidified shell is subjected to the mechanical deformations, which can lead to the defects formation and, as a results, to a breakout. Traditionally, the results of the flow simulation, performed by the fi...
Article
Full-text available
A numerical analysis is carried out to explore the variety of flow structures induced inside a conducting fluid emerging from the interaction of an electric current source with an external axial magnetic field. Results are obtained for Shercliff (S) numbers up to 10¹⁰ and Hartmann (Ha) numbers up to 115, for a single magnetic Prandtl number of Pm=8...
Article
In this paper we show that the presence of liquid flow around a crystal growing by precipitation can induce dissymmetry in growth similar to that described by anisotropic interfacial kinetic coefficients. A front tracking interface model based on a cellular automaton approach was applied to the growth of a Fe2Al5 crystal (also known as top dross pa...
Data
Turbulent jet flow under the applied transversal magnetic field at Reynolds number Re=850 and interaction number N=0.05. Displays the distribution of the induced electric field at the parallel to the magnetic field plane (top), magnitude of velocity (left) and the rotation direction (middle and right) on the corresponding vortical structures.
Data
Turbulent jet flow under the applied transversal magnetic field at Reynolds number Re=2700 and interaction number N=0.05. Displays the distribution of the induced electric field at the parallel to the magnetic field plane (top), magnitude of velocity (left) and the rotation direction (middle and right) on the corresponding vortical structures.
Data
Turbulent jet flow under the applied transversal magnetic field at Reynolds number Re=4050 and interaction number N=0.05. Displays the distribution of the induced electric field at the parallel to the magnetic field plane (top), magnitude of velocity (left) and the rotation direction (middle and right) on the corresponding vortical structures.
Article
Full-text available
Magnetohydrodynamic instability in a high-intensity arc, similar to typical arcs in DC electric arc furnaces, is simulated using an induction based model under 2D axisymmetric conditions. Time-averaged results show a good agreement with steady-state calculated results expected for a stable arc. The transient results declare that z-pinch close to th...
Cover Page
Full-text available
Simulation in Werkstoffwissenschaft: Vakhrushev A, Kharicha A, Liu Z, Wu M, Ludwig A, Nitzl G, Tang Y, Hackl G, Watzinger J, Electric Current Distribution During Electromagnetic Braking in Continuous Casting. Metall. Mater. Trans. B 2020, 51, 2811–2828, https://doi.org/10.1007/s11663-020-01952-3
Article
Full-text available
During the last decade, the chair for ‘Simulation and Modelling of Metallurgical Processes’ (SMMP) has worked on different metallurgical processes with the highlights of the following five industrial relevant topics: (i) modelling the as-cast structures of large steel castings; (ii) exploring the formation mechanisms of macrosegregation; (iii) desc...
Article
Spatial evolution of electrically conducting submerged jet flow is studied by numerical simulations for the case of a transverse uniform magnetic field. This situation occurs frequently in metallurgical industry where permanent magnetic fields are applied to control the liquid metal jets. We investigate through numerical simulations the flow charac...
Article
Full-text available
Transport phenomena including the electromagnetic, concentration of ions, flow, and thermal fields in the electroslag remelting (ESR) process made of slag, electrode, air, mold, and melt pool are computed considering tertiary current distribution. Nernst-Planck equations are solved in the bulk of slag, and faradaic reactions are regarded at the met...
Article
Full-text available
Mold electromagnetic stirring (M-EMS) has been introduced into the continuous casting of steel billets to promote the formation of a central equiaxed zone; however, the formation mechanism of the equiaxed crystals and the effect of M-EMS on crystal transport are not fully understood. Currently, a three-phase volume average model was used to study t...
Article
Full-text available
A fully coupled model is proposed to investigate the influence of flow on electrochemical mass transfer at the interface between the electrolyte and an electrically conductive droplet. The electric current flows through the droplet, and consequently the droplet acts as both anode and cathode. Computations of flow, concentration of reactant, and ele...
Article
Full-text available
The clogging of the submerged entry nozzle (SEN) during the continuous casting of steel can be divided into two stages: the “early stage,” when the initial layer of the clog covers the SEN refractory surface owing to chemical reactions, and the “late stage,” when the clog layer continues to grow because of the deposition of non-metallic inclusions...
Article
Full-text available
A 2D axisymmetric two-phase model was developed to study the effect of an arc impingement on the liquid metal inside an electric arc furnace. In addition to the arc flow dynamics, the model covered the heat transfer and magneto hydrodynamics of the arc and the liquid metal. Through a parametric study, three different parameters were considered to p...
Cover Page
Full-text available
Cover Story (https://www.mdpi.com/2075-4701/11/9): The heat losses in the submerged entry nozzle (SEN) region were investigated using a novel numerical approach by coupling the convection and heat transfer in the liquid slag and melt pool. It was revealed that the parasitic solidification occurred inside an SEN bore with partially or completely abs...
Article
Full-text available
Continuous casting (CC) is one of the most important processes of steel production; it features a high production rate and close to the net shape. The quality improvement of final CC products is an important goal of scientific research. One of the defining issues of this goal is the stability of the casting process. The clogging of submerged entry...
Article
Full-text available
In this study, a first attempt is made to bridge capillary-driven fragmentation and grain transport using a mixed columnar-equiaxed solidification model. Grain transport is an intrinsic feature of the employed solidification model which has been extensively investigated over the years. Regarding the capillary-driven fragmentation event, a new corre...
Data
This animation shows poloidal and toroidal velocity field in the melt pool of VAR process considering a time-varying axial magnetic field (AMF) with ten seconds for the reversal time of the direction of magnetic field. The article and the animation are also available in: https://link.springer.com/article/10.1007/s11663-021-02264-w
Data
Detailed description of the animated supplementary results for the paper: Vakhrushev, A., Kharicha, A., Karimi-Sibaki, E. et al. Generation of Reverse Meniscus Flow by Applying An Electromagnetic Brake. Metall Mater Trans B (2021). https://doi.org/10.1007/s11663-021-02247-x
Data
Simulation results of the turbulent flow under the applied EMBr of 156 mT showing the distribution of the induced electric current, velocity field and the turbulent structures (defined by the iso-surface Qcrit=100). The flow alternation is significant: turbulence is mostly damped; corresponding redistribution of the linear momentum causes accelerat...
Data
Simulation results of the turbulent flow under the applied EMBr of 441 mT showing the distribution of the induced electric current, velocity field and the turbulent structures (defined by the iso-surface Qcrit=100). The opposite vortex dominates and occupies the upper part of the mold. It is accompanied by strong reverse flow zones above and below...
Data
Simulation results of the turbulent flow under the applied EMBr of 366 mT showing the distribution of the induced electric current, velocity field and the turbulent structures (defined by the iso-surface Qcrit=100). The flow pattern is dramatically changed: the meniscus is deaccelerated; two reverse flow zones are formed above and below the jets; a...
Data
Simulation results of the turbulent flow under the applied EMBr of 39 mT showing the distribution of the induced electric current, velocity field and the turbulent structures (defined by the iso-surface Qcrit=100). The flow is slightly rearranged under the magnetic field; however, no significant change is observed.
Article
Full-text available
A comprehensive numerical model is proposed to study the influence of an axial magnetic field (AMF) on the solidification behavior of a Titanium-based (Ti–6Al–4V) vacuum arc remelting (VAR) ingot. Both static and time-varying AMF are examined. The proposed 2D axisymmetric swirl model includes calculating electromagnetic and thermal fields in the en...
Article
Full-text available
A numerical study is presented that deals with the flow in the mold of a continuous slab caster under the influence of a DC magnetic field (electromagnetic brakes (EMBrs)). The arrangement and geometry investigated here is based on a series of previous experimental studies carried out at the mini-LIMMCAST facility at the Helmholtz-Zentrum Dresden-R...
Conference Paper
Full-text available
The present paper presents briefly a 2D numerical model for the simulation of faceted crystal growth, taken into account the flow hydrodynamics. This model was applied to the dross build-up growth (Fe2Al5 faceted crystals) occurring during the production of Zn coated (Galvanizing industry) on the bath hardware. In the galvanizing industry their occ...
Article
The numerical simulation of the horizontal solidification of pure tin under natural convection and under forced convection induced by Electromagnetic Stirring (EMS) is presented and compared with experimental results obtained by the ‘AFRODITE’ benchmark setup, described in several previous publications [6–10]. The experiment consists in solidifying...
Article
A forced flow was experimentally shown to influence the solidification microstructure of metal alloys by modifying the coarsening/ripening law. In some technical alloys (AlSi7Fe1), this flow effect can also be significantly suppressed due to the formation of intermetallic precipitates ( β -Al 5 FeSi) that can block the flow in the mushy region. The...
Article
Melting or re-melting accompanies solidification in many technical castings. For example, during ingot casting, some crystal fragments or equiaxed grains can enter the superheated region and re-melt, while solidification continues in other regions. Solidification and remelting occurring simultaneously at different locations present an important spe...
Article
Full-text available
A combination of both conventional and advanced high-resolution characterization techniques was applied to study the modified layers on the surface of three composite Al-Cr arc cathodes with identical nominal composition of Al-50 at.% Cr but varying powder grain sizes. The results revealed that the modified layers consist mainly of metastable phase...
Data
Results of a 3D simulation is presented using the animation which shows the influence of an axial magnetic field (AMF) considering 5 seconds of the reversal time of the direction of AMF on the velocity and thermal fields in the melt pool of VAR process exposed by a diffusive arc with the radius equal to that of the electrode.
Poster
Full-text available
This course held in English is designed for engineers and scientists from industry and research centers who wish to improve their knowledge in the field of MHD. Participants should have a degree in applied mathematics, physics, mechanical engineering, materials science, metallurgy, or chemistry. Although the theoretical background of MHD is reviewe...
Article
Full-text available
This study focuses on the flow-solidification interaction during the solidification of NH4Cl – 70.43 wt.%H2O solution in a water-cooled mould with a large sample thickness (100 × 80 × 10 mm³). First part of the paper is to use a volume-average-based dendritic solidification model to reproduce an experiment in which transient flow is monitored in-si...
Article
In the production of single-crystal turbine blades for use in aircraft engines with unidirectional solidification techniques, it is confirmed that the casting geometry had great influence on the formation of macrosegregation or spurious/stray crystals. In this study, a two-phase solidification model is used to investigate the geometrical effect on...
Article
3D structure of the clog is considered for modelling the flow and solidification in the open pores/channels of the clog. It is verified that solidification cannot occur before clogging if the molten steel has sufficient superheat and the SEN is properly preheated. However, solidification plays a role in stabilizing/strengthening the clog structure....