Jan Hantusch - Academia.edu (original) (raw)
Papers by Jan Hantusch
Thermal Science and Engineering Progress
Welding in the World, 2020
The aluminothermic welding (ATW) process is the most commonly used welding process for welding ra... more The aluminothermic welding (ATW) process is the most commonly used welding process for welding rails (track) in the field. The large amount of weld metal added in the ATW process may result in a wide uneven surface zone on the rail head, which may, in rare cases, lead to irregularities in wear and plastic deformation due to high dynamic wheel-rail forces as wheels pass. The present paper studies the introduction of additional forging to the ATW process, intended to reduce the width of the zone affected by the heat input, while not creating a more detrimental residual stress field. Simulations using a novel thermo-mechanical FE model of the ATW process show that addition of a forging pressure leads to a somewhat smaller width of the zone affected by heat. This is also found in a metallurgical examination, showing that this zone (weld metal and heat-affected zone) is fully pearlitic. Only marginal differences are found in the residual stress field when additional forging is applied. I...
Archives of Metallurgy and Materials, 2018
The aluminothermic reaction is a type of self-propagating high-temperature synthesis to produce h... more The aluminothermic reaction is a type of self-propagating high-temperature synthesis to produce high quality metals and metal oxides en route. The main use of the aluminothermic reaction is in the field of railway welding. The multiphase flow of steel, slag and air in differently shaped crucibles has been numerically investigated in this work with the volume-of-fluid method. The simulations were carried out with the multiphase solver of the open source toolbox OpenFOAM. To validate the numerical results of the three-dimensional simulations, an experiment was carried out to investigate the discharge of a water-oil system from the crucible. A comparison to a numerical 3D simulation showed reasonable accurate results. It can be said that the solver is capable of predicting the point of the oil penetration of the water phase in the experiment.
L'invention concerne un generateur de chaleur destine a stimuler un forage. Le generateur de ... more L'invention concerne un generateur de chaleur destine a stimuler un forage. Le generateur de chaleur comprend un reservoir de combustible tubulaire (22) qui comporte deux segments fermes (23) ou plus, separes l'un de l'autre, qui sont disposes l'un a la suite de l'autre dans la direction longitudinale et qui sont chacun remplis de combustible (30) au moins partiellement. Le generateur de chaleur comprend egalement au moins un allumeur (40) destine a allumer le combustible dans l'un des segments (23) au moins. Les extremites des segments sont reliees de telle sorte que le combustible se trouvant dans un segment suivant peut etre enflamme sous l'effet de la chaleur generee lors de la combustion du combustible dans un segment precedent. L'invention concerne en outre un procede de stimulation de forage a l'aide d'un generateur de chaleur selon l'invention.
Thermal Science and Engineering Progress
Gegenstand der Arbeit ist die Entwicklung und Modellierung eines keramischen Filters zur Abscheid... more Gegenstand der Arbeit ist die Entwicklung und Modellierung eines keramischen Filters zur Abscheidung von nichtmetallischen Teilchen aus Stahlschmelzen. Ausgehend von einem Konzept eines Umlenkabscheiders wurde dieser mit Hilfe von Experimenten und numerischen Berechnungen auf seine Wirkungsweise und Einsatzfähigkeit für größere Stahlmengen untersucht. Wassermodellversuche dienten zur Erfassung des Geschwindigkeitsfeldes und der Teilchenbewegungen. Durch Vergleich mit numerischen Berechnungen und die Variation von Parametern wurde die Abscheidewirkung des Filters untersucht. In Technikumsversuchen mit Flüssigstahl erfolgte die Verifizierung der Modellvorstellung aus den numerischen Berechnungen und Wassermodellexperimenten. Eine Abscheidung konnte qualitativ nachgewiesen werden. Die gewonnenen Ergebnisse führten zur Entwicklung und Patentierung eines neuen Typs des Einschlussabscheiders. Der neu entwickelte Spiralabscheider weist zahlreiche technologische Vorteile gegenüber dem Umlen...
World Congress on Mechanical, Chemical, and Material Engineering, 2021
The solid-liquid phase front inside the mould progresses from the rail end towards the weld centr... more The solid-liquid phase front inside the mould progresses from the rail end towards the weld centre and from rail base to rail head, such that the temporal and spatial evolution of the solid-liquid phase front results in a V-shaped solidification. Finally, the simulation results are qualitatively compared with experiments conducted at Goldschmidt Holding GmbH. The predicted temperature profiles in the rail during preheating and cooling stage, fusion zone (FZ) and heat-affected zone (HAZ) have shown a good agreement with experiments.
For permanently closing holes at a selected location, a method is proposed on, a shaped body is f... more For permanently closing holes at a selected location, a method is proposed on, a shaped body is formed by a first aluminothermic process, the reactant is a damping means is attached thereto at first a support structure is generated at this point, that a sealing closure of the borehole and is directed to the preparation of the permanent closure main reaction is carried out on the aluminothermic by means of a second method. The shaped body is suitable because of its material properties, to withstand the thermal and mechanical stresses on the main reaction and in particular a leakage of the thermite melt in the wellbore to prevent reliably.
A mixture for closing off oil or natural gas wells consists of a thermite mixture to which an add... more A mixture for closing off oil or natural gas wells consists of a thermite mixture to which an additive of at least one rare earth metal with a proportion of 1.5% by weight of the mixture is added. The mixture forms after ignition and completion of an aluminothermic reaction, a molten Thermit steel, which has a reduced surface tension and, for this reason, within a heat affected zone improved wetting and bonding capacity for surrounding materials such. B. concrete, mountain particles and the steel of a bore lining pipe. The result is a closure body which projects into the surrounding mountains, thus anchored in this and is suitable for the representation of a permanent and reliable sealing of the bore.
Industrial & Engineering Chemistry Research, 2018
A combustion front quenching (CFQ) technique is used to investigate the separation of reaction pr... more A combustion front quenching (CFQ) technique is used to investigate the separation of reaction products during a fast self-propagating high-temperature synthesis (SHS) thermite reaction, which is applied to the aluminothermic welding of rails. Quenching of the reaction zone with melt temperature at approximately 2400 K enables the possibility of analyzing intermediate stages during exothermic SHS type reactions and the prediction of a time duration for a complete separation of the products Fe, Al 2 O 3 and intermetallics. An average separation time is then used to validate a 3D phase field solver phaseFieldFoam and solution parameters through application of the diffusive Cahn-Hilliard equation, also known as model B.
Steel Research, 1996
The majority of steels produced by continuous casting is fully At-killed. Ceramic foam and multi ... more The majority of steels produced by continuous casting is fully At-killed. Ceramic foam and multi hole filters have been tested so far in laboratory and small scale production experiments to lower the total oxygen content of steel melts. The use of such filters in tundishes has hitherto been limited by their insuffiicient mechanical and thermal durability over extended periods. Owing to their small pore sizes, these fifters allow a high inclusion separation efficiency, but a limited mass throughput. Therefore a technique is looked for to extract non-metallic inclusions efficiently from the melt at higher mass throughputs. Further ideas led to a new ceramic inclusion separator which has been tested in small scale experimental runs. To verify the flow and separation process, a water model has been built and numerical modelling was applied. The results of the molten steel experiments, the water model and the mathematical modelling are described and compared to each other. For the small scale it is confirmed that the new experimental device may yield high filtration efficiencies. Entwicklung eines neuen Keramik-EinschluBabscheiders fUr Stahlschmelzen. Der uberwiegende Teil des heute vergossenen Stahls ist AI-desoxidiert. Die Erprobung keramischer Schaum-und Kanalfilter zur Verbesserung des oxidischen Reinheitsgrades von Stahl• schmelzen lst ein Anliegen von experimentellen und betriebstechnischen Untersuchungen. Der Einsatz solcher Filter in StranggieBvertei• lern war bisher durch deren geringe mechanische und thermische Haltbarkeit begrenzt. Bedingt durch die geringe Porengr6Be besitzen diese Filter einen hohen Filtrationswirkungsgrad, sind aber damit gleichzeitig in ihrem Mengendurchsatz stark eingeschrankt. Es wurde deshalb nach einer M6glichkeit gesucht, nichtmetallische Elnschlusse auch bei h6heren Mengendurchsatzen effektiv aus der Schmelze zu extrahieren. Erste Vorstellungen dazu wurden in einem Keramik-EinschluBabscheider umgesetzt und kleintechnisch erprobt. Zur Verifizierung der in einem solchen EinschluBabscheider ablaufenden Strornunqsund Abscheidungsvorgange wurden Versuche an einem Wassermodell durchgefOhrt und mit numerischen Berechnungen OberprOft. Die Ergebnisse der kleintechnischen Versuche, der Wassermodellversuche und der numerischen Berechnungen werden miteinander verglichen. Es konnte gezeigt werden, daB mit der beschriebenen Konstruktion im kleintechnischen MaBstab gute Filtrationwirkungsgrade erreicht werden.
Steel Research, 2001
In steelmaking processes, various efforts are made in order to enhance steel cleanness. Among oth... more In steelmaking processes, various efforts are made in order to enhance steel cleanness. Among other approaches, the volume of the tundish has been increased and flow-controlling devices are used. The extended mean residence time of steel in the tundish leads to an improved inclusion separation. In the present study, the degree of inclusion separation in different tundish configurations is determined through numerical modelling. Flows in the tundish has been calculated under isothermal and non-isothermal conditions. The numerical model is based on a Euler Lagrange approach. The flow and the temperature field are described through Reynolds averaged transport equations in conjunction with a turbulence model. Mathematische Modellierung der Stromung und des Verhaltens disperser Phasen in einem V-formigen Verteiler. Bei der Stahlherstellung werden verschiedene MaBnahmen Reinheitsgradverbesserung ausprobiert. Unter anderen sind die Volumina der StranggieBverteiler verqrofsert und stromungslenkende Einbauten in die Verteiler eingesetzt worden. Die erhohte mittlere Verweilzeit des Stahls im Verteiler filhrt zu einer verbesserten Abscheidung der nichtmetallischen EinschlOsse. In der vorliegenden Arbeit wird der Abscheidegrad von nichtmetallischen EinschlOssen in verschiedenen Verteiler-Konfigurationen durch numerische Modellierung bestimmt. Die Verteilerstrornunq ist unter isothermen und nicht-isothermen Bedingungen berechnet worden. Das numerische Modell basiert auf einem Euler-Lagrange-Ansatz. Die Strornunq und das Temperaturfeld werden durch die Reynolds-gemittelten Transportgleichungen in Verbindung mit einem Turbulenzmodell beschrieben.
Thermal Science and Engineering Progress
Welding in the World, 2020
The aluminothermic welding (ATW) process is the most commonly used welding process for welding ra... more The aluminothermic welding (ATW) process is the most commonly used welding process for welding rails (track) in the field. The large amount of weld metal added in the ATW process may result in a wide uneven surface zone on the rail head, which may, in rare cases, lead to irregularities in wear and plastic deformation due to high dynamic wheel-rail forces as wheels pass. The present paper studies the introduction of additional forging to the ATW process, intended to reduce the width of the zone affected by the heat input, while not creating a more detrimental residual stress field. Simulations using a novel thermo-mechanical FE model of the ATW process show that addition of a forging pressure leads to a somewhat smaller width of the zone affected by heat. This is also found in a metallurgical examination, showing that this zone (weld metal and heat-affected zone) is fully pearlitic. Only marginal differences are found in the residual stress field when additional forging is applied. I...
Archives of Metallurgy and Materials, 2018
The aluminothermic reaction is a type of self-propagating high-temperature synthesis to produce h... more The aluminothermic reaction is a type of self-propagating high-temperature synthesis to produce high quality metals and metal oxides en route. The main use of the aluminothermic reaction is in the field of railway welding. The multiphase flow of steel, slag and air in differently shaped crucibles has been numerically investigated in this work with the volume-of-fluid method. The simulations were carried out with the multiphase solver of the open source toolbox OpenFOAM. To validate the numerical results of the three-dimensional simulations, an experiment was carried out to investigate the discharge of a water-oil system from the crucible. A comparison to a numerical 3D simulation showed reasonable accurate results. It can be said that the solver is capable of predicting the point of the oil penetration of the water phase in the experiment.
L'invention concerne un generateur de chaleur destine a stimuler un forage. Le generateur de ... more L'invention concerne un generateur de chaleur destine a stimuler un forage. Le generateur de chaleur comprend un reservoir de combustible tubulaire (22) qui comporte deux segments fermes (23) ou plus, separes l'un de l'autre, qui sont disposes l'un a la suite de l'autre dans la direction longitudinale et qui sont chacun remplis de combustible (30) au moins partiellement. Le generateur de chaleur comprend egalement au moins un allumeur (40) destine a allumer le combustible dans l'un des segments (23) au moins. Les extremites des segments sont reliees de telle sorte que le combustible se trouvant dans un segment suivant peut etre enflamme sous l'effet de la chaleur generee lors de la combustion du combustible dans un segment precedent. L'invention concerne en outre un procede de stimulation de forage a l'aide d'un generateur de chaleur selon l'invention.
Thermal Science and Engineering Progress
Gegenstand der Arbeit ist die Entwicklung und Modellierung eines keramischen Filters zur Abscheid... more Gegenstand der Arbeit ist die Entwicklung und Modellierung eines keramischen Filters zur Abscheidung von nichtmetallischen Teilchen aus Stahlschmelzen. Ausgehend von einem Konzept eines Umlenkabscheiders wurde dieser mit Hilfe von Experimenten und numerischen Berechnungen auf seine Wirkungsweise und Einsatzfähigkeit für größere Stahlmengen untersucht. Wassermodellversuche dienten zur Erfassung des Geschwindigkeitsfeldes und der Teilchenbewegungen. Durch Vergleich mit numerischen Berechnungen und die Variation von Parametern wurde die Abscheidewirkung des Filters untersucht. In Technikumsversuchen mit Flüssigstahl erfolgte die Verifizierung der Modellvorstellung aus den numerischen Berechnungen und Wassermodellexperimenten. Eine Abscheidung konnte qualitativ nachgewiesen werden. Die gewonnenen Ergebnisse führten zur Entwicklung und Patentierung eines neuen Typs des Einschlussabscheiders. Der neu entwickelte Spiralabscheider weist zahlreiche technologische Vorteile gegenüber dem Umlen...
World Congress on Mechanical, Chemical, and Material Engineering, 2021
The solid-liquid phase front inside the mould progresses from the rail end towards the weld centr... more The solid-liquid phase front inside the mould progresses from the rail end towards the weld centre and from rail base to rail head, such that the temporal and spatial evolution of the solid-liquid phase front results in a V-shaped solidification. Finally, the simulation results are qualitatively compared with experiments conducted at Goldschmidt Holding GmbH. The predicted temperature profiles in the rail during preheating and cooling stage, fusion zone (FZ) and heat-affected zone (HAZ) have shown a good agreement with experiments.
For permanently closing holes at a selected location, a method is proposed on, a shaped body is f... more For permanently closing holes at a selected location, a method is proposed on, a shaped body is formed by a first aluminothermic process, the reactant is a damping means is attached thereto at first a support structure is generated at this point, that a sealing closure of the borehole and is directed to the preparation of the permanent closure main reaction is carried out on the aluminothermic by means of a second method. The shaped body is suitable because of its material properties, to withstand the thermal and mechanical stresses on the main reaction and in particular a leakage of the thermite melt in the wellbore to prevent reliably.
A mixture for closing off oil or natural gas wells consists of a thermite mixture to which an add... more A mixture for closing off oil or natural gas wells consists of a thermite mixture to which an additive of at least one rare earth metal with a proportion of 1.5% by weight of the mixture is added. The mixture forms after ignition and completion of an aluminothermic reaction, a molten Thermit steel, which has a reduced surface tension and, for this reason, within a heat affected zone improved wetting and bonding capacity for surrounding materials such. B. concrete, mountain particles and the steel of a bore lining pipe. The result is a closure body which projects into the surrounding mountains, thus anchored in this and is suitable for the representation of a permanent and reliable sealing of the bore.
Industrial & Engineering Chemistry Research, 2018
A combustion front quenching (CFQ) technique is used to investigate the separation of reaction pr... more A combustion front quenching (CFQ) technique is used to investigate the separation of reaction products during a fast self-propagating high-temperature synthesis (SHS) thermite reaction, which is applied to the aluminothermic welding of rails. Quenching of the reaction zone with melt temperature at approximately 2400 K enables the possibility of analyzing intermediate stages during exothermic SHS type reactions and the prediction of a time duration for a complete separation of the products Fe, Al 2 O 3 and intermetallics. An average separation time is then used to validate a 3D phase field solver phaseFieldFoam and solution parameters through application of the diffusive Cahn-Hilliard equation, also known as model B.
Steel Research, 1996
The majority of steels produced by continuous casting is fully At-killed. Ceramic foam and multi ... more The majority of steels produced by continuous casting is fully At-killed. Ceramic foam and multi hole filters have been tested so far in laboratory and small scale production experiments to lower the total oxygen content of steel melts. The use of such filters in tundishes has hitherto been limited by their insuffiicient mechanical and thermal durability over extended periods. Owing to their small pore sizes, these fifters allow a high inclusion separation efficiency, but a limited mass throughput. Therefore a technique is looked for to extract non-metallic inclusions efficiently from the melt at higher mass throughputs. Further ideas led to a new ceramic inclusion separator which has been tested in small scale experimental runs. To verify the flow and separation process, a water model has been built and numerical modelling was applied. The results of the molten steel experiments, the water model and the mathematical modelling are described and compared to each other. For the small scale it is confirmed that the new experimental device may yield high filtration efficiencies. Entwicklung eines neuen Keramik-EinschluBabscheiders fUr Stahlschmelzen. Der uberwiegende Teil des heute vergossenen Stahls ist AI-desoxidiert. Die Erprobung keramischer Schaum-und Kanalfilter zur Verbesserung des oxidischen Reinheitsgrades von Stahl• schmelzen lst ein Anliegen von experimentellen und betriebstechnischen Untersuchungen. Der Einsatz solcher Filter in StranggieBvertei• lern war bisher durch deren geringe mechanische und thermische Haltbarkeit begrenzt. Bedingt durch die geringe Porengr6Be besitzen diese Filter einen hohen Filtrationswirkungsgrad, sind aber damit gleichzeitig in ihrem Mengendurchsatz stark eingeschrankt. Es wurde deshalb nach einer M6glichkeit gesucht, nichtmetallische Elnschlusse auch bei h6heren Mengendurchsatzen effektiv aus der Schmelze zu extrahieren. Erste Vorstellungen dazu wurden in einem Keramik-EinschluBabscheider umgesetzt und kleintechnisch erprobt. Zur Verifizierung der in einem solchen EinschluBabscheider ablaufenden Strornunqsund Abscheidungsvorgange wurden Versuche an einem Wassermodell durchgefOhrt und mit numerischen Berechnungen OberprOft. Die Ergebnisse der kleintechnischen Versuche, der Wassermodellversuche und der numerischen Berechnungen werden miteinander verglichen. Es konnte gezeigt werden, daB mit der beschriebenen Konstruktion im kleintechnischen MaBstab gute Filtrationwirkungsgrade erreicht werden.
Steel Research, 2001
In steelmaking processes, various efforts are made in order to enhance steel cleanness. Among oth... more In steelmaking processes, various efforts are made in order to enhance steel cleanness. Among other approaches, the volume of the tundish has been increased and flow-controlling devices are used. The extended mean residence time of steel in the tundish leads to an improved inclusion separation. In the present study, the degree of inclusion separation in different tundish configurations is determined through numerical modelling. Flows in the tundish has been calculated under isothermal and non-isothermal conditions. The numerical model is based on a Euler Lagrange approach. The flow and the temperature field are described through Reynolds averaged transport equations in conjunction with a turbulence model. Mathematische Modellierung der Stromung und des Verhaltens disperser Phasen in einem V-formigen Verteiler. Bei der Stahlherstellung werden verschiedene MaBnahmen Reinheitsgradverbesserung ausprobiert. Unter anderen sind die Volumina der StranggieBverteiler verqrofsert und stromungslenkende Einbauten in die Verteiler eingesetzt worden. Die erhohte mittlere Verweilzeit des Stahls im Verteiler filhrt zu einer verbesserten Abscheidung der nichtmetallischen EinschlOsse. In der vorliegenden Arbeit wird der Abscheidegrad von nichtmetallischen EinschlOssen in verschiedenen Verteiler-Konfigurationen durch numerische Modellierung bestimmt. Die Verteilerstrornunq ist unter isothermen und nicht-isothermen Bedingungen berechnet worden. Das numerische Modell basiert auf einem Euler-Lagrange-Ansatz. Die Strornunq und das Temperaturfeld werden durch die Reynolds-gemittelten Transportgleichungen in Verbindung mit einem Turbulenzmodell beschrieben.