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23 pages, 15123 KiB

Open AccessArticle

Physical and Numerical Modeling of the Impeller Construction Impact on the Aluminum Degassing Process

by Kamil Kuglin, Michał Szucki, Jacek Pieprzyca, Simon Genthe, Tomasz Merder and Dorota Kalisz

Materials 2022, 15(15), 5273; https://doi.org/10.3390/ma15155273 - 30 Jul 2022

Cited by 3 | Viewed by 1137

This paper presents the results of tests on the suitability of designed heads (impellers) for aluminum refining. The research was carried out on a physical model of the URO-200, followed by numerical simulations in the FLOW 3D program. Four design variants of impellers [...] Read more.

This paper presents the results of tests on the suitability of designed heads (impellers) for aluminum refining. The research was carried out on a physical model of the URO-200, followed by numerical simulations in the FLOW 3D program. Four design variants of impellers were used in the study. The degree of dispersion of the gas phase in the model liquid was used as a criterion for evaluating the performance of each solution using different process parameters, i.e., gas flow rate and impeller speed. Afterward, numerical simulations in Flow 3D software were conducted for the best solution. These simulations confirmed the results obtained with the water model and verified them. Full article

(This article belongs to the Special Issue Physical and Numerical Modeling of Process Metallurgy)

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21 pages, 9855 KiB

Open AccessArticle

Numerical and Physical Study on New Simple Design of Subflux Flow Controller for One-Strand Tundish

by Adam Cwudziński

Materials 2022, 15(11), 3756; https://doi.org/10.3390/ma15113756 - 24 May 2022

Viewed by 1460

Abstract

Tundish metallurgy is essential for continuous steel casting technology. In this study, the subflux flow controller (SFC) installed in the tundish pouring zone was tested, demonstrating the possibility of simultaneously reducing the dimensions of the flow control device (FCD) and effectively influencing the [...] Read more.

Tundish metallurgy is essential for continuous steel casting technology. In this study, the subflux flow controller (SFC) installed in the tundish pouring zone was tested, demonstrating the possibility of simultaneously reducing the dimensions of the flow control device (FCD) and effectively influencing the structure of the liquid steel flow. On the basis of computer simulations and water model trials, results were obtained describing the hydrodynamic structure in considered variants of the one strand slab tundish. Considering the influence of the SFC on the steel flow structure in the tundish, and the gradient of the wall shear stress and total pressure on the SFC surface/tundish walls, the most optimal SFC variant for a single-strand wedge-type tundish is SFC No. 2C. Full article

(This article belongs to the Special Issue Physical and Numerical Modeling of Process Metallurgy)

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11 pages, 3873 KiB

Open AccessArticle

Physical Modeling of the Impeller Construction Impact on the Aluminum Refining Process

by Mariola Saternus and Tomasz Merder

Materials 2022, 15(2), 575; https://doi.org/10.3390/ma15020575 - 13 Jan 2022

Cited by 9 | Viewed by 1523

Abstract

Obtaining high-quality aluminum is associated with the use of an effective method of refining, which is argon-purging, in which gas bubbles are introduced into the liquid metal by means of rotary impellers. Various rotary impellers are used in the industry; however, if a [...] Read more.

Obtaining high-quality aluminum is associated with the use of an effective method of refining, which is argon-purging, in which gas bubbles are introduced into the liquid metal by means of rotary impellers. Various rotary impellers are used in the industry; however, if a newly designed impeller is constructed, it should be tested prior to industrial use. For this purpose, physical modeling is used, which enables the investigation of the phenomena occurring during refining and the selection of optimal processing parameters without costly research carried out in the industry. The newly designed rotary impeller was tested on the physical model of a URO-200 batch reactor. The flow rate of refining gas was: 10, 15 and 20 dm³·min⁻¹, whereas rotary impeller speed was 300, 400 and 500 rpm. The research consists of a visualization test showing the schemes of the gas bubbles’ dispersion level in the liquid metal and experiments for removing oxygen from water, which is an analogue of removing hydrogen from aluminum. Full article

(This article belongs to the Special Issue Physical and Numerical Modeling of Process Metallurgy)

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19 pages, 6494 KiB

Open AccessArticle

Evolution of Chemical Composition and Modeling of Growth Nonmetallic Inclusions in Steel Containing Yttrium

by Dorota Kalisz, Paweł L. Żak, Sergey Semiryagin and Sergey Gerasin

Materials 2021, 14(23), 7113; https://doi.org/10.3390/ma14237113 - 23 Nov 2021

Cited by 5 | Viewed by 1479

Abstract

The programs WYK_Stal and Bi-Growth, developed at AGH-UST, Kraków, Poland, were used for simulating the refining process, the formation of non-metallic inclusions, and their growth. The Fe-Y-Al-O-S-Ca system in pre-oxidized steel was analyzed, where yttrium formed precipitates from both O and S. When [...] Read more.

The programs WYK_Stal and Bi-Growth, developed at AGH-UST, Kraków, Poland, were used for simulating the refining process, the formation of non-metallic inclusions, and their growth. The Fe-Y-Al-O-S-Ca system in pre-oxidized steel was analyzed, where yttrium formed precipitates from both O and S. When first Al and second Y were added to steel, the proportion of Al₂O₃ inclusions remained constant. This resulted in higher yttrium losses for oxide formation, whereas the sulfur content promoted sulfide phase formation. The introduction of yttrium at the end of refining contributed to reducing the consumption of this element in the non-metallic phase formation. The addition of aluminum and then calcium were sufficient to achieve a high degree of deoxidation and desulfurization. Calculations performed with WYK_Stal for both (a) and (c) versions of the model showed that the sulfide phase was constituted by CaS and FeS (model c) and CaS (model (a)). The participation of the calcium sulfide phase turned out to be dominant in the inclusions. Their presence was also identified in the slag phase. Simulations of the growth of complex oxide and oxo-sulfide inclusions using the Bi_Growth program showed that the yttrium content of the steel has a decisive role in the formation of complex oxide inclusions and the final oxygen content of the steel. In contrast, for the growth of oxide-sulfide inclusions, the character of growth is determined by the sulfur content of steel. Full article

(This article belongs to the Special Issue Physical and Numerical Modeling of Process Metallurgy)

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24 pages, 11843 KiB

Open AccessArticle

Numerical Analysis on Erosion and Optimization of a Blast Furnace Main Trough

by Hao Yao, Huiting Chen, Yao Ge, Han Wei, Ying Li, Henrik Saxén, Xuebin Wang and Yaowei Yu

Materials 2021, 14(17), 4851; https://doi.org/10.3390/ma14174851 - 26 Aug 2021

Cited by 5 | Viewed by 1926

Abstract

The main trough of a blast furnace (BF) is a main passage for hot metal and molten slag transportation from the taphole to the torpedo and the slag handling. Its appropriate working status and controlled erosion ensure a safe, stable, high-efficiency and low-cost [...] Read more.

The main trough of a blast furnace (BF) is a main passage for hot metal and molten slag transportation from the taphole to the torpedo and the slag handling. Its appropriate working status and controlled erosion ensure a safe, stable, high-efficiency and low-cost continuous production of hot metal. In this work, the tapping process of a main trough of a BF in the east of China was numerically studied with the help of a CFD library written in C++, called OpenFOAM, based on the use of the Finite Volume Method (FVM). The results show that turbulence intensity downstream of the hot metal impact position becomes weaker and the turbulence area becomes larger in the main trough. During the tapping, thermal stress of wall refractory reaches the maximum value of

1 {. 7 \times 10}^{7}

Pa at the 4 m position in the main trough. Furthermore, baffles in the main trough placed between 5.8 m and 6.2 m were found to control and reduce the impact of the turbulence on the refractory life. The metal flowrate upstream of the baffles can be decreased by 6%, and the flow velocity on the upper sidewall and bottom wall decrease by 9% and 7%, respectively, compared with the base model. By using baffles, the minimum fatigue life of the refractory in the main trough increases by 15 tappings compared with the base model, so the period between the maintenance stops can be prolonged by about 2 days. Full article

(This article belongs to the Special Issue Physical and Numerical Modeling of Process Metallurgy)

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19 pages, 6624 KiB

Open AccessArticle

Physical and Numerical Modeling of the Slag Splashing Process

by Viktor Sinelnikov, Michał Szucki, Tomasz Merder, Jacek Pieprzyca and Dorota Kalisz

Materials 2021, 14(9), 2289; https://doi.org/10.3390/ma14092289 - 28 Apr 2021

Cited by 6 | Viewed by 1930

Abstract

The influence of technological factors on the process of slag splashing was analyzed in the paper. The problems were solved in several stages using our own and commercial calculation programs and laboratory tests. Based on the performed calculations and simulations, factors affecting the [...] Read more.

The influence of technological factors on the process of slag splashing was analyzed in the paper. The problems were solved in several stages using our own and commercial calculation programs and laboratory tests. Based on the performed calculations and simulations, factors affecting the slag splashing were determined. It was observed that the high efficiency of the process can be achieved by optimizing numerous technological parameters, e.g., flow parameters, pressure, and temperature of the nitrogen stream, height and angle of the lance position, as well as slag height into which the gas stream enters and MgO consumption. In addition, the chemical and mineralogical composition of the slag and its physicochemical parameters should be also considered. The obtained results of numerical simulations of slag splashing in the oxygen converter coincide with the results of experiments carried out using the physical model of oxygen converter. This means that the simulations well represent the real course of the slag splashing process for the studied variants. Full article

(This article belongs to the Special Issue Physical and Numerical Modeling of Process Metallurgy)

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20 pages, 8278 KiB

Open AccessArticle

Evolution of the Numerical Model Describing the Distribution of Non-Metallic Inclusions in the Tundish

by Tomasz Merder, Jacek Pieprzyca, Marek Warzecha, Piotr Warzecha and Artur Hutny

Materials 2021, 14(9), 2229; https://doi.org/10.3390/ma14092229 - 26 Apr 2021

Cited by 9 | Viewed by 1662

Abstract

Continuous casting is one of the steel production stages, during which the improvement in the metallurgical purity of steel can be additionally affected by removing nonmetallic inclusions (NMIs). This can be achieved by means of various types of flow controllers, installed in the [...] Read more.

Continuous casting is one of the steel production stages, during which the improvement in the metallurgical purity of steel can be additionally affected by removing nonmetallic inclusions (NMIs). This can be achieved by means of various types of flow controllers, installed in the working space of the tundish. The change in the steel flow structure, caused by those flow controllers, should lead to an intensification of NMIs removal from the liquid metal to the slag. Therefore, it is crucial to understand the behavior of nonmetallic inclusions during the flow of liquid steel through the tundish, and particularly during their distribution. The presented paper reports the results of the modeling studies of NMI distribution in liquid steel, flowing through the tundish. CFD modeling methods—using different models and computation variants—were employed in the study. The obtained CFD results were compared with the results of laboratory tests (using a tundish water model). The results of the performed investigations allow us to compare both methods of modeling; the investigated phenomena were microparticle distribution and mass microparticle concentration in the model fluid. The validation of the CFD results verified the analyzed computation variants. The aim of the research was to determine which numerical model is the best for describing the studied phenomenon. This will be used as the first phase of a larger research program which will provide for a comprehensive study of the distribution of NMIs flowing through tundish steel. Full article

(This article belongs to the Special Issue Physical and Numerical Modeling of Process Metallurgy)

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20 pages, 7611 KiB

Open AccessArticle

Effect of Thermal Buoyancy on Fluid Flow and Residence-Time Distribution in a Single-Strand Tundish

by Dong-Yuan Sheng and Pär G. Jönsson

Materials 2021, 14(8), 1906; https://doi.org/10.3390/ma14081906 - 11 Apr 2021

Cited by 20 | Viewed by 2383

Abstract

Natural convection of molten steel flow in a tundish occurs due to the temperature variation of the inlet stream and heat losses through top surface and refractory walls. A computational fluid dynamics (CFD) model was applied to study the effect of thermal buoyancy [...] Read more.

Natural convection of molten steel flow in a tundish occurs due to the temperature variation of the inlet stream and heat losses through top surface and refractory walls. A computational fluid dynamics (CFD) model was applied to study the effect of thermal buoyancy on fluid flow and residence-time distribution in a single-strand tundish. The CFD model was first validated with the experimental data from a non-isothermal water model and then applied to both scale-down model and prototype. The effects of flow control devices, including weir, dam and turbulence inhibitor, were compared and analyzed. Parameter studies of different heat losses through the top surface were performed. The results show that thermal buoyancy has a significant impact on the flow pattern and temperature distributions of molten steel in the tundish. The increase of heat loss through the top surface shortens the mean residence time of molten steel in the tundish, leading to an increase in dead volume fraction and a decrease in plug flow volume fraction. Full article

(This article belongs to the Special Issue Physical and Numerical Modeling of Process Metallurgy)

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19 pages, 3796 KiB

Open AccessEditor’s ChoiceArticle

Effect of Froude Number on Submerged Gas Blowing Characteristics

by Jonas L. Svantesson, Mikael Ersson and Pär G. Jönsson

Materials 2021, 14(3), 627; https://doi.org/10.3390/ma14030627 - 29 Jan 2021

Cited by 4 | Viewed by 1696

Abstract

The flow behavior of gas in compressible and incompressible systems was investigated at an ambient temperature in an air–water system and at an operating process temperature in the IronArc system, using computational fluid dynamics. The simulation results were verified by experiments in the [...] Read more.

The flow behavior of gas in compressible and incompressible systems was investigated at an ambient temperature in an air–water system and at an operating process temperature in the IronArc system, using computational fluid dynamics. The simulation results were verified by experiments in the air–water system and established empirical equations to enable reliable predictions of the penetration length. The simulations in the air–water system were found to replicate the experimental behavior using both the incompressible and compressible models, with only small deviations of 7–8%. A lower requirement for the modified Froude number of the gas blowing to produce a jetting behavior was also found. For gas blowing below the required modified Froude number, the results illustrate that the gas will form large pulsating bubbles instead of a steady jet, which causes the empirical equation calculations to severely underpredict the penetration length. The lower modified Froude number limit was also found to be system dependent and to have an approximate value of 300 for the studied IronArc system. For submerged blowing applications, it was found that it is important to ensure sufficiently high modified Froude numbers of the gas blowing. Then, the gas penetration length will remain stable as a jet and it will be possible to predict the values using empirical equations. Full article

(This article belongs to the Special Issue Physical and Numerical Modeling of Process Metallurgy)

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15 pages, 2498 KiB

Open AccessArticle

Calculation of Coke Layers Situation in the Cohesive Zone of Blast Furnace

by Mikolaj Bernasowski, Arkadiusz Klimczyk and Ryszard Stachura

Materials 2021, 14(1), 192; https://doi.org/10.3390/ma14010192 - 3 Jan 2021

Cited by 2 | Viewed by 2914

Abstract

Coke is the only batch component that does not soften in blast furnace thermal conditions. It is especially important at the temperatures of the cohesive zone forming because coke layers are the only gas-permeable charge. The aim of the work described in this [...] Read more.

Coke is the only batch component that does not soften in blast furnace thermal conditions. It is especially important at the temperatures of the cohesive zone forming because coke layers are the only gas-permeable charge. The aim of the work described in this article is the identification of individual coke layers situation in the cohesive zone. Numerical calculations of the cohesive zone situation are based on the horizontal below burden probe measures, however, coke layers are calculated using analytical geometry. The results can be presented as a bitmap; the individual and total area of the coke layers passing gases through the cohesive zone is also calculated. This form of results allows for subjective but quick assessment of the blast furnace operation by its crew. Full article

(This article belongs to the Special Issue Physical and Numerical Modeling of Process Metallurgy)

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