scholarly journals Geometric Modification of the Tundish Impact Point

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 944 ◽  
Author(s):  
Branislav Buľko ◽  
Ivan Priesol ◽  
Peter Demeter ◽  
Peter Gašparovič ◽  
Dana Baricová ◽  
...  
Keyword(s):  
Slag Phase ◽  
Refractory Lining ◽  
Dead Zone ◽  
Steel Slag ◽  
Phase Interface ◽  
Evaluation Criteria ◽  
Physical Modelling ◽  
Slag Layer ◽  
Steel Flow ◽  
The Impact

In connection with the increasing requirements for cleanliness in conticast steel, it is necessary to develop original solutions. The tundish, as the last refractory-lined reactor, gives enough space to remove inclusions by optimizing the flow of steel. The basic component of the tundish is the impact pad, the shape of which creates a suitable flow of steel, thus making it part of the tundish metallurgy. The optimal steel flow in the tundish must avoid creating dead zone areas, or the slag “eye” phenomenon in the slag layer around the ladle shroud, and is intended to create conditions for the release of inclusions by promoting reactions at the steel-slag phase interface. The flow also has to prevent excessive erosion of the tundish refractory lining. This paper compares the standard impact pad with the “Spheric” spherical impact pad using computional fluid dynamiscs (CFD) tools and physical modelling. The evaluation criteria are residence time and flow in the tundish at three different casting speeds.

scholarly journals Steel/Slag Interface Behavior under Multifunction Electromagnetic Driving in a Continuous Casting Slab Mold

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 983 ◽  
Author(s):  
Xiaohui Sun ◽  
Bin Li ◽  
Haibiao Lu ◽  
Yunbo Zhong ◽  
Zhongming Ren ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Computational Models ◽  
Steel Slag ◽  
Evaluation Criteria ◽  
Surface Velocity ◽  
Interface Behavior ◽  
Continuous Casting Slab ◽  
Measurement Results ◽  
Control Technologies ◽  
Steel Flow

The transient numerical model combined with the volume of fluid (VOF) approach is employed to investigate the steel/slag interface behavior under multifunction electromagnetic driving in a continuous casting slab mold. Here, electromagnetic stirring (EMS) and electromagnetic braking (EMBr), respectively, are chosen as flow multifunction control technologies in the upper and lower areas of the mold. The computational models are validated with measurement results. The results show that multifunction electromagnetic driving changes the flow pattern, which has the potential to simultaneously meet the requirements of the steel flow in the regions above and below the nozzle, ensuring the uniformity and activity of the molten steel in the upper region of the mold and avoiding the excessive depth of the impinging jet. After EMS, the steel forms a deflected circulation flow at the steel/slag interface, and the surface velocity distribution is more uniform. EMBr still has the function of stabilizing the meniscus when multifunction electromagnetic driving is applied. Taking wave height and wave amplitude as evaluation criteria, the influence of EMS and EMBr on the steel/slag interface can be evaluated and controlled to some extent by observing the key points.

scholarly journals Experimental Methods of Validation for Numerical Simulation Results on Steel Flow through Tundish

2016 ◽  
Vol 61 (4) ◽  
pp. 2057-2060
Author(s):  
J. Pieprzyca ◽  
P. Warzecha ◽  
T. Merder ◽  
M. Warzecha
Keyword(s):  
Numerical Simulation ◽  
Liquid Steel ◽  
Flow Distribution ◽  
Physical Modelling ◽  
Simulation Techniques ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
Steel Flow ◽  
Liquid Flows ◽  
The Impact

Abstract The article presents experimental results on the impact of tundish flow regulator influencing the liquid steel flow course. The research was conducted based on the hybrid modelling methods understood as a complementary use of Computational Fluid Dynamics (CFD) methods and physical modelling. Dynamic development of numerical simulation techniques and accessibility to highly advanced and specialized software causes the fact that these techniques are commonly used for solving problems related to liquid flows by using analytical methods. Whereas, physical modelling is an important cognitive tool in the field of empirical identification of these phenomena. This allows for peer review and specification of the researched problems. By exploiting these relationships, a comparison of the obtained results was performed in the form of residence time distribution (RTD) curves and visualization of particular types of liquid steel flow distribution zones in the investigated tundish.

scholarly journals On Modelling Parasitic Solidification Due to Heat Loss at Submerged Entry Nozzle Region of Continuous Casting Mold

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1375
Author(s):  
Alexander Vakhrushev ◽  
Abdellah Kharicha ◽  
Menghuai Wu ◽  
Andreas Ludwig ◽  
Yong Tang ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Steel Slag ◽  
Phase Interface ◽  
Steel Production ◽  
Submerged Entry Nozzle ◽  
Casting Process ◽  
Material Model ◽  
Slag Layer ◽  
Continuous Casting Mold ◽  
High Production Rate

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 nozzles (SENs) typically results in asymmetric mold flow, uneven solidification, meniscus fluctuations, and possible slag entrapment. Analyses of retained SENs have evidenced the solidification of entrapped melt inside clog material. The experimental study of these phenomena has significant difficulties that make numerical simulation a perfect investigation tool. In the present study, verified 2D simulations were performed with an advanced multi-material model based on a newly presented single mesh approach for the liquid and solid regions. Implemented as an in-house code using the OpenFOAM finite volume method libraries, it aggregated the liquid melt flow, solidification of the steel, and heat transfer through the refractory SENs, copper mold plates, and the slag layer, including its convection. The introduced novel technique dynamically couples the momentum at the steel/slag interface without complex multi-phase interface tracking. The following scenarios were studied: (i) SEN with proper fiber insulation, (ii) partial damage of SEN insulation, and (iii) complete damage of SEN insulation. A uniform 12 mm clog layer with 45% entrapped liquid steel was additionally considered. The simulations showed that parasitic solidification occurred inside an SEN bore with partially or completely absent insulation. SEN clogging was found to promote the solidification of the entrapped melt; without SEN insulation, it could overgrow the clogged region. The jet flow was shown to be accelerated due to the combined effect of the clogging and parasitic solidification; simultaneously, the superheat transport was impaired inside the mold cavity.

Interaction between Molten Steel, Alumina Lining Refractory and Slag Phase

2013 ◽  
Vol 13 (1-2) ◽  
pp. 133-143
Author(s):  
Jiling Wang ◽  
Lifeng Zhang ◽  
Shufeng Yang ◽  
Yongfeng Chen ◽  
Jingyu Li ◽  
...  
Keyword(s):  
Reaction Time ◽  
Molten Steel ◽  
Reaction Layer ◽  
Erosion Rate ◽  
Laboratory Experiments ◽  
Slag Phase ◽  
Steel Slag ◽  
Slag Layer ◽  
Layer Steel ◽  
Over Time

AbstractLaboratory experiments exploring the interaction between molten steel, slag and lining refractory were performed. The transient erosion and reaction over time were investigated, and the transient change of the reaction layer and inclusions generated in the molten steel were evaluated using optical microscopy and SEM-EDS. Without slag addition before remelting, the FeO from reoxidation entered the space between the lining refractory and the steel and strengthened the erosion of the lining refractory. Several layers were found from the steel to the original lining refractory layer: steel phase, FeO layer, a FeO-rich lining layer and an Original Lining (OL)-rich lining layer. The thickness of the reaction layer increased nearly linearly with the reaction time at an erosion rate of 4.2 µm/min. With slag addition before remelting, the reaction layer between the steel and the original lining materials included several sub-layers: a gap, a slag layer, an FeO-rich lining layer and an Original Lining (OL)-rich lining layer. The thickness of the reaction layer nearly linearly increased with the reaction time and with an erosion rate of 5.7 µm/min. Slags were entrained into the steel occasionally.

scholarly journals Assessing Architecture-and-Landscape Integration as a Basis for Evaluating the Impact of Construction Projects on the Cultural Landscape of Tourist Seaside Resorts

Land ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 17
Author(s):  
Wojciech Bal ◽  
Magdalena Czalczynska-Podolska
Keyword(s):  
Construction Projects ◽  
Cultural Landscape ◽  
Negative Impact ◽  
Residential Buildings ◽  
Evaluation Criteria ◽  
Development Project ◽  
Clear Trend ◽  
Original Culture ◽  
Construction Plans ◽  
The Impact

The coastline of Western Pomerania has natural and cultural assets that have promoted the development of tourism, but also require additional measures to ensure the traditional features and characteristics are protected. This is to ensure that new developments conform to a more uniform set of spatial structures which are in line with the original culture. Today, seaside resorts are characterized by a rapid increase in development with a clear trend towards non-physiognomic architectural forms which continually expand and encroach on land closer to the coastline. This results in a blurring of the original concepts that characterized the founding seaside resort. This study evaluates 11 development projects (including a range of hotels, luxury residential buildings and hotel suites) built in 2009–2020 in the coastal area of Western Pomerania. An assessment of architecture-and-landscape integration for each development project was made, using four groups of evaluation criteria: aesthetic, socio-cultural, functional and locational factors. The study methodology included a historical and interpretative study (iconology, iconography, historiography) and an examination of architecture-and-landscape integration using a pre-prepared evaluation form. Each criterion was first assessed using both field surveys and desk research (including the analysis of construction plans and developer materials), and then compared with the original, traditional qualities of the town. This study demonstrates that it is possible to clearly identify the potential negative impact of tourism development on the cultural landscape of seaside resorts, and provides recommendations for future shaping, management and conservation of the landscape.

scholarly journals Body Composition Changes in Gastric Cancer Patients during Preoperative FLOT Therapy: Preliminary Results of an Italian Cohort Study

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 960
Author(s):  
Emanuele Rinninella ◽  
Antonia Strippoli ◽  
Marco Cintoni ◽  
Pauline Raoul ◽  
Raffaella Vivolo ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Body Composition ◽  
Tumor Regression ◽  
Evaluation Criteria ◽  
Tumor Regression Grade ◽  
Skeletal Muscle Index ◽  
Before And After ◽  
Gastric Cancer Patients ◽  
The Impact ◽  
Composition Changes

Background: The impact of the new chemotherapy, fluorouracil plus leucovorin, oxaliplatin, and docetaxel (FLOT) on body composition in gastric cancer (GC) patients remains unknown. We assessed body composition changes of GC patients receiving the FLOT regimen and their impact on treatment outcomes. Methods: Preoperative pre- and post-FLOT computed tomography (CT) scans of advanced GC patients were studied. Lumbar skeletal muscle index (SMI) and adipose indices were calculated before and after FLOT. Results: A total of 26 patients were identified between April 2019 and January 2020. Nineteen patients were sarcopenic at diagnosis. The mean BMI decreased (from 24.4 ± 3.7 to 22.6 ± 3.1; p < 0.0001) as well as the SMI (from 48.74 ± 9.76 to 46.52 ± 9.98; p = 0.009) and visceral adipose index (VAI) (from 49.04 ± 31.06 to 41.99 ± 23.91; p = 0.004) during preoperative FLOT therapy. BMI, SMI, and VAI variations were not associated with toxicity, Response Evaluation Criteria in Solid Tumors (RECIST), response, delay and completion of perioperative FLOT chemotherapy, and the execution of gastrectomy; a decrease of SMI ≥ 5% was associated with a higher Mandard tumor regression grade (p = 0.01). Conclusions: Almost three-quarters (73.1%) of GC patients were sarcopenic at diagnosis. Preoperative FLOT was associated with a further reduction in SMI, BMI, and VAI. These changes were not associated with short-term outcomes.

Generazioni e valutazione sociale delle occupazioni

2009 ◽  
pp. 81-97
Author(s):  
Amalia Caputo ◽  
Daniela Napoletano
Keyword(s):  
Labor Market ◽  
Key Words ◽  
Social Desirability ◽  
Social Stratification ◽  
Generational Differences ◽  
Evaluation Criteria ◽  
Social Evaluation ◽  
Labor Flexibility ◽  
The Social ◽  
The Impact

- In this article the authors analyse the social evaluation of occupations, examining the impact of generation on the judgments about the social desirability of occupations. The authors show that some generational differences are noticeable when looking at the criteria that respondents use to order occupations.Key words: Generation, Labor flexibility, Evaluation criteria, Labor market, Social Stratification, Occupational Stratification Scale

scholarly journals Analysis of the impact of changes in the stator magnetic circuit on static properties of the electromagnetic linear motor model

2018 ◽  
Vol 67 (3) ◽  
pp. 71-81
Author(s):  
Krzysztof Just ◽  
Paweł Piskur
Keyword(s):  
Magnetic Force ◽  
Permanent Magnets ◽  
Magnetic Circuit ◽  
Evaluation Criteria ◽  
Static Properties ◽  
Independent Variable ◽  
The Mean ◽  
Electro Magnetic ◽  
The Impact ◽  
Maximum Minimum

In this paper, the static characteristics as a function of changes in geometric dimensions of the stator magnetic circuit of the linear stepper actuator with permanent magnets is presented. The stator is built from a series of cylindrical coils encapsulated with ferromagnetic case. The runner is made of permanent magnet rings connected with ferromagnetic spacers. The electromagnetic interac-tion between the stator and the runner for the sequential supply of coils was analyzed. The electro-magnetic force as a function of the geometry of the coils and the ferromagnetic housing for the con-stant graduation of the runner was determined. The maximum, minimum, and average values of the electromagnetic force as a function of the geometric independent variable were determined. The ratio of the mean force to the maximum, and mechanical work calculated as the integral of the force on the path of the runner was adopted as the evaluation criteria. A comparison between the maximum, average and relative values of forces as a function of the geometric dimensions of the stator was made. Keywords: modelling and simulation, linear actuator, finite element method, field calculations, cogging force, magnetic force.

scholarly journals Evaluation of the implementation of Batik-skills training program

2019 ◽  
Vol 5 (2) ◽  
pp. 130-143
Author(s):  
Hendro Prasetyono ◽  
Dedeh Kurniasari ◽  
Laila Desnaranti
Keyword(s):  
Training Program ◽  
Evaluation Model ◽  
Evaluation Criteria ◽  
Skills Training ◽  
Product Evaluation ◽  
Program Improvement ◽  
Educational Facilities ◽  
Evaluation Of Learning ◽  
The Impact ◽  
And Training

The purpose of this study is to evaluate the implementation of batik skills training program as a recommendation for program improvement. The method used in this research is a qualitative approach using Context, Input, Process, and Product evaluation model. Samples were taken from the Institute of Skills and Training in the areas of Jakarta, Bogor, Depok, Bekasi, and Tangerang. The results of the evaluation components that meet the evaluation criteria are all aspects of the context component, discipline and learning process, while the components of batik teachers' education qualifications, the use of educational facilities and infrastructure standards, curriculum components, program financing, evaluation of learning outcomes, mastery of theoretical competencies, practices, and impacts to program participants have not been met. The batik skills training program needs to be continued with some improvement. It is recommended for the product components, especially on the impact aspects felt by graduates, to be improved.

scholarly journals A Simulation and Optimization Study of the Swirling Nozzle for Eccentric Flow Fields of Round Molds

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 691
Author(s):  
Peng Lin ◽  
Yan Jin ◽  
Fu Yang ◽  
Ziyu Liu ◽  
Rundong Jing ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Rotation Angle ◽  
Steel Slag ◽  
Submerged Entry Nozzle ◽  
Operating Conditions ◽  
Gas Absorption ◽  
Simulation And Optimization ◽  
Bias Flow ◽  
The Impact

In continuous casting, the nozzle position may deviate from the center under actual operating conditions, which may cause periodic fluctuation of the steel-slag interface and easily lead to slag entrapment and gas absorption. Swirling nozzles can reduce these negative effects. A mathematical simulation method based on a round mold of steel components with a 600 mm diameter is applied to study the flow field of molten steel in a mold. The swirling nozzle is optimized through the establishment of a fluid dynamics model. Meanwhile, a 1:2 hydraulic model is established for validation experiments. The results show that, when the submerged entry nozzle (SEN) is eccentric in the mold, it results in serious bias flow, increasing the drift index in the mold up to 0.46 at the eccentric distance of 50 mm. The impact depth of liquid steel and turbulent kinetic energy can be decreased by increasing the rotation angle of the nozzle. The nozzle with one bottom hole, which significantly decreases the bottom pressure and turbulent kinetic energy, greatly weakens the scour on nozzle and surface fluctuation. In the eccentric casting condition, using the optimized swirling nozzle that employs a 5-fractional structure, in which the rotation angle of 4 side holes is 30° and there is one bottom outlet, can effectively restrain bias flow and reduce the drift index to 0.28, a decline of more than 39%.

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