Instability of Fluid Flow and Level Fluctuation in Continuous Thin Slab Casting Mould

Shen, Bingzhen; Shen, Houfa; Liu, Baicheng

doi:10.2355/isijinternational.47.427

Cited by 22 publications

(19 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, several researchers from both industry and academia have proven various devices and operating strategies in order to improve the quality of steel produced through this process [1][2][3][4]. Surface defects and slag entrapment are significant defects that deteriorate the quality of steel that is produced by the continuous casting process [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Numerical and Physical Parametric Analysis of a SEN with Flow Conditioners in Slab Continuous Casting Mold

Gonzalez-Trejo

Real-Ramirez

Miranda-Tello

et al. 2017

Archives of Metallurgy and Materials

View full text Add to dashboard Cite

Some of the most recent technologies that improves the performance in continuous casting process has installed infrastructure outside the mold to modify the natural fluid flow pattern to obtain a quasi-steady condition and promote a uniform solidified shell of steel. The submerged entry nozzle distributes the liquid steel in the mold and can be used to obtain the flow symmetry condition with external geometry improvements. The fluid flow conditioners were located near the outlet ports of the nozzle. The aim of the modifiers is to impose a pseudo symmetric pattern in the upper zone of the mold by inhibiting the fluid exchange between the zones created by conditioners. This work evaluates the effect of the thickness and length of the fluid-flow modifiers on the overall performance of the submerged nozzle. These properties of the fluid-flow modifiers were normalized based on two of the geometric dimensions of the standard equipment. Numerical and physical simulations suggest that the flow modifier should be as thin as possible.

show abstract

Section: Introductionmentioning

confidence: 99%

Numerical and Physical Parametric Analysis of a SEN with Flow Conditioners in Slab Continuous Casting Mold

Gonzalez-Trejo

Real-Ramirez

Miranda-Tello

et al. 2017

Archives of Metallurgy and Materials

View full text Add to dashboard Cite

show abstract

“…Por lo que, la colada continua de planchón delgado en moldes tipo embudo, ha ido posicionándose y teniendo gran aceptación debido a: la disminución en el espesor del planchón, a su relativamente alta velocidad de colada y a que en este proceso se llega al producto final en menos pasos comparado con la colada en moldes de planchón convencional. Sin embargo, éste proceso debe ser mejorado, ya que su alta velocidad de colada trae como consecuencia problemas operacionales, por lo que el estudio del flujo de fluidos juega un papel clave ya que por una parte la geometría compleja del molde y la buza de descarga involucran problemas asociados con alteraciones en el patrón de flujo generado al interior del molde ocasionando la oscilación de los chorros de descarga provenientes de los puertos de la buza, lo cual provoca la re-fusión de la capa de acero recién solidificada del planchón, así como fluctuación de la interfase metal-escoria [1][2][3][4][5][6][7]. Lo anterior, origina la presencia de otros fenómenos tales como vórticidades debido al flujo altamente turbulento existente al interior del molde [5][6][7]13].…”

Section: Introductionunclassified

Simulación matemática para la optimización del patrón de flujo entregado por una buza para el molde de colada continua de planchón delgado

2018

View full text Add to dashboard Cite

RESUMENEntender el comportamiento de las oscilaciones de los chorros al interior del molde de planchón delgado tipo embudo es esencial para asegurar una entrega de acero líquido constante, mejorar el control de los patrones de flujo y consecuentemente incrementar la productividad de la planta y la calidad del producto final. Para lograr esto se llevó a cabo un estudio del efecto del diseño interno de la buza sobre la fluido dinámica del molde, intentando determinar el origen de las oscilaciones de los chorros. Se hizo uso de la simulación matemática para estudiar éstos fenómenos.En la modelación matemática, se recurrió a las ecuaciones fundamentales, el modelo de turbulencia RSM y el modelo Multifásico VOF. Las ecuaciones gobernantes son discretizadas y resueltas mediante el método iterativo-segregado implícito implementado en FLUENT®.Los resultados, de la simulación matemática, muestran que aun para diseños de buza con un comportamiento operacional estable, las oscilaciones de los chorros permanecen presentes y se hacen más intensos para altas velocidades de colada e inmersiones de buza profundas. El análisis de cada una de las buzas simuladas muestra que la geometría interna origina perturbaciones en el flujo en las zonas donde las áreas transversales internas cambian, generando presiones dinámicas altas y bajas promoviendo una tendencia para que el acero líquido salga preferentemente por uno de los puertos. Se encontró un delicado balance de fuerzas, el cual, se da sobre sobre la punta de la bifurcación interna de la buza. Este balance está relacionado con las velocidades fluctuantes y la presión ferrostática. Si este balance es roto las oscilaciones son más intensas, originando variaciones permanentes de la velocidad de flujo másico de un puerto a otro. Además, se encontró que existe la formación continua de un camino de vórtices el cual se genera a partir de la separación de la capa límite en el divisor de los puertos, fenómeno que intensifica la oscilación periódica de los chorros.Palabras clave: Diseño de buza; simulación matemática; molde de planchón delgado tipo embudo; oscilación de los chorros; turbulencia. ABSTRACTUnderstanding the behavior of the oscillations of the jets into the mold of thin slab funnel is essential to ensure a constant supply of liquid steel, improve control of the flow patterns and consequently increase plant productivity and the final product quality. To achieve this, we conducted a study of the effect of the internal design of the nozzle on the fluid dynamics of the mold, trying to determine the origin of the oscillations of the jets. Use of mathematical and physical simulation was done to study these phenomena.For the mathematical modeling it resorts to the fundamental equations, the RSM turbulence model and VOF multiphase model. The governing equations are discretized and solved by iteration-segregated implicit method implemented in FLUENT®.The results of the mathematical simulation are showing that even for a nozzle designs with a stable operational performance, the oscillat...

show abstract

“…[1][2][3][4] Unsteady flows often lead to poor level control and uneven solidification within the mould; which have been linked to the formation of defects such as deep oscillation marks, cracks, depressions, etc. [5][6][7] These defects are strongly linked to the mechanisms of initial shell solidification and growth in the mould. However, solidification itself is a complex combination of physical phenomena which include heat transfer, phase transformations and solid mechanics interacting simultaneously with the metal flow to form the solid shell within a time lapse of few seconds.…”

Section: Introductionmentioning

confidence: 99%

Recent Developments of a Numerical Model for Continuous Casting of Steel: Model Theory, Setup and Comparison to Physical Modelling with Liquid Metal

López¹,

Jalali²,

Björkvall³

et al. 2014

ISIJ Int.

View full text Add to dashboard Cite

Recent developments of an advanced numerical model for Continuous Casting of steel unveiled at the previous 2010 CSSCR Conference in Sapporo, Japan are presented. These include coupling of the existing multiphase, heat transfer and solidification model to argon injection for tracking bubble trajectories in the SEN, metal bulk and across the slag bed after passing through the metal surface. Hence, description of a method for adding gas injection in combination with a multiphase model for tracking metal/slag interfaces (Discrete Phase Model + Volume Of Fluid, DPM+VOF) is given.Validation is supported by tests on a revamped Continuous Casting Simulator (CCS-1) based on a low melting point alloy, which can realistically replicate the flow conditions in the caster. Metal-slag-argon flow predictions were compared to observations in the physical model showing good agreement on features such as discharging jets, rolls, standing waves and argon distribution measured through a variety of techniques such as ultrasound, electromagnetic probes and video sequences. Ultimately, the model makes possible the prediction of stable or unstable flows within the mould as a function of different argon flow-rates and bubble sizes. Application to industrial practice is an ongoing task and preliminary results are illustrated. The robustness of the model combined with direct observations in CCS-1 make possible the description of phenomena difficult to observe in the caster (e.g. argon injection and metal flow), but critical for the stability of the process and the quality of cast products.

show abstract

Instability of Fluid Flow and Level Fluctuation in Continuous Thin Slab Casting Mould

Cited by 22 publications

References 11 publications

Numerical and Physical Parametric Analysis of a SEN with Flow Conditioners in Slab Continuous Casting Mold

Numerical and Physical Parametric Analysis of a SEN with Flow Conditioners in Slab Continuous Casting Mold

Simulación matemática para la optimización del patrón de flujo entregado por una buza para el molde de colada continua de planchón delgado

Recent Developments of a Numerical Model for Continuous Casting of Steel: Model Theory, Setup and Comparison to Physical Modelling with Liquid Metal

Contact Info

Product

Resources

About