Numerical Calculation of Circulation Flow Rate in the Degassing Rheinstahl-Heraeus Process.

Park, Young‐Geun; Doo, Won-Chul; Yi, Kyongsu; An, Sang-Bok

doi:10.2355/isijinternational.40.749

Cited by 70 publications

(75 citation statements)

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“…The details for the calculation methods of the Ar gas behavior and fluid flow are represented in Ref. 9).…”

Section: Calculation Of Gas Behavior and Fluid Flowmentioning

confidence: 99%

A New Numerical Model for Predicting Carbon Concentration during RH Degassing Treatment

Park

2003

ISIJ International

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A new decarburization model for the RH system was constructed to calculate the decarburization reaction using a three-dimensional fluid dynamics program. The behavior of Ar gas and the entire fluid flow in the RH process were considered. On the basis of this fluid flow, the decarburization reaction could be calculated by establishing the decarburization reaction model, which considers thermodynamics, reaction kinetics, and the decarburization sites (Ar bubble surface, bath surface, and the CO bubble formation at inner sites). The model showed good agreement with two RH operation results. Using this numerical model, the contributions of each reaction were investigated.KEY WORDS: decarburization; reaction model; reaction site; reaction area; reaction rate.where g is the acceleration due to gravity (m/s 2 ), r l and r g are the densities of the Ar gas and the melt (kg/m 3 ), V p is the volume of the plume (m 3 ) and a is the average volume fraction of the gas. The plume volume was calculated from the plume shape, which is affected by the pressure of the vacuum vessel, nozzle number and position, gas flow rate etc.. The average volume fraction is the total volume ratio of gas in the plume realm. In addition, gas bubble expansion due to the pressure drop and heat transfer from melt during rising was calculated and this effect was considered when calculating the total buoyancy force. In the Ref. 9), the bubble expansion due to only pressure drop was considered. In this study, the numerical model was modified to consider both the thermal expansion and pressure drop, Szekely's model 11) is modified as In Eq. (2), r l is the density of the melt, R b is the radius of the bubble, T is temperature in the bubble, R b and T 0 are radius and temperature at the nozzle respectively, P V is the pressure of the vacuum vessel and H is the height of the melt. To solve Eq. (2), the temperature should be known. ) and C is the heat capacity (J/kg · K). h is the heat transfer coefficient (J/m 2 · s · K) and the value can be derived from the penetration theory with the assumption of gas phase control. Komarove et al. derived heat transfer coefficient from experiments.12) Because the analysis in the Ref. 12) was based on spherical and constant size bubble, there should be some difference in the value of h and further study should be necessary to derive more realistic h value.The buoyancy force calculated by Eq. (1) was inserted as the external force for the velocity components (u, v, w) in the three dimensional Navier-Stokes equation to calculate fluid flow. The numerical model can predict the effects of the operational conditions and shapes of the RH system on fluid flow. 13) Calculation of Decarburization ReactionIn this study, the decarburization reaction was simulated by calculating the dissolved carbon concentration during the RH process. The numerical model included mass transport of dissolved carbon and oxygen due to convection and diffusion and the reaction rate at the reaction sites. The reaction rate was calculated respectively...

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“…The details for the calculation methods of the Ar gas behavior and fluid flow are represented in Ref. 9).…”

Section: Calculation Of Gas Behavior and Fluid Flowmentioning

confidence: 99%

A New Numerical Model for Predicting Carbon Concentration during RH Degassing Treatment

Park

2003

ISIJ International

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“…O fator de calibração encontrado foi 0,6, e este valor é aplicável tanto para a água como para a solução ZnCl2 (Figura 7). Na Figura 7 nota-se que a taxa de circulação aumenta com o aumento da vazão de gás injetado, tal como esperado e reportado por Seshadri et al [8], Almeida et al [9], Park et al [2] e outros. Não foi possível identificar a influência da profundidade de imersão da perna sobre a taxa de circulação, tanto para os experimentos utilizando água, quanto solução de ZnCl2.…”

Section: Velocimetria Piv (Particle Image Velocimetry)unclassified

“…O grau de vácuo, a taxa de circulação bem como a agitação tem efeitos importantes nas taxas de reação (ZHANG et al [1]). Como a medição da taxa de circulação na indústria é difícil de ser realizada, Park et al [2] destacam a importância da utilização de modelos físicos e simulações matemáticas para investigar os efeitos de diversos parâmetros sobre a taxa de recirculação. Yang et al [3] lembram que a etapa de refino do aço no RH representa uma das últimas oportunidades para realizar a dessulfuração, e por este motivo, o reator RH tem sido aplicado na produção de aços ultrabaixo teor de enxofre.…”

Section: Introductionunclassified

Taxa De Circulação E Previsão Do Comportamento Metal/Escória Em Modelo Físico De Um Reator Rh

Peixoto¹,

Barony²,

Gabriel³

et al. 2017

Anais Do Seminário De Aciaria, Fundição E Metalurgia De Não-Ferrosos

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ResumoNo reator RH, a otimização do fluxo recirculatório de aço entre a câmara de vácuo e a panela é a chave para promover as reações de refino. Neste trabalho, foram utilizados água e solução de cloreto de zinco (ZnCl2) como fluido similar ao aço para investigar a taxa de circulação no modelo a frio de um reator RH em escala 1:7,5. A taxa de circulação foi determinada utilizando o método de pontes de Strain Gages. A técnica PIV foi utilizada de modo a calibrar e validar os resultados. O aumento da vazão de gás de 30l/min para 120l/min resultou na elevação da taxa de circulação para ambos os fluidos. Cálculos preliminares demonstraram que há grande diferença nas condições de arraste de escória entre os sistemas água/óleo e ZnCl2/óleo. Palavras-chave: Modelamento físico; PIV; Desgaseificador RH. CIRCULATION RATE AND PREDICTION OF THE METAL/SLAG BEHAVIOR IN PHYSICAL MODEL OF A RH REACTOR AbstractIn RH reactor, the optimization of the steel circulatory flow between the vacuum chamber and the ladle is the key factor to promote the refining reactions. In this work, water and zinc chloride solution (ZnCl2) were employed as similar fluid to steel in order to investigate the circulation rate in a cold model of a RH reactor built on 1:7.5 scale. The circulation rate was determined using the method of strain gage bridges. The PIV technique was used to calibrate and validate the results. With an increasing on gas flow rate from 30l/min to 120l/min, the recirculation flow rate increased for both fluids (água e ZnCl2). Initial calculations showed that there is a great difference in the conditions of slag dragging between water/oil and ZnCl2/oil systems.

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“…Zhang et al 7) built a decarburization model by adding the fluid flow in the vacuum vessel and ladle. The flow pattern of steel melt in the ladle was analyzed by the computation fluid dynamics (CFD) [6][7][8][9][10][11][12][13][14][15] and perfect mixing time 14,15) was also calculated by the time-change in a tracer concentration at a given point after a tracer injection.…”

Section: Introductionmentioning

confidence: 99%

Fluid Mixing in Ladle of RH Degasser Induced by Down Flow

et al. 2016

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Numerical Calculation of Circulation Flow Rate in the Degassing Rheinstahl-Heraeus Process.

Cited by 70 publications

References 5 publications

A New Numerical Model for Predicting Carbon Concentration during RH Degassing Treatment

A New Numerical Model for Predicting Carbon Concentration during RH Degassing Treatment

Taxa De Circulação E Previsão Do Comportamento Metal/Escória Em Modelo Físico De Um Reator Rh

Fluid Mixing in Ladle of RH Degasser Induced by Down Flow

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