Effect of snorkel shape on the fluid flow during RH degassing process: mathematical modelling

Abstract

A mathematical model was developed to investigate the effect of snorkel shape on the recirculation rate and the erosion of the lining refractory during RH degassing process. A particle image velocimetry technique was used to measure the velocity distribution in a water modelling experiment. The calculated results were well validated with the measured ones. In the mathematical model, the interfaces between the molten steel and the gas phase, and the motion of argon bubbles were simulated and tracked using VOF + DPM model by which the argon bubbles were treated as the discrete phase in the molten steel and the top gas phase, and the top gas phase was treated as a second continuous phase. It was found that the recirculation rate of the molten steel with oval snorkels was significantly larger than that with round snorkels. For round snorkels, the optimum gas flow rate was 1800 L min −1 and it was 2800 L min −1 for oval snorkels. Furthermore, the volume distribution of the argon in the radial direction of the upsnorkel with oval snorkels was much more homogeneous than that with round snorkels. Meanwhile, the predicted maximum wall shear stress showed that the bottom and the sidewall of the ladle with round snorkels were more seriously eroded than that with oval snorkels. Therefore, the oval snorkel was beneficial to improve the service life of the RH degasser.

Avaliação De Desgaste De Refratário Por Erosão No Reator Rh via Modelamento Físico E Matemático

“…al. [11] observaram uma forte semelhança entre as curvas de taxa de circulação e tensão cisalhante máxima nas paredes laterais e no fundo da panela. Os valores de tensão de cisalhamento na panela foram superiores ao do presente trabalho, já que Ling et.…”

“…Ling et al [11] indicaram que conhecer a distribuição da tensão de cisalhamento nas paredes do reator via modelamento matemático ajuda a prever a erosão do revestimento refratário. O ponto de tensão máxima cisalhante é o ponto preferencial ao desgaste.…”

“…Luo et al [12] também utilizaram os recursos do modelamento matemático, validados por simulações em um modelo a frio, para calcular taxa de circulação e tempo de mistura, bem como investigar a tensão de cisalhamento nas paredes para prever desgaste preferencial da estrutura refratária do reator RH. Ling et al [11] e Luo et al [12] afirmam que, se comparadas às pernas de formato redondo, as pernas de forma oval aumentam a taxa de circulação e diminuem a tensão de cisalhamento do aço líquido nas paredes laterais e no fundo da panela, aumentando a vida útil da mesma no sistema RH. Ambos trabalhos mostram a tendência cada vez maior do uso de simulações computacionais em estudos de desgaseificadores RH, assim como Zhu et al [13], Chen e He [14] e Peixoto et al [15].…”

Modeling on the Fluid Flow and Mixing Phenomena in a RH Steel Degasser with Oval Down‐Leg Snorkel

“…It is generally considered that the circulation rate and the mixing time are two significant parameters during the RH process. Thus, many researchers have developed physical or mathematical models to simulate the multiphase fluid flow, mixing phenomena, behaviors of bubbles and inclusions, and decarburization process during the RH treatment. Based on previous works on circulation rate of RH, some empirical formulas are listed in Table , which includes the formulas put forward at the first time and excludes similar equations reported later.…”

“…While little results were reported to study the shape of RH snorkels, which has always been round until the oval snorkel was proposed by Kuwabara . The oval snorkels favored to enhance the circulation rate of RH reactor …”