Predictions of melt circulation rate in a rh degasser by mathematical modelling of two phase flow
Leonardo Neves
, Carlos André Ruy Carneiro, Rafael Fernandes Reis, Roberto Parreiras Tavares
UFMG-Federal University of Minas Gerais,Avenida. Antônio Carlos, 6627 – Pampulha – 31.270-901 – Belo Horizonte – MG,Metallurgical and Materials Engineering Departament – Brazil.
DOI:
https://doi.org/10.7494/cmms.2010.4.0291
Abstract:
Modeling of turbulent two phase flow is not a simple task, particularly under the conditions prevailing in metallurgical reactors. Different forces have to be considered and different models have been proposed to evaluate these forces. None of these models has been fully validated and they usually require the definition of coefficients whose values change according to the system being studied. In the case of the RH degasser, the variations of pressure and temperature inside the computational domain and the presence of a free surface add more difficulties to the development of an accurate mathematical model. In the present work, a mathematical model for two phase flow in a RH degasser has been developed using the commercial software Ansys-CFX. In this first approach, the mathematical model was developed to simulate two phase flow in a physical model of the RH degasser, using water to simulate steel. In this physical model, the variations of pressure are much less significant and an isothermal domain can be considered. Different models for turbulence and also for the interphase drag and non-drag forces have been considered. An Eulerian-Eulerian approach has been adopted. The predictions of the model in terms of melt circulation rate were compared to experimental results obtained in a physical model of a RH degasser. In this model, water was used to simulate liquid steel and air was used to simulate argon. The melt circulation rate in the physical model was determined by the injection of a solution of potassium chloride at the upleg snorkel and measuring the variation of its concentration with time at the downleg snorkel. Images taken from the physical model at the upleg snorkel and of the vacuum chamber were also used to validate the predictions of the model. The predictions of melt circulation rates with the different versions of the mathematical model were close to the experimental results, but none of the models could exactly reproduce the variation of the melt circulation rate with the gas flow rate. These results indicate that some adjustments are still required to improve the quality of the predictions of the mathematical model.
Cite as:
Neves, L., Carneiro, C., Reis, R., & Tavares, R. (2010). Predictions of melt circulation rate in a rh degasser by mathematical modelling of two phase flow . Computer Methods in Materials Science, 10(4), 207 – 213. https://doi.org/10.7494/cmms.2010.4.0291
Article (PDF):
Keywords:
RH degasser, Two-phase flow, Mathematical modeling, Circulation rate, Drag and non-drag forces
References: