Carlos Gonzalez Rivera
@unam.mx
Facultad de Química, Departamento de Ingeniería Metalúrgica
Universidad Nacional Autónoma de México
Professor at the National University of Mexico (UNAM), Faculty of Chemistry, Department of Metallurgical Engineering, for more than 25 years. Main research interest: experimental techniques to study Solidification Kinetics , Metallurgical engineering and Processes Analysis and simulation, Foundry. Member of the Sistema Nacional de Investigadores since 1999, Member of the Academia Mexicana de Ciencias since 2001
EDUCATION
PhD Doctorado en Ciencias Químicas, Facultad de Química, UNAM, México
Dipome d'etudes Approfondies en Science des Materiaux et Metallurgie, Institut National Polytechnique de Grenoble, LTPCM France
Ingeniero Químico Metalúrgico, Facultad de Química, UNAM, México
RESEARCH INTERESTS
Experimental techniques to study Solidification Kinetics , Metallurgical engineering and Processes Analysis and simulation, Foundry, Alloys for biomedical applications, Steel, materials processing.
Scopus Publications
Scopus Publications
David Israel Posadas-Navarro, Carlos González-Rivera, Marco Aurelio Ramírez-Argáez, and Gabriel Ascanio
Elsevier BV
Luis Enrique Jardón-Pérez, Alberto N. Conejo, Adrian Manuel Amaro-Villeda, Carlos González-Rivera, and Marco Aurelio Ramírez-Argáez
Iron and Steel Institute of Japan
Carlos González-Rivera, Marco A. Ramirez-Argáez, Adrián Amaro-Villeda, Gerardo Trápaga-Martínez, and Luis Enrique Jardón-Pérez
Wiley
Luis E. Jardón-Pérez, Carlos González-Rivera, Gerardo Trápaga-Martínez, Adrián Amaro-Villeda, and Marco A. Ramírez-Argáez
Wiley
L. E. Jardón-Pérez, A. M. Amaro-Villeda, G. Trápaga-Martínez, C. González-Rivera, and M. A. Ramírez-Argáez
Springer Science and Business Media LLC
A 1/17th water physical model of a 200-ton steel ladle furnace with a single gas injection was used to simulate bath heating using a single burner to mimic the heat flux due to electric arcs in the industrial steel ladle. Two phases were considered, using water to simulate the molten steel and air to simulate the argon injection at a flow rate of 1.54 NL min−1. The planar Laser-Induced Fluorescence (PLIF) technique was for the first time experimentally implemented to measure temperature fields in a longitudinal plane of the gas-stirred ladle model. PLIF employs a laser source of 532-nm wavelength to light water seeded with rhodamine B, which emits fluorescence depending on its temperature, after a complex calibration is made. Next, the fluorescence is captured by a camera with a 550-nm wavelength filter. The PLIF measurements were validated by local thermocouple measurements at five different locations in the measurement plane. Temperature fields measured by PLIF are in good agreement with those obtained locally by thermocouples, so the PLIF technique can be used to measure temperature fields with the advantage of getting a complete temperature contour field, in contrast to point values of temperatures with thermocouples. Experiments were carried out to study the thermal mixing for two common tuyere positions, i.e., axisymmetric and eccentric (mid-radius) positions. Results on the injection mode show that axisymmetric gas injection is a more efficient heat transfer configuration between the burner and the liquid phase than is the symmetric injection mode for the particular heating configuration studied in this work.
Luis E. Jardón-Pérez, Carlos González-Rivera, Marco A. Ramirez-Argaez, and Abhishek Dutta
MDPI AG
Ladle refining plays a crucial role in the steelmaking process, in which a gas stream is bubbled through molten steel to improve the rate of removal of impurities and enhance the transport phenomena that occur in a metallurgical reactor. In this study, the effect of dual gas injection using equal (50%:50%) and differentiated (75%:25%) flows was studied through numerical modeling, using computational fluid dynamics (CFD). The effect of gas flow rate and slag thickness on mixing time and slag eye area were studied numerically and compared with the physical model. The numerical model agrees with the physical model, showing that for optimal performance the ladle must be operated using differentiated flows. Although the numerical model can predict well the hydrodynamic behavior (velocity and turbulent kinetic energy) of the ladle, there is a deviation from the experimental mixing time when using both equal and differentiated gas injection at a high gas flow rate and a high slag thickness. This is probably due to the insufficient capture of the velocity field near the water–oil (steel–slag) interface and slag emulsification by the numerical model, as well as the complicated nature of correctly simulating the interaction between both gas plumes.
Carlos González-Rivera, Anthony Harrup, Carla Aguilar, Adrián M. Amaro-Villeda, and Marco A. Ramírez-Argáez
Springer Science and Business Media LLC
In this work, a new computer-aided cooling curve analysis method (CA-CCA) called metal/mold energy balance method (MEB) is presented. Its originality relies on taking into account the thermal history, the mass, and the heat capacity of both the sample and the mold containing it, for the determination of the latent heat of fusion and the evolution of the solid fraction of metallic samples contained into metallic molds without using a baseline curve. The MEB method is based on the numerical processing of the cooling curves of the sample and the mold, which are obtained using two thermocouples, one located at the thermal center of the sample and the other placed into the mold wall. The mold containing the sample is thermally isolated at its top and bottom. The method was applied to explore its capability to determine values of latent heat of fusion and solid fraction evolution when compared to reported values in the literature of five metals of commercial purity (Cd, Zn, Sn, Pb, and Al) and two Al-based alloys (Al–7%Si and Al–14%Cu). The performance of the MEB method was compared with the results obtained by processing the cooling curves of the metal and alloys under study using the Newton baseline method, the dynamic baseline method, and the equation-based Newtonian method. The obtained results suggest that MEB method offers a simple and easy way to obtain accurate experimental values of latent heat of fusion with small errors respect to the reference reported values, while results on solidification paths are similar to those predicted by the other CA-CCA methods.
Carlos Gonzalez-Rivera, Adrian Amaro-Villeda, and Marco A. Ramirez-Argaez
IEEE
En este trabajo se aplica el método de análisis de curvas de enfriamiento asistido por computadora llamado Balance de Energía Metal/Molde (MEB) a una aleación hipoeutéctica de Al-7.5% Si para determinar el calor latente de fusión y la ruta de solidificación de esta aleación y comparar sus predicciones con respecto a los valores de calor latente reportados en la literatura. Para tal efecto, se preparó la aleación líquida en un crisol de carburo de silicio dentro de un horno eléctrico, utilizando cargas de aluminio y silicio de pureza comercial. La composición química de la aleación se controló utilizando un espectrómetro de emisión por chispa. Se utilizaron moldes cilíndricos de acero inoxidable para contener a las muestras de aleaciones líquidas. Una vez que se preparó la aleación líquida y el molde, la muestra líquida se transfirió al molde y los termopares se insertaron en la muestra y en el molde para obtener sus curvas de enfriamiento durante el enfriamiento y la solidificación de la muestra. Las curvas de enfriamiento fueron procesadas numéricamente por el método MEB, basado en balances de energía aplicados al sistema compuesto muestra de aleación liquida / molde. Las curvas de enfriamiento obtenidas para la muestra de aleación bajo estudio también se procesaron numéricamente utilizando dos de los métodos de análisis de curvas de enfriamiento newtonianos más utilizados, con el propósito de comparar sus rendimientos en la determinación del calor latente de solidificación y en la evolución de la fracción sólida. Los resultados obtenidos en este trabajo sugieren que el método MEB presenta un mejor desempeño en la determinación del calor latente de fusión y predice evoluciones de fracción sólida similares a las predichas por los métodos newtonianos convencionales.
Luis E. Jardon-Perez, Carlos Gonzalez-Rivera, and Marco A. Ramirez-Argaez
IEEE
One of the most important parameters to define the performance of the steelmaking ladle furnace is the mixing time. The most popular method to determine the mixing time is through an immersed probe to measure changes in conductivity or pH in a single point. An alternative method to measure mixing time is through the experimental technique called Planar Laser-Induced Fluorescence (PLIF). This technique measures concentrations changes of a fluorescent tracer in a whole plane of the system in a non-intrusive way and it has not been reported before in the literature to measure mixing times in these systems. In this work, details on the use of PLIF in physical models of ladle furnaces are studied, such as the effect of the model scale and the effect of the kind of water employed to do the measurements.
Luis E. Jardón-Pérez, Adrian Amaro-Villeda, Carlos González-Rivera, Gerardo Trápaga, A. N. Conejo, and Marco A. Ramírez-Argáez
Springer Science and Business Media LLC
The planar laser-induced fluorescence (PLIF) technique was implemented to measure mixing time in a 1/17 water model of a 200-ton ladle furnace. The results were compared to those obtained using the conventional method of pH probes. PLIF determinations were done at two different planes, and pH probe determinations were performed at two different locations. The results suggest that mixing times measured by PLIF are similar to those obtained under optimal conditions by the pH probe and that PLIF technique is more accurate and less sensitive to the location of the measurement than the pH probe method. In addition, the particle image velocimetry (PIV) technique was used to measure the effect of the immersed probe on the fluid-dynamic structure of the system. The presence of the probe affects greatly fluid dynamics and consequently the mixing behavior, which could explain the differences found in its mixing time measurements at different probe locations. This study shows the feasibility of the PLIF technique used to measure mixing time in physical models of gas-stirred ladles; it is not intrusive and allows the visualization of the mixing phenomena in a complete plane of the system.
Luis E. Jardón-Pérez, Daniel R. González-Morales, Gerardo Trápaga, Carlos González-Rivera, and Marco A. Ramírez-Argáez
MDPI AG
In this work, the effects of equal (50%/50%) or differentiated (75%/25%) gas flow ratio, gas flow rate, and slag thickness on mixing time and open eye area were studied in a physical model of a gas stirred ladle with dual plugs separated by an angle of 180°. The effect of the variables under study was determined using a two-level factorial design. Particle image velocimetry (PIV) was used to establish, through the analysis of the flow patterns and turbulence kinetic energy contours, the effect of the studied variables on the hydrodynamics of the system. Results revealed that differentiated injection ratio significantly changes the flow structure and greatly influences the behavior of the system regarding mixing time and open eye area. The Pareto front of the optimized results on both mixing time and open eye area was obtained through a multi-objective optimization using a genetic algorithm (NSGA-II). The results are conclusive in that the ladle must be operated using differentiated flow ratio for optimal performance.
Ernesto Mancilla, Wiener Cruz‐Méndez, Marco Aurelio Ramírez‐Argáez, Carlos González‐Rivera, and Gabriel Ascanio
Wiley
Marco Ramírez-Argáez, Abhishek Dutta, A. Amaro-Villeda, C. González-Rivera, and A. Conejo
MDPI AG
Mixing phenomena in metallurgical steel ladles by bottom gas injection involves three phases namely, liquid molten steel, liquid slag and gaseous argon. In order to numerically solve this three-phase fluid flow system, a new approach is proposed which considers the physical nature of the gas being a dispersed phase in the liquid, while the two liquids namely, molten steel and slag are continuous phases initially separated by a sharp interface. The model was developed with the combination of two algorithms namely, IPSA (inter phase slip algorithm) where the gas bubbles are given a Eulerian approach since are considered as an interpenetrating phase in the two liquids and VOF (volume of fluid) in which the liquid is divided into two separate liquids but depending on the physical properties of each liquid they are assigned a mass fraction of each liquid. This implies that both the liquid phases (steel and slag) and the gas phase (argon) were solved for the mass balance. The Navier–Stokes conservation equations and the gas-phase turbulence in the liquid phases were solved in combination with the standard k-ε turbulence model. The mathematical model was successfully validated against flow patterns obtained experimentally using particle image velocimetry (PIV) and by the calculation of the area of the slag eye formed in a 1/17th water–oil physical model. The model was applied to an industrial ladle to describe in detail the turbulent flow structure of the multiphase system.
Luis Enrique Jardón Pérez, Adrián Amaro-Villeda, A. N. Conejo, Carlos González-Rivera, and Marco A. Ramírez-Argáez
Informa UK Limited
ABSTRACT The hydrodynamic performance of a gas-stirred ladle is analyzed experimentally, through a factorial experimental design, through physical modeling and particle image velocimetry techniques, to find the effects of the nozzle position, and its number, the gas flow rate and the presence or not of an oil layer on the flow velocity field, the turbulent kinetic energy distribution, and the open eye area, A. Flow patterns changed drastically in the presence of one or two plugs and as a result of the nozzle’s positions. The turbulent flow fields showed significant differences under the presence or absence of an oil layer and the open eye area strongly depends on the gas flow rate, the position and the number of nozzles. Responses , , and A were statistically processed to identify the relevant effects of each variable on , , and A. These responses were used to calculate the optimum process conditions that minimize A and maximize both and , and then improve mixing efficiency in ladles using multi-objective optimization through the genetic algorithm (GAmultiobj). A Pareto characterization and its analysis were performed to reveal the embedded operation rules allowing optimum performances of the ladle for specific production goals.
Diego Abreu-López, Adrián Amaro-Villeda, Francisco Acosta-González, Carlos González-Rivera, and Marco Ramírez-Argáez
MDPI AG
A mathematical model was developed to describe the hydrodynamics of a batch reactor for aluminum degassing utilizing the rotor-injector technique. The mathematical model uses the Eulerian algorithm to represent the two-phase system including the simulation of vortex formation at the free surface, and the use of the RNG k-e model to account for the turbulence in the system. The model was employed to test the performances of three different impeller designs, two of which are available commercially, while the third one is a new design proposed in previous work. The model simulates the hydrodynamics and consequently helps to explain and connect the performances in terms of degassing kinetics and gas consumption found in physical modeling previously reported. Therefore, the model simulates a water physical model. The model reveals that the new impeller design distributes the bubbles more uniformly throughout the ladle, and exhibits a better-agitated bath, since the transfer of momentum to the fluids is better. Gas is evenly distributed with this design because both phases, gas and liquid, are dragged to the bottom of the ladle as a result of the higher pumping effect in comparison to the commercial designs.
Luis E. Jardón-Pérez, A. López-Gutierrez, Alfredo Vazquez, C. González-Rivera, and M. A. Ramirez-Argaez
Cambridge University Press (CUP)
AbstractLadle refining plays a key role in achieving the quality of the steel since in this reactor temperature and chemical composition is adjusted, elimination of non-metallic inclusions is performed, and also deoxidation and desulphurization are operations taking place in the refining process. Specifically, the metal-slag mass exchanges have not received much attention through scientific studies. In this work, a rigorous study on the mass exchange between metal and slag is presented through a scaled water physical model. In the model, thymol (playing the role of a solute such as sulfur) is added to the water (playing the role of steel) and silicon oil (playing the role of slag) picks up the thymol, while the ladle is agitated with the central injection of gas. The evolution of thymol concentration in time was measured. Also, a mathematical model was developed and cast into the commercial CFD code Fluent Ansys to represent the fluid flow phenomena and the mass transfer through the solution of the continuity equation, the turbulent momentum conservation equations and the species mass conservation equation. There is a good agreement between the measured and the computed results regarding the thymol concentration evolution in water and consequently the mathematical model was validated regarding the mass species metal-slag exchanges and it may be used to study metal-slag exchanges in the steel ladle such as deoxidation or desulphurization.
M. Ramírez-Argáez, D. Abreú López, and C. González Rivera
Cambridge University Press (CUP)
ABSTRACTRecent studies on aluminum degassing [1, 2] show that although the impeller speed and the gas flow rate are important process variables in terms of the productivity and operational costs, the impeller design is also a key design parameter influencing the productivity and the quality of the aluminum in foundry shops. In this work, an improved design of an impeller is tested through a water physical model and mathematical modeling and its performance is compared against commercial designs of impellers. A full-scale water physical model of a batch aluminum degassing unit was used to test the impellers by using the same operating conditions (580 rpm and 40 liters per minute) and by performing deoxidation from water by purging nitrogen into the water saturated with oxygen (similar to the dehydrogenation). A mathematical model based on first principles of mass and momentum conservation equations was developed and solved numerically in the commercial CFD code ANSYS Fluent to describe the hydrodynamics of the system with the objective of explaining the deoxidation kinetics observed in the experiments. It has been found that the new impeller design shows a better performance than the commercial designs in terms of degassing kinetics for the conditions used in this study, which is explained since the new design promotes a flow dynamics that increases the pumping effect, creating a bigger pressure drop and fluid flow patterns which help to drag and distribute more evenly the bubbles in the entire ladle than the commercial designs.
Marco Ramírez-Argáez and Carlos González-Rivera
Springer International Publishing
Ladle refining plays a key role in achieving the quality of the steel. Specifically the metal-slag mass exchange is studied through a scaled water physical model in which thymol, a solute, is added to the water (steel) and silicon oil (slag) picks up the thymol, while the ladle is agitated with the central gas injection and samples of water were taken to track the thymol concentration with time with a UV-visible spectrophotometer. Also, a mathematical model was developed and solved with the CFD code Fluent Ansys to represent the fluid flow and the mass transfer phenomena through the solution of the continuity, the turbulent momentum conservation and species mass conservation equations. A good agreement between the measured and the computed results regarding the thymol concentration evolution in water was found so the model was validated and it may be used to study metal-slag exchanges in the steel ladle.
Ernesto Mancilla, Wiener Cruz-Méndez, Isaías E. Garduño, Carlos González-Rivera, Marco Aurelio Ramírez-Argáez, and Gabriel Ascanio
Elsevier BV
Abstract The hydrodynamic performance of a stirred ladle, for an aluminum degassing system in turbulent regime, is analyzed experimentally. This study explores the dynamic flow features due to the bubble dispersion on the gas–liquid flow. Diverse impellers with geometrical differences are tested with the purpose of comparing the influence in the flow behavior. Three rotor-injector devices are compared, including two conventional designs and one new rotor design. The rotor performance is evaluated at two gas flow rates. The velocity fields are investigated in a water physical model under flow conditions similar to those encountered in the degassing process of molten aluminum. The particle image velocimetry (PIV) technique is employed to obtain the velocity fields during the degassing process. In such a way, instantaneous measurements of the water flow field for gassed and ungassed conditions were obtained. Considering the two gassing conditions, it is found that the flow patterns changed drastically with all the rotors tested. Moreover, the turbulent flow field results showed significant differences under gassing and ungassed conditions. Here, it is demonstrated that the rotor geometries strongly affect the distribution of turbulent intensities. It was found that the new rotor exhibits the better performance under gassed conditions, showing high turbulent intensities, producing a higher gas breakup rate and promoting the formation of small bubbles that can be easily distributed over the entire ladle. This is due to its asymmetrical geometry, as is exposed in the present analysis.
M. Hernández-Hernández, J.L. Camacho-Martínez, C. González-Rivera, and M.A. Ramírez-Argáez
Elsevier BV
Abstract A physical model of a batch aluminum degassing reactor equipped with the rotor-injector technique was used to measure deoxidation kinetics of water, assuming that this kinetics is similar to dehydrogenization of aluminum. Performances of three different impeller designs were tested with the model, two of them available commercially, while the third one is a design proposed in this work, which shows a better performance than the two commercial designs reducing the degassing time between 14% and 34%, the gas consumption between 14% and 32%, and an increment in gas efficiency between 22% and 49% compared with the commercial designs. Performance of the impellers in aluminum was tested in a pilot degassing unit, and again, the impeller design proposed showed a better performance by reducing the amount of hydrogen in liquid aluminum after 10 min of degassing 1/2 respect to the commercial design A and 2/3 respect to the design B.
Juan A. López, Marco A. Ramírez-Argáez, Adrián M. Amaro-Villeda, and Carlos González
Cambridge University Press (CUP)
ABSTRACTA very realistic 1:17 scale physical model of a 140-ton gas-stirred industrial steel ladle was used to evaluate flow patterns measured by Particle Image Velocimetry (PIV), considering a three-phase system (air-water-oil) to simulate the argon-steel-slag system and to quantify the effect of the slag layer on the flow patterns. The flow patterns were evaluated for a single injector located at the center of the ladle bottom with a gas flow rate of 2.85 l/min, with the presence of a slag phase with a thickness of 0.0066 m. The experimental results obtained in this work are in excellent agreement with the trends reported in the literature for these gas-stirred ladles. Additionally, a mathematical model was developed in a 2D gas-stirred ladle considering the three-phase system built in the physical model. The model was based on the Eulerian approach in which the continuity and the Navier Stokes equations are solved for each phase. Therefore, there were three continuity and six Navier-Stokes equations in the system. Additionally, turbulence in the ladle was computed by using the standard k-epsilon turbulent model. The agreement between numerical simulations and experiments was excellent with respect to velocity fields and turbulent structure, which sets the basis for future works on process analysis with the developed mathematical model, since there are only a few three-phase models reported so far in the literature to predict fluid dynamics in gas-stirred steel ladles.
Marco Ramírez-Argáez, Enrique Jardón, and Carlos González-Rivera
Cambridge University Press (CUP)
ABSTRACTIn this study a process analysis of the melting process of solid particles in a bath of same composition is performed using both experimental information and theoretical computations. An experimental setup was used to measure the thermal histories and to follow the evolution with time of the size of solid metallic spherical particles being melted in a metallic bath of same composition. For such a purpose, pure aluminum was used during the experiments for both solid particles and liquid bath. A mathematical model was also developed based on first principles of heat transfer to simulate the melting kinetics of a cold metallic spherical particle immersed in a hot liquid bath of same composition. The mathematical model was reasonably validated when compared against the experimental results obtained in this work. A process analysis of the melting process was performed to determine the effect of the initial temperature and size of the solid particle, the bath temperature and the convective heat transfer coefficient on the melting time and on the energy consumption.The analysis showed that the variable presenting the most significant effect on both the melting time and the energy consumption is the convective heat transfer coefficient between the particle and the bath, since an increment in such a parameter accelerates the melting process and saves energy. Therefore, proper stirring of the bath is highly recommended to enhance the melting of metallic alloying additions in the metallic baths.
C. Gonzalez-Rivera, M. Morua, and M. Ramirez-Argaez
AIP Publishing LLC
A methodology is proposed to obtain the grain growth coefficients operating during solidification of a near eutectic Al-Ni alloy from data on solid fraction evolution, latent heat of solidification and., volume grain density. These parameters are obtained using Newton Thermal Analysis (NTA), metallographic methods and the Free Growth Method (FG). In order to validate the methodology a heat transfer-solidification kinetics model was implemented. Results suggest that this methodology could be applied to obtain useful information needed to simulate grain growth during eutectic solidification.
Marco Ramírez-Argáez, Enrique Jardón, A. N. Conejo, and Carlos González-Rivera
AIP Publishing LLC
In this study a process analysis of the melting process of solid particles in a bath of its own composition is performed using both experimental information and theoretical computations. An experimental setup was used to measure thermal histories and the evolution of the size of metallic solid spherical particles with time, being melted in a metallic bath of its own composition. For such a purpose pure aluminum was used during the experiments for both solid particles and liquid bath. Also, a mathematical model was developed based on first principles of heat transfer to simulate melting kinetics of a cold metallic spherical particle immersed in a hot liquid bath of its own composition. The mathematical model was reasonable validated when compared against the experimental results obtained in this work. A process analysis of the melting process was performed to determine the effect of the initial temperature and size of the solid particle, the bath temperature and the convective heat transfer coefficient on the melting time and on the energy consumption. From the analysis it was found that the variable presenting the most significant effect on both the melting time and the energy consumption is the convective heat transfer coefficient between the particle and the bath since an increment in such a parameter accelerates the melting process and saves energy. Therefore, proper stirring of the bath is highly recommended to enhance the melting of metallic alloying addition to metallic baths.