Baokuan Li

• Northeastern University

A transient three-dimensional (3D) comprehensive model has been developed to study the solidification and macrosegregation of electroslag remelted H13 steel. The electromagnetic phenomenon, heat transfer, two-phase flow, and solute transport during the remelting and hot topping stages are included. The growth of ingots is achieved by the dynamic la...

The rapid change of the slag-metal interface and flow pattern is the main factor causing the abnormal increase of inclusions. Therefore, a 1/4-scale water model experiment and three-phase simulation was established to study the flow pattern transition, slag entrainment and slag eye evolution in a two-strand continuous casting tundish under quasi-st...

In this study, a coupled multiphysics field model combining finite‐element and finite‐volume modeling is developed to investigate the effect of fusion‐welded component geometric dimension on electroslag fusion welding (ESFW) process, and the reliability of the model is verified experimentally. In the results, it is shown that for fusion‐welded part...

The CFD-PBM model (Euler–Euler model coupled with a population balance model) is proposed in this study. A mathematical framework based on the coupled CFD-PBM decarburization process is established, considering decarburization reactions at three primary locations: the surface of the Ar bubbles, the free surface of the vacuum chamber, and the steel...

A three-dimensional flow-heat transfer-solidification coupled model was developed based on the finite element method to simulate the shrinkage cavity and porosity defects of a novel nickel-based cast superalloy K4800. The influence of pouring and preheating temperatures on shrinkage volume, Niyama value at the solidification front, temperature grad...

This study employs computational fluid dynamics (CFD) coupled with the population balance model (PBM) to explore the sensitivity of the drag model for the predictive accuracy of the gas–liquid two-phase flow in continuous casting (CC) mold. Several single bubble drag models have been numerically evaluated for high turbulent intensity and gas flow r...

Limited quantitative research exists on the complex phenomenon of slag splashing in converters. A comprehensive modeling framework is developed to fill this gap, integrating a 3D two‐phase flow model with a volume of fluid‐discrete phase model two‐way conversion model. This framework explores droplet behavior during splashing for converter protecti...

High-temperature titanium alloys, with the advantages such as low density, high specific strength, and excellent high-temperature creep resistance, are critical structural materials for achieving weight reduction and improving thrust-to-weight ratio in aerospace engines. The primary method for industrial production of titanium alloy ingots is Vacuu...

Current intensity is a critical parameter in the vacuum arc remelting (VAR) process, significantly impacting the molten pool, solidification structure, and ultimately, the quality of the ingot. This study establishes a transient electromagnetic-fluid-thermal-solidified coupled model to examine the effects of current intensity on the shape of molten...

In addressing the retrofitting issues of conventional non-induction heating tundish, a novel butterfly-type induction heating tundish model was devised. A three-dimensional coupled mathematical model of magnetic, thermal, and fluid fields was established to investigate the temperature distribution, flow characteristics, and temperature rise curves...

Strand electromagnetic stirring (SEMS) is widely applied in thin-slab continuous casting to promote the equiaxed crystal ratio (ECR). However, the effects of alternate electromagnetic stirring on the evolution of solidification macrostructure and ECR remain poorly understood. And the formation of the equiaxed crystal region beneath the stand and eq...

An 1/4 ladle water model is build, a differential flow bottom blowing method with different flow ratios is proposed, and an Eulerian multiphase flow model which coupling of the Eulerian model and the Volume of Fluid (VOF) interface tracking method was established to study the flow field, mixing time, slag eyes area and its fluctuation in ladle wate...

Established a 1/4 water model experimental system to study the mixing phenomenon and slag eye during ladle refining process. On the basis of traditional equal flow bottom blowing method, differential flow bottom blowing methods with different flow ratios were proposed, the optimal bottom blowing ratio that minimizes mixing time and slag eyes area w...

The flow pattern in an opaque mold cannot be readily visible, and worker experience plays a major role in controlling it, even though it has a significant impact on slab quality in a continuous casting (CC) mold. An Eulerian–Eulerian two‐fluid model is used to comprehensively study the two‐phase flow of argon and molten steel in a slab CC mold. The...

Metal-based additive manufacturing methods is exerting a high degree of freedom to expand product design ideas and weaken manufacturing obstacles. However, the regulation of microstructure is still one of the challenges in constructing high-precision parts. The numerical simulation has excellent accuracy and economy in predicting the evolution of m...

A transient three-dimensional (3D) coupled model is developed to investigate the melting and rotation of the solid electrode during the electroslag remelting (ESR) process. The large eddy simulation (LES) method is utilized to model the multiphase flow. The slag/metal interface is precisely tracked utilizing the volume of fluid (VOF) approach with...

As an essential slagging raw material in blast furnace iron making, quicklime, which requires high chemical activity, is produced in parallel flow regenerative(PFR)lime kilns. The PFR lime kiln supports a wide range of fuels and can calcine a wide range of particle sizes while maintaining a high reactivity, which enhances the high temperature hard-...

Electromagnetic braking (EMBr) is critical for suppressing the turbulence in the mold and developing a high-speed thin-slab continuous casting technology. The main problem is that the relationship between EMBr strength and flow patterns in a funnel mold is still inconclusive. Effects of magnetic induction intensity on the flow pattern and slag-meta...

Strand electromagnetic stirring (SEMS) is widely applied in thin slab continuous casting to improve the equiaxed crystal ratio (ECR) of steel. To provide a deeper insight into the role of SEMS in controlling the flow pattern, superheat transportation, macrosegregation, and as-cast structure in the whole strand. A three-phase equiaxed-columnar solid...

The slag droplet entrainment is a common phenomenon in steel refining processes, which may lead to inclusions and defects. In the multiphase flow system, the distinct interface and tiny blobs possess a wide range of spatial and temporal scales and make it hard to be simulated. In numerical methods, the volume of fluid (VOF) approach is appropriate...

The ferrochrome settling behavior significantly affects the smelting performance of a submerged arc furnace. This paper presents a three-dimensional (3D) transient mathematical model simulating the complex multiphase flow and thermochemical phenomena inside an industrial furnace. Via the model, the smelting phenomena are clarified in terms of elect...

Submerged arc furnace is a smelting device with high efficiency but huge electricity consumption. A novel structure of direct current (DC) submerged arc furnace is investigated for ferrochrome production to save electric energy. For this purpose, a three-dimensional transient multi-physics model is developed to simulate this arc furnace. Via the mo...

During the electroslag remelting (ESR) process, the effect of dynamic formation of slag skin on magneto-hydrodynamic multiphase flow and temperature field is studied using a 2-D axisymmetric model. The electromagnetic field is described by user-defined functions. The dynamic formation and distribution of multiphase slag skin, as well as the interfa...

The ferrochrome settling behavior significantly affects the smelting performance of a submerged arc furnace. This paper presents a three-dimensional (3D) transient mathematical model simulating the complex multiphase flow and thermochemical phenomena inside an industrial furnace. Via the model, the smelting phenomena are clarified in terms of elect...

The blowing flow is a key factor in molten bath stirring to affects the steel-bath interface fluctuation and chemical reaction in the top-bottom-blowing converter. The Volume of Fluid (VOF) method is widely used to capture the gas-liquid interface. However, some limitations exist in dealing with the interface curvature and normal vectors of the com...

The slab heating process inside a walking-beam reheating furnace is critical for slab quality. This paper presents a comprehensive CFD model simulating the fuel combustion, flow field, temperature distribution , and heating process of walking slabs in an industrial-scale furnace. It explicitly considers the effects of dislocated skids and skid butt...

In the electroslag remelting (ESR) process, low‐frequency power supply can significantly reduce power consumption and achieve three‐phase balance of power supply. Therefore, a transient coupling model of fluid flow, heat transfer, and component transport in the ESR process, which is coupled to the electromagnetic field calculated using Maxwell 3D s...

To get a basic understanding of the solute transportation and chemical inhomogeneity in directional columnar structures, the anisotropic permeability law was integrated into a volume-averaged columnar solidification model. Ten isotropic and anisotropic permeability laws were adopted to discuss the effect of the mushy zone permeability on macrosegre...

The production of fused magnesia is a process in which raw materials are melted and recrystallized in the electric-fused magnesia furnace (EFMF). Temperature is the key factor that affects production, but it is difficult to be observed and monitored due to the high internal temperature. Thus, the working current is the standard for workers to judge...

Single Snorkel Furnace (SSF) vacuum refining furnace is a novel external refining equipment for high clean steel production. RH is a molten steel refining technology developed by Rheinstahl-Heraeus company. Compared with the traditional RH furnace, the SSF furnace has the advantages of a simple structure, high refining efficiency, and low productio...

In the direct energy deposition (DED) process, the highly energetic laser, rapid melting, and solidification processes lead to complex heat transfer and flow phenomena. A three-dimensional finite element model (FEM) is established to study the effect of process parameters on the melt pool and solidification quality during the DED process. The heat...

The volume-averaged solidification model has generated considerable research interest in metallurgical areas. The model is complicated but flexible to address many problems faced. However, few previous studies focused on the role of the growth direction of the columnar crystal axis in this model. The current work aims to integrate the columnar grow...

A multi-physics coupling model is developed to study the effect of the electric current path on the electroslag remelting (ESR) process. The electromagnetic field is calculated in the whole system including the molten slag, solidified slag, ingot and mold by the finite element method (FEM), while the two-phase flow, heat transfer, and solidificatio...

The steel strip feeding process can effectively improve the macrosegregation, central porosity, shrinkage, cracking, and other defects of continuous casting (CC) round blooms. Based on the volume-averaged method, a three-phase mix columnar-equiaxed solidification model is established, which considers the nucleation, growth of the columnar and equia...

The electromagnetic stirring force generated by the axial magnetic field (AMF) interacting with the process current greatly affects the solidification process and consequently the metallurgical quality of ingots, but there are few studies about the effect of AMF on the multi-physics field involving solute transport during VAR process. Based on this...

A better understanding of the interaction between particle and the wall in rotating drums is of great interest. Two Fluid Model (TFM) coupled with kinetic theory of granular flow (KTGF) is used for investigating the wall shear stress of particle phase in a rotating drum. The distribution characteristic of wall shear stress and the effects of operat...

Limestone of different particle sizes is often calcined together to improve production efficiency, but the calcination effect of mixed particle size limestone is difficult to guarantee. To investigate the effect of different particle size combinations on calcination, this study uses a porous media model and a shrinking core model to simulate the ca...

Quicklime is an essential reducing agent in the steel smelting process and its calcination from limestone is accompanied by considerable energy consumption. As a relatively economical lime kiln, the Parallel Flow Regenerative (PFR) lime kiln is used as the main equipment for the production of quicklime by various steel industries. PFR lime kilns ge...

Multi-size bubbly flow in a one-quarter-scale water model of a continuous casting mold was simulated using the inhomogeneous multiple size group (IMUSIG) model. The Sauter mean bubble diameter, gas volume fraction, interfacial area density, turbulence kinetic energy, and velocity field predicted by the IMUSIG and multiple size group (MUSIG) models...

The arc characteristics especially the arc distribution of the vacuum arc remelting (VAR) process are closely related to the ingot evolution and consequently the final product quality. Taking segregation defects and solidification quality as the indexes to evaluate the final product quality under different arc distributions, a three-dimensional ful...

As an excellent reducing agent, lime has an important role in the steel production process. Annular Shaft Kiln (ASK) has been widely used in the lime production industry for its low cost, low footprint, high chemical activity, easy construction, and easy maintenance. Due to the high temperature generated inside ASK during operation, it is hard to o...

The desulfurization behavior in the electromagnetically controlled vibrating-electrode electroslag remelting (ESR) furnace was analyzed, modeled, and numerically simulated. A new transient fully coupled mathematical model with the magneto-hydro-dynamic (MHD) multiphase method based on the dynamic mesh-based approach has been developed. Results demo...

The two-fluid model (TFM) coupled with the kinetic theory of granular flow (KTGF) has gradually been used for modeling dense granular flows and mixing in rotating drums in recent years. In the present paper, a review is made from the perspective of model development and model application. It is found that several frictional viscosity models were pr...

Segregation defects greatly affect the service performance and working life of castings during the vacuum arc remelting (VAR) process. However, the corresponding research on the prediction of segregation defects is still not comprehensive. Through considering the influence of water-cooled crucible on the electromagnetic field inside an ingot, a ful...

A walking beam type reheating furnace with advanced control technology has been evaluated by combined energy and exergy analysis. In order to gain insight into the performance of the present furnace, the results of energy analysis are compared with those in published papers and the irreversibility of the furnace is analyzed via exergy destruction c...

In order to meet the requirement of high-quality ingots, the vibrating electrode technique in the electroslag remelting (ESR) process has been proposed. Non-metallic inclusions in ingots may cause serious defects and deteriorate mechanical properties of final products. Moreover, the dimension, number and distribution of non-metallic inclusions shou...

A population balance model based on the multiple-size-group (MUSIG) approach was developed to investigate the multi-size bubbly flow in a slab continuous casting mold. Firstly, effects of the bubble size group number, the initial bubble diameter, and the calibration factors for breakage and coalescence in MUSIG model on the multi-size bubbly flow w...

A comprehensive transient model is developed to study the effect of electrode rotation on the evolution of metal pool profiles and the solidification quality of ESR ingots. Magnetohydrodynamic flow, heat transfer, solidification, and electrode melting are considered simultaneously in the model. The growth of the ESR ingot is predicted using the dyn...

A three-dimensional transient multi-physical field model with comprehensive reduction reaction consideration has been developed to capture the complex processes of a three-phase submerged arc furnace. The multi-physics model integrates electromagnetic, fluid flow, reduction reaction, and thermodynamics phenomenon in unison computational framework....

A transient three-dimensional mathematical model is developed to study the slag entrapment in a continuous-casting mold. The unsteady turbulent flow is computed using the large eddy simulation (LES). The sub-grid scale structure is modeled by Smagorinsky–Lilly model. The movements of discrete bubbles, as well as three continuous phases (air-slag-st...

Feeding a steel strip into a continuous casting (CC) mold is an effective method for improving the internal quality of CC slabs. An alloy experiment and three-phase mixed columnar-equiaxed solidification modeling were used to investigate the solidification structure evolution during the cold strip feeding process. The Euler method was adopted to tr...

The present investigation demonstrates the transient multiscale bubble behaviors including the bubble homogeneous nucleation, continuous growth, disordered collision and coalescence, and disturbed detachment under the anode in the CuSO4 aqueous solution electrolysis process by experimental and numerical methods. The combined approach of the volume...

Electromagnetic fields have emerged as powerful tools for addressing current problems in thin slab continuous casting processes in the iron and steel industry. Substantial studies have been undertaken on the fundamental effects of electromagnetic brakes (EMBr) and strand electromagnetic stirring (SEMS). However, little attention has been focused on...

Purging plugs are widely used in the secondary refining process, and its service life determines the downtime and usage efficiency of the whole ladle. This study focuses on comparing the heat transfer and thermomechanical behaviour of purging plug with different slits to obtain the reason for the long service life of purging plug by thermal-structu...

A ¼-scale water-model experiment is conducted to investigate the trajectories, velocities and size distribution of bubbles in a continuous-casting mold. A high-speed camera and a laser are used to record the transient bubble distribution. The region of interest is delimited to include the motion range of floating bubbles in the upper mold, and divi...

The main objective of this paper is to establish a mathematical framework to analyze the complex material and energy performance of the calcinations process based on the fundamental mass and energy conservations. The synergy degree of vital order parameters was defined and evaluated to assess the status and order of the calcination process. Further...

The main objective of this paper is to establish a mathematical framework to analyze the complex thermal economic performance of the calcination process. To find the factors affecting exergy efficiency loss, different exergy destruction is investigated in detail. Furthermore, the exergy flow cost model for exergy cost saving has also been developed...

In order to investigate the solute distribution and freckles formation during directional solidification of superalloy ingots, a mathematical model with coupled solution of flow field, solute and temperature distribution was developed. Meanwhile, the reliability of this model was verified by the experimental and simulation results in relevant liter...

A transient 3D integrated model has been developed to investigate the role of a rotating electrode on the improvement of productivity and refining ability in the electroslag remelting process. All essential considerations of the fluid flow, heat transfer, and inclusion removal are incorporated in the model. The electrode melting rate is predicted b...

In order to decrease total oxygen content, vacuum electroslag remelting is developed. Vacuum refining is supposed to be conductive to deep degassing in steelmaking process, such as carbon monoxide. A transient model coupling the magnetohydrodynamic flow and heat transfer was therefore proposed to investigate the effect of vacuum on oxygen control d...

An electroslag remelting process (ESR) with the two series-connected electrodes has the advantage of little inductance, lower power consumption and high melting rate, which is used to produce large-scale or rectangular ingot. A transient three-dimensional multi-physical field model has been developed to understand the two-phase flow and heat transf...

Electroslag remelting (ESR) is a secondary refining technique with consumable-electrode used in manufacturing high performance and high added-value materials. The ingot quality depends on the macrosegregation of solute elements and distribution of inclusions. A mathematical method has been developed to understand the solute transport and inclusion...

A transient coupled model has been developed to investigate the effect of remelting atmosphere on the oxygen transfer during electroslag remelting (ESR) process. The electromagnetics, three-phase flow, heat transfer and species transport were solved simultaneously. The Lorentz force and Joule heating were incorporated into the momentum and energy c...

Size-induced particle segregation in rotating drums has been investigated using an Eulerian continuum approach (ECA). The mixing processes of a binary mixture were respectively predicted in an unbaffled drum, a drum with a “+” shaped central baffle and a drum with a “-” shaped central baffle. Qualitative comparisons with DEM results showed that ECA...

This paper aims to present a review of numerical models for the gas-steel-slag three-phase flow in gas-stirred ladles. The modeling frameworks is classified as: mixture model, interfacial model, multi-fluid model and Eulerian-Lagrangian (EL) model. The interfacial model is good at simulating the interfacial structure among phases, while the multi-f...

The three-dimensional (3D) transient mathematical models are developed to explore the single and multiscale bubble dynamics beneath the inclined downward-facing surface of the anode in the aluminum reduction cell. The single bubble motion is traced by the volume of fluid (VOF) method. For the multiscale bubble, the discrete phase model (DPM) combin...

Circular slits are introduced in purging plugs for alleviating the stress concentration to prolong their service life. The effects of slits with different geometries on the mixing time, inclusion removal rate, and slag eye area were studied herein, by water model method. Experimental results show that the inclusion removal rate decrease with increa...

Ladle baking technology is a widely adopted method in the iron and steel industry. For reducing defects such as center segregation of billet, it is crucial to minimize the heat loss of molten steel; maintaining a high drawing speed and low superheat during the continuous casting process. Nevertheless, it is well known that the traditional air combu...

The composition analysis, inclusion and microstructure characterizations for two ingots processed by Ar gas protective electroslag remelting (ESR) and vacuum ESR as well as thermodynamic calculation were carried out to explore mechanisms of cleanliness improvement and microstructure refinement of ingot processed by vacuum ESR. The results show that...

With increasing demands for high quality and ultra-low oxygen grade steel, the electroslag remelting process carried out under vacuum has been developed. A transient model coupling the magnetohydrodynamic flow, heat transfer and species transport was proposed to study the effect of vacuum on oxygen transfer during the electroslag remelting process....

To investigate the fracture behavior of cement-bonded corundum castables, various cement contents and pre-treating temperatures have been comparatively studied using the wedge splitting method and the digital image correlation technique. The results show that the microstructure enhances the mechanical properties, so the fracture energy and the maxi...

Five heats were carried out to study the effects of SiO 2 containing slag for electroslag remelting (ESR) on inclusion characteristics of 42CrMo steel. Fluoride vaporization at elevated temperature from slags was also explored by thermogravimetric analysis. The results show that fluoride vaporization is dominated by slag viscosity and component act...

The cement-bonded corundum castables are often subjected to great temperature gradient in the service process of purging plugs for refining ladle. The mechanical properties of such castables are of particular interest in the serviceability and the safety of purging plug, which are significantly influenced by the microstructures including the amount...

This work deals with the effects of the contact angle as an essential factor in bubble motions underneath downward-facing surfaces of the anode in the aluminum reduction cell. First, a transient three-dimensional (3D) mathematical model is employed to study a single bubble motion with the volume of fluid (VOF) method. In addition, a transient 3D mo...

The structure, vaporization behavior and crystallization of CaF2–CaO–Al2O3 slags with different SiO2 contents for electroslag remelting were investigated by employing the TG and DSC measurements in conjunction with the Raman spectroscopy measurement for linking the macroscopic physicochemical property and microstructure information. The results sho...