LES-Modelling and Experimental Investigation of the Melt Flow in Induction Furnaces (original) (raw)
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Metallurgical and Materials Transactions B, 2018
In the paper, a new water model of the turbulent recirculating flow in an induction furnace is introduced. The water model was based on the principle of the stirred vessel used in process engineering. The flow field in the water model was measured by means of particle image velocimetry in order to verify the model's performance. Here, it is indicated that the flow consists of two toroidal vortices similar to the flow in the induction crucible furnace. Furthermore, the turbulent flow in the water model is investigated numerically by adopting eddy-resolving turbulence modeling. The two toroidal vortices occur in the simulations as well. The numerical approaches provide identical time-averaged flow patterns. Moreover, a good qualitative agreement is observed on comparing the experimental and numerical results. In addition, a numerical simulation of the melt flow in a real induction crucible furnace was performed. The turbulent kinetic energy spectrum of the flow in the water model was compared to that of the melt flow in the induction crucible furnace to show the similarity in the nature of turbulence.
Modeling of the turbulent flow in induction furnaces
Metallurgical and Materials Transactions B, 2006
Experimental results show that heat- and mass-transfer processes in recirculating turbulent flows, which comprise several vortexes of the mean flow, are significantly influenced by low-frequency large scale flow oscillations. The large eddy simulation (LES) model reproduces with good conformity not only these oscillations together with the dynamics of the macroscopic coherent structure, but also the turbulent energy transfer. Numerical studies,
Numerical modelling of recirculated liquid metal flows in induction furnaces with the cold crucible
Magnetohydrodynamics
The experimental and numerical investigations of the turbulent melt flow are carried out in various laboratory and industrial sized induction furnaces, like induction crucible furnace and induction furnace with cold crucible. The results of the transient 3D LES simulation of the turbulent melt flow revealed the large scale periodic flow instabilities and the temperature distribution in the melt, which both are in good agreement with the expectations based on the data from the experiments. In order to investigate convective heat and mass transport mechanisms in the considered flow the discrete particle tracing approach has been carried out. The studies, presented in this paper, contain the numerical simulation of turbulent melt flow of experimental and industrial size induction furnaces and demonstrate the possibility of using the three-dimensional transient LES approach for successful simulation of heat and mass transfer processes in metallurgical applications.
Magnetohydrodynamics
The paper presents new results of the long-term computations of turbulent flow and low-frequency oscillations of the temperature field in the industrial induction channel furnace (ICF) with a widened channel branch and different iron yoke positions. The computations of turbulent heat and mass exchange in the melt are performed using a 3D transient Large Eddy Simulation (LES) approach. A 3D electromagnetic (EM) model was used for Lorentz force density computations, which act as a source term in the Navier-Stokes equations of the melt flow. The distributions of alloying additions into the melt and disjointed impurities due to channel erosion are discussed for a symmetrical ICF and an ICF with one widened branch of the channel. Cloud distributions and particle trajectories are obtained using a Lagrangian approach along with LES modelled velocity and thermal fields. A long-term analysis of the particle transport for industrial ICFs has been performed for the first time.
The computations of electromagnetic (EM), hydrodynamic (HD) and thermal fields based on developed 3D models are performed for: i) almost axis-symmetrical MHD-device with bottom and submerged and non-submerged top electrodes with single phase alternating current (AC) and cylindrical coil around the melt; ii) MHD-device with three-phases current supplied over three submerged top electrodes as well as with EM stirrer, which is the side non-symmetrical inductor, the source of "travelling" magnetic field. Obtained flow patterns are the results of competition of electro-vortex convection (EVC) and electromagnetic convection (EMC), which appear due to conductive and inductive current supply accordingly. For axis-symmetrical MHD-device the melt rotation appears as the cross effect of interaction of inductive or conductive current with magnetic fields, produced by other type of power supply. For axis-symmetrical MHD-device with non-submerged top electrode the intensity of EVC is for an order greater then intensity of termogravitational convection (TGC).
Numerical studies of the melting process in the induction furnace with cold crucible
COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 2008
Purpose-Aims to present recent activities in numerical modeling of cold crucible melting process. Design/methodology/approach-3D numerical analysis was used for electromagnetic problem and 3D large eddy simulation (LES) method was applied for fluid flow modeling. Findings-The comparative modeling shows, that higher H/D ratio of the melt is more efficient when total power consumption is considered, but this advantage is held back by higher heat losses through the crucible walls. Also, calculations reveal that lower frequencies, which are energetically less effective, provide better mixing of the melt. Originality/value-3D electromagnetic model, which allows to take into account non-symmetrical distribution of Joule heat sources, together with transient LES fluid flow simulation gives the opportunity of accurate prediction of temperature distribution in the melt.
The simulation of the motion of solid particles in the turbulent flow of induction crucible furnaces
The process of the motion of solid particles in the metal melt is simulated in the present paper. The model consists of the flow and the particles movement calculation at each time step. The simulation of the EM induction governed turbulent flow is carried out using the Large Eddy Simulation (LES) method with the Smagorinsky subgrid viscosity model. The motion of the solid non-conductive particles is simulated using the Lagrangian equation that takes into account drag, buoyancy, EM, lift, acceleration and added mass forces. The application of two models of the particle collisions with the wall (non-slipping by the wall and slipping by the wall) is analyzed for particles with different densities. The particles with different densities are considered. The typically scheme of the motion of the particle cloud is obtained and the regions of the concentration of big particles are estimated.
LES modeling of heat and mass transfer in turbulent recirculated ∞ows
2000
Experimental results show that heat and mass transfer processes in the turbulent melt ∞ow of induction furnaces are signiflcantly in∞uenced by low-frequency large scale os- cillations of the main ∞ow eddies. Large Eddy Simulation (LES) of the turbulent melt ∞ow in induction crucible furnace carries out with good conformity the transient three- dimensional oscillations of the dominating toroidal ∞ow eddies.