Computer modeling of coupled electromagnetic, temperature and magnetohydrodynamic fields in the induction heating and melting devices (original) (raw)
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Numerical Modeling of Cold Crucible Induction Melting
This paper describes a numerical solution method for the simulation of a cold crucible induction melting process involving the coupling of electromagnetic, temperature and turbulent velocity fields. The cold crucible induction melting (CCIM) is a process to melt extremely reactive alloys when purity is required. An example of such an alloy is titanium, which can be used for the manufacturing of medical implants, turbine blades and turbocharger rotors. During the CCIM process, the metal charge is contained on a water cooled segmented cooper crucible, and the energy necessary to heat, melt, and overheat the charge is generated by an electromagnetic field induced by a solenoidal coil surrounding the crucible. Once the charge is melted, the induced electromagnetic forces push the metal away from the wall. Hence, the electromagnetic field and the associated force fields are strongly coupled to the free surface dynamics of the liquid metal, the turbulent fluid flow within it, and the heat...
Iconic Research and Engineering Journals, 2019
Inductive heating is a fast and environmentally friendly heating method that employs eddy current resistance loses in heating of conducting materials. The eddy current being a product of magnetic induction process resulting from the electromagnetic fields generated by an induction coil powered by a high frequency voltage source. Due to the complexity of the system, the design of the induction heating systems often requires the use of mathematical and computer simulation tools which helps in shortening the development time and cost. Both analytical and computer modeling techniques were employed in this study. The analytical modeling was used in computing the electrical parameters of the induction coil that makes for optimal heating of the work-piece for any heating application while the computer modelling was used to investigate thermal dynamic characteristics of the inductively heated work piece. A 2-D axisymmetric computer model of a cylindrical graphite crucible work piece of dimensions (6 cm height, 2 cm external diameter and 1.5 cm internal diameter) was simulated in the study with 60 Amps excitation current at 100 kHz resonant frequency. A heating temperature of about 1386 oC was achieved around 600 seconds simulation time. The coil inductance of 0.03 mH was obtained for analysis using copper tube coil of radius 0.5 cm and coil diameter 7.5 cm. The derived parameters will then be used in the fabrication of the induction heating system for experimental validation of aluminum melting process.
Analytical, Numerical and Experimental Validation of Coil Voltage in Induction Melting Process
International Journal of Electromagnetics ( IJEL )
This paper presents, mathematical model of induction heating process by using analytical and numerical methods. In analytical method, series equivalent circuit (SEC) is used to represent induction coil and work piece. Induction coil and workpiece parameters (resistance and reactance) are calculated by standard formulas along with Nagaoka correction factors and Bessel functions. In Numerical method, magnetic vector potential formulation is done and finite element method (FEM) is used to solve the field equations. Analytically and numerically computed parameters such as equivalent coil resistance, reactance, coil voltage, work piece power are compared and found that they are in good agreement. Analytically and numerically obtained coil voltages at different frequencies are validated by experimental results. This mathematical model is useful for coil design and optimization of induction heating process.
Electromagnetic and thermal-flow modeling of a cold-wall crucible induction melter
Metallurgical and Materials Transactions B, 2005
An approach for modeling cold-wall crucible induction melters is described. Materials in the melt and melter are nonferromagnetic. In contrast to other modeling studies reported in the literature, the numerical models use commercial codes. The ANSYS finite-element code [1] is employed for electromagnetic field simulations and the STAR-CD finite-volume code [2] for thermal-flow calculations. Results from the electromagnetic calculations in the form of local Joule heat and Lorentz force distributions are included as source terms in the thermal-flow analysis. This loosely coupled approach is made possible by the small variation in temperature and, consequently, small variation in electrical properties across the melt as well as the quasi-steady-state nature of the thermal-flow calculations. A three-dimensional finite-element grid for electromagnetic calculations is adapted to a similar axisymmetric finite-volume grid for data transfer to the thermal-flow model. Results from the electromagnetic model compare well with operational data from a 175-mm-diameter melter. Results from the thermal-flow simulation provide insight about molten metal circulation patterns, temperature variations, and velocity magnitudes. Initial results are included for a model that simulates the formation of a solid (skull) layer on the crucible base and wall. Overall, the modeling approach is shown to produce useful results that relate operational parameters to the physics of steady-state melter operation.
Modelling induction melting energy savings
Electromagnetic processing of liquid metals involves dynamic change of the fluid volume interfacing with a melting solid material, gas or vacuum, and possibly a different liquid. Electromagnetic field and the associated force field are strongly coupled to the free surface dynamics and the heat-mass transfer. We present practical modelling examples of the flow and heat transfer using an accurate pseudo-spectral code and the k-omega turbulence model suitable for complex and transitional flows with free surfaces. The 'cold crucible' melting is modelled dynamically including the melting front gradual propagation and the magnetically confined free surrounding interface. Intermittent contact with the water-cooled segmented wall and the radiation heat losses are parts of the complex problem.
Thermal Engineering, 2012
Advanced energy saving technologies of induction heating of metals are discussed. The impor tance of the joint simulation of electromagnetic and temperature fields on induction heating is demonstrated. The package of specialized programs for simulating not only induction heating devices, but also technologies that employ industrial heating has been developed. An intimate connection between optimal design and con trol of induction heaters is shown.
Precise Induction Heating of Non-ferrous Cylindrical Billets
Asian Journal of Applied Sciences, 2014
Electromagnetic treatment of materials by induction is becoming more widely used in science and industry. The method of electromagnetic processing can be successfully used for melting and heat treatment of titanium and zirconium alloys. Different technologies using induction precise heating before plastic deformation are discussed in this paper. For alloys of many metals such as titanium, zirconium, niobium, tantalum, etc., it is important to provide precision heating with a high degree of homogeneity of the temperature field and strict adherence to the condition of heating. This is explained by polymorphism of these alloys, their chemical activity at high temperatures and the specific thermal and electrical properties. It is very important for induction heating to define the extreme achievable unevenness of the temperature field. Optimal control can be used for massive billets to reduce significantly the heating time, energy expenses and to improve the quality of the temperature field distribution. Optimization of induction heating process can be achieved by synchronous solution of the problem of optimal control and design. Keywordsinduction heating, the method of electromagnetic processing, non-ferrous alloys, precise heating _________________________________________________________________________________ 2. REQUIREMENTS AND PECULIARITIES FOR HEATING BILLETS FROM NON-FERROUS ALLOYS BY INDUCTION METHOD Unlike steel heating titanium heating has features associated with the physical and chemical properties of the material and with high demands of consumers for quality products in accordance with international and national standards in aviation industry. Requirements for heating billets from non-ferrous alloys: formation of an extremely possible uniform temperature field along the length and cross section of the billet; exclusion of overheating the billet; minimizing the heating time .
Numerical Simulation of Induction Heating of Steel Plate Products
2018
Main methods of induction heating of steel plate products are discussed in this paper. Different 2D and 3D models are developed for investigation and design of the induction coils for heating steel slabs and strip. A new concept of universal induction coils that allow using a combination of longitudinal and transverse flux for heating plate products is discussed in this paper. Keywords— Coupled electromagnetic and temperature fields, electromagnetic processing of metals, induction heating, multiphysics problems
The development of a numerical model for the melting process of Al-Ti alloy target material in vacuum induction furnace with cold crucible (VIFCC) was described. It is a two-dimensional computational methodology to calculate electromagnetic field, heat transfer field and fluid flow field. Based on the aid of the finite element method with the commercial software-ANSYS, a superimposition method of a layer of copper and a slit to simulate the VIFCC melting process was used. The method was effective to save large quantity of memory and computing time. Meanwhile, a temperature distribution profile during the melting process was obtained. Validity of the model was confirmed by comparison between the result from calculation and those from direct measurement by optical pyrometer and indirect investigation by ingot macrostructure. A relatively good agreement was found. Further, a nearly directional solidification structure was obtained under properly controlling the cooling rate and heating power. Therefore, such model developed in this article is feasible.