Department D 7 - Electrophysics

Laboratory of High Temperature Gas Dynamics

Laboratory of Coupled Problems in Electrical Engineering

Applications

Applications

The theory developed in the laboratory has been employed in the following application domains:

Induction heating (simultaneous and continuous), induction hardening, induction drying
We have developed an original integrodifferential model of continuous induction heating (the inductor slowly moves along the charge). The model is based on current densities both in the inductor (external and eddy currents) and heated charge (eddy currents). Only the active parts of the system need to be discretized and the boundary conditions are included in the kernel functions of the corresponding integrals. The principal advantage of the model is the elimination of remeshing of the solved arrangement at every time step (unlike in FEM). The drawback of the model is the necessity to work with dense matrices. Related papers P. Karban, I. Dolezel, P. Solin: Computation of General Nonstationary 2D Eddy Currents in Linear Moving Arrangements Using an Integro-Differential Approach, COMPEL 25, No. 3, 2006, pp. 635–641. P. Karban, I. Dolezel, P. Solin: Integrodifferential Model of Eddy Currents in Axisymmetric Nonmagnetic Bodies Heated by Moving Inductor, Archives for Electrical Engineering 54, No. 4, 2006, pp. 197–207. I. Dolezel, P. Karban, M. Donatova, P. Solin: Integrodifferential Approach to Solution of Eddy Currents in Linear Structures with Motion. Math. Comput. Simul. 80, Issue 8 (2010), pp. 1636–1646. I. Dolezel, P. Karban, P. Solin: Integral Methods in Low-Frequency Electromagnetics. Wiley, Hoboken, NJ, 388 pages.
Thermoelasticity generated by induction, thermoelastic setting of position, hot pressing
Thermoelasticity produced by induction heating is prospective in many industrial and laboratory applications. From the physical viewpoint, the process represents a triply coupled unsteady nonlinear problem with mutual interaction of electromagnetic, temperature and thermoelastic displacement fields. The problem must be often supplemented with the solution of the contact problem. We have developed numerical methods and algorithms for these problems in cooperation with the Ukrainian Academy of Sciences, Czech Technical University in Prague and University of West Bohemia in Pilsen. Related papers I. Dolezel, P. Karban, B. Ulrych, M. Pantelyat, Y. Matyukhin, P. Gontarowskiy, Numerical Model of a Thermoelastic Actuator Solved as a Coupled Contact Problem. COMPEL 36 (2007), No. 4, pp. 1063–1072. I. Dolezel, P. Karban, B. Ulrych, M. Pantelyat, Y. Matyukhin, P. Gontarowsky, N. Shulzhenko, Limit Operation Regimes of Actuators Working on Principle of Thermoelasticity, IEEE Trans. Magn. 44 (2008), No. 6, pp. 810–813. I. Dolezel, P. Karban, P. Kropik, and D. Panek. Accurate Control of Position by Induction Heating-Produced Thermoelasticity. IEEE Trans. Magn. 46 (2010), accepted. I. Dolezel, V. Kotlan, E. Kronerova, B. Ulrych: Induction Thermoelastic Actuator with Controllable Operation Regime. COMPEL 39 (2010), accepted.
Electromagnetic stirring, melting, melting in levitation
Electromagnetic melting and stirring in crucibles belong to basic technologies for preparation and processing selected metals and their alloys. The purpose of electromagnetic stirring is homogenization of melt, its degasification and more favorable solidification (suppresion of growth of undesirable dendritic crystals). From the physical viewpoint, the problem represents a complicated, multiply coupled task (interaction of electromagnetic field, temperature field and field of flow together with the problem of free surface). Even more complex is modeling of melting in levitation that is employed in case that the resultant metal must be extremely pure (melting in a crucible can lead to its pollution from the refractory).
Pumping of molten metals (asynchronous pumps, MHD pumps), flow of molten metal in a pipe
Another technology that is widely used for processing of molten metals is their pumping (or dosing). The team deals with modeling of specific pumps (mainly magnetohydrodynamic, but also asynchronous pumps) and relevants problems of electromagnetically driven flow. The mathematical models of all above problems are mostly solved by own algorithms and computer codes.
Electromagnetic actuators in a number of different versions
Electromagnetic actuators are devices transforming electric energy to mechanical work. The team pays attention to several classes of these devices: combined electromagnetic-thermoelastic actuators for accurate setting of position and special actuators with permanent magnets whose static characteristic must satisfy some required properties.

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