|
| |
|
| |
|
|
Techniky zpracování tuhých a tekutých kovů založené na elektromagnetické indukci
Doležel, Ivo ; Šolín, Pavel ; Musil, Ladislav ; Ulrych, B. ; Karban, P. ; Barglik, J.
A lot of up-to-date industrial technologies associated with treatment of solid and liquid metals are based on thermal and force effects of electromagnetic field. The fundamental process is induction heating of metals that precedes a number of consequent operations such as tempering, drying, melting, stirring, hardening, hot pressing etc. The paper summarizes physical essence of the above processes (that usually represent complex coupled problems) and presents their mathematical and computer models as well as possible methods of their solutions.
|
|
| |
|
|
Jev "zamrzlého pole" v elektricky vodivých médiích, řešený prostředky klasické elektrodynamiky
Doležel, Ivo ; Karban, P. ; Mayer, D. ; Ulrych, B.
The concept "frozen field" is often used in association with behavior of strongly electrically conductive media. Being introduced in astrophysics the phenomenon consists in drift of magnetic field by electrically well conductive medium (plasma or ionized mixture of gas and dust particles) that moves due to some primary mechanism not immediately associated with this magnetic field. This paper presents the description of the effect by means of classical electrodynamics in nonrelativistic medium and its solution in an integral formulation.
|
|
|
Řešení nestacionárních problémů vířivých proudů integrálním přístupem
Doležel, Ivo ; Karban, P.
Althout most eddy problems are theoretically solved by various differential techniques, there exist several classes of tasks where use of the differential approach may be complicated or even prohibitive. Mentioned can be, for example, problems characterized by geometrical incommensurability of individual subdomains, by their motion or by ignorance of the boundary conditions. In such a case, application of the integral approach may be an advantage. The paper presents the theoretical background of the method.
|
|
| |
|
|
Noise, vibration and electromagnetic phenomena produced by semiconductor converters in traction vehicles
Budek, P. ; Chmelíček, M. ; Jehlička, Vladimír ; Škramlík, Jiří
Due to the recent employment of up-to-date control electronic and electromechanical devices in cars of City Mass Transportation, new problems arise concerning the dynamics, noise, and the radiation of electromagnetic fields. Their environmental impacts, however, have not been discussed sufficiently, so far.
|
|
|
Program pro výpočet provozních parametrů velkých transformátorů
Karban, P. ; Doležel, Ivo
About fifteen years ago Prof. Doležel started developing a relatively large program package for solution of a wide spectrum of tasks associated with operation of large power transformers. The program ordered by one of the principal Czech manufacturers - ŠKODA Plzeň - was written in FORTRAN 77 for environment MS-DOS supplemented with memory extender DBOS and contained the following modules: Solution of 2D magnetic field distribution in the window. It could be calculated either analytically (provided that the window contains no ferromagnetic subdomains such as shunts) or numerically, using the finite element method.
|
|
|
Elektromagnetické a teplotní pole v roztaveném hliníku míchaném v kelímkové indukční peci
Barglik, J. ; Doležel, Ivo ; Ulrych, B. ; Mach, M. ; Trutwin, D.
The paper deals with the mathematical and computer modeling of quasi-coupled electromagnetic, temperature and hydrostatic fields in molten aluminium in a typical crucible induction furnace. After the process of melting, the melt is further inductively heated to reach the casting temperature that is typically higher by about 200 C than the melting point. Then the active power of inductors is reduced to a level making possible only to keep the temperature at that value. During that time, however, more or less intensive stirring of the melt takes place because of presence of the Lorentz forces acting in melt.
|
guest ::
