Numerický model tuhnutí kruhového předlitku

Abstract

Ph.D. thesis deals with numerical modeling of temperature fields, a round billet in continuous casting of steel. Emphasis is given to the mathematical nature of transfer phenomena that affect the casting blank (heat conduction, convection and radiation), but also the methods of solving thermal problems (analytical, numerical). The numerical methods are discussed in more detail the finite element method (FEM) and the finite diferences method (FDM) that creates the core of most commercially used simulation software for modeling of temperature fields in various technological processes. Part of this work is the characterization and the basic methods for uniqueness in terms of primary, secondary and tertiary cooling zone. It compiled its own sophisticated software - Tefis - solving the problems of temperature fields by means of an explicit (numerical) method of networking. Custom solutions are implemented using the Fourier´s-Kirchhoff´s equation in its differential form of enthalpy, which includes the shrinkage rate of billet. Explicit methods networks are generally subject to compliance with the numerical stability of the solution, for this reason, the issue is presented in a doctoral dissertation examined in detail. Software Tefis are performed a series of computer simulations, different to the method of sensitivity analysis, examined the effects of different levels of steel in the crystallizer, different casting speeds, different temperatures of the steel liquidus temperature and the difference in intensity in the secondary cooling zone on the overall temperature field of continuously cast billets. Part of the doctoral thesis is to find adequate constants (K n) provided mocninnového Field's Law, describing the setting blanks, always under scrutiny for a specific technological option. Functional verification is, done through a commercial software package provided by Swiss firm ProCast ESI Group, which addresses the thermal field, finite element method. The software calculated the temperature field, some groups of steels, are compared with results of experimental measurements of real-casting machine.