Chapters authored
Numerical Study of Turbulent Flows and Heat Transfer in Coupled Industrial-Scale Tundish of a Continuous Casting Material in Steel Production
This chapter describes the numerical simulations of a coupled industrial scale of the tundish and continuous casting process. The governing equations are presented, and the numerical procedure is discussed in a common framework. The coupled solutions are presented for the transient turbulent flows within the tundish, solidifying zone and extracting regions with the coupling phenomena of heat and mass transfer. The tundish region flow and refractory are calculated using the inlet and outlet boundary conditions in order to estimate the filling phenomena. The transitions and cooling zones for the thin slab continuous casting process are designed to account for the control of the solidified skin in order to avoid breakout. We compared the numerical predictions of the temperatures with industrial monitoring data for a reference case in order to verify the consistence of the model predictions. A parallel version of the numerical code is proposed aiming to improve the computation time keeping numerical accuracy.
Part of the book: Numerical Simulations in Engineering and Science
Dependence of Surface Tension and Viscosity on Temperature in Multicomponent Alloys
Viscosity modeling for pure metals and alloys is widely studied, and many solutions for dependence of viscosity on temperature can be found in the literature for pure metals and alloys. Many of these depend on experimental data for pre-exponential and exponential coefficients. Two key models include: (i) Kaptay model for pure metals, which is completely independent of experimental data and depends only on general constants A and B for a large set of pure metals with few exceptions and (ii) Kaptay viscosity model for liquid alloys derived on the same principles, a temperature-dependent viscosity only as a function of thermophysical properties of the alloy components. In the case of surface tension, the main available models are divided into four groups: Butler formulation-based models, density-functional models, semi-empirical models, and thermodynamic geometric models. Considering the absence of adequate models for surface tension, in this work, two equations relating surface tension and viscosity for pure metals are analyzed as a function of temperature. Regarding the Egry surface tension-viscosity relation for pure metals, a new relation equation for multicomponent alloys is proposed. By applying the proposed equation, the surface tension is calculated and plotted as a function of temperature for ternary and quaternary aluminum alloys.
Part of the book: Wettability and Interfacial Phenomena
On the Determination of Molar Heat Capacity of Transition Elements: From the Absolute Zero to the Melting Point
Molar specific heat is one of the most important thermophysical properties to determine the sensible heat, heat of transformation, enthalpy, entropy, thermal conductivity, and many other physical properties present in several fields of physics, chemistry, materials science, metallurgy, and engineering. Recently, a model was proposed to calculate the Density of State by limiting the total number of modes by solid–liquid and solid–solid phase nucleation and by the entropy associated with phase transition. In this model, the new formulation of Debye’s equation encompasses the phonic, electronic, and rotational energies contributions to the molar heat capacity of the solids. Anomalies observed in the molar specific heat capacity, such as thermal, magnetic, configurational transitions, and electronic, can be treated by their transitional entropies. Model predictions are compared with experimental scatter for transitional elements.
Part of the book: Recent Advances in Numerical Simulations