Modeling of Electric Arc Furnaces ( EAF ) with electromagnetic stirring
Electromagnetic stirring can play an important role in modern Electric Arc Furnaces (EAF), as they often operate far from equilibrium conditions, with tap-to-tap times of 45 minutes or less, high electric power input and significant energy additions from fuel and oxygen. Numerical modeling is used extensively in ABB’s current efforts to optimize the EAF process with electromagnetic stirring. The modeling approach uses a Finite-Element method (FEM) for computing the forces generated by the electromagnetic stirrer, whereas the resulting flow properties, heat and mass transfer in the system is computed using a Finite-Volume (FVM) flow solver. The paper presents the numerical model in greater detail and discusses some important results. We show that electromagnetic stirring gives a more than ten-fold increase of flow velocities and circulation, compared with a flow driven by natural convection alone. The global circulation created by electromagnetic stirring dramatically reduces temperature differences in the melt, thus reducing super-heating of the melt surface and risks for cold regions. Efficient mixing of chemical species, together with even temperatures, is beneficial for efficiency and controllability of the chemical reactions in the slag-metal interface.
Effect of Arc Length on Fluid Flow and Mixing Phenomena in AC Electric Arc Furnaces
Fluid flow and mixing phenomena in an industrial three phase Electric Arc Furnace has been investigated, as a function of arc length. Velocity and temperature fields as well as mixing times were computed, assuming that liquid steel occupies the whole computational domain and buoyancy forces are responsible for convective flow. It is reported a strong effect of arc length on both fluid flow and mixing time, suggesting a metallurgical practice with long arc operation to improve the melting kinetics of the metallic charge. Thermal stratification has also been confirmed, however the volume of hot steel increases when arc length also increases.
The mark of sexual preference in the interpretation of texts: preface to a homosexual reading.
Since reading is an interaction or confrontation between the reader and the text-an interaction that depends upon the background and perspectives of the reader as well as on the text being read-we can assume that the dynamics of sexuality and sexual object choice will influence how readers ascribe meaning to literary texts. In fact, although other aspects of our identities come into play when we read, sexual identity is unique and central because of the role that it plays in the creation of subjectivity. Specifically, male homosexuality informs and structures the reading of texts. But what does it be a homosexual reader or to effectuate a homosexual reading of a particular text?