EXPERIENCES IN PHYSICOCHEMICAL MODELLING OF OXYGEN CONVERTER PROCESS (BOF)
Oxygen converting of hot metal (LD/BOF) is contemplated as an object of simulation. Oxygen converting is a highly complex thermo-chemical process comprising a series of matter and energy transformation and transportation steps that makes the simulation very challenging. The basic principles of CONSIM 5 oxygen converter simulator are presented. Simulator is a comprehensive combination of a physical model with several empirical submodels describing all properties and processes that affect the final result of a converter blow, final mass and composition of steel, slag, dust and converter gas as well as the end temperature of steel. CONSIM simulator is used for simulation of series of high and low carbon steel blows. Simulated steel temperatures, oxygen consumption, blow time and iron oxide content of slag are compared with measured values. Problems of simulation and requirements for quantitative simulation of oxygen converter process are discussed.
Mathematical simulation of interdendritic solidification of low-Alloyed and stainless steels
A mathematical model for simulating the interdendritic solidification of low-alloyed and stainless steels is presented based on thermodynamic and diffusion calculations made in one volume element in the mushy zone. The method involves the determination of stable phases (ferrite, austenite, liquid, and FeMnS) as well as their fractions and compositions at any temperature during solidification. The model was tested by comparing calculations with experiments, and reasonable agreement was demonstrated. The model also includes a routine for predicting the liquid undercooling caused by solute accumulation ahead of the dendrite tips.
Integrated two-beam antenna array featuring dual-circular polarization
A concept of an integrated antenna array featuring two independent beams and dual circular polarization has been described. The antenna array consists of two radiating elements which are excited at two orthogonally placed feeding ports with the use of four appropriately connected 3-dB/90° directional couplers. Therefore, such an array generates two symmetrically located beams having right-handed circular polarization (RHCP) and identical two beams having left-handed circular polarization (LHCP). The presented concept has been verified by the design and measurements of an antenna array operating at 2.4 GHz frequency range.