Modeling of Electromagnetic Field and Liquid Metal Pool Shape in an Electroslag Remelting Process with Two Series-Connected Electrodes

In paper problem concerning inoculation of primary structure of aluminum with purity of 99,5% and 99,8%, which is realized mainly by intensification of liquid metal movement in mould is presented. In aim of realization of forced movement during the crystallization of liquid metal was used rotating electromagnetic field produced by the induction coil supplied by current with elevated frequency. The degree of structure refinement was represented by equiaxed crystals zone content on transverse section of ingot and average area of macro-grain in this zone. Effect of structure refinement obtained by influence of electromagnetic field was compared with refinement obtained by use of traditional inoculation, which consists in introducing of additives i.e. titanium, boron and carbon to metal bath. The results of studies and their analysis show possibility of effective refinement of pure Al primary structure, only with use of rotating electromagnetic field and without necessity of application of inoculants such a Ti, B and C. This method of inoculation is important, because inoculants decrease the degree of purity and electrical conductivity of pure Al. Moreover Ti and B are reason of point cracks formation during rolling of ingots.

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Natural Convection Heat Transfer in a Rectangular Liquid Metal Pool With Bottom Heating and Top Cooling

Volume 2: Thermal Hydraulics ◽

10.1115/icone14-89182 ◽

2006 ◽

Author(s):

Il S. Lee ◽

Yong H. Yu ◽

Hyoung M. Son ◽

Jin S. Hwang ◽

Kune Y. Suh

Keyword(s):

Heat Transfer ◽

Natural Convection ◽

Liquid Metal ◽

Convection Heat Transfer ◽

Bottom Surface ◽

Natural Convection Heat Transfer ◽

Metal Pool ◽

Convection Heat ◽

Integral System ◽

Bottom Heating

An experimental study is performed to investigate the natural convection heat transfer characteristics with subcooled coolant to create engineering database for basic applications in a lead alloy cooled reactor. Tests are performed in the ALTOS (Applied Liquid-metal Thermal Operation Study) apparatus as part of MITHOS (Metal Integrated Thermo Hydrodynamic Operation System). A relationship is determined between the Nusselt number Nu and the Rayleigh number Ra in the liquid metal rectangular pool. Results are compared with correlations and experimental data in the literature. Given the similar Ra condition, the present test results for Nu of the liquid metal pool with top subcooling are found to be similar to those predicted by the existing correlations or experiments. The current test results are utilized to develop natural convection heat transfer correlations applicable to low Prandtl number Pr fluids that are heated from below and cooled by the external coolant above. Results from this study are slated to be used in designing BORIS (Battery Optimized Reactor Integral System), a small lead cooled modular fast reactor for deployment at remote sites cycled with MOBIS (Modular Optimized Brayton Integral System) for electricity generation, tied with NAVIS (Naval Application Vessel Integral System) for ship propulsion, joined with THAIS (Thermochemical Hydrogen Acquisition Integral System) for hydrogen production, and coupled with DORIS (Desalination Optimized Reactor Integral System) for seawater desalination. Tests are performed with Wood’s metal (Pb-Bi-Sn-Cd) filling a rectangular pool whose lower surface is heated and upper surface cooled by forced convection of water. The test section is 20 cm long, 11.3 cm high and 15 cm wide. The simulant has a melting temperature of 78°C. The constant temperature and heat flux condition was realized for the bottom heating once the steady state had been met. The test parameters include the heated bottom surface temperature of the liquid metal pool, the input power to the bottom surface of the section, and the coolant temperature.

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