Antje Rückert

Particle Distribution and Separation in Continuous Casting Tundish

The tundish as a part of a continuous casting machine combines the discontinuous ladle metallurgy with the continuous solidification of slabs in the mould. The tundish plays a major role in the challenging task of “clean steel” production. That means the smallest number of inclusions and high cleanliness in all steel grades after changing the conditions at the inlet of the tundish. Inclusions hinder the metal forming process and lead often to fatigue. The cleanliness of steels is important to fulfil the customers requirements. In the present study inclusion removal was simulated in a 1:3 scaled water model of a single-strand tundish for the production of stainless steels with a particle counter. The particle counter is capable of counting a large number of particles with a wide range of diameters. The separation rate for particle diameters from dP = 1 - 250 μm was determined with a counter for the water model tundish. With similarity conditions for the particles this deposition rate can be transformed to the melt flow in a steel tundish. The separation rate was measured for different flow rates in the water model tundish. A larger flow rate decreased the separation rate. Additionally, the separation rate for the tundish fitted with an impact pad was measured and showed a significant increase of separation for particles with a smaller diameter. Furthermore, the particle distribution in the tundish for different size groups of particles was investigated with and without an impact pad. Numerical simulations were carried out with the finite-volume commercial code FLUENT using the realizable k-e turbulence model. A special boundary condition for the separation of particles at the surface was implemented.

Approach for Pyrolysis Gas Release Modelling and Its Potential for Enhanced Energy Efficiency of Aluminium Remelting Furnaces

Within the scope of the Advanced Metals and Processes (AMAP) research cluster in Aachen (Germany) the aluminium recycling process in melting furnaces is investigated with regard to resource and energy efficiency. When organic-contaminated material is charged into the furnace, pyrolysis gases are released as soon as the material temperature exceeds approximately 350 °C (662 °F). Those gases mainly consist of hydrocarbons, hydrogen and small fractions of other species. Thus, they are an energetic contribution to the furnace atmosphere and should be considered as such by the burner control unit in order to reduce the amount of unburnt fuel in the off-gas as well as primary energy consumption. This is achieved by post-processing data from lab-scale pyrolysis experiments in MatLab and bringing it into a format suitable for computational fluid dynamics (CFD) simulations. In this article an insight into the modelling approach and the model application in ANSYS Fluent CFD is given.