No abstract

No abstract

No abstract

No abstract

The fluid flow in a continuous casting tundish is numerically and physically simulated by means of water models. Results of residence time distribution (RTD) measurements and laser-optical measurements (Laser Doppler Anemometry -LOA, Digital Particle Image Velocimetry -DPIV) are used to validate the numerical results for water before the numerical simulation is transferred to the steel melt. The investigations are focused on both steady-state and transient casting conditions. To reduce vortexing and turbulence in the tundish different types of turbo-stoppers are installed in the water models and their influence on the spacious flow structure is discussed. The turbo-stopper produces higher turbulence in the inlet region of the tundish, but this region is spatially more limited in relation to the flow without turbo-stopper. Thereby a more homogeneous flow is created at the outlet of the tundish with better conditions for particle separation. Basic design criteria for the geometry of a turbo-stopper are developed. Moreover, the processes of first tundish filling and ladle change are simulated at a downscaled water model and these results are compared with numerical simulations using a Volume of Fluid (VoF) model. This multiphase model is able to reproduce the motion of gas bubbles and waves at the free surface. Numerische und physikalische Simulation vonStromungsphanomenen im StranggieBverteiler. Die Stromung im StranggieBverteiler wird anhand von Wassermodellen numerisch und physikalisch simuliert. Die Ergebnisse von Verweilzeitmessungen (RTD) und laser-optischen Messungen (Laser Doppler Anemometry -LOA, Digital Particle Image Velocimetry -DPIV) werden verwendet, um die numerischen Resultate fiir die Wasserstromung zu validieren. AnschlieBend wird die numerische Simulation auf Stahlschmelzen Obertragen. Die Untersuchungen umfassen sowohl stationii.re als auch instationare GieBbedingungen. Zur Reduzierung der Wirbelbildung und Turbulenz werden verschiedene Turbostopper in die Wassermodelle eingebaut. Der Einfluss des Turbostoppers auf die groBraumige Stromungsstruktur wird diskutiert. Im Einlaufbereich des StranggieBverteilers erzeugt der Turbostopper eine hohere Turbulenz, die jedoch gegenOber dem Fall ohne Turbostopper raumlich starker begrenzt ist. Dadurch wird eine homogenere Stromung im Auslaufbereich mit besseren Abscheidebedingungen fOr nichtmetallische Partikel induziert. Wesentliche Gestaltungsmerkmale fOr die Geometrie eines Turbostoppers werden erortert. Ferner werden der FOllvorgang des StranggieBverteilers und der Pfannenwechsel an einem verkleinerten Wassermodell simuliert. Die Ergebnisse werden mit numerischen Simulationen eines Volume-of-Fluid-Modells (VoF) verglichen. Mit diesem Mehrphasenmodell lassen sich die Bewegungen der Gasblasen und Wellen an der freien Oberflache berechnen. steel research 7 4 (2003) No. 1

No abstract

The tundish plays a major role in the continuous casting process. The flow in a tundish has a very substantial effect on the quality of the final product and on efficient casting conditions. Efforts are being made worldwide to obtain the most favourable shape of tundish interior by using dams, weirs and gas curtains. The aim of these flow control devices is to reduce the dead zone areas and improve the conditions for the separation of non‐metallic inclusions. Numerous model studies are being carried out to explain the effect of the tundish working space shape and steel flow conditions on the inclusions floating processes. The presented article shows the results of investigations performed to obtain the mass exchange characteristics in the investigated tundish. The measurements were done directly at the steel plant during normal working conditions. By controlling the changing content of manganese in steel, the residence time distribution (RTD) characteristics were acquired. The RTD characteristics are also obtained with a water model of the tundish with dimensional scale of 1:3. Parallel to the water model, numerical simulation based on mathematical modelling of fluid flow, relying on the system of differential equations, is employed in the research work. Numerical simulations were carried out with the finite‐volume commercial code FLUENT using the standard k‐ε turbulence model. The primary purpose of the investigations carried out is to present the characteristics describing the transitory zone in a six‐strand tundish. It is shown that the F‐curve, describing the transitory zone, can be obtained by using different measurement techniques. Tracer concentration characteristics for the model of tundish obtained from both modelling techniques ‐ physical as well as numerical ‐ are very similar.

No abstract