Simulación matemática para la optimización del patrón de flujo entregado por una buza para el molde de colada continua de planchón delgado

<p></p><p>ABSTRACT Understanding the behavior of the oscillations of the jets into the mold of thin slab funnel is essential to ensure a constant supply of liquid steel, improve control of the flow patterns and consequently increase plant productivity and the final product quality. To achieve this, we conducted a study of the effect of the internal design of the nozzle on the fluid dynamics of the mold, trying to determine the origin of the oscillations of the jets. Use of mathematical and physical simulation was done to study these phenomena. For the mathematical modeling it resorts to the fundamental equations, the RSM turbulence model and VOF multiphase model. The governing equations are discretized and solved by iteration-segregated implicit method implemented in FLUENT®. The results of the mathematical simulation are showing that even for a nozzle designs with a stable operational performance, the oscillations of the jets remain present and become more intense for high casting speeds and deeper nozzle. The analysis of each of the simulated nozzles show that the internal geometry causes flow disturbances in areas where the internal cross-sectional areas change, generating high and low dynamic pressures and promoting a tendency for the liquid steel to exit preferably by one of the ports. A delicate balance of forces, in the order of micro-scales, was found and is given on the tip of the internal bifurcation of the nozzle. This balance is related to the fluctuating speeds and the ferrostatic pressure. If this balance is broken the oscillations are more severe, causing permanent changes in the mass flow rate from one port to another. In addition, it was found that there is continuous formation of a vortex path which is generated from the separation of the boundary layer on the splitter ports, a phenomenon that intensifies the periodic oscillation of the jets</p><p></p

Design and Optimization of the Internal Geometry of a Nozzle for a Thin-Slab Continuous Casting Mold

Understanding the phenomena that cause jet oscillations inside funnel-type thin-slab molds is essential for ensuring continuous liquid steel delivery, improving flow pattern control, and increasing plant productivity and the quality of the final product. This research aims to study the effect of the nozzle’s internal design on the fluid dynamics of the nozzle-mold system, focusing on suppressing vorticity generation below the nozzle’s tip. The optimized design of the nozzle forms the basis of the results obtained through numerical simulation. Mathematical modeling involves fundamental equations, the Reynolds Stress Model for turbulence, and the Multiphase Volume of Fluid model. The governing equations are discretized and solved using the implicit iterative-segregated method implemented in FLUENT®. The main results demonstrate the possibility of controlling jet oscillations even at high casting speeds and deep dives. The proposed modification in the internal geometry of the nozzle is considered capable of modifying the flow pattern inside the mold. The geometric changes correspond with 106% more elongation than the original nozzle; the change is considered 17% of an inverted trapezoidal shape. Furthermore, there was a 2.5 mm increase in the lower part of both ports to compensate for the inverted trapezoidal shape. The newly designed SEN successfully eliminated the issue of jet oscillations inside the mold by effectively preventing the intertwining of the flow. This improvement is a significant upgrade over the original design. At the microscale, a delicate force balance occurs at the tip of the nozzle’s internal bifurcation, which is influenced by fluctuating speeds and ferrostatic pressure. Disrupting this force balance leads to increased oscillations, causing variations in the mass flow rate from one port to another. Consequently, the proposed nozzle optimization design effectively controls microscale fluctuations above this zone in conjunction with changes in flow speed, jet oscillation, and metal–slag interface instability