Visualization and measurement of turbulent flow inside a SEN and off the ports

Abstract

This work describes a visualization technique that allows to register and analyze flow inside a Submerged Entry Nozzle (SEN) model. The internal flow has a swirling pattern that produces characteristic flow conditions that can be used in efficiently supplying liquid steel from the tundish to the mold in the continuous casting process. The visualization method is a first step in analyzing the characteristics of the internal flow and hence in designing new SENs. A LED light source is employed to illuminate the SEN which reduces the reflections in the images. To enhance visualizations and measurements, a transparent cell consisting of a cubic volume with reduced dimensions was used to capture images from the high-speed camera and to record the flow pattern within the SEN. The SEN model consists of a vertical, constant diameter tube with two rounded exit ports located at the bottom with a downward angle of 15° each. The working fluid is water and reaches Re=10,000 within the cell. We also use the laser illuminated Particle Imaging Velocimetry (PIV) to calculate the velocity of fluid within the SEN and close to the exit ports. We confirm previously reported formation of three vortexes that interact with each other altering the swirl motion of the exit flow. Experimental results were compared with numerical simulations. The comparisons contribute to the validation of findings of Computational Fluid Dynamics (CFD) and Smoothed-Particle Hydrodynamics (SPH) results. Qualitative and quantitative similarities were found. Both physical and numerical results display a high turbulent flow behavior at the lower zone of the SEN. Experimental and numerical methods may be used together as a development method to measure and evaluate the characteristics of the flow behavior inside and outside the SEN model in order to design a better SEN to increase the quality of the steel slab.