Concentration Measurements in a Water Model Tundish using the Combined DPIV/PLIF Technique

Abstract

The mixing process in a 1:3 scaled water model of a single‐strand tundish for the production of stainless steel is investigated using the combined DPIV/PLIF (Digital Particle Image Velocimetry/Planar Laser Induced Fluorescence) technique. The velocities in the water model are measured in different light sheet planes up to a size of 300 mm · 1100 mm by the conventional DPIV method. The variation of the time‐dependent concentration field is measured in the same plane by the PLIF method. The tracers are polyamide particles for DPIV and a rhodamine 6G solution as fluorescent dye for PLIF. Due to the special calibration procedure of the DPIV/PLIF system, the optical, geometrical and physical parameters do not have to be determined analytically, thus leading to reliable results. The experiments are carried out with a turbulent Reynolds number of Re = 5000 and show that the mixing process correlates with the quasi steady‐state flow pattern. The residence time of some water region in the tundish model is significantly longer than the mean residence time (θ < 5). Such information is important for the steel production because the number of mixed slabs produced during sequence casting with a grade change is closely related to the mixing of the tundish melt. The presented laser‐optical investigations have been used to establish the combination of DPIV and PLIF technique. The results of combined DPIV/PLIF measurements will be used to validate numerical simulations of the mixing processes in water models of metallurgical reactors.