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Use of electromagnetic induction tomography for monitoring liquid metal/gas flow regimes on a model of an industrial steel caster

Terzija, N.; Yin, W.; Peyton, A.; Gerbeth, G.; Stefani, F.; Timmel, K.; Wondrak, T.

Monitoring of the steel flow through the submerged entry nozzle (SEN) during continuous casting presents a challenge for the instrumentation system because of the high temperature environment and the limited access to the nozzle in between the tundish and the mould. Electromagnetic inductance tomography (EMT) presents an attractive tool to visualize the steel flow profile within the SEN.
In this paper, we investigate various flow regimes over a range of stopper positions and gas volume flow rates on a model of a submerged entry nozzle. A scaled (approx. 10:1) experimental rig consisting of a tundish, stopper rod, nozzle and mould was used. Argon gas was injected through the centre of the stopper rod and the behaviour of the two phase GaInSn / Argon flow was studied. The experiments were performed with GaInSn as an analogue for liquid steel, which has similar conductive properties as molten steel and allows the measurements at the room temperature. The electromagnetic system used in our experiments to monitor the behavior of the two phase GaInSn / Argon flow consisted of an array of 8 equally spaced inductive coils arranged around the object, a data acquisition system and a host computer. The present system operates with a sinusoidal excitation waveform with a frequency of 20 kHz and the system has a capture rate of 40 frames per second.
The results show the ability of the system to distinguish the different flow regimes and to detect the individual bubbles. Sample tomographic images given in the paper clearly illustrate the different flow regimes.

Keywords: two­phase flow study; electromagnetic inductance tomography; industrial steel caster model

Permalink: https://www.hzdr.de/publications/Publ-14636
Publ.-Id: 14636