Comparison of Contactless Inductive Flow Tomography with Ultrasound-Doppler Velocimetry in a large Rayleigh-Bénard Convection Cell

Contactless inductive flow tomography (CIFT) can reconstruct the global 3D flow field in liquid metals. The technique is based on measuring very small magnetic fields induced by currents in the conducting liquid arising from the fluid motion under the influence of two primary excitation fields and solving the according linear inverse problem [1]. We present experimental results of CIFT measurements on a large cylindrical vessel with a height of 640 mm and a diameter of 320 mm, i.e. aspect ratio 0.5, filled with the eutectic alloy GaInSn. The liquid metal is heated from the bottom and cooled from the top, i.e. a so-called Rayleigh-Bénard (RB) convection cell. The temperature gradient drives a complex flow, that varies spatially and temporally [2-5].
The experimental set-up includes a number of Fluxgate sensors for highly sensitive measurements of the induced magnetic field in the order of 10 nT [6] as well as Ultrasound-Doppler velocimetry probes, that directly measure the velocity of the flow along their line-of-sight. Our preliminary measurements used only the excitation field in vertical direction, yet show a very high agreement of the time-dependent velocity profiles measured by UDV and the according CIFT data, projected onto the line-of-sight of the UDV sensors.

Acknowledgement
This work was supported by the German Research Foundation (DFG) under project no. 374994652. T.V. and F.S. also thank the DFG for support under the grant VO 2331/1.

REFERENCES
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