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Measurement techniques for liquid metal based nuclear coolants 151

Fig. 3.5.3 Velocity profiles of LBE pipe flow for different flow rates measured at COMPLOT
facility.

Fig. 3.5.4 Schematic sketch of a container equipped with five pairs of ultrasound transducers in
order to detect the rising path and the diameter of a single bubble.

3.5.3 Inductive measurement techniques

Contactless flow measurement techniques exploit the high electric conductivity of liq-
uid metals in the order of 1MS/m by using the principle of induction. The bases of
these measurement techniques are the Maxwell’s equations with the magnetohydro-
dynamic approximation (Davidson, 2001). Typically, an externally generated mag-
netic field is applied to the fluid, and perturbations of that magnetic field are
measured outside the fluid, which are caused either by the change of the electric con-
ductivity in the volume or by the moving of liquid metal through the magnetic field.
The first induction principle can be exploited for level or bubble detection (Gundrum
et al., 2016) and is the key principle of the mutual inductance tomography (MIT),